Earth & Life Science
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I.
Description of the subject This learning area is designed to provide a general background for the understanding of Earth Science and Biology. It presents the history of the Earth through geologic time. It discusses the Earth’s structure, composition, and process. Issues, concerns, and problems pertaining to natural hazards are included. It also deals with the basic principles and processes in the study of biology. It covers life processes and interactions at the cellular, organism, population, and ecosystem levels.
II.
Objectives 1. To have a better understanding of the origin of the Earth and its species 2. To appreciate the importance of the existence of the living and non-living things on earth 3. To familiarize the students with the metabolic processes of living organisms 4. To motivate the students to participate in the conservation and protection of life forms and environment
III.
Table of Content Chapter 1: 1.1 1.2
THE ORIGIN AND STRUCTURE OF THE EARTH Universe and Solar System Earth and Earth System
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Chapter 2: 2.1 2.2 2.3 2.4 2.5
EARTHY MATERIALS AND PROCESSES Rocks and Minerals Exogenic Processes Endogenic Processes Crustal Deformation Processes History of Earth
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Chapter 3:
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3.1 3.2 3.3
NATURAL HAZARDS, MITIGATION, AND ADAPTATION Geological Processes and Hazard Hydrometeorological Phenomena and Hazard Coastal Processes and Their Effects
Chapter 4: 4.1 4.2 4.3
INTRODUCTION TO LIFE SCIENCE Concept of Life Origin of the First Life Form Evolution : Unifying Themes in the Study of Life
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Chapter 5: 5.1 5.2 5.3
BIOENERGETICS Cell Photosynthesis Cellular Respiration
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Chapter 6: 6.1
PERPETUATION OF LIFE Plant and Animal Reproduction
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6.2 6.3
Process of Genetic Engineering Benefits and Risks of Using GMOs
Chapter 7: 7.1 7.2 7.3 7.4 7.5 7.6 7.7
HOW ANIMALS SURVIVE Different Metabolic Processes Gas Exchange with the Environment Circulation: The Internal Transport System Homeostasis The Immune System Nervous System The Body in Motion
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Chapter 8: 8.1 8.2
HOW PLANTS SURVIVE Plant Form and Function Plant Growth and Development
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Chapter 9: 9.1 9.2
THE PROCESS OF EVOLUTION Evidence of Evolution The Origin and Extinction of Species
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Chapter 10: INTERACTION AND INTERDEPENDENCE 10.1 The Principles of Ecosystem 10.2 Biotic Potential and Environmental Resistance 10.3 Effects of Human Activities to the Natural Ecosystem
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CHAPTER 1: THE ORIGIN AND STRUCTURE OF THE EARTH Objectives: 1. To state the different hypotheses explaining the origin of the universe 2. To describe the different hypotheses explaining the origin of the solar system 3. To explain the current advancements/ discoveries on the solar system
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4. To recognize the uniqueness of the earth, being the only planet in the solar system with properties necessary to support life 5. To describe the four subsystem of the earth 6. To identify and describe the layers of the earth Lesson 1.1:
UNIVERSE AND SOLAR SYSTEM
Universe is an all space-time, matter and energy including the solar system, all stars and galaxies and content of intergalactic space, regarded as a whole. There are three various theories explaining the origin of the universe; Steady State Theory. It states that the counting of the galaxies in our Universe is constant and new galaxies which are forming continuously are filling the empty spaces which are created by those heavenly bodies which have crossed the boundary lines of observable Universe. This theory proposes that the overall structure of the universe is always the same at any point in time and space. This structure is maintained even when certain events, such as birth of new stars, occur. It is balanced by the death of old stars. Pulsating Theory: In this theory it is assumed that there is continuous expansion and contraction in universe. It proposes that the universe will keep expanding more and more then slowly it stop. Then it will start to contract due to gravitation. This contraction will continue until the universe become more compact and will later explode and expand again. Big Bang Theory: It proposes that the entire universe was once condensed in a very small and compact particle called primeval nucleus. It is estimated that about 20 billion years ago, primeval nucleus suddenly exploded in a big bang. The force of this explosion caused matter to scatter in any direction forming a universe. Biblical Belief on the Formation or Creation of the Universe “Genesis 1:1 - In the beginning God created the heavens and the earth. “ The very first claim made in the Bible is that there was a beginning. Since Genesis 1 describes how God created the universe, and in a certain sequence, there is no doubt that he did that exactly. God created the universe. SOLAR SYSTEM Just a part of the vast universe is our solar system. It is located somewhere in Milky Way Galaxy. It consists of the sun being at the center, minor and major planets and other celestial bodies like satellites, comets, asteroids and meteoroids. ORIGIN OF THE SOLAR SYSTEM There are major theories that explain the origin of the solar system. 1. Nebular Hypothesis Theory. According to this theory, the sun and other celestial bodies orbiting around it where formed from a nebula- a spinning cloud of gases. These clouds are gravitationally unstable, and matter coalesces within them to smaller denser clumps, which then rotate, collapse, and form stars. 2. Accretion Theory. Accretion is the gradual increase in the size of an object by the buildup of matter due to gravity. The accretion theory says that a protosun passing through a cloud of interstellar materials pulled this material along
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causing it to swirl around the protosun. As the protosun evolved into the sun, the material it accreted gradually formed the planets and other revolving bodies. 3. Tidal Theory. According to this theory, the time when the sun about to form (protosun), a large body passing around it may have drawn some gaseous materials from it. The mass of gaseous materials drawn did not completely escape gravitational pull of the protosun. It continued to spin around it, eventually becoming more dense and gradually formed into planetesimals. These planetisimals give rise to the planets and their satellites. Space exploration by means of manned and unmanned spacecrafts give us information about the solar system and beyond. Achieving spaceflight enabled humans to begin to explore the solar system and the rest of the universe, to understand the many objects and phenomena that are better observed from a space perspective, and to use for human benefit the resources and attributes of the space environment. Study questions: 1. What are the major theories pertaining to the nature of expanding galaxy? Explain each. 2. Why do some scientists believe that the universe is expanding? 3. What are the major theories about the origin of the solar system? Explain each. 4. How is space exploration benefits mankind?
Homework: Lesson 1.2:
Research on the current information about space exploration. EARTH AND EARTH SYSTEM
Earth is the only planet in the solar system capable of supporting life. Complex and brilliant combination of gases, composition and structure of earth are some of the reasons why it can sustain life. EARTH SUBSYSTEM Earth is a very complex place. The earth consists of four distinct yet connected spheres. All of the processes on Earth are driven by four “spheres”, which we describe individually, but are really all connected.
GEOSPHERE The Geosphere describes all of the rocks, minerals and ground that are found on and in Earth. This includes all of the mountains on the surface, as well as all of the liquid rock in the mantle below us and the minerals and metals of the outer and inner cores. The continents, the ocean floor, all of the rocks on the surface, and all of the sand in the deserts are all considered part of the geosphere. Basically, if it looks like solid ground, it's part of the 'ground' sphere.
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HYDROSPHERE Planet Earth has been called the "Blue Planet" due to the abundant water on its surface Over 70 percent of the surface area of the earth is covered by water. All the earth’s water, solid or in liquid form, those that are contained in glaciers, rocks, soil and the air, comprise the earth’s hydrosphere. SOURCES OF WATER Ocean. A big portion of earth’s water is found in ocean. The oceans cover more than 70 percent of the Earth's surface and contain 97 percent of the Earth's water. If the ocean's total salt content were dried, it would cover the continents to a depth of 5 feet. Together with the atmosphere, oceans regulate global temperatures, shape weather and climate patterns, and cycle elements through the biosphere. Ocean Structure and Composition Like the atmosphere, the oceans are not uniformly mixed but are structured in layers with distinct properties. Pressure increases with depth as the weight of the overlying air and water increase. Atmospheric pressure at sea level is 14.7 pounds per square inch , and pressure increases by an additional atmosphere for every 10 meters of descent under water. Layers of the ocean The Epipelagic, or sunlight, zone (so called because most visible light in the oceans is found here) comprises the first 200 meters below the surface, and is warm and mixed by winds and wave action. At a depth of about 200 meters, the Continental Shelf (the submerged border of the continents) begins to slope more sharply downward, marking the start of the Mesopelagic, or twilight zone. Here water temperature falls rapidly with depth to less than 5°C at 1,000 meters. This sharp transition, which is called the thermocline, inhibits vertical mixing between denser, colder water at depths and warmer water nearer the surface. About 18 percent of the total volume of the oceans is within this zone. Below 1,000 meters, in the Bathypelagic, or midnight, zone, water is almost uniformly cold, approximately 4°C. No sunlight penetrates to this level, and pressure at the bottom of the zone (around 4,000 meters depth) is about 5,880 pounds per square inch. Little life exists at the Abyssopelagic (abyssal) zone, which reaches to the ocean floor at a depth of about 6,000 meters. Together, these cold, deep layers contain about 80 percent of the total volume of the ocean. The deepest layer of the ocean is the Hadal Zone or Trench Zone. The deepest trench on earth is Mariana Trench, also called Marianas Trench, lies in the floor of the western North Pacific Ocean. INLAND WATERS Household, commercial and agricultural water supply mainly come from inland bodies of water. Two major inland waters are described below. 1. Rivers A volume of a fresh flowing water across the surface of the land usually to the sea. Rivers flow in channels. 2. Lakes A reservoir of relatively still water that is surrounded by land. It is formed from the accumulation of large amounts of water in natural or artificial
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depressions on the surface of the land. Other inland waters include ponds, spring, stream, wetlands, floodplains and reservoirs. GROUNDWATER It is the water found underground in the cracks and spaces in soil, sand and rock. It is stored in and moves slowly through geologic formations of soil, sand and rocks called aquifers. It results from the accumulation of water penetrating through small openings called pores in the rocks or soil. This process is known as percolation. Groundwater supplies drinking water, used for irrigation to grow crops and an important component in many industrial processes. A MASSIVE BODY OF ICE About 2 percent of earth’s waters is in a form of solid, a massive bodies of ice called glaciers. Deposited snow that falls during winter season piles up yearly. This accumulated snow transforms the lower layers into solid ice. THE HYDROLOGIC CYCLE (WATER CYCLE) Water on earth is continuously moving. It endlessly circulating through the hydro- logic cycle. As water goes in a cycle, it changes its states. From liquid to ice to gas and back again. Sun heats water causing the water to evaporate. Rising air currents take the water vapor up in the atmosphere. The vapor rises into the air where cooler temperatures cause it to condense into clouds. Air currents move the cloud. Cloud particles collide, grow, and fall out of the sky as precipitation. Most of the precipitation return to the oceans. ATMOSPHERE A very huge envelope of air that surrounds the earth and pulled by the gravitational force of the earth is called atmosphere. The earth’s atmosphere is primarily composed of 78 percent nitrogen and 21 percent of oxygen. Other gases like argon, carbon dioxide, carbon monoxide, ozone, hydrogen, helium and other inert gases make up the remaining 1 percent. The earth’s atmosphere is made up of different layers as shown in the table below.
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BIOSPHERE The biosphere is where all forms of life exist. Since life exist in the air, in water and on the ground, its boundaries overlap other “sphere” because life can be found everywhere on earth. The biosphere is sometimes thought of as one large ecosystem — a complex community of living and nonliving things functioning as a single unit. INNER PART OF THE EARTH The planet Earth is made up of different layers: the very thin, brittle crust, the mantle, and the core; the mantle and core are each divided into two parts. Although the core and mantle are about equal in thickness, the core actually forms only 15 percent of the Earth's volume, whereas the mantle occupies 84 percent. The crust makes up the remaining 1 percent. Crust The crust is the outermost part of the earth and is very thin compared to the other layers. It is a part where the living organisms dwell in. It forms a very thin continuous layer that extends underneath the ocean and continents. 2 KINDS of CRUST 1. Continental crust is mostly composed of different types of granites. Geologists often refer to the rocks of the continental crust as “sial” which stands for silicate and aluminum, the most abundant minerals in continental crust. Cratons are the oldest and most stable part of the continental lithosphere and are found deep in the interior of most continents. 2. Oceanic crust is mostly composed of different types of basalts. Rocks of the oceanic crust are referred to as “sima” which stands for silicate and magnesium, the most abundant minerals in oceanic crust. The Mantle It is the mostly-solid bulk of Earth’s interior. The mantle lies between Earth’s dense, super heated core and its thin outer layer, the crust. It is made up of silicates, magnesium oxide, iron, aluminum, calcium, sodium, and potassium. The mantle is divided into two layers: the upper mantle and the lower mantle. Mantle Plumes A mantle plume is an upwelling of superheated rock from the mantle. Mantle plumes are the likely cause of “hot spots,” volcanic regions not created by plate tectonics. The Core It is the dense center and hottest part of earth. The core is made almost entirely of iron and nickel. The Gutenberg discontinuity is the boundary between the core and the mantle. The core is made of two layers: a) Outer Core - borders the mantle. Bullen discontinuity is the hottest part of the
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core. b) Inner Core- is a hot, dense ball of iron. The temperature of the inner core is far above the melting point of iron. Bullen discontinuity is the boundary separating these two layers. Earth’s Magnetic Field Earth’s magnetic field protects the planet from the charged particles of the solar wind. Without the shield of the magnetic field, the solar wind would strip Earth’s atmosphere of the ozone layer that protects life from harmful ultraviolet radiation. CHAPTER TEST: Read each questions carefully. Write the letter of the correct answer in the blank. __1. In what sphere of the earth are the rocks and minerals found? a. Atmosphere c. Hydrosphere __2 __3.
__4.
__5.
__6.
b. Biosphere d. Geosphere What parts of the earth make up the hydrosphere? a. Glaciers c. seawater and inland water b. Groundwater d. All of the above What part of Earth's spheres is composed of a mixture of gases? a. Atmosphere c. Geosphere b. Biosphere d. Hydrosphere Why only few lives exist below bathypelagic zone? a. No sunlight penetrates on this zone b. Water is very cold c. Water pressure is very high d. All of these When is the accumulated pile of snow become glaciers? a. When it undergo cementation and compaction b. Upon reaching a certain mass and acted upon by gravity c. When it piled up in huge amount and solidify d. When the temperature dropped very low Earth’s atmosphere is consists mostly of what gas? a. CO2 b. He c. N2 d. O2
__7. In the troposphere, as the altitude rise, what happen to the temperature? a. decreases b. increases c. constant d. extremely hot __8. In what layer of the atmosphere, many satellites orbit? a. exosphere b. troposphere c. mesosphere d. stratosphere __9. What is the largest part of the earth? a. Biosphere b. Geosphere c. Atmosphere d. Hydrosphere __10. What is the importance of magnetic field? a. It protects the earth from the solar wind. b. It keeps our planet in orbit. c. It protects us from harmful UV rays. d. It gives us many minerals.
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CHAPTER 2: EARTHY MATERIALS AND PROCESSES Lesson 2.1:
ROCKS AND MINERALS
Objectives: 1. 2.
To identify common rock-forming minerals using their physical and chemical properties To classify rocks into igneous, sedimentary, and metamorphic
Rocks Rock or stone is a naturally occurring solid aggregate of one or more minerals. The Earth's outer solid layer, the lithosphere, is made of rock. The types and abundance of minerals in a rock are deter-mined by the manner in which the rock was formed. Many rocks contain silica (SiO2); a compound of silicon and oxygen that forms 74.3% of the Earth's crust. This material forms crystals with other compounds in the rock. Geological Classification of rocks according to Characteristics such as 1. mineral and chemical composition, 2. permeability, 3. the texture of the constituent particles, 4. and particle size. These physical properties are the end result of the processes that formed the rocks. Over the course of time, rocks can transform from one type into another, as described by the geological model called the rock cycle. These events produce three general classes of rocks : igneous , sedimentary, and metamorphic.
1. Igneous: Igneous rocks form from the cooling of melted rock (either lava or magma) into solid form. If the cooling occurs underground, the rock is an intrusive, or plutonic, igneous rock. If the cooling occurs on the earth's surface, the rock is an extrusive or volcanic rock. Molten material within the Earth is called magma; it is “lava” once it has erupted onto the surface.
2. Metamorphic: Metamorphic rocks form when existing rocks are subjected to intense heat and pressure, usually deep below the earth's surface. These conditions change the original minerals of the rock into new minerals.
3. Sedimentary: Sedimentary rocks are either detrital or chemical. a. Detrital rocks are formed by the compaction of separate particles, or sediments, into a rock. b. Chemical sedimentary rocks form from minerals that have been dissolved in water and precipitate out, forming a solid rock.
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Geologists describe sedimentary rocks according to the size and shape of the particles in them or their mineral Oxygen (O) 46.6% composition (in the case of chemical Silicon (Si) 27.7% sedimentary rocks). Rock Cycle The rocks of earth's crust are constantly being recycled and changed into new forms through geologic processes. This continual transformation of rocks from one type to another is called the rock cycle.
Aluminum (Al) Iron (Fe) Calcium (Ca) Sodium (Na) Potassium (K) Magnesium (Mg)
8.1% 5.0% 3.6% 2.8% 2.6% 2.1%
Rock Cycle
How rock type can be changed? Rock can be changed through the processes of weathering, heating, melting, cooling, and compaction. Any one rock type can be changed into a different rock type as its chemical composition and physical characteristics are transformed. The minerals and metals found in rocks have been essential to human civilization. Minerals Minerals are the fundamental components of rocks. They are naturally occurring inorganic substances with a specific chemical composition and an orderly repeating atomic structure that defines a crystal structure. Silicate minerals are the most abundant components of rocks on the Earth's surface, making up over 90% by mass of the Earth's crust. The common non-silicate minerals, which constitute less than 10% of the Earth's crust, include carbonates, oxides, sulfides, phosphates and salts. A few elements may occur in pure form. These include gold, silver, copper, bismuth, arsenic, lead, tellurium and carbon.
Although 92 naturally occurring elements exist in nature, only eight of these are common in the rocks of the Earth's crust. Together, these eight elements make up more than 98% of the crust (Table 1). Table 1. The eight most common elements in the Earth’s crust( by mass )
Rock Forming Minerals: The physical properties of minerals, such as their hardness, lustre, color, cleavage, fracture, and relative density can be used to identify minerals.
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These general characteristics are controlled mainly by their atomic structure (crystal structure). Common rock-forming minerals: These are specimens of minerals from the University of Auckland's collection. Along with the common rock-forming minerals, including apatite, corundum, diamond, fluorite, topaz and talc to illustrate minerals used in Moh's Scale of Hardness.
apatite
augite
biotite
fluorite
garnet
gypsum
calcite
chlorite
corundum
diamond
hornblende
ilmenite
magnetite
muscovite
Classification and Identification of Minerals Minerals are classified according to their chemical composition. 1. Definite fixed composition, Quartz is always SiO2, and calcite is always CaCO3. 2. Form both by inorganic and organic processes. For example, calcite (CaCO3) is a common vein mineral in rocks, and also a shell-forming material in many life forms. Calcite of organic origin conforms to the above definition except for the requirement that it be inorganic. 3. "Mineraloids" While not truly falling into the category of minerals, they are still usually classified as minerals. Two well-known examples are Mercury, which lacks a crystal structure due to its liquid state, and Opal, which also lacks a crystal structure as well as a definitive chemical formula. Despite the fact that these mineraloids lack certain essential characteristics of minerals, they are classified as minerals in most reference guides including the acclaimed Dana's System of Mineralogy. 4. Organic minerals is another unique category of minerals. While this term is technically an oxymoron, since the definition of a mineral requires it to be inorganic, there are several naturally occurring rare organic substances with a definitive chemical formula. The best example of this is Whewellite. Most reference guides and scientific sources make an exception to these substances and still classify them as minerals. Study Questions: 1. What are the physical properties of minerals ? 2. How are rocks classified ? 3. Describe how the following rocks are formed. 12 a. igneous rock b. sedimentary rock c. metamorphic rock
Lesson 2.2 :
EXOGENIC PROCESSES
Exogenic process includes geological phenomena and processes that originate externally to the Earth’s surface. Generally related to the: atmosphere, hydrosphere and biosphere, and therefore to processes of: o weathering, o erosion, o transportation, o deposition, o denudation etc. Exogenic factors and processes could also have sources outside Earth, for instance under the influence of the Sun, Moon, etc. The above mentioned processes constitute essential landform-shaping factors. Their rate and activity very often depends on local conditions, and can also be accelerated by human actions. The combined functions of exogenic and endogenic factors influences the present complicated picture of the Earth’s surface. Mountains, valleys and plains seem to change little, if at all, when left to nature, but they do change continuously. The features of the Earth’s surface temporary forms in a long sequence of change that began when the planet originated billions of years ago, and is continuing today. The process that shaped the crust in the past are shaping it now. By understanding them, it is possible to imagine, in a general way, how the land looked in the distant past and how it may look in the distant future. Landforms are limitless in variety. Some have been shaped primarily by: streams of water, glacial ice, waves and currents and movements of the Earth‘s crust or volcanic eruptions. These are landscapes typical of deserts and others characteristic of humid regions. The arctic makes its special mark on rock scenery, as do the tropics. Because geological conditions from locality to locality are never quite the same, every landscape is unique. Rock at or near the surface of the continents breaks up and decomposes because of exposure. The processes involved are called weathering.
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Weathering Weathering is the decomposition and disintegration of rocks and minerals at the Earth’s surface. Erosion Erosion is the removal of weathered rocks and minerals by moving water, wind, glaciers and gravity. The four processes – weathering, erosion, transportation and deposition work together to modify the earth’s surface. The Work of Weathering Weathering produces some landforms directly, but is more effective in preparing rocks for removal by mass wasting and erosion. Weathering influences relief in every landscape. Freezing and thawing Water expands when it freezes. If water accumulates in a crack and then freezes, its expansion pushes the rock apart and the process is called frost wedging. In a temperate climate, water may freeze at night and thaw during the day. Ice cements the rock temporarily, but when it melts, the rock fragments may tumble from a steep cliff. Large piles of loose angular rocks, called talus slopes, lie beneath many cliffs. These rocks fell from the cliffs mainly as a result of frost wedging. Temperature changes Sudden cooling of a rock surface may cause it to contract so rapidly over warmer rock beneath that it flakes or grains break off. This happens mostly in deserts, where intense daytime heat is followed by rapid cooling after. Lesson 2.3:
Endogenic Process
Endogenic processes include tectonic movements of the crust, magmatism , metamorphism, and seismic activity. Endogenic processes have been responsible for shaping the earth’s relief and the formation of many of the important mineral resources. The principal energy sources for endogenic processes are: 1. heat 2 the redistribution of material in the earth’s interior according to density - The earth’s deep heat originates chiefly from radiation. - The continuous generation of heat in the earth’s interior results in the flow of heat toward the surface. With the proper combination of materials, temperature, and pressure, chambers and layers of partial melting may occur a t certain depths within the earth.
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The asthenosphere, the primary source of magma formation, is such a layer in the upper mantle. Convection currents may arise in the asthenosphere and they are hypothesized to be lithosphere.
In the zones of the volcanic belts of the island arcs and continental margins, the principal magma chambers are associated with super deep dip faults, slanting beneath the continents from the ocean side to depths of about 700 km.
Under the influence of the heat flow or under the direct influence of the heat carried by rising abyssal magma , magma chambers form in the crust itself . Reaching the near surface parts, the magma is intruded into them in the form of variously shaped intrusive bodies or is extruded onto the surface , forming volcanoes.
Gravitational differentiation has led to the stratification of the earth into geospheres of varying density.
Is also manifested in the form of tectonic movements , which, in turn, lead to the tectonic deformation of crustal and upper mantle rocks.
The accumulation and subsequent discharge of tectonic stresses along active faults causes earthquakes. It is hypothesized that a combination of these processes leads to the temporal unevenness of the release of heat and light matter toward the surface , which , in turn , can be explained by the occurrence of tectonic magmatic cycles in the history of the earth’s crust. The spatial irregularities of the same abyssal processes may explain division of the crust into more or less geologically active regions, for example, into geosynclines and platforms. Study Question: What is the difference between exogenic and endogenic process ?
Lesson 2.4:
CRUSTAL DEFORMATION PROCESSES
Crustal Deformation I. Deformation of rocks in Earth's crust takes many forms; A. Changes in volume, shape, and position can occur alone or in combination. 1. Stress = applied force = cause of the deformation a. Types of stress include: 1) Tensional-stretching, increased volume 2) Compressional - squeezing, decreased volume 3) Shear - change in shape 2. Strain = resulting deformation B. Causes of deformation 1. Confining pressure - due to the load of overlying rocks
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2. Stresses applied at plate boundaries - usually not uniform instead this is a directed pressure C. Types of deformation (affected by confining pressure and temperature) 1. Deformation by flow a. Elastic-recoverable, small amounts of strain, doesn’t happen to rocks b. Plastic-permanent; rocks flow as movement occurs along small structural defects. 2. Brittle deformation - rupture - rock moves in opposite directions on either side of a break. II. Strike and dip are used to describe the orientation of planar features. A. Outcrop - site where rocks are exposed at the surface B. Dip - the angle of inclination of the bedding surface down off the horizontal C. Strike - the trend or direction of the strata or the bearing of any horizontal line on the plane perpendicular to the direction of dip. III. Features of plastic deformation - Folds A. Folds-wavelike undulations caused by bending of rocks usually produced by horizontal compressive stresses – occurs at great depths inside the Earth under great temperatures and pressures B. Terminology 1. Axial plane - a plane through a rock fold that includes the axis-divides the fold as symmetrically as possible. 2. Axis-the ridge or place of sharpest folding. 3. Limb- 1 of 2 parts of the fold-on either side of axis. 4. Plunge-angle that fold axis makes with the horizontal C. Types of folds 1. Anticline- arching or upwarping of rock layers 2. Syncline- downwarping of rock layers 3 .Monocline- double flexure of rock layers 4. Dome -non-linear, anticlinal fold-beds dip away from central area in all directions 5.Basin - non - linear, synclinal fold-beds dip towards central area from all directions. D. Description of folds 1. Symmetrical-dips of opposite limbs of fold are approximately equal 2. Overturned-asymmetrical fold with one limb tilted beyond vertical 3. Recumbent-overturned fold with a horizontal axis 4. Plunging-axis of fold penetrates into ground IV. Features of brittle deformation - Faults and Joints A. Joints- breaks in rock mass with no appreciable relative movement of rocks on opposite sides of break. Sheet jointing causes formation of exfoliation domes and cooling results in columnar joints in basalt. B. Faults- breaks in rock mass where appreciable movement of rocks on opposite sides of the break has occurred. Faults are classified on the basis of the relative movement of blocks on either side of the fault. 1. Terminology a. Hanging wall -block of rock immediately above fault surface b. Footwall-block of rock immediately below fault surface 2. Dip-slip faults-movement of the two blocks is up and down the dip of the fault-primarily vertical
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a. Normal fault- footwall moves up with respect to hanging wall (associated with tensional stress) Graben and horst-features characterized by down-dropped and uplifted blocks of rock, respectively, bordered by pairs of normal faults. b. Reverse and thrust- footwall moves down with respect to hanging wall (associated with compressional stress and usually lots of folding) 3. Strike-slip and transform faults-movement of the two blocks on either side of the break is along the strike and dominantly horizontal (associated with shear stress) a. Right lateral and left lateral b. Transform fault -special kind of strike-slip fault, found along plate boundaries, which accommodates motion between crustal plates. The SAN ANDREAS FAULT is a right lateral strike-slip transform fault. C. Deformation of Earth's Crust occurs abruptly or gradually 1. Abrupt movements are associated with earthquakes. 2. Gradual movements = creep = semi-continuous movement. Deformation of rock involves: changes in the shape and/or volume of these substances. Changes in shape and volume occur when stress and strain causes rock to buckle and fracture or crumple into folds. A fold can be defined as a bend in rock that is the response to compressional forces. Folds are most visible in rocks that contain layering. Plastic deformation of rock to occur, a number of conditions must be met, including: The rock material must have the ability to deform under pressure and heat. The higher the temperature of the rock the more plastic it becomes. Pressure must not exceed the internal strength of the rock. If it does, fracturing occurs. Deformation must be applied slowly. A number of different folds have been recognized and classified by geologists: 1. The simplest type of fold is called a monocline. This fold involves a slight bend in otherwise parallel layers of rock.
Figure 1 - Monocline Fold
2. An anticline is a convex up fold in rock that resembles an arch like structure with the rock beds (or limbs) dipping way from the center of the structure. Note how the rock layers dip away from the center of the fold are roughly symmetrical. Fiigure 2- Anticline Fold
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3. A syncline is a fold where the rock layers are warped downward (Figure 3 and 4). Both anticlines and synclines are the result of compressional stress.
Figure 3
Figure 4
More complex fold types can develop in situations where lateral pressures become greater. The greater pressure results in anticlines and synclines that are inclined and asymmetrical. The following illustration shows two anticline folds which are inclined. Also note how the beds on either side of the fold center are asymmetrical. shows two anticline folds which are inclined. Also note how the beds on either side of the fold center are asymmetrical. Figure 5 4. A recumbent fold develops if the center of the fold moves from being once vertical to a horizontal position. Recumbent folds are commonly found in the core of mountain ranges and indicate that compression and/or shear forces were stronger in one direction. Extreme stress and pressure can Figure 6 sometimes cause the rocks to shear along a plane of weakness creating a fault. We call the combination of a fault and a fold in a rock an over thrust fault. Faults form in rocks when the stresses overcome the internal strength of the rock resulting in a fracture. A fault can be defined as the displacement of once connected blocks of rock along a fault plane. This can occur in any direction with the blocks moving away from each other. Faults occur from both tensional and compressional forces. This shows the location of some of the major faults located on the Earth. Location of some of the major faults on the Earth. Note that many of these faults are in mountainous regions. There are different kinds of faults. These faults are named according to the type of stress that acts on the rock and by the nature of the movement of the rock blocks either side of the fault plane. 1. Normal faults occur when tensional forces act in opposite directions and cause one slab of the rock to be displaced up and the other slab down. Normal faults
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2. Reverse faults develop when compressional forces exist. Compression causes one block to be pushed up and over the other block.
Reverse faults 3. A graben fault is produced when tensional stresses result in the subsidence of a block of rock. On a large scale these features are known as Rift Valleys. 4. A horst fault is the development of two reverse faults causing a block of rock to be pushed up.
graben fault
horst fault
5. The final major type of fault is the strike-slip or transform fault. These faults are vertical in nature and are produced where the stresses are exerted parallel to each other. A well-known example of this type of fault is the San Andreas fault in California. Transcurrent fault zones on and off the West coast of North America. (Source: U.S. Geological Survey). EARTH QUAKES An earthquake is a sudden vibration or trembling in the Earth. Earthquake motion is caused by the quick release of stored potential energy into the kinetic energy of motion. Most earthquakes are produced along: faults, tectonic plate boundary zones, or along the mid-oceanic ridges At these areas, large masses of rock that are moving past each other can become locked due to friction. Friction is overcome when the accumulating stress has enough force to cause a sudden slippage of the rock masses. The magnitude of the shock wave released into the surrounding rocks is controlled by: the quantity of stress built up because of friction, the distance the rock moved when the slippage occurred, and ability of the rock to transmit the energy contained in the seismic waves. Stratified Rock The stratified rocks form more than nine-tenths of the earth's surface, and if the entire series of them were present at any one place, they would have a maximum thickness of about thirty miles, but no such place is known. The regions of greatest sedimentary accumulation are the shallower parts of the oceans, while those regions which have remained as dry land, through long ages, may not only have had no important additions to their surfaces, but have lost immense thicknesses of rock through denudation. The great oceanic abysses are also areas of excessively slow sedimentation, and thus the thickness of the stratified rocks varies much from point to point, a
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variation which has been increased by the irregularities of upheaval and depression and of different rates of denudation. Even with this irregularity in the formation and removal of the stratified rocks, it would be exceedingly difficult to investigate the entire series of them, if they had all retained the original horizontal positions in which they were first laid down. In many places, however, the rocks have been steeply tilted and then truncated by erosion, so that their edges form the surface of the ground, and thus great thicknesses of them may be examined without descending below the surface. Stratification, or division into layers, is the most persistent and conspicuous characteristic of the sedimentary rocks. In studying the sedimentary deposits of the present day we learned that by the sorting power of water and wind, heterogeneous material is arranged into more or less homogeneous beds, separated from one another by distinct planes of division, and the same thing is true of the sedimentary rocks stratification of all ages. This division into more or less parallel layers is called, and the extent to which the division is carried varies according to circumstances. A single member, or bed, of a stratified rock, whether thick or thin, is called a layer, though for purposes of distinction, excessively thin layers are called lamince. Each layer or lamina represents an uninterrupted deposition of material, while the divisions between them, or bedding planes, are due to longer or shorter pauses in the process, or to a change, if only in a film, of the material deposited. A stratum is the collection of layers of the same mineral substance, which occur together and may consist of one or many layers. The passage from one stratum to another is generally abrupt and indicates a change in the circumstances of deposition, either in the depth of water, or in the character of the material brought to a given spot, or both. So long as conditions remain the same, the same kind of material will accumulate over a given area, and thus immense thicknesses of similar material may be formed. To keep up such equality of conditions, the depth of water must remain constant, and hence the bottom must subside as rapidly as the sediment accumulates. Usually, a section of thick rock masses shows continual change of material at different levels. Given figure is a section of the rocks in Beaver County, Pennsylvania, in which several different kinds of beds register the changes in the physical geography of that area.
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1. At the bottom of the section is a coal seam, the consolidated and carbonized vegetable matter which accumulated in an ancient fresh-water swamp. 2. Next came a subsidence of the swamp, allowing water to flow in, in which were laid down mixed sands and gravels. 3. The accumulations eventually shoaled the water and enabled a second peat swamp to establish itself; this is registered in the second coal bed, the thinness of which indicates that the second swamp did not last so long as the first. 4. Renewed subsidence again flooded the bog, as is shown by the stratum of shale which overlies the second coal bed. 5. Next, the water was shoaled by an upheaval, and argillaceous sands were laid down, which now form the flaggy sandstones overlying the shale. 6. The twenty-five feet of sandstone, aided by continued slow rise, silted up the water and allowed a third peat bog to grow, the result of which is the third coal seam, while a repetition of the subsidence once more brought in the water, in which were laid down the seventy feet of gravel at the top of the section. In this fashion the succession of strata records the changes which were in progress while those strata were forming. Whether the beds, other than the coal seams, were laid down in fresh water, or in salt, by a lake, a flooded river, or the sea, may be determined from the fossils contained in those beds. In the absence of fossils it is not always possible to make the distinction. Similar changes in the strata may be occasioned by the steady lowering of a land surface through denudation. This diminishes the velocity of the streams, which, in its turn, changes the character of the materials which the rivers bring to the sea. We have no trustworthy means of judging how long a time was required for the formation of any given stratum or series of strata, but it is clear that different kinds of beds accumulate at very different rates. The coarser materials, like conglomerates and sand-stones, were piled up much more rapidly than the shales and limestones; so that equal thicknesses of different kinds of strata imply great differences in the time required to form them. Comparing like strata with like, the thickness of a group of rocks is a rough measure of the time involved in their formation, and that very thick masses imply a very long lapse of time, but it cannot be inferred that the number of years or centuries or millennia required.
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Geological chronology can be relative only. Such a relative chronology is by the order of succession of the beds. Obviously the lowest stratum is the oldest and the one at the top the newest. This may be put as a general principle, that, unless strata have lost their original position through disturbance or dislocation, their order of superposition is their order of relative age. It is for this reason that in geological sections the strata are numbered and read from below upward. Change in the character of the strata takes place not only vertically, but also horizontally, since no stratum is universal, even for a single continent. The study of the processes of sedimentation which, showed that the character of the bottom in the ocean or in lakes is subject to frequent changes, varying with the depth of water and other factors. The same is true of the ancient sea and lake bottoms, now represented by the stratified rocks of the land. Strata may persist with great evenness and uniform thickness over vast areas, and in such cases the bedding planes remain sensibly parallel. But sooner or later, the beds, whenever they can be traced far enough, are found to thin out to edges and to dovetail in with beds of a different character. When the strata are of constant thickness for considerable distances, and the bedding planes remain parallel, the stratification is said to be regular. In many cases these changes take place rapidly from point to point, and then the strata are plainly of lenticular shape, thickest in the middle, thinning quickly to the edges. Here the bedding planes are distinctly not parallel, and the stratification is irregular. An example of rapid horizontal changes is given in the two accompanying parallel sections (Fig.7), taken through the same beds, only twenty feet apart. In these sections the differences of thickness of the coal seams and of the sands and clays which separate them are very striking. Fig. 7. - Parallel sections near Colorado Springs, Col. (Hay-den).
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The finer details of structure of the stratified rocks, such as cross-bedding, ripple and rill-marks, rain-prints, tracks of animals, and the like, likewise afford valuable testimony as to the circumstances under which the rocks were laid down.
Study Question : Explain how rocks in Earth's crust deform.
Fig. 7
Lesson 2.5: HISTORY OF EARTH In the very beginning of earth's history, this planet was a giant, red hot, roiling, boiling sea of molten rock - a magma ocean. The heat had been generated by the repeated high speed collisions of much smaller bodies of space rocks that continually clumped together as they collided to form this planet. As the collisions tapered off the earth began to cool, forming a thin crust on its surface. As the cooling continued, water vapor began to escape and condense in the earth's early atmosphere. Clouds formed and storms raged, raining more and more water down on the primitive earth, cooling the surface further until it was flooded with water, forming the seas. It is theorized that the true age of the earth is about 4.6 billion years old, formed at about the same time as the rest of our solar system. The oldest rocks geologists have been able to find are 3.9 billion years old. Using radiometric dating methods to determine the age of rocks means scientists have to rely on when the rock was initially formed (as in - when its internal minerals first cooled). In the infancy of our home planet the entire earth was molten rock - a magma ocean. Since we can only measure as far back in time as we had solid rock on this planet, we are limited in how we can measure the real age of the earth. Due to the forces of plate tectonics, our planet is also a very dynamic one; new mountains forming, old ones wearing down, volcanoes melting and reshaping new crust. The continual changing and reshaping of the earth's surface that involves the melting down and reconstructing of old rock has pretty much eliminated most of the original rocks that came with earth when it was newly formed. So the age is a theoretical age.
When Did Life on Earth Begin? Scientists are still trying to unravel one of the greatest mysteries of earth: When did "life" first appear and how did it happen? It is estimated that the first life forms on earth were primitive, one-celled creatures that appeared about 3 billion years ago. That's pretty much all there was for about the next two billion years. Then suddenly those single celled organisms began to evolve into multicellular organisms. Then an unprecedented profusion of life in incredibly complex forms began to fill the oceans. Some crawled from the seas and took residence on land, perhaps to escape predators in the ocean. A cascading chain of new and increasingly differentiated forms of life appeared all over the planet, only to be virtually annihilated by an unexplained mass extinction. It would be the first of several mass extinctions in Earth's history. Scientists have been looking increasingly to space to explain these mass extinctions that have been happening almost like clockwork since the beginning of
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"living" time. Perhaps we've been getting periodically belted by more space rocks (ie. asteroids), or the collision of neutron stars happening too close for comfort? Each time a mass extinction occurred, life found a way to come back from the brink. Life has tenaciously clung to this small blue planet for the last three billion years. Scientists are finding new cues as to how life first began on earth in some really interesting places the deep ocean. Checking the Fossil Record Scientists have studied rocks using radiometric dating methods to determine the age of earth. Another really cool thing they've found in rocks that tells us more about the story of earth's past are the remains of living creatures that have been embedded in the rocks for all time. We call these fossils. It has been the careful study of earth's fossil record that has revealed the exciting picture about the kinds of creatures that once roamed this planet. Fossilized skeletons of enormous creatures with huge claws and teeth, ancient ancestors of modern day species (such as sharks) that have remained virtually unchanged for millions of years, and prehistoric jungles lush with plant life, all point to a profusion of life and a variety of species that continues to populate the earth, even in the face of periodic mass extinctions. By studying the fossil record scientists have determined that the earth has experienced very different climates in the past. In fact, general climactic conditions, as well as existing species, are used to define distinct geologic time periods in earth's history. For example, periodic warming of the earth - during the Jurassic and Cretaceous periods - created a profusion of plant and animal life that left behind generous organic materials from their decay. These layers of organic material built up over millions of years undisturbed. They were eventually covered by younger, overlying sediment and compressed, giving us fossil fuels such as coal, petroleum and natural gas. Alternately, the earth's climate has also experienced periods of extremely cold weather for such prolonged periods that much of the surface was covered in thick sheets of ice. These periods of geologic time are called ice ages. Entire species of warmerclimate species died out during these time periods, giving rise to entirely new species of living things which could tolerate and survive in the extremely cold climate. Believe it or not, humans were around during the last ice age - the Holocene (about 11,500 years ago) - and we managed to survive. Creatures like the Woolly Mammoth - a distant relative of modern-day elephants - did not. Read about a really exciting recent find of a perfectly-preserved, frozen Woolly Mammoth! This was a particularly exciting find because it wasn't a fossil that scientists found, but actual tissue, which still has its DNA record intact. Also, read more about the Ice Man - another frozen tissue sample of a human being who was frozen into the high mountains of France. He was just recently discovered as thousands of years of ice pack have finally melted from around his body. Rocks in the mantle and the core are still hot from the formation of the Earth about 4.6 billion years ago. When the Earth formed, material collided at high speeds. These collisions generated heat (try clapping your hands together - they get hot) that heat became trapped in the Earth. There is also heat within the earth produced by radioactive decay of naturally-occurring radioactive elements. It is the same process that allows a nuclear reactor to generate heat, but in the earth, the radioactive material is much less concentrated. However, because the earth is so much bigger than a nuclear power plant it can produce a lot of heat. Rocks are good insulators so the heat has been slow to dissipate.
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This heat is enough to partially melt some rocks in the upper mantle, about 50100 km below the surface. It partially melt because the rocks don't completely melt. Most rocks are made up of more than one mineral, and these different minerals have different melting temperatures. This means that when the rock starts to melt, some of the minerals get melted to a much greater degree than others. The main reason this is important is that the liquid (magma) that is generated is not just the molten equivalent of the starting rock, but something different. The most common type of magma produced is basalt (the stuff that is erupted at mid-ocean ridges to make up the ocean floors, as well as the stuff that is erupted in Hawai'i). Soon after they're formed, little drops of basaltic magma start to work their way upward (their density is slightly less than that of the solid rock), and pretty soon they join with other drops and eventually there is a good flow of basaltic magma towards the surface. If it makes it to the surface it will erupt as basaltic lava. CHAPTER TEST : Identification. Write the correct answer in the blank. _______________1. the first life form on earth _______________2. a rock formed from cooled melted rock _______________3. a characteristic that is persistent to sedimentary rocks _______________4. a molten rock _______________5. breaks in rock mass caused by the movement of rocks on opposite sides _______________6. rocks that are subjected to intense heat and pressure _______________7. seismic activity is included in this process _______________8. It is the collection of layers of the same mineral substance, which occur together and may consist of one or many layers. _______________9. the remains of living creatures that have been embedded in the rocks _______________10.It is a sudden vibration or trembling in the Earth. CHAPTER 3: NATURAL HAZARDS, MITIGATON, AND ADAPTATION Objectives: 1. To identify different geological processes and hydrometeorological phenomena 2. To describe the various hazards that may happen in the events of earthquakes, volcanic eruptions, landslides and hydrometeorological phenomena 3. To describe how coastal processes result in coastal erosion, submersion and saltwater intrusion Throughout the history of this planet, natural hazards have had great impact. From the prehistoric to biblical hazards to the tragic events of recent times, humanity has been afflicted by natural disasters. Lesson 3.1: GEOLOGICAL PROCESSES AND HAZARDS Geological processes are dynamics at work in the earth’s landforms and surfaces. It involved landslide, volcanic eruption, and earthquake that are in some points destructive and in others constructive.
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EARTHQUAKE An earthquake is caused by a sudden release of strain in the earth's interior. The sudden release of strain occurs because the strength of the straining material is exceeded by the strain that has accumulated within that material. There are two main causes of earthquakes: 1. explosive volcanic eruptions 2. tectonic activity associated with plate margins and faults Effects of an Earthquake The destruction caused by an earthquake depends largely on its magnitude and duration. The destructive effects of an earthquake can be classified into primary and secondary effects. Primary effects are the immediate damage caused by the quake, such as collapsing buildings, roads and bridges, which may kill many people.
Myanmar 6.9 magnitude earthquake (April 2016)
Nepal 7.8 magnitude earthquake (April 2015)
Secondary Effects are the after-effects of the earthquake, such as fires, tsunami, landslides and diseases. Fire. Earthquakes destroy gas pipes and electric cables, causing fires to spread. Landslides. Earthquakes often cause landslides, especially in steep river valleys and areas of weak rocks. Disease and famine. Fresh water supplies are often cut off causing typhoid and cholera. Lack of shelter and food causes much suffering. Soil liquefaction. When soil with high water content, are violently shaken they lose their mechanical strength and behave like a fluid and so buildings can literally sink. Tsunami. Earthquake can cause huge underwater waves called tsunami. Rock slipping along a fault under the ocean causes it.
On March 11, 2011, a magnitude-9 earthquake shook northeastern Japan, unleashing a savage tsunami
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LANDSLIDE Landslide, also called landslip is the movement of rock, debris or earth down a slope. They result from the failure of the materials which make up the hill slope and are driven by the force of gravity. Landslides can be triggered by natural causes or by human activity. They range from a single boulder in a rock fall or topple to tens of millions of cubic meters of material in a debris flow. Landslides cause property damage, injury and death and adversely affect a variety of resources. Human activity, such as agriculture and construction, can increase the risk of a landslide. Irrigation, deforestation, mining and water leakage are some of the common activities that weaken the slope. In January 2012, a landslide hit mining site in Compostela Valley in a remote area of the southern Philippines. The mountainside of the village collapsed when most residents were asleep, sweeping away about 50 houses, shanties and other buildings. (See fig.below)
Davao
City,
Philippines
(January
5,2012)
A
landslide
occurred
in
Pantukan,
Compostela
Valley.
VOLCANIC ERUPTION Volcanic eruption begins when pressure on the magma chamber forces magma up through the conduit and out of the volcano’s vent. It varies considerably. Eruptions may be violent, mild or quiet. Magma composition, magma temperature, and the amount of dissolved gases in the magma are the primary factors that determine whether a volcano erupts violently or quietly. Volcanic eruptions can cause serious impacts on living things, the economy as well as in the environment. It is both beneficial and destructive. Benefits of Volcanic Eruption 1. Agricultural Benefits. After volcanic eruption, the lava can turn into one of the most fertile soil. Places near the volcanoes have a fertile soil favorable for the farmers. The biggest plantation of abaca in the Philippines is in the foot of Mt. Mayon. The Rice Granary of the Philippines in Central Luzon is located in the surrounding area of Mt. Pinatubo. 2. Economic and Recreational Benefits. Volcanoes can promote tourism. Hot springs in the surrounding places of volcanoes are one of the favorite recreational destination of many people.
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3. Energy Benefits. Volcanoes provide resources for energy extraction, also known as geothermal resources. With enough supply of water and steady source of heat, steam can be generated to power turbines that can spin generators to produce electricity. 4. Industrial Benefits. Volcanoes contain minerals, a good source of chemical and industrial materials. Harmful Effects of Volcanic Eruption 1. Volcanic ashes pose potential hazards to living things, agriculture and properties. 2. Volcanic eruption contribute to global warming. 3. Massive flow of lahar can destroy properties and lives of many people. Review Question: What hazards may happen in the event of earthquake, landslide, and volcanic eruption ?
Lesson 3.2:
HYDROMETEOROLOGICAL PHENOMENA AND HAZARDS
Hydrometeorological Hazards It is a process or phenomenon of atmospheric, hydro-logical or oceanographic nature that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage. Hydrometeorological hazards are driven by hydrological processes. It is a long accepted fact that the Pacific is one of the most natural disaster prone regions in the world. Aside from the threat of geological hazards, the Pacific region is subject to a wide range of hydrometeorological hazards. These includes: tropical cyclones, severe storms, storm surges, floods/ flash floods, droughts, fires/ wild fires, and cold waves.
FLOOD A flood occurs when water overflows or inundates land that's normally dry. Most common is when rivers or streams overflow their banks. Floods are among the most frequent and costly hydrological hazard. Ongoing flooding can intensify to flash flooding in cases where intense rainfall results in a rapid surge of rising flood waters. Effects of flooding Floods can have devastating consequences and can have effects on the econo my, environment and people. Economic During floods (especially flash floods), roads, bridges, farms, houses and automobiles are destroyed. All these come at a heavy cost to people and the government. Environment The environment also suffers when floods happen. Chemicals and other hazardous substances end up in the water and eventually contaminate the water bodies that floods end up in. Additionally, flooding causes kills animals, and
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others insects are introduced to affected areas, distorting the natural balance of the ecosystem. People and Animals Many people and animals have died in flash floods. Many more are injured and others made homeless. Water supply and electricity are disrupted and people struggle and suffer as a result. In addition to this, flooding brings a lot of diseases and infections including military fever, pneumonic plague, leptospirosis and dysentery. Sometimes insects and snakes make their ways to the area and cause a lot of havoc.
Flood Hazard Mapping Flood Hazard Mapping is a vital component for appropriate land use planning in flood-prone areas. It creates easily-read, rapidly-accessible charts and maps which facilitate the identification of areas at risk of flooding and also helps prioritize mitigation and response efforts . Flood hazard maps are designed to increase awareness of the likelihood of flooding among the public, local authorities and other organizations. They also encourage people living and working in flood-prone areas to find out more about the local flood risk and to take appropriate action (Environment Agency, 2010). The Philippine government has made geo-hazard maps, which outline areas prone to natural disasters. (See fig.) TROPICAL CYCLONE Tropical cyclones are warm-core low pressure systems associated with a spiral inflow of mass at the bottom level and spiral outflow at the top level. They always form over oceans where sea surface temperature, also air temperatures are greater than 26°C. The air accumulates large amounts of sensible and latent heat as it spirals towards the center. The Philippines is prone to tropical cyclones due to its geographical location. 1. Strong Winds The strong wind associated to tropical cyclones is hazardous to properties, people, plants and animals. 2. Heavy Rainfall Strong and heavy rains could cause floods especially in low-lying areas. Flash floods are also associated to tropical cyclones. Flash floods are sudden occurrences and cannot be predicted. 3. Storm Surge. A storm surge is a term used for big waves and high tides that occur during tropical cyclones. 4. Tornado. It is a violent storm that strike as a powerful rotating mixture of wind and thunderstorm clouds, extending to the ground from the cloud in a funnel shape. DROUGHT Drought is characterized by below-average precipitation in a given region, resulting in prolonged shortages in its water supply. The strong likelihood of reduced rainfall during an El Niño event increases the risk of drought in the Philippines.
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IMPACTS OF DROUGHT Drought often results in mass displacements of population. It leads to water and food shortages and is likely to have a long-term environmental, economic and health impact on the population. Droughts lower the quality of soil resulting to low crop yield. Bodies of water dry out and water animals will die. The health and quality of freshwater biomes become affected. Hunger and malnutrition Farmers need to spend more money for the irrigation. Less or no rains means drier conditions and more bush fire. Farms are destroyed. Review questions: 1. What are some of the hazards associated to hydrometeorological phenomena and how can you minimize the damages that they cause? 2. Hazard map is being used now to monitor natural hazard. How does it help in mitigating the effects of natural hazard?
Lesson 3.3:
COASTAL PROCESSES AND THEIR EFFECTS
Coastal Processes The shoreline is affected by waves (produced by wind at sea) and tides (produced by the gravitational effect of the moon and sun). Waves Waves are caused by wind. Wave height in the open ocean is determined by three factors. Wind speed. The greater the wind speed, the larger the waves. Wind duration. The greater the duration of the wind (or storm) the larger the waves. Fetch. The greater the fetch (area over which the wind is blowing - size of storm) the larger the waves. TIDES Tides result from the gravitational attraction of the sun and the Moon on the oceans. The four ways that waves and tides erode the coast are described below:
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Hydraulic action. Air becomes trapped in joints and cracks in the cliff face. When a wave breaks, the trapped air is compressed which weakens the cliff and causes erosion. Abrasion. Bits of rock and sand in waves are flung against the cliff face. Over time they grind down cliff surfaces like sandpaper. Attrition. Waves smash rocks and pebbles on the shore into each other, and they break and become smaller and smoother. Solution. Weak acids contained in sea water will dissolve some types of rock such as chalk or limestone. Sea Level Rise and Coastal Erosion Scientific research indicates sea levels worldwide have been rising at a rate of 0.14 inches (3.5 millimeters) per year since the early 1990s. The trend, linked to global warming, puts thousands of coastal cities and even whole islands at risk of being claimed by the ocean. This slow sea level rise helps to increase the rate of coastal erosion. When sea levels rise rapidly, as they have been doing, even a small increase can have devastating effects on coastal habitats. As seawater reaches farther inland, it can cause destructive erosion, flooding of wetlands, contamination of aquifers and agricultural soils, and lost habitat for fish, birds, and plants. When large storms hit land, higher sea levels mean bigger, more powerful storm surges that can strip away everything in their path. In addition, hundreds of millions of people live in areas that will become increasingly vulnerable to flooding. Higher sea levels would force them to abandon their homes and relocate. Low-lying islands could be submerged completely.
Aside from coastal erosion, coastal processes result in submersion and seawater intrusion. Seawater intrusion is the movement of ocean water into fresh groundwater, causing contamination of the groundwater by salt. Although shoreline changes induced by erosion and accretion are natural processes that take place over a range of time scales, most of the causes affecting coastal communities are due to human intervention. Human activities along the coast like land reclamation, port development, improper waste disposal in combination with the natural forces often exacerbate coastal erosion in many places and jeopardize opportunities for coasts to fulfill their socioeconomic and ecological roles in the long term at a reasonable societal cost. COPING UP WITH NATURAL HAZARDS Mitigation is a measure taken prior to the impact of a disaster to minimize its effects. Because of geographical location of our country, we are prone to different natural hazards- Earthquake, tropical cyclones, volcanic eruptions, landslide, flashfloods and other natural calamities. Coping up with various hazards is extremely challenging especially for the people directly affected. CHAPTER TEST
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I. Identify the terms being referred to. ____________1. It is caused by a sudden release of strain in the earth's interior. ____________2. It is the movement of rock, debris or earth down a slope. ____________3. It begins when pressure on the magma chamber forces magma up through the conduit and out of the volcano’s vent. ____________4. It is a phenomenon of atmospheric, hydrological or oceanographic nature that may cause loss of life, injury or damage to property. ____________5. It occurs when water overflows or inundates landthat is normally dry. ____________6. a vital component for appropriate land use planning in flood-prone areas ____________7. a term used for big waves and high tides that occurs during tropical cyclones ____________8. a below-average precipitation in a given region, resulting in prolonged shortages in its water supply ____________9. the movement of ocean water into fresh groundwater, causing contamination of the groundwater by salt ____________10. a measure taken prior to the impact of a disaster to minimize its effects
CHAPTER 4: INTRODUCTION TO LIFE SCIENCE Objectives: 1. To help instructors manage the presentation of biological information with the goal of producing scientifically literate students 2. To help each student to acquire information according to his or her own learning style 3. To help students relate this information to their own lives so as to understand its importance and relevance
Lesson 4.1:
CONCEPT OF LIFE
What is life? Before we can address this question, we must first consider what qualifies something as “living.” What is life? This is a difficult question to answer, largely because life itself is not a simple concept. If you try to write a definition of “life,” you will find that it is not an easy task, because of the loose manner in which the term is used. Imagine a situation in which two astronauts encounter a large, amorphous blob on the surface of a planet. How would they determine whether it is alive? Movement. One of the first things the astronauts might do is observe the blob to see if it moves. Most animals move about, but movement from one place to another in itself is not diagnostic of life. Most plants and even some animals do not move about, while numerous non-living objects, such as clouds, do move. The criterion of movement is thus neither Necessary (possessed by all life) nor sufficient (possessed only by life. Sensitivity. The astronauts might prod the blob to see if it responds. Almost all living things respond to stimuli. Plants grow toward light, and animals retreat from fire. Not all stimuli produce responses, however. Imagine kicking a redwood tree or singing to a
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hibernating bear. This criterion, although superior to the first, is still inadequate to define life. Death. The astronauts might attempt to kill the blob. All living things die, while inanimate objects do not. Death is not easily distinguished from disorder, however; a car that breaks down has not died because it was never alive. Death is simply the loss of life, so this is a circular definition at best. Unless one can detect life, death is a meaningless concept, and hence a very inadequate criterion for defining life. Complexity. Finally, the astronauts might cut up the blob, to see if it is complexly organized. All living things are complex. Even the simplest bacteria contain a bewildering array of molecules, organized into many complex structures. However a computer is also complex, but not alive. Complexity is a necessary criterion of life, but it is not sufficient in itself to identify living things because many complex things are not alive. To determine whether the blob is alive, the astronauts would have to learn more about it. Probably the best thing they could do would be to examine it more carefully and determine whether it resembles the organisms we are familiar with, and if so, how. Fundamental Properties of Life All known organisms share certain general properties. To a large degree, these properties define what we mean by life. The following fundamental properties are shared by all organisms on earth. Cellular organization. All organisms consist of one or more cells—complex, organized assemblages of molecules enclosed within membranes. Sensitivity. All organisms respond to stimuli—though not always to the same stimuli in the same ways. Growth. All living things assimilate energy and use it to grow, a process called metabolism. Plants, algae, and some bacteria use sunlight to create covalent carbon bonds from CO2 and H2O through photosynthesis. This transfer of the energy in covalent bonds is essential to all life on earth. Development. Multicellular organisms undergo systematic gene-directed changes as they grow and mature. Reproduction. All living things reproduce, passing on traits from one generation to the next. Although some organisms live for a very long time, no organism lives forever, as far as we know. Because all organisms die, ongoing life is impossible without reproduction. Regulation. All organisms have regulatory mechanisms that coordinate internal processes. Homeostasis. All living things maintain relatively constant internal conditions, different from their environment.
Study Question : If sensitivity is one of the fundamental properties of life , give three examples of plants and explain how each demonstrate its sensitivity to stimuli.
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Lesson 4.2:
ORIGIN OF THE FIRST LIFE FORM
Theories about the Origin of Life The question of how life originated is not easy to answer because it is impossible to go back in time and observe life’s beginnings; nor are there any witnesses. There is testimony in the rocks of the earth, but it is not easily read, and often it is silent on issues crying out for answers. There are, in principle, at least three possibilities: 1. Special creation. Life forms may have been put on earth by supernatural or divine forces. 2. Extraterrestrial origin. Life may not have originated on earth at all; instead, life may have infected earth from some other planet. 3. Spontaneous origin. Life may have evolved from inanimate matter, as associations among molecules became more and more complex. Special Creation. The theory of special creation, that a divine God created life is at the core of most major religions. The oldest hypothesis about life’s origins, it is also the most widely accepted. Far more Americans, for example, believe that God created life on earth than believe in the other two hypotheses. Many take a more extreme position, accepting the biblical account of life’s creation as factually correct. This viewpoint forms the basis for the very unscientific “scientific creationism”. Extraterrestrial Origin. The theory of panspermia proposes that meteors or cosmic dust may have carried significant amounts of complex organic molecules to earth, kicking off the evolution of life. Hundreds of thousands of meteorites and comets are known to have slammed into the early earth, and recent findings suggest that at least some may have carried organic materials. Nor is life on other planets ruled out. For example, the discovery of liquid water under the surface of Jupiter’s ice-shrouded moon Europa and suggestions of fossils in rocks from Mars lend some credence to this idea. The hypothesis that an early source of carbonaceous material is extraterrestrial is testable, although it has not yet been proven. Indeed, NASA is planning to land on Europa, drill through the surface, and send a probe down to see if there is life. Spontaneous Origin. Most scientists tentatively accept the theory of spontaneous origin, that life evolved from inanimate matter. In this view, the force leading to life was selection. As changes in molecules increased their stability and caused them to persist longer, these molecules could initiate more and more complex associations, culminating in the evolution of cells.
Study Question : Among the theories of the origin of life, which theory do you think is the most credible one? Explain your answer.
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Lesson 4.3.
EVOLUTION (UNIFYING THEMES IN THE STUDY OF LIFE)
One of the most important theories in biology is evolution. Ever since its formulation in the mid-1800s by two English naturalists, Charles Darwin and Alfred Russel Wallace, the theory of evolution has been supported by fossil finds, geological studies, radioactive dating of rocks, genetics, molecular biology, biochemistry, and breeding experiments. Evolution is the unifying theory that explains the origin of diverse forms of life as a result of changes in their genetic make-up. The theory of evolution states modern organisms descended, with modification, from pre-existing life-forms. In the word of biologist Theodosius Dobzhansky, “Nothing in biology makes sense, except in the light of evolution.” Why don’t snakes have legs? Why are there dinosaur fossils but no living dinosaurs? Why are monkeys so like us, not only in appearance, but also in the structure of their genes and proteins? The answers to those questions, and thousands more, lie in the process of evolution. Evolution is so vital to our understanding and appreciations of biology that we must review its important principle before going further. CHAPTER TEST Identify the word being described by the given statement. _______________1. According to this theory, modern organisms have descended from pre-existing organisms and underwent modification through the passing of years. _______________2. the property of life to produce offspring _______________3. the theory that states that all life forms on earth are created by a divine being _______________4. the theory that claims that all living things have originated from non-living things _______________5. According to this theory, life on earth has started from cosmic dust. _______________6. It refers to the sum of all chemical reactions that occur in living organisms. _______________7. remains of dead plants and animals _______________8. the theory that states that life forms on earth were transported from other planets by the aliens _______________9. the two scientist who made a study of evolution of organisms _______________10. CHAPTER 5: BIOENERGETICS Objectives: 1. To understand how cell carry out functions in performing life activities 2. To explain how photosynthetic organisms use light energy to form energy-rich compound 3. To describe how organisms obtain and utilize energy Lesson 5.1: CELL Unicellular organisms are capable of independent existence and they can perform the essential functions of life. Anything less than a complete cell does not ensure independent living. Hence, cell is called the fundamental structural and functional unit of life.
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DISCOVERY OF THE CELL The invention of the microscope help scientists to study what a living organisms composed of. Even today the study of cells reveals more detail, and its secrets, which are in fact the secrets of life itself, are revealed with ever increasing clarity. Robert Hooke an English scientist was the first to observed cell and in doing so he named them cells. He examined a slice of cork in a primitive microscope and he saw tiny boxes, which he thoughts looked like a room and led to him calling them cell. However what Hooke actually saw was the dead cell walls of plant cells (cork) as it appeared under the microscope. THE CELL THEORY The cell theory was first proposed by Matthias Schleiden (1838) and Theodore Schwann (1839). Rudolf Virchow (1855) later added the concept of formation of cells; to this theory. The cell theory is as follows: a. All living things are made of cells b. It is the smallest living unit structure and function of all organisms. c. All cells arise from pre-existing cells. TYPE OF CELL Living things vary in terms of the number of cells they have. Some living things are multicellular. Others are unicellular. Two types of cells compose living things. In the case of bacteria and cyanobacteria have prokaryotic cells. These cell lack distinct nuclei and only have few organelles that are not membrane-bound. In contrast, eukaryotic cells have distinct nuclei and contained several membrane-bound organelles. Animals, plants, protists and fungi have eukaryotic cell. (See the illustration below for the comparison of the two types of cells)
PROKARYOTES
vs.
EUKARYOTES
Comparison of a prokaryotic and eukaryotic cell
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PARTS AND FUNCTIONS OF A EUKARYOTIC CELL The structures that make up a Eukaryotic cell are determined by the specific functions carried out by the cell. Thus, there is no typical eukaryotic cell. Nevertheless, eukaryotic cells generally have three main components: A cell membrane, a nucleus, and a variety of other organelles. THE CELL MEMBRANE (PLASMA MEMBRANE)
The cell membrane is a complex barrier separating every cell from its external environment.
It is “Selectively Permeable"- which means it regulates what passes into and out of the cell.
The cell membrane functions like a gate, controlling which molecules can enter and Carrier proteins in or on the membrane are specific, only allowing a small group of very similar molecules through. For instance, α- glucose is able to enter; but β – glucose is not. Many molecules cannot cross at all. The cell membrane is a fluid mosaic of proteins floating in a phospholipid bilayer. The rest of the cell membrane is mostly composed of phospholipid molecules. They have only two fatty acid ‘tails’ as one has been replaced by a phosphate group (making the ‘head’. The head is charged and so polar; the tails are not charged and so are non-polar. Thus the two ends of the phospholipid molecule have different properties in water. The phosphate head is hydrophilic and so the head will orient itself so that it is as close as possible to water molecules. The fatty acid tails are hydrophobic and so will tend to orient themselves away from water. Cells are bathed in an aqueous environment and since the inside of a cell is also aqueous, both sides of the cell membrane are surrounded by water molecules. This causes the phospholipids of the cell membrane to form two layers, known as a phospholipid bilayer. In this, the heads face the watery fluids inside and outside the cell, whilst the fatty acid tails are sandwiched inside the bilayer. The cell membrane is constantly being formed and broken down in living cells.
THE NUCLEUS
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It is a membrane bound structure that contains the cell's hereditary information and controls the cell's growth and reproduction. It is the command center of a eukaryotic cell and is commonly the most prominent organelle in a cell. The nucleus is surrounded by a double membrane called the nuclear envelope, which has many nuclear pores through which mRNA, and proteins can pass. These pores make it look like a golf ball. Most nuclei contain at least one nucleolus (plural, nucleoli). The nucleoli are where ribosomes are synthesized. (see fig. above for the illustration)
THE CYTOPLASM Everything within the cell membrane which nucleus is known as the cytoplasm.
is
not the
Cytosol is the jelly-like mixture in which the other organelles are suspended. Organelles carry out specific functions within the cell. In Eukaryotic cells, most organelles are surrounded by a membrane , but in prokaryotic cells there are no membrane-bound organelles.
Study Questions: 1. What are the 3 main parts of the cell? Describe each. 2. Why is cell membrane called “permeable membrane”? 3 . What does it mean by hydrophilic and hydrophobic? 4. What is the main function of the nucleus? 5. Why do animals could not withstand long exposure under the sun without water while plants can?
The Different Organelles and Their Functions
ORGANELLES 1. Cell wall
FUNCTION Provides mechanical support and maintains cell shape in plant cell. It prevents water loss in plants and protect from over expansion by too much water.(Animals have no cell wall)
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2. 3. 4. 5.
mitochondrion vacuole Golgi Apparatus lysosomes
6. centrioles 7. endoplasmic reticulum 8. chloroplastids 9. nuclear membrane 10. Nucleoplasm 11. Ribosomes 12. Cytoskeleton 13. Microbodies
Lesson 5.2:
Provides energy for the cell in the form of ATP Stores water, food and waste for the cells Sorts, packages and secretes cellular products The “suicide bag”. They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria. Formation of the spindle fiber during cell division Translocation of materials within the cell and in and out of the nucleus Gives green color of plants Separates the nuclear contents from the contents of cytoplasm Synthesis of RNA and production of ribosomes They use the RNA synthesized by the nucleolus in making specific amino acid. The cytoskeleton is responsible for cell shape, motility of the cell as a whole, and motility of organelles within a cell They contain enzymes that are essential in neutralizing toxic materials that are product of cellular metabolism
PHOTOSYNTHESIS
Life on Earth is solar powered. The chloroplasts in plants and other photosynthetic organisms capture light energy from the sun and convert it to chemical energy that is stored in sugar and other organic molecules. This conversion process is called photosynthesis. Let’s begin by placing photosynthesis in its ecological context. Photosynthesis nourishes almost the entire living world directly or indirectly. An organism acquires the organic compounds it uses for energy and carbon skeletons by one of two major modes: autotrophic nutrition or heterotrophic nutrition. Almost all plants are autotrophs; the only nutrients they require are water and minerals from the soil and carbon dioxide from the air. Specifically, plants are photoautotrophs, organisms that use light as a source of energy to synthesize organic substances. Photosynthesis also occurs in algae like kelp, certain other unicellular eukaryotes, and some prokaryotes b. Euglena a. Kelp
d. purple sulfur bacteria c. Cyanobacteria
Photoautotrophs. Aside from plants, these organisms use light energy to drive the synthesis of organic molecules from carbon dioxide and (in most cases) water. They feed themselves and the entire living world. On land, plants are the predominant producers of food. In aquatic environments, photoautotrophs include unicellular and multicellular algae, such as this kelp (a); some non-algal unicellular eukaryotes, such as Euglena (b); the prokaryotes called cyanobacteria (c); and other photosynthetic prokaryotes, such as these purple sulfur bacteria (d), which produce sulfur.
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On the other hands, heterotrophs obtain organic material by the second major mode of nutrition. Unable to make their own food, they live on compounds produced by other organisms, the autotrophs. Photosynthesis Converts Light Energy To Chemical Energy Of Food The remarkable ability of an organism to harness light energy and use it to drive the synthesis of organic compounds emerges from structural organization in the cell: Photosynthetic enzymes and other molecules are grouped together in a biological membrane, enabling the necessary series of chemical reactions to be carried out efficiently. Chloroplasts: The sites of photosynthesis in plants. All green parts of a plant, including green stems and unripened fruit, have chloroplasts, but the leaves are the major sites of photosynthesis in most plants . There are about half a million chloroplasts in a chunk of leaf with a top surface area of 1 mm 2. Chloroplasts are found mainly in the cells of the mesophyll, the tissue in the interior of the leaf. Carbon dioxide enters the leaf, and oxygen exits, by way of microscopic pores called stomata (singular, stoma; from the Greek, meaning “mouth”). Water absorbed by the roots is delivered to the leaves in veins. Leaves also use veins to export sugar to roots and other non-photosynthetic parts of the plant.(singular, stoma; from the Greek, meaning “mouth”). Water absorbed by the roots is delivered to the leaves in veins. Leaves also use veins to export sugar to roots and other non-photosynthetic parts of the plant. A chloroplast has an envelope of two membranes surrounding a dense fluid called the stroma. Suspended within the stroma is a third membrane system, made up of sacs called thylakoids, which segregates the stroma from the thylakoid space inside these sacs. In some places, thylakoid sacs are stacked in columns called grana (singular, granum). Chlorophyll, the green pigment that gives leaves their color, resides in the thylakoid membranes of the chloroplast. It is the light energy absorbed by chlorophyll that drives the synthesis of organic molecules in the chloroplast. Now that we have looked at the sites of photosynthesis in plants, we are ready to look more closely at the process of photosynthesis.
Photosynthesis in Leaf leaf cross section
Mesophyll cell
chloroplas t
The Process That Feeds the Biosphere - Photosynthesis 6 CO2 + 6 H2O
C6H12O6 + 6 O2
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The equation for photosynthesis may look simple but actually it is a very complex process. It involves two stages, which involve a step by step series of chemical reaction. 1. Light reactions (the photo part of photosynthesis) - which capture solar energy and transform it into chemical energy; and 2. Calvin cycle (the synthesis part) - which uses that chemical energy to make the organic molecules of food. During photosynthesis, plants carry out three vital energy conversions; 1. Conversion of light energy to electron energy 2. Conversion of electron energy to short-term energy storage(ATP) 3. Conversion of short-term energy storage (ATP) to long-term energy storage (sugars) Light Dependent Reactions The light dependent reactions capture the energy of sunlight, storing it as chemical energy in two different energy-carrier molecules ATP and NADPH). The chemical energy stored in these molecules will be used to power the synthesis of highenergy storage molecules like glucose, during light- independent reactions. As the term implies, light-dependent reactions can take place only in the presence of light (solar energy). The light-dependent reactions take place in the thylakoid membranes, or grana, of the chloroplasts. The thylakoid membranes contain highly organized assemblies of proteins, chlorophyll and the photosystems.
The process begins with Photosystem II, where trapped light energy is used to split water, a process known as photolysis: H2O → 2H++ 2e− + ½O2 The electrons are used to generate ATP, by passing them along a series of electron carriers, losing energy as they do so, before they join Photosystem I, replacing electrons lost there. Photosystem I also traps light energy, and uses it to excite electrons along a series of carrier molecules. Combined with the H+ ions formed in Photosystem I, they react with NADP to produce reduced NADP (also known as NADPH2): NADP + 2H+ + 2e− → reduced NADP The end-products of the light reaction are thus ATP and reduced NADP, (also called NADPH) which move into the stroma of the chloroplast ready to act as the raw materials for the light-independent reactions (see figure above) Notice that the light
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reactions produce no sugar; that happens in the second stage of photosynthesis, the Calvin cycle. Light Independent Reactions (Calvin Cycle) This process was named from the fact that they do not require light to take place. The Calvin cycle is named for Melvin Calvin, who, along with his colleagues James Bassham and Andrew Benson, began to simplify its steps. Calvin cycle is anabolic, building carbohydrates from smaller molecules and consuming energy. Carbon enters the Calvin cycle in the form of CO2 and leaves in the form of sugar. The cycle spends ATP as an energy source and consumes NADPH as reducing power for adding highenergy electrons to make the sugar. The carbohydrate produced directly from the Calvin cycle is actually not glucose, but a three-carbon sugar; the name of this sugar is glyceraldehyde 3-phosphate (G3P). For the net synthesis of one molecule of G3P, the cycle must take place three times, fixing three molecules of CO2—one per turn of the cycle. Calvin cycle is divided into three phases: carbon fixation, reduction, and regeneration of the CO2 acceptor. Phase 1: Carbon fixation. The Calvin cycle incorporates each CO2 molecule, one at a time, by attaching it to a five-carbon sugar named ribulose bisphosphate(RuBP). The enzyme that catalyzes this first step is RuBP carboxylase-oxygenase, or (rubisco) the most abundant protein in chloroplasts and is also thought to be the most abundant protein on Earth. The product of the reaction is a six-carbon intermediate that is shortlived because it is so energetically unstable that it immediately splits in half, forming two molecules of 3-phosphoglycerate (for each CO2 fixed). Phase 2: Reduction. Each molecule of 3-phosphoglycerate receives an additional phosphate group from ATP, becoming 1,3-bisphosphoglycerate. Next, a pair of electrons donated from NADPH reduces 1,3-bisphosphoglycerate, which also loses a phosphate group in the process, becoming glyceraldehyde 3-phosphate (G3P). Specifically, the electrons from NADPH reduce a carboxyl group on 1,3-bisphosphoglycerate to the aldehyde group of G3P,which stores more potential energy. G3P is a sugar—the same three-carbon sugar formed in glycolysis by the splitting of glucose. Notice in fig. below that for every three molecules of CO2 that enter the cycle, there are six molecules of G3P formed. But only one molecule of this three-carbon sugar can be counted as a net gain of carbohydrate because the rest are required to complete the cycle. The cycle began with 15 carbons’ worth of carbohydrate in the form of three molecules of the fivecarbon sugar RuBP. Now there are 18 carbons’ worth of carbohydrate in the form of six molecules of G3P. One molecule exits the cycle to be used by the plant cell, but the other five molecules must be recycled to regenerate the three molecules of RuBP.
The Calvin cycle. This diagram summarizes three turns of the cycle, tracking carbon atoms (gray balls). The three phases of the cycle correspond to the phases discussed in the text. For every three molecules of CO2 that enter the cycle, the net output is one molecule of glyceraldehyde 3phosphate (G3P), a three-carbon sugar. The light reactions sustain the Calvin cycle by regenerating the required ATP and NADPH.
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Phase 3: Regeneration of the CO2 acceptor (RuBP). In a complex series of reactions, the carbon skeletons of five molecules of G3P are rearranged by the last steps of the Calvin cycle into three molecules of RuBP. To accomplish this, the cycle spends three more molecules of ATP. The RuBP is now prepared to receive CO 2 again, and the cycle continues. For the net synthesis of one G3P molecule, the Calvin cycle consumes a total of nine molecules of ATP and six molecules of NADPH. The light reactions regenerate the ATP and NADPH. The G3P spun off from the Calvin cycle becomes the starting material for metabolic pathways that synthesize other organic compounds, including glucose (formed by combining two molecules of G3P), the disaccharide sucrose, and other carbohydrates. Neither the light reactions nor the Calvin cycle alone can make sugar from CO2.
Study Questions: 1. What is photosynthesis? Where does it take place? 2. What is the by-product of photosynthesis? 3. What is the by-product of light dependent reactions? Calvin cycle? 4. What is the relationship between light dependent reactions and the Calvin cycle? 5. What happen to the ATP and NADPH as it enters the Calvin cycle? 6. What do you call the 3-carbon sugar that is produced directly in Calvin Cycle?
Lesson 5.3:
CELLULAR RESPIRATION
Cellular processes are made possible by means of energy. Where does this energy come from? Whereas only photosynthetic cells can make sugar using photosynthesis . All cells need to be able to break down sugars they take in from their environment and turn it into energy to be used in cellular work. You have learned that ATP is the short term energy currency of the cell that is generated by the mitochondria. The conversion of long- term energy storage such as glucose into ATP is called respiration. During cellular respiration, sugar is broken down to CO 2 and H2O, and in the process, ATP is made that can then be used for cellular work.
C6H12O6 + 6O2----------> 6CO2 + 6H2O + ~38 ATP (The overall reaction for cellular respiration -
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the reverse reaction of photosynthesis)
STAGES OF CELLULAR RESPIRATION 1. Glycolysis. Glycolysis is known as “splitting of sugar”. One Glucose (C6H12O6) is broken down to 2 molecules of pyruvic acid, results in the production of 2 ATPs for every glucose. It is an anaerobic process - proceeds whether or not O2 is present. Aerobic conditions produce pyruvate and anaerobic conditions produce lactate as the end products of glycolysis. At the end, the process yields a 2 pyruvate molecule and 2ATP. 2. Krebs Cycle (Tricarboxylic Acid Cycle). Recall that the pyruvate is the end product of glycolysis. Pyruvate is transported to the mitochondrial matrix, where it is broken down via Krebs Cycle. The pyruvate diffuses down its concentration gradient into the mitochondria until it reaches the mitochondrial matrix, where it is used in cellular respiration. In the matrix, pyruvate reacts with coenzyme A(CoA) forming CO2 and acetyl CoA. When acetyl CoA enters the Krebs Cycle, CoA is released. One set of the reactions in the cycle produces 3 NADH, 1 FADH 2, 2 CO2 and 1 ATP for each acetyl CoA. Because each glucose molecule yields 2 pyruvates, the total energy harvest per glucose molecule in the matrix is 2 ATP, 8 NADH and FADH2. 3.Electron Transport System. Energetic electrons produced by the Krebs Cycle are carried to electron transport chains in the inner mitochondrial membrane. At this point, the cell has gained only 4 ATP molecules from the original glucose molecule: 2 during glycolysis and 2 during Krebs cycle. The cell has, however, captured many energetic electrons in carrier molecules. The carriers deposit their electrons in electron transport chain. Energy released by the electrons during the transfer is used to pump hydrogen ions from the matrix across the inner membrane. The movement of the hydro-gen ions down their gradient through the pores of ATP synthesizing enzymes drives the synthesis of 32-34molecules of ATP. ATP accounting from 1 glucose molecule: Pathways ATP Yield 1. Glycolysis 2 ATP 2. Krebs Cycle 2 ATP 3. ETS 34 ATP 38 ATP -2 ATP Energy expended
to transport NADPH from glycolysis to mitochondria
NET
36 ATP
Anaerobic Respiration Have you experienced muscle cramp? How does it happen? In aerobic respiration, glucose is converted to ATP in a presence of oxygen. If you are climbing a very steep hill. You start breathing harder to get oxygen. After a while, your breathing rate and your heart rate reach their maximum. Yet even this maximum isn’t delivering enough oxygen to your system. At that point, you switch over to anaerobic respiration.
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Anaerobic means without oxygen. In humans, what you’ll do is take glucose, and, in many steps, break it down to two molecules of a three carbon molecule called lactic acid. Lactic acid causes the muscle cramps. Comparative Summary of Photosynthesis and Cellular Respiration Photosynthesis 1. 2. 3. 4. 5. 6.
Stores energy in sugar molecules Uses carbon dioxide and water Increases weight Occurs in cell containing chloroplasts Produces oxygen in green organisms Produces ATP with energy from light
Cellular Respiration Releases energy from sugar molecules Releases carbon dioxide and water Decreases weight Occurs in all living cells Utilizes oxygen Produces ATP with energy released from sugar
Study Questions: 1. What is the end product of glycolysis? 2. What is the product of glycolysis that takes place in anaerobic condition? 3. Where does Krebs cycle take place? What is the end product of this stage? 4. How many ATP is produced in aerobic respiration? 5. What is the effect if pyruvic acid cannot proceed to Krebs cycle?
CHAPTER TEST: Read each question carefully. Write the letter of the correct answer in the blank. ___1. Who discovered the cell? a. Anton Van Leeuwenhoek c. Robert Brown b. Christian de Duve d. Robert Hooke ___2. To what structure are digestive enzymes or hydrolytic enzymes associated? a. Golgi apparatus c. ribosomes b. Lysosomes d. smooth ER ___3. In a cell, where does protein synthesis take place? a. Lysosomes c. nucleus b. Mitochondria d. ribosomes ___4. What gives plant cell a box-like shape? a. Cell wall c. nucleus b. Chloroplasts d. vacuole ___5. Where does photosynthesis take place in plant cell? a. Chloroplasts c. mitochondria b. ER d. ribosomes ___6. What process takes place in the stroma? a. Calvin cycle c. Light dependent reactions b. ETS d. Kreb cycle ___7. Which of the following processes is not a part of Calvin Cycle? a. Carbon fixation c. Glycolysis b. Carbon reduction d. Regeneration of RuBP ___8. What generates most of the ATP in cellular respiration? a. ETS b. Calvin Cycle c. Glycolysis d. Kreb cycle
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___9. What is the net amount of ATP produce during cellular respiration? a. 2 ATP b. 30 ATP c. 36 ATP d. 38 ATP ___10. How does photosynthesis and cellular respiration differ in terms ATP production? a. Photosynthesis produces ATP with energy from light while cellular respiration produces ATP with energy from glucose b. Photosynthesis produces ATP with energy from glucose while cellular respiration produces ATP with energy from light c. Photosynthesis produces more ATP than cellular respiration d. Photosynthesis produces ATP and water while cellular respiration produces glucose only
CHAPTER 6: PERPETUATION OF LIFE Lesson 6.1: PLANT AND ANIMAL REPRODUCTION All living things reproduce. Reproduction is the process of generating offspring. There are two main types of reproduction: sexual and asexual. Some organisms reproduce by only one type of reproduction and others can reproduce by both. This chapter looks at the differences, advantages and disadvantages of sexual and asexual reproduction. Asexual reproduction The type of reproduction where cells from only one parent are used, is called asexual. Only genetically-identical organisms are produced by this type of reproduction. Evolutionary asexual reproduction came before sexual reproduction. Asexual reproduction in bacteria Asexual reproduction is very common in microorganisms. Bacteria reproduce by binary fission. During binary fission, the cell divides into two daughter cells that are similar in size and shape. Asexual reproduction in plants Asexual reproduction in plants is also called vegetative reproduction. It usually involves only the plant's vegetative structures like roots, stems and leaves. For example, raspberries can produce a new generation using their stems; potatoes, using their roots; and geraniums can be grown from any piece of a parent plant. Sporulation Some types of mold reproduce through sporulation. They produce reproductive cells - spores - that are stored in special spore cases until they are ready to be released. After they are released they will develop into new, individual organisms. Bread mold reproduces by sporulation. Asexual reproduction in animals Some invertebrate animals (without a backbone) reproduce by asexual reproduction. Animals can reproduce asexually in the following ways: Budding During budding, a new organism starts growing from the parent's body. At first it looks like a bud. This bud later develops into a mature organism. Sometimes it stays
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attached to the parent's body and sometimes it breaks off. Hydras reproduce by budding. Gemmules are special structures that are found in sea sponges. A parent sponge releases gemmules that later develop into mature sponges. Regeneration In the process of regeneration, detached pieces of the parent's body can develop into a new organism if this body part contains enough genetic information. Some flat worms and starfish can reproduce by regeneration. Advantages and disadvantages of asexual reproduction Asexual reproduction works well for organisms that stay in one place. Because they do not move, it is difficult for them to find a mating partner. Stable environments are the best places for organisms that reproduce asexually. Asexual reproduction is also much less time and energy consuming. Asexually-produced generation does not have any genetic variations. That means that these organisms will not have any 'material' for adapting to environmental changes. That is why many asexually-reproducing organisms can reproduce sexually as well. Sexual reproduction During sexual reproduction, two gametes from both parents fuse, forming a zygote. A zygote is also referred to as a fertilized egg. All gametes are haploid cells, meaning they have only one set of chromosomes (1n). So, when gametes fuse, they form a diploid organism: 1n+1n=2n. Sexual reproduction in algae The simplest form of sexual reproduction in algae is conjugation, in which two similar organisms fuse, exchange genetic material and then break apart. Some multicellular green algae undergo a process called alternation of generations. During this process, generations of different types of organisms are produced: haploid and diploid. Haploid generation reproduces sexually. It is followed by diploid generation that reproduces asexually. Sexual reproduction in flowering plants Flowers contain both male and female parts. The female part is called the pistil, which consists of the ovary, ovule, style and stigma at the tip. Inside the ovary are the ovules. Each ovule contains an egg cell. The male structure is called the stamen. It consists of the filament and the pollen-producing anther. A new seed is formed when an egg cell joins with a pollen cell in the process of pollination. Pollination occurs when pollen grains are carried from the anther of the stamen to the stigma of the pistil. Sexual reproduction in animals Animal male gamete is called spermatozoan or sperm. Sperm is a mobile cell that moves using its 'tail', called flagellum. Female gamete is called an ovum. It does not move and it is much larger than sperm. Types of fertilization There are two main types of fertilization.
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1. Internal fertilization During internal fertilization, eggs are fertilized inside the female's body. Animals, like reptiles and birds, lay eggs after fertilization. New offspring develop outside the female's body. All eggs are covered by a protective shell. Mammal females, except monotremes, develop a new embryo inside their body. This extra protection increases an organism's chances of survival. 2. External fertilization During external fertilization, the egg is fertilized outside the female's body. Male and female gametes are released into these species' surroundings where they fuse, forming a zygote. This type of fertilization usually occurs in water. Amphibians and fish are examples of animals that reproduce in this way. Hermaphrodites Hermaphrodites are animals that have both female and male reproductive organs. Earthworms and leeches are hermaphrodites, but as they produce eggs and sperm at different times, they need a mate to reproduce. Flatworms are hermaphrodites that can self-fertilize. Parthenogenesis In some animal species, eggs can develop without fertilization in a process called parthenogenesis. Some types of birds and bees can reproduce by parthenogenesis. Plants: A plants life cycle starts with a seed. When it receives the right amount of sunlight, water, and air, it will begin to grow. The Seed sprouts, then grows into roots, a stem, then develops leaves, flowers and more seeds. The sprouted seed which grows down into the soil is called root. The part which grows to the surface of the soil is the stem. Later, leaves begin to form from the stem, and that seed is then called a ‘seedling’ as it can produce and prepare food. Slowly and steadily it develops as a plant, sheds seeds, and the cycle continues. Animals: Animals that give birth to babies and feed them with their milk are called mammals. Examples are humans, cows, and dogs. Other animals lay eggs and hatch them to reproduce new babies. Some insects lay eggs and the young ones have to undergo the process of metamorphosis. Reproductive system of a flower The flower is a plant which has an interesting reproductive system. The flower is what we know as angiosperm which means that they have seeds in a closed ovary. The flower has many parts which make it up including petals, sepals (small leaves under the flower ) carpels (female reproductive organs) and the stamens (male reproductive organs.) The Carpels: (female reproductive organs) Within a flower there can be many carpels. If there are more than one carpel it is referred to as a pistil. In each carpel is an ovary, which is similar to that of a female human. In here are where the eggs are the produced. A style is found on top of the ovaries and looks like a long tube. The style is where the male gametes come down to reach the ovaries. On top of the style is the stigma. The stigma's function is to receive the male pollen so the flower can undergo fertilization.
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The Stamens: (male reproductive organs) A stamen is basically the male reproductive organs. Within the stamen is an anther. An anther's function is to create pollen. It also contains filaments. Filaments hold the pollen in place making it easier for the pollen to be taken with the wind. Within the pollen is the male reproductive cells. This pollen finds the stigma, goes down the style where it will find and bind with the ovaries Fertilization: course, pollen must fuse with the egg to start fertilization, but how does this process actually work? The process is known as pollination. This process is helped by animals such as bees which carry pollen from all kinds of different flowers. As they buzz around the bees drop some of the pollen on the stigma. Once the stigma feels the pollen, the its way down these tubes and fuses with the eggs and then the flower starts to pollinate and create a seed. Types of Flowers: There are many types of flowers all over the world and not all of them have both of these reproductive organs in them. Some flowers have only one and therefore depend on other animals in order to reproduce. These flowers are known as Imperfect flowers. The flowers which have both of these organs are known as perfect flowers. The image on the side shows a labeled diagram of the reproductive parts of the flower and briefly outlines its functions.
Reproductive system of Animals The reproductive system of animals depends on what animal they are. Most animals have reproductive systems similar to that of humans. Animals must pair with a partner of the opposite sex in order to reproduce. Quite opposite to the flower, animals have either the male reproductive system or the female reproductive system. Review Questions : Identify the word being described by the given statement. ______________1. part of the flower that produces the pollen ______________2. animals having both the male and female sex organs ______________3. a type of reproduction which uses only the cells from one parent ______________4. flowers having both the reproductive organs ______________5. the fertilized egg of animals
Lesson 6.2: PROCESS OF GENETIC ENGINEERING Genetic engineering is the process of manually adding new DNA to an organism. The goal is to add one or more new traits that are not already found in that organism. Examples of genetically engineered (transgenic) organisms currently on the market
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include plants with resistance to some insects, plants that can tolerate herbicides, and crops with modified oil content. DNA Deoxyribonucleic acid or DNA is a genetic material which is stored in the nucleus. The nucleus is a part of the eukaryotic cell and contains nucleic acids and it is responsible in protein production. Small segments of DNA are called genes. Each gene holds the instructions for how to produce a single protein. DNA is usually a double-helix and has two strands running in opposite directions. DNA is the recipe for life. It is a molecule found in the nucleus of every cell and is made up of 4 subunits called bases and are represented by the letters A ( Adenine ), T ( Thymine), G ( Guanine ), and C ( Cytosine ). The order of these subunits in the DNA strand holds a code of information for the cell. The genetic language uses 4 letters to spell out the instructions for how to make the proteins an organism will need to grow and live. Structures of the Bases
Pairing of Subunits In the double-stranded DNA, the two strands run in opposite directions and the bases pair up such that A always pairs with T and G always pairs with C. The A-T basepair has 2 hydrogen bonds and the G-C base-pair has 3 hydrogen bonds. The G-C interaction is therefore stronger (by about 30%) than A-T, and A-T rich regions of DNA are more prone to thermal fluctuations. The smaller base is always paired with a bigger one. The effect of this is to keep the two chains at a fixed distance from each other all the way along. These particular pairs fit exactly to form very effective hydrogen bonds with each other. It is these hydrogen bonds which hold the two chains together. Exploring a DNA chain The backbone of DNA is based on a repeated pattern of a sugar group and a phosphate group. The full name of DNA, deoxyribonucleic acid, gives the name of the sugar present - deoxyribose. Deoxyribose is a modified form of another sugar called ribose. Ribose is the sugar in the backbone of RNA, ribonucleic acid.
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Each of the four corners where there isn't an atom shown has a carbon atom in the ring. Deoxyribose, as the name might suggest, is ribose which has lost an oxygen atom - "de-oxy".
Numbering of carbon atoms in deoxyribose ring The carbon atom to the right of the oxygen is numbered 1, and then around (clockwise direction ) to the carbon on the CH2OH side group as number 5. Attaching a phosphate group The other repeating part of the DNA backbone is a phosphate group. A phos- phate group is attached to the sugar molecule in place of the –OH group OH on the 5’ carbon O–P=O
Attaching a base and making a nucleotide One of four bases, cytosine (C) , thymine ( T ), adenine ( A ), and guanine ( G ), is added to the above structure to form a DNA strand ( nucleotide ).These bases attach in place of the -OH group on the 1' carbon atom in the sugar ring.
simplified diagram of nucleotide
nucleotide
Location of Bonding on Base Structures with Sugar Ring These bases attach in place of the –OH group on the 1’ carbon atom in the sugar ring. The nitrogen and hydrogen atoms ( in blue ) on each molecule show where these molecules join on to the deoxyribose. In each case, the hydrogen is lost together with the -OH group on the 1'
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carbon atom of the sugar. This is a condensation reaction - two molecules joining together with the loss of a small one (not necessarily water).
Example of nucleotide containing cytosine
Joining the nucleotides into a DNA Strand A DNA strand is simply a string of nucleotides joined together. The phosphate group on one nucleotide links to the 3’ carbon atom on the sugar of another one. In the process, a molecule of water is lost – another condensation reaction.
Adding more nucleotides in the same way build up a DNA chain for one strand. Pairing the two strands of DNA chains forms the structure resembling a ladder twisted into a spiral , called the double helix. One chain of DNA strand
Final structure for DNA with 2 strands , each at opposite direction
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How is genetic engineering done? Genetic engineering, also called transformation, works by physically removing a gene from one organism and inserting it into another, giving it the ability to express the trait encoded by that gene. The process of genetic engineering requires the successful completion of five steps : Step 1 : DNA Extraction DNA is extracted from the desired organism. A sample of an organism containing the gene of interest is taken through a series of steps to remove the DNA. Step 2 : Gene Cloning The second step of the genetic engineering process is gene cloning. During DNA extraction, all of the DNA from the organism is extracted at once. Scientists use gene cloning to separate the single gene of interest from the rest of the genes extracted and make thousands of copies of it. Step 3 : Gene Design Once a gene has been cloned, genetic engineers begin the third step, designing the gene to work once inside a different organism. This is done in a test tube by cutting the gene apart with enzymes and replacing gene regions that have been separated. Step 4 : Transformation or Gene Insertion Since plants have millions of cells, it would be impossible to insert a copy of the transgene into every cell. Therefore, tissue culture is used to propagate masses of undifferentiated plant cells called callus. These are the cells to which the new transgene will be added. The new gene is inserted into some of the cells using various techniques. Some of the more common methods include the gene gun, agrobacterium, micro-fibers, and electroporation. The main goal of each of these methods is to transport the new gene(s) and deliver them into the nucleus of a cell without killing it. Transformed plant cells are then regenerated into transgenic plants. The transgenic plants are grown to maturity in greenhouses and the seed they produce, which has inherited the transgene, is collected. Step 5 : Backcross Breeding Transgenic plants are crossed with elite breeding lines using traditional plant breeding methods to combine the desired traits of elite parents and the transgene into a single line. The offspring are repeatedly crossed back to the elite line to obtain a high yielding transgenic line. The result will be a plant with a yield
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potential close to current hybrids that expresses the trait encoded by the new transgene. Genetic engineering compared to traditional breeding Although the goal of both genetic engineering and traditional plant breeding is to improve an organism’s traits, there are some key differences between them. While genetic engineering manually moves genes from one organism to another, traditional breeding moves genes through mating, or crossing, the organisms in hopes of obtaining offspring with the desired combination of traits. Traditional breeding is effective in improving traits, however, when compared with genetic engineering, it does have disadvantages. Since breeding relies on the ability to mate two organisms to move genes, trait improvement is basically limited to those traits that already exist within that species. Genetic engineering, on the other hand, physically removes the genes from one organism and places them into the other. This eliminates the need for mating and allows the movement of genes between organisms of any species. Therefore, the potential traits that can be used are virtually unlimited. Breeding is also less precise than genetic engineering. In breeding, half of the genes from each parent are passed on to the offspring. This may include many undesirable genes for traits that are not wanted in the new organism. Genetic engineering, however, allows for the movement of a single, or a few, genes. The improvement of crops with the use of genetics has been occurring for years. Traditionally, crop improvement was accomplished by selecting the best looking plants/seeds and saving them to plant for the next year’s crop. Plant breeding is an important tool, but has limitations. First, breeding can only be done between two plants that can sexually mate with each other. This limits the new traits that can be added to those that already exist in that species. Second, when plants are mated, (crossed), many traits are transferred along with the trait of interest including traits with undesirable effects on yield potential. Genetic engineering is a new type of genetic modification. It is the purposeful addition of a foreign gene or genes to the genome of an organism. A gene holds information that will give the organism a trait. Genetic engineering is not bound by the limitations of traditional plant breeding. Genetic engineering physically removes the DNA from one organism and transfers the gene(s) for one or a few traits into another. Since crossing is not necessary, the 'sexual' barrier between species is overcome. There- fore, traits from any living organism can be transferred into a plant. This method is also more specific in that a single trait can be added to a plant. Exercise : Write the sequence of bases on a strand of DNA that is complementary to the following DNA strand : CATGCCTAAGCCAT
Lesson 6.3:
BENEFITS AND RISKS OF USING GMOs
What is a GMO? GMOs, or genetically modified organisms, are organisms whose genetic material has been altered using genetic engineering. Genetic engineering is the modification of an organism's phenotype by altering its genetic make-up. Genetic engineering is
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primarily performed by simple mating or gene recombination. GMOs range from microorganisms like yeast and bacteria to insects, plants, fish and mammals. Genetically modified crops (GM crops) are those engineered to introduce a new trait into the species. Purposes of GM crops generally include resistance to certain pests, diseases, or environmental conditions, or resistance to chemical treatments (e.g. resistance to a herbicide). Other purpose of genetic modification of crops is to enhance its nutritional value, as seen in the case of golden rice. The use of GM crops is widely debated. At the moment there is no known harm in consuming genetically modified foods. GM foods are developed – and marketed – because there is some perceived advantage either to the producer or consumer of these foods. This is meant to translate into a product with a lower price, greater benefit (in terms of durability or nutritional value) or both. Issue on GMOs Those who are pro-GMO claim that GMOs are not only safe for us and the environment, but also potentially, a very beneficial development. Those who are antiGMO argue that the risk of negative consequences to our environment is high and very difficult to predict. It is important to determine the magnitude of potential damage to our environment due to the spread of GMO genes into wild plants and microbes. GM crops can cause short and long term effects on the environment. Benefits of Using GMOs 1. a decreased use of pesticides and insecticides 2. reduced greenhouse gas emissions 3. increased nutritional values in foods 4. contribute to an increase in the number of functional foods or nutraceutical foods with added benefits 5. better taste 6. faster output of cops 7. more crops can be grown on less land 8. genetically modified animals have higher resistance to disease and overall better health Risks of Using GMOs 1. potential development of allergens 2. production of toxic substance to “non-target” organisms 3. increased endocrine disruption , reproductive disorders, and accelerated aging 4. antibiotic resistance 5. unknown effects 6. soil and water pollution Some Potential Consequences to the Environment Include: 1. Unintended selection 2. Unwanted change in gene expression 3. Unintended effect on non GM weeds, pests, or pathogens 4. Survival and persistence beyond intended zone 5. Production of toxic substance to 'non-target' organisms 6. "Horizontal Gene transfer "
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CHAPTER TEST I. True or False. Write T if the statement is correct and F if it is not. _____1. Animals perform asexual reproduction. _____2. The pistil is the plant’s female reproductive organ. _____3. Adenine always pairs with guanine. _____4. DNA and RNA are examples of nucleic acids. _____5. The genetic language uses 3 letters . _____6. Gene cloning is the second phase of genetic engineering process _____7. A DNA consists of 4 strands. _____8. All flowers have both the reproductive organs. _____9. Wind can be a medium of cross-pollination in flowers. _____10.In a DNA strand, there is no particular ruling in pairing the bases. II. Identify the word being described by the given statement. _______________1. these are formed from phosphoric acid, a sugar molecule, and a nitrogen- containing base group _______________2. the chemical carriers of an organism’s genetic information _______________3. the animal male gametes _______________4. GMOs stand for _______________5. a ribose which has lost an oxygen atom _______________6. the process of manually introducing new DNA to an organism _______________7. The two strands of DNA runs in what direction. _______________8. the process of reproduction in some molds _______________9. the female gamete of plants ______________10. It means having seeds in a closed ovary. CHAPTER 7: HOW ANIMALS SURVIVE Lesson 7.1:
Different Metabolic Processes
Objectives : 1. To define metabolism 2. To differentiate between catabolism and anabolism 3. To explain the different metabolic processes involved in the various organ systems Metabolism Metabolism is from the Greek word metabolē , meaning "change" It is a set of life-sustaining chemical trans- formations within the cells of living organisms. The three main purposes of metabolism are the conversion of food/fuel to energy to run cellular processes, the conversion of food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates, and the elimination of nitrogenous wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transport of substances into and
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between different cells, in which case the set of reactions within the cells is called intermediary metabolism. Metabolism is usually divided into two categories : a). catabolism - the breaking down of organic matter by way of cellular respiration b). anabolism - the building up of components of cells such as proteins and nucleic acids. Usually, breaking down releases energy and building up consumes energy. The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed through a series of steps into another chemical, by a sequence of enzymes. Enzymes are crucial to metabolism because they allow organisms to drive desirable reactions that require energy that will not occur by themselves, by coupling them to spontaneous reactions that release energy. Enzymes act as catalysts that allow the reactions to proceed more rapidly. Metabolic Processes Metabolic processes are sequences of biochemical reactions that take place within living cells to maintain life. They can be divided into two main types : A. Catabolic processes involve the breakdown of complex molecules from food into smaller units that can be used as building blocks for new molecules or to provide energy B. Anabolic processes involve the use of energy to build new chemicals that become components of cells. These reactions are made possible by a number of organic catalysts known as enzymes. Together, the two types of metabolic processes allow the transformation of the raw materials, or nutrients, that are taken in by an organism into tissue. One compound, common to all cellular life, is essential to these trans- formations. Adenosine triphosphate (ATP) is used to store energy obtained from nutrients, such as carbohydrates, and to release energy when it is required for the building of new molecules. Catabolic Processes Some organisms, such as green plants, make their own food from inorganic materials, while others, such as animals, consume organic materials to obtain their nutrition. The food consumed by animals can be broken down into three main types — carbohydrates, lipids (fats and oils), and proteins. Digestion involves catabolic processes that break these down into simpler components. For example, relatively complex carbohydrates, such as polysaccharides and disaccharides are broken down into glucose, and proteins are broken down into amino acids. These simpler compounds may be used by anabolic processes to build new materials, or they may be further broken down to provide energy. Cellular respiration is the process by which the carbohydrate glucose (C 6H12O6) is broken down into carbon dioxide (CO2) and water (H2O), producing energy that is stored in ATP. The procedure involves oxidation, and where there is atmospheric oxygen available it is used in what is known as aerobic respiration. This is the process that takes place in animals, plants and some microorganisms. In conditions where no free oxygen is present, anaerobic respiration takes place. This is found only in certain microorganisms that live in soil, decaying organic matter, under the sea, deep underground, and in the intestines of animals. These organisms use alternatives such as nitrates, sulfates, fumarate, and even sulfur in place
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of free oxygen. Anaerobic respiration is much less efficient than the aerobic process, and produces much less ATP . In animals, lipids are also oxidized to carbon dioxide and water, but the first few steps are different. The chemistry of organisms takes place in a water-based environment, but fats and oils do not mix with water. The first step is to emulsify these substances, which means converting them into a form that will mix with water, in the same way that detergents can help clean up oil spills. This is done by soap-like substances contained in bile released by the gall bladder into the small intestine. The lipids are then broken down into fatty acids and glycerol, which can be absorbed through the intestines, and which can then undergo oxidation reactions similar to those performed on carbohydrates. Proteins are very large, complex molecules, made up of building blocks known as amino acids. They are metabolized by various reactions that split them up into their amino acids, which can be absorbed, and then used within cells. Generally, proteins are not used to provide energy, but instead the amino acids are utilized to manufacture new proteins to build tissue and muscle. In cases where no carbohydrate or fat is available in the diet, and the body has used up its fat reserves, proteins may be used to generate energy, by oxidation of their amino acids. In these cases, the body may start breaking down muscle proteins. Anabolic Processes Also known as biosynthesis, these are reactions that use up the energy stored in ATP by catabolic processes. They include the building of proteins from amino acids and the construction of DNA from nucleotides. In animals, the muscle contractions that power movement can also be included, as these require the use of stored energy. In plants, the synthesis of glucose from carbon dioxide and water through photosynthesis is another anabolic pathway. How do animal cells get food Food to an animal cell is glucose. Glucose is a monosaccharide (a simple sugar) produced by plants in the process known as photosynthesis. Glucose is used to produce the energy to make another molecule called ATP (adenosine triphosphate) which is the "energy currency" of the cell (This process is called cellular respiration and this process takes place in the mitochondria of the cell.) All cells, regardless of what living thing they are in, require glucose to make ATP in sufficient quantities to run their metabolism. Animals get this glucose by eating plants or animals that eat plants. The glucose that the cells do not use is stored in the tissues of the plants. When we eat plants or animals, the glucose is often stored in larger molecules called polysaccharides (starches). During the process of digestion, these molecules are broken down to glucose. Other molecules made from these simple sugars include the disaccharides, or double sugars (table sugar, sucrose, is one of these). Once these molecules are broken down, the glucose enters the cell via diffusion. Once the cell has the glucose, it is transported to the mitochondria where it is then processed to form the ATP. How Cells Obtain Energy from Food Cells require a constant supply of energy to generate and maintain the biological order that keeps them alive. This energy is derived from the chemical bond energy in food molecules, which thereby serve as fuel for cells. Sugars are particularly important fuel molecules, and they are oxidized in small steps to carbon dioxide (CO2) and water . In this section we trace the major steps in the
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breakdown, or catabolism, of sugars and show how they produce ATP, NADH, and other activated carrier molecules in animal cells. We concentrate on glucose breakdown, since it dominates energy production in most animal cells. A very similar pathway also operates in plants, fungi, and many bacteria. Other molecules, such as fatty acids and proteins, can also serve as energy sources when they are funneled through appropriate enzymatic pathways. Exercise : Identify the word being described by the given statement. _______________1. a type of metabolism that consumed energy _______________2. a monosaccharide produced by plants in the process known as photosynthesis _______________3. a type of respiration that does not require oxygen in its chemical reaction _______________4. also known as cellular respiration _______________5. It is where the energy is stored during respiration or break down of food.
Lesson 7.2:
GAS EXCHANGE WITH THE ENVIRONMENT
Objectives: 1. To give the importance of gas exchange 2. To describe how some animals exchange respiratory gases Gas exchange Gas exchange is the process by which oxygen and carbon dioxide (the respiratory gases) move in opposite directions across an organism's respiratory membranes, between the air or water of the external environment and the body fluids of the internal environment. Oxygen is needed by cells to extract energy from organic molecules, such as sugars, fatty acids, and amino acids. Carbon dioxide is produced in the process and must be disposed. Principles of Gas Exchange The random movement of molecules is called diffusion. Although individual molecules move randomly, a substance can have directed movement, or net diffusion. The net diffusion of a substance occurs because of a difference in its concentration, or gradient , along its course. Within an animal's body as oxygen is used up and carbon dioxide produced, the concentration gradient of the two gases provides the direction for their diffusion. For example, as air or water nears the respiratory membrane, the oxygen concentration on the outside of the membrane is higher than on the internal side so oxygen diffuses inward. The concentration gradient for carbon dioxide is in the opposite direction, and so net diffusion of carbon dioxide keeps it diffusing out of the body. The solubility of the respiratory gases in water is low, and the solubility of oxygen is only about one-twentieth that of carbon dioxide. Special transport molecules within body fluids increase the oxygen content by holding oxygen molecules within circulating fluids. These molecules are called respiratory pigments and include hemoglobin , which is red, and hemocyanin, which is blue. These molecules combine with oxygen at the
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respiratory membrane, where oxygen concentrations are relatively high and easily release the oxygen in deeper tissues, which are low in oxygen.
Filaments of a salmon's gills. In fish, water is pumped across gills to enable gas exchange
Gills are respiratory organs that absorb oxygen from water as it flows over the gill surface
Animals with small bodies exchange respiratory gases sufficiently through the body surface without specialized respiratory membranes. Even some vertebrates, such as small, slender salamanders, exchange respiratory gases solely across the skin, which is richly supplied with blood vessels. Larger animals require an extended surface for gas exchange. For most fish, many aquatic invertebrates, and some terrestrial invertebrates the specialized respiratory organs are the gills. In crustaceans, gills are often found where the legs attach to the body; moving the legs sweeps water across the gill surfaces. In fish and some mollusks, gills are ventilated by muscular contractions that pump water across the respiratory surface. Terrestrial animals must protect their respiratory membranes from drying out. Many spiders have book lungs, which are specialized, leaf-shaped, inward folds of the cuticle, surrounded by an air chamber that can be ventilated with muscular contractions. In larger terrestrial insects, the respiratory organs are inward, branching, tubular extensions of the body wall called tracheae. The system is so extensive that most cells are in close proximity to a tracheal branch and the tissues do not depend on blood circulation for gas transport. Terrestrial vertebrates generally have lungs. Endotherms, such as birds and mammals, have a high metabolic rate and a correspondingly high respiratory surface area. Birds have one-way flow through their lungs, enabled by a complex system of airstoring sacs. Mammals, reptiles, and amphibians have saclike lungs with tidal (two way) air flow. This results in residual air remaining in the lungs, reducing the concentration of available oxygen in comparison to bird lungs. Reptile lungs have fewer air sacs and less respiratory surface area than mammals, and amphibian lungs have less surface area than reptilian lungs.
Review Questions:: Identify the word being described by the given statement. _______________1. the 2 respiratory gases _______________2. _______________3. the gas that must be eliminated from the animal’s body _______________4. the respiratory organ of fish that absorbs oxygen _______________5. the spreading of gas molecules
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Lesson 7.3:
CIRCULATION - THE INTERNAL TRANSPORT SYSTEM
Objectives: 1. To differentiate between cardiovascular system and lymphatic system 2. To identify the components of blood 3. To describe the functions of the major components of the circulatory system Circulatory System The circulatory system, also called the cardiovascular system or the vascular system, is an organ system that permits blood to circulate and transport nutrients (such as amino acids and electrolytes), oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body to provide nourishment and help in fighting diseases, stabilize temperature and pH, and maintain homeostasis. Two Separate Systems of the Circulatory System : 1.) cardiovascular system - distributes blood 2.) lymphatic system - circulates lymph Blood is a fluid consisting of plasma, red blood cells, white blood cells, and platelets that is circulated by the heart through the vertebrate vascular system, carrying oxygen and nutrients to and waste materials away from all body tissues. Lymph is essentially recycled excess blood plasma after it has been filtered from the interstitial fluid (between cells) and returned to the lymphatic system. Two Types of Circulatory System 1. open circulatory system - blood moves freely inside the body cavity and soaks the cells with nourishment 2. closed circulatory system - blood is pumped through tube, supplying cells with food and oxygen and carrying away waste products Human circulatory system constitute the following : 1. Heart - a muscular organ located slightly to the left of the middle of your chest ; pumping device for the circulation of blood
2. Blood Vessels a. Veins - take blood back toward your heart b. Arteries - take oxygen-rich blood away from the heart c. Capillaries - are very tiny blood vessels that form a connection between arteries and veins; facilitate the transfer of oxygen, nutrients and wastes in and out of the body 3.Blood - a constantly circulating fluid providing the body with
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nutrition, oxygen, and waste removal Components of blood and their functions : a. Red Blood Cells - take oxygen from the lungs and transport it to the rest of the body cells b. White Blood Cells - fight off germs and give protection from diseases c. Platelets – help in blood clotting d. Plasma – liquid part of the blood
Exercise : True or False. Write T if the statement is correct and F if it is not. _______1. It is the vein that takes away oxygenated blood away from the heart. _______2. The red blood cells defend the body from harmful organisms. _______3. The most dominant part of the blood is the platelets. _______4. The human circulatory system is a closed circulatory system. _______5. Veins are bigger than capillaries.
Lesson 7.4 :
HOMEOSTASIS
Objectives : 1. To describe homeostasis 2. To give examples of homeostasis 3. To give the importance of homeostasis What is homeostasis ? Homeostasis is the property of a system in which variables are regulated so that internal conditions remain stable and relatively constant. Examples of homeostasis include the regulation of temperature and the balance between acidity and alkalinity (pH), water levels, presence of waste, salt and other electrolytes, and metabolism. Human homeostasis is the process that maintains the stability of the human body's internal environment in response to changes in external conditions. Internal components of homeostasis 1. Concentration of oxygen and carbon dioxide 2. pH of the internal environment 3. Concentration of nutrients and waste products 4. Concentration of salt and other electrolytes 5. Volume and pressure of extracellular fluid What is Homeostasis in Animals? The bodies contain billions of cells of all different types that work together for a common cause. They contain many organ systems: the digestive system, the respiratory system, the circulatory system, the nervous system, the skeletal system, etc.
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And all those systems have to stay in balance with each other. In the case of animals like humans, even a small change to the state inside of the body can be deadly. So to prevent this, animals have developed something called homeostasis. Energy balance in the human body The bodies of animals are able to control the flow of energy using neurological and chemical signals. Not only can they control how much of the food they eat is stored as fat, but they can send signals to the that which cause you to fill hungry or full. Temperature Temperature is a very delicate example of homeostasis, especially for warmblooded animals like humans. Warm-blooded animals need an almost constant body temperature. Heat is produced by the liver and muscle contractions, and is a product of metabolizing food. The human body has lots of mechanisms to cool down and heat up. When one feels unusually cold or hot, his internal body temperature hasn't changed much at all - it's just that his body is panicking and trying to cool him off or heat him up. If he get too hot, bodily processes will start working and he will die, so the system is highly sensitive to any changes. Importance of homeostasis of internal fluids to animals Animals expend a significant amount of energy in maintaining homeostatic conditions within the body, including salt and water balance. o Animal tissues have a high water content; insufficient water intake can cause dehydration. o Salts (ions) are essential for many biological functions; they are found in all body fluids. o Salt and water balance are maintained in spite of disturbances during routine bodily processes. Excretory systems assist in the regulation of salt and water balance while removing toxic waste products. o
Most aquatic invertebrates that live in salt water are osmoconformers, but most fish are osmoregulators; marine and freshwater fish face different problems in maintaining a salt/water balance.
Animals that live on land must find fresh water to drink and risk water loss by evaporation. Salts are lost in the sweat of mammals which is essential for cooling the body. o
Osmoregulation Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes (salts in solution) to keep the fluids from becoming too diluted or too concentrated. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the osmotic pressure of a solution, the more water tends to move into it. Pressure must be exerted on the hypertonic side of a selectively permeable membrane to prevent diffusion of water by osmosis from the side containing pure water.
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Kidneys play a very large role in animal osmoregulation by regulating the amount of water reabsorbed from glomerular filtrate in kidney tubules, which is controlled by hormones such as antidiuretic hormone (ADH), aldosterone, and angiotensin II. Therefore, a large proportion of water is reabsorbed from fluid to prevent a fair proportion of water from being excreted.
Exercise : True or False. _____1. Filtered sea water can be used to replenish lost water in the body. _____2. Kidney helps in the removal of toxic waste substance from the human body _____3. Drinks, like Gatorade can restore salts during heavy exercise. _____4. Salt is necessary to maintain the water content in the human body. _____5. A change in the internal state of the human body can be fatal.
Lesson 7.5:
THE IMMUNE SYSTEM
Objectives: 1. To describe the role of white blood cells in the body system 2. To name the components of the immune system IMMUNE SYSTEM The immune system is a complex network of organs containing cells that recognize foreign substances in the body and destroy them. It protects vertebrates against pathogens, or infectious agents, such as viruses, bacteria, fungi, and other parasites. The human immune system is the most complex. The major components of the immune system Lymph nodes - small, bean-shaped structures that produce and store cells that fight infection and disease and are part of the lymphatic system Spleen - the largest lymphatic organ in the body, which is on the left side, under the ribs and above the stomach, contains white blood cells that fight infection or disease Bone marrow - the yellow tissue in the center of the bones produces white blood cells. This spongy tissue inside some bones, contains immature cells, called stem cells, which could morph into any human cell. Lymphocytes - these small white blood cells play a large role in defending the body against disease. The two types of lymphocytes are B-cells , which make antibodies that attack bacteria and toxins, and T-cells, which help destroy infected or cancerous cells. Thymus - this small organ is where T-cells mature. It maintains the production of antibodies that can result in muscle weakness. Leukocytes - these disease-fighting white blood cells identify and eliminate pathogens and protect the body from harmful microorganisms Leukocytes come in two basic types that combine to seek out and destroy disease-causing organisms or substances.
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The two basic types of leukocytes are: 1. phagocytes, cells that chew up invading organisms 2. lymphocytes, cells that allow the body to remember and recognize previous invaders and help the body destroy them Three Kinds of Immunity A. Innate immunity - or natural immunity. Primitive system of defense against pathogens which are possess by all animals . 2 parts of innate immunity a. humoral innate immunity - involves substances found in humors or body fluids which interfere with the growth of pathogens b. cellular innate immunity - is carried out by cells called phagocytes that ingest and degrade pathogens and by so called natural killer cells that destroy certain cancerous cells. B. Passive immunity - is "borrowed" from another source and it lasts for a short time. For example, antibodies in a mother's breast milk give a baby temporary immunity to diseases the mother has been exposed to. This can help protect the baby against infection during the early years of childhood. C. Adaptive immunity – or active immunity ; develops throughout our lives. It Involves the lymphocytes and develops as people are exposed to diseases or immunized against diseases through vaccination. Immune response is the defensive reaction of the adaptive immune system. Adaptive immunity works with innate immunity to provide vertebrates with a heightened resistance to microorganisms, parasites, and other intruders that could harm them. However, adaptive immunity is also responsible for allergic reactions and for the rejection of transplanted tissue, which it may mistake for a harmful foreign invader. How Immune System Works When antigens (foreign substances that invade the body) are detected, several types of cells work together to recognize them and respond. These cells trigger the B lymphocytes to produce antibodies, which are specialized proteins that lock onto specific antigens. Once produced , these antibodies stay in a person's body, so that if his or her immune system encounters that antigen again, the antibodies are already there to do their job. So if someone gets sick with a certain disease, like chickenpox, that person usually won't get sick from it again. This is also how immunizations prevent certain diseases. An immunization introduces the body to an antigen in a way that doesn't make someone sick, but does allow the body to produce antibodies that will then protect the person from future attack by the germ or substance that produces that particular disease.
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T-cells (a type of lymphocyte attacking a cancer cell
Exercise : Identify the word being described below. ________________1. It is the body's defense against infectious organisms and other invaders. ________________2. It is the antibody present in mother’s milk. ________________3. They are also known as leucocytes. ________________4. immunity that is only temporary ________________5. leukocytes that engulf or eat pathogens
Lesson 7.6 :
NERVOUS SYSTEM
Objectives : 1. To describe the functions of neuron and glial cells 2. To identify the parts of the human nervous system Nervous system The nervous system is the part of an animal's body that coordinates its voluntary and involuntary actions and transmits signals to and from different parts of its body. Animals with a defined head possess a two-part nervous system: 1. the central nervous system (CNS) consists of the animal's brain and spinal cord 2 the peripheral nervous system (PNS) consists of all the nerves that travel from the CNS to the rest of the animal's body How the nervous system works The nervous system contains two main categories or types of cells: neurons and glial cells. The nervous system receives the stimuli, sends messages about the stimuli to different parts of the body, interprets what the stimuli mean to the organism’s existence, and coordinates the organism’s response or reaction to the stimuli. The receptor - effector mechanism is the simplest system that allows a simple organism’s body to coordinate its reaction to a stimuli. Insects and worms have ganglia, highly developed neurons, which are true message centers, and from which central nervous system evolved. In other vertebrates and humans, the nervous system comprised the central nervous system and the peripheral nervous system. The nervous system is defined by the presence of a special type of cell, called the neuron, also known as a "nerve cell". Neurons have special structures that allow them to send signals rapidly and precisely to other cells. They send these signals in the form of electrochemical waves travelling along thin fibers called axons, which cause
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chemicals called neuro-transmitters to be released at junctions called synapses. A cell that receives a synaptic signal from a neuron may be excited, inhibited, or otherwise modulated. The connections between neurons can form neural circuits and also neural networks that generate an organism's perception of the world and determine its behavior. Along with neurons, the nervous system contains other specialized cells called glial cells which provide structural and metabolic support. Among the most important functions of glial cells are to support neurons and hold them in place; to supply nutrients to neurons; to insulate neurons electrically; to destroy pathogens and remove dead neurons; and to provide guidance cues directing the axons of neurons to their targets.Glial cells are the most abundant cell types in the central nervous system. Types of glial cells include oligodendrocytes, astrocytes, ependymal cells, Schwann cells, microglia, and satellite cells. Parts and Functions of the Brain : 1. cerebral cortex – analyzes data, learn new information, form thoughts, make decisions 2. corpus collosum - communication between the left and right hemisphere 3. frontal lobe – cognition and memory 4. hypothalmus – controls maintenance functions such as eating 5. temporal lobe – auditory reception and interpretation 6. pituitary gland – master endocrine gland 7. pons – controls arousal and regulates respiration 8. medulla – controls heartbeat and breathing 9. spinal cord – controls simple reflexes 10.parietal lobe – body orientation 11.thalamus – relays messages between lower brain centers and cerebral cortex 12.cerebellum – coordinates voluntary movement and balance
Exercise : Fill in the blank with the correct answer. 1. Among the nervous system cells, ____________ cells are the most abundant . 2. The central nervous system consists the __________ and the ____________. 3. Signals are send to the other cells by _________________________________. 4. Neuron cells are hold in their position by ______________________________. 5. The peripheral nervous system is made up of ___________________________.
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Lesson 7.7 :
BODY IN MOTION
Objectives : 1. To describe the functional relationship of the muscular and skeletal system 2. To be familiarized with the parts of the muscular and skeletal system Muscular System The muscular system is an organ system consisting of skeletal, smooth and cardiac muscles. It permits movement of the body, maintains posture, and circulates blood throughout the body. The muscular system in vertebrates is controlled through the nervous system, although some muscles (such as the cardiac muscle) can be completely autonomous. Together with the skeletal system it forms the musculoskeletal system, which is responsible for movement of the human body. Muscles Muscle tissues are formed from specialized cells called muscle fibers that joined together to constitute the muscular system. These tissues are tough and elastic and their predominant function is contractibility. Muscles, attached to the bones or internal organs and blood vessels, are responsible for movement. Nearly all movement in the body is the result of muscle contraction. Muscles could either be voluntary or involuntary. Involuntary muscles ( nonstriated )are muscles that cannot be controlled by the conscious thought of the organism while voluntary muscles ( striated muscles )can be. Examples of non-striated muscles are the heart and the smooth muscles. Hand and leg muscles are striated muscles. There are approximately 639 skeletal muscles in the human body. Importance of muscles Muscles provide strength, balance, posture, movement and heat for the body to keep warm. The integrated action of joints, bones, and skeletal muscles produces obvious movements such as walking and running. Skeletal muscles also produce more subtle movements that result in various facial expressions, eye movements, and respiration. Three types of muscles : A. Smooth muscle - found lining the walls of blood vessels, visceral organs (such as the digestive tract and uterus) and are also found attached to hairs in the integument B. Cardiac muscle - are found solely in the musculature of the heart wall - cardiac muscle does not fatigue readily, which is a desirable trait in the muscles that maintain circulation of blood C. Skeletal muscle - skeletal muscles are closely associated with the skeleton and are used in
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locomotion - fibers are closely associated with connective tissues and are under voluntary control by the nervous system - there are approximately 639 skeletal muscles in the human body Skeletal System Skeletal system is the system of bones, associated cartilages and joints of human body. Together these structures form the human skeleton. Skeleton can be defined as the hard framework of human body around which the entire body is built. Almost all the hard parts of human body are components of human skeletal system. Joints are very important because they make the hard and rigid skeleton allow different types of movements at different locations. Functions of human skeleton: Human skeleton performs some important functions that are necessary for survival of human beings. 1. STRENGTH, SUPPORT AND SHAPE: It gives strength, support and shape to the body. Without a hard and rigid skeletal system, human body cannot stand upright, and it will become just a bag of soft tissues without any proper shape. 2. PROTECTION OF DELICATE ORGANS: In areas like the rib cage and skull, the skeleton protects inner soft but vital organs like heart and brain from external shocks. Any damage to these organs can prove fatal, therefore protective function of skeleton is very important. 3. LEVERAGE FOR MOVEMENTS: Bones of the human skeleton in all parts of body provide attachment to the muscles. These muscles provide motor power for producing movements of body parts. In these movements the parts of skeleton acts like levers of different types thus producing movements according to the needs of the human body. 4. PRODUCTION OF RED BLOOD CELLS: Bones like the sternum, and heads of tibia have hemopoeitic activity (blood cells production). These are the sites of production of new blood cells. Main parts of skeleton There are two main parts of the skeleton: 1. Axial skeleton - includes the skull, the spine and the ribs and sternum ; has 80 bones Skull - includes bones of the cranium, face, and ears (auditory ossicles) Hyoid - U-shaped bone or complex of bones located in the neck between the chin and larynx Vertebral Column - includes spinal vertebrae Thoracic Cage -includes ribs and sternum (breast bone) 2. Appendicular skeleton - includes the bones of the limbs, the shoulder girdle, and pelvic girdle ;has 126 bones Pectoral Girdle - includes shoulder bones (clavicle and scapula) Upper Limbs - includes bones of the arms and hands
Pelvic Girdle - includes hip bones
Lower Limbs - includes bones of the legs and feet
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Parts of the Skeleton
Parts of the Skull
Skeleton Components The skeleton is composed of fibrous and mineralized connective tissues that give it firmness and flexibility. It consists of the following : 1. Bone - a type of mineralized connective tissue that contains collagen and calcium phosphate, a mineral crystal. Calcium phosphate gives bone its firmness. Bone tissue may be compact or spongy. Bones provide support and protection for body organs. 2. Cartilage - a form of fibrous connective tissue that is composed of closely packed collagenous fibers in a rubbery gelatinous substance called chondrin. Cartilage provides flexible support for certain structures in adult humans including the nose, trachea, and ears. 3. Tendon - a fibrous band of connective tissue that is bonded to bone and connects bone to bone. 4. Ligament - a fibrous band of connective tissue that joins bones and other connective tissues together at joints. 5. Joint - a site where two or more bones or other skeletal components are joined together. Animal locomotion and its importance Locomotion is any of a variety of movements or methods that animals use to move from one place to another. Some modes of locomotion are self-propelled, e.g., running, swimming, and flying. There are also many animal species that depend on their environment for transportation, a type of mobility called passive locomotion, e.g., rolling (some beetles). Animals move to find food, a mate, a suitable habitat, to escape predators and for survival. Different media for locomotion
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Animals move through four types of environment : aquatic (in or on water ) , terrestrial (on ground or other surface), fossorial (underground), and aerial (in the air).
CHAPTER TEST: Identify the word being described by the given statement. _______________1. muscles that cannot be controlled consciously by an organism _______________2. the framework of the human body _______________3. a fibrous tissue that connects bone to bone _______________4. give shape to the body _______________5. It is where the new blood cells are produced. _______________6. the hard protective covering of the brain _______________7. It is made up of collagen and calcium phosphate. _______________8. It pertains to bones of the arms and hands. _______________9. the part of the brain that is responsible for cognition and memory ______________10. part of the brain that controls heartbeat and breathing ______________11. immunity develops throughout our lives ______________12. It is used to store energy obtained from nutrients. ______________13. the system in the circulatory that distributes blood ______________14. blood vessels that take oxygen-rich blood away from the heart ______________15. It is the measure of the tendency of the water to move into one solution from another by osmosis.
CHAPTER 8: Lesson 8.1:
HOW PLANTS SURVIVE
PLANT FORM AND FUNCTION
Objectives : 1. To identify the parts of a plant 2. To describe the function of the different plant organs Hierarchy of cellular architecture of living organisms At the lowest level are cells o Example: Parenchyma, Sclerenchyma, vessel elements
Cells are organized together to form tissues o
Example: xylem, phloem
Tissues are organized together to form organs (two or more tissues performing specific functions) o
Example: Leaves, stamens
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Organs are organized together to form organ systems o
Example: Flowers, shoots
Plant Cells and Tissues A mature vascular plant (any plant other than mosses and liverworts), contains several types of differentiated cells. These are grouped together in tissues. Some tissues contain only one type of cell. Some consist of several. A. Meristematic tissues – the main function is mitosis . The cells are small, thin-walled, with no central vacuole and no specialized features. It is located at the growing points of roots and stems. B. Protective tissues– cover the surface of leaves and the living cells of roots and stems. Its cells are flattened with their top and bottom surfaces parallel. The upper and lower epidermis of the leaf are examples of protective tissue.
C. Parenchyma cells – large, thin-walled, and usually have large central vacuole. They are often partially separated from each other and are usually stuffed with plastids. In areas not exposed to light, colorless plastids predominate and food storage is the main function.
D. Sclerenchyma – the walls of these cells are very thick and built up in a uniform layer around the entire margin of the cell. Often, the cells dies after its all wall was fully formed. Sclerenchyma cells give mechanical support to other cells types.
E. Collenchyma cells –have thick walls that are specially thick at their corners. These cells provide mechanical support for the plant. They are found in areas that are growing rapidly and need to be strengthened. The petiole of leaves is usually reinforced with collenchyma.
F. Xylem – conducts water and dissolved minerals from the roots to all the other parts of the plants. These are thick-walled tubes that can extend vertically through several feet of xylem tissues. It gives strength to a trunk. G. Phloem – transport sugars from one part to another. It is made of sieve tube elements and companion cells.
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Longitudinal section (companion cell and sieve tube)
Vascular bundle showing the xylem and the phloem
Plant Organ Systems In plants, just as in animals, similar cells working together form a tissue. When different types of tissues work together to perform a unique function, they form an organ; organs working together form organ systems. Vascular plants have two distinct organ systems: a shoot system and a root system . The shoot system consists of two portions: the vegetative (non-reproductive) parts of the plant, such as the leaves and the stems; and the reproductive parts of the plant, which include flowers and fruits. The shoot system generally grows above ground, where it absorbs the light needed for photosynthesis. The root system, which supports the plants and absorbs water and minerals, is usually underground. Shoot system A. Vegetative part 1. Leaf – is an organ of a vascular plant and is the principal lateral appendage of the stem . The plant leaf is an organ whose shape promotes efficient gathering of light for photosynthesis. The form of the leaf must also be balanced against the fact that most of the loss of water a plant might suffer is going to occur at its leaves (transpiration). Leaves are extremely variable in terms of their size, shape, and adornments (such as small hairs on the face of the leaf). Although the leaves of most plants carry out the same basic functions, there is nonetheless an amazing variety of leaf sizes, shapes, margin types, forms of attachment, ornamentation , and color. Parts of a leaf : midrib a. apex – the tip of the blade b. margin – the surrounding edge of the blade c. vein – the slender structure branching from the midrib d. base – the lower part of the blade where midrib starts e. petiole – the stalk which attaches the blade to the stem f. stipule – leaf-like structure arising from the lower part of the petiole g. midrib - the slender structure dividing the blade into right half and left half 2. Stem – is the part of the plant that holds up other structures such as the leaves and flowers. It conducts water and food substances through the xylem and phloem. (cross-section of stem) Internal Features of Stem Apical meristem – Tissues at the tip of a stem capable of cell division, gives rise to
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stem elongation. Epidermis – Outer layer of wax-coated cells that provides protection and covering. Cortex – Primary tissues of a stem externally bound by the epidermis and internally by the phloem. Vascular bundle : Xylem tissues – Distribute water and minerals from the roots up through the plant. Xylem provides the structural support in plants, becoming the “woody ” tissue. Cambium tissues are the single-celled layer of meristematic (dividing) tissues that continually divides to form phloem tissues toward the outside and xylem tissues toward the inside. Cell division of the cambium tissue adds width to the stem. Phloem tissues (inner bark) – distribute sugars ( products of photosynthesis ) throughout the plant. It is important to understand what happens when the phloem is blocked, as when a tree is girdled with a tie or rope. The stem often enlarges just above the blockage due to the sugars moving down from the leaves cross-section of for distribution throughout the plant. Tissues stem below the blockage slowly starve. Roots die back, eventually leading to death of the plant. Pith – Center of dicot plant stems. In some plants the pith breaks down forming a hollow stem. In older woody plants, the pith is filled with rigid xylem wood fiber. Monocot or Dicot Monocot and dicot stems differ in the arrangement of their vascular system. In monocot stems, the xylem and phloem are paired in bundles, with bundles dispersed throughout the stem. Monocot and dicot stems differ in the arrangement of their vascular system . In monocot stems, the xylem and phloem are paired in bundles, with bundles dispersed throughout the stem.
monocot stem cross-
In woody dicot plants, the rings grow to make a complete ring around the stem. Xylem growth makes the “annual rings” used to tell a tree’s age. In woody dicot plants, water and mineral movement occurs in the more recent years of xylem rings. Drought reduces the size of the annual rings ( size of xylem tubes ) and thus the potential for water and nutrient movement. Multi-year droughts, with their corresponding reduction in xylem size , have long-term impacts on plant growth potential. cross-section of dicot stem
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Left: herbaceous/ Right: woody Woody dicot stems are used in tree and shrub identification. Features to look at include the cross section shape of the pith ( rounded, star, or triangular) and whether the pith is solid, hollow, or chambered. Stem pith is used in plant identification. It may be solid, hollow or chambered .In a cross-section, the pith may be rounded, triangular or star shaped. External Features of Stem Bud – A stem's primary growing point. Buds can be either leaf buds (vegetative) or flower buds (reproductive). These buds can be very similar in appearance, but flower buds tend to be plumper than leaf buds. Terminal bud – Bud at the tip of a stem. In many plants, auxin (a plant hormone) released from the terminal bud suppresses development of lateral buds, thereby focusing the growth of the plant upward rather than outward. If the terminal bud is removed during pruning (or natural events) the lateral buds will develop and the stem becomes bushy. Lateral buds – grow from the leaf axils on the side of a stem. Bud scales – a modified leaf protecting and covering a bud Naked bud – bud without a protective bud scale Leaf scar – Mark left on stem where leaf was attached. Often (External features of stem) used in woody plant identification. Bundle scar – Marks left in the leaf scar from the vascular tissue attachment. Used in woody plant identification. Lenticel – Pores that allow for gas exchange. Terminal bud scale scars or annual growth rings – Marks left on stem from the terminal bud scales in previous years. Terminal bud scale scars are an external measure of annual growth. Therefore, they are important in assessing plant vigor. Node – Segment of stem where leaves and lateral buds are attached. Internode – Section of a stem between two nodes. Bark – Protective outer tissue that develops with age. Used in woody plant identification.
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Node and Internode
Terminal bud scars or annual growth rings
Bud type The type of bud is also used in plant identification.
Common Types of Stems Woody Plants: Shoot – First year growth on a woody or herbaceous plant. Twig – Woody stem less than one year old. Branch – Woody stem more than one year old. Trunk – Main support stem(s) of woody plants. Water sprouts – Juvenile adventitious shoots arising on a branch. Generally very rapid, upright-growth, and poorly attached to the main limb. Suckers – Juvenile adventitious shoots arising from the roots, generally rapid, uprightgrowing. Canes – Stems with relatively large pith and usually living for only one to two years (roses, grapes, blackberries, and raspberries).
Modified Stems: Bulb – Thickened, underground stem with fleshy storage leaves attached at base (lilies, onions) Corm – Short, thickened, underground stem with reduced scaly leaves (gladiolus) Crown – Compressed stem having leaves and flowers growing above and roots beneath ( dandelion , strawberry plant, African violet) Stolon (or runner) –Horizontal, above-ground stems often forming roots and/or plantlets at their tips or nodes ( strawberry runners, spider plants) Rhizome – Horizontal, underground stem, typically forms roots and plantlets at tips or nodes (iris, bent grass, cannas)
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Spur – Very compressed, fruiting twig found on some apples, pears, cherries, and ginkgo. Twining stems – Modified stems used for climbing. Some twist clockwise (hops, honeysuckle); others twist counter-clockwise (pole beans, Dutchman’s pipe). Tuber – Enlarged rhizome containing stored food. (The “eyes” of an Irish potato are the modified buds.) Tuberous stem – Short, flattened, modified storage stem (tuberous begonias, dahlias). Unlike tubers, which have buds scattered all over, tuberous stems only have leaf buds on the "up" end. B. Reproductive part 1. Flower- is the reproductive organ of plants classified as angiosperms. All plants have the means and corresponding structures for reproducing sexually. The basic function of a flower is to produce seeds through sexual reproduction. Seeds are the next generation, and serve as the primary method in most plants by which individuals of the species are dispersed across the landscape. Structure of a Flower : Pistil – Central female organ of the flower. It is generally bowling-pin shaped and located in the center of of the flower. Stigma – receives pollen, typically flattened and sticky Style – connective tissues between stigma and ovary Ovary – contains ovules or embryo sacs Ovules – unfertilized, immature seeds Stamen – male flower organ Anthers – pollen-producing organs Filament – stalk supporting anthers Petals – Usually colorful modified leaves that make up the “flower”, collectively called the corolla. They may contain perfume and nectar glands. Sepals – Protective leaf-like enclosures for the flower buds, usually green, collectively called calyx. Sometimes highly colored like the petal as in iris. Receptacle – base of the flower Pedicel – flower stalk of an individual flower Monocot or Dicot Flower The number of sepals and petals is used in plant identification. Dicots typically have sepals and petals in fours , fives , or multiples thereof. Monocots typically have flower parts in threes or multiples of three. Terms Defining Flower Parts
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Complete flower is a flower containing sepals, petals, stamens, and pistil while Incomplete flower lacks those parts. Perfect flower contains male and female parts while imperfect flower lacks either male or female parts. Pistillate flower contains only female parts while staminate flower contains only male parts. 2. Fruit. Fruit evolves from the maturing ovary following pollination and fertilization. Fruits can be either fleshy or dry. They contain one or more seeds. It is the structural part that typically surrounds the seed which contains the germ of life of the next generation. Fruit is the actual agent of dispersal in most flowering plants. Fruit Structure Fruit consists of carpels where the ovules (seeds) develop and the ovary wall or pericarp, which may be fleshy (as in apples) or dry and hard (as in an acorn). Some fruits have seeds (mature ovules) enclosed within the ovary (apples, peaches, oranges, squash and cucumbers). The peel of an orange, the pea pod, the sunflower shell, and the skin flesh and pit of a peach are all derived from the pericarp. Other fruit have seeds that are situated on the periphery of the pericarp (corncob, strawberry flesh).
In apples, the ovary wall becomes the fleshy part of the fruit. Notice the small fruit structure in the blossom. Fruit Types : Fruits are classified according to the arrangement from which they derive. There are four types — simple, aggregate, multiple, and accessory fruits. Simple fruits develop from a single ovary of a single flower and may be fleshy or dry. Principal fleshy fruit types are the berry, in which the entire pericarp is soft and pulpy (e.g., the grape, tomato, banana, hesperidium, and blueberry) and the drupe, in which the outer layers may be pulpy, fibrous, or leathery and the endocarp hardens into a pit or stone enclosing one or more seeds (e.g., the peach, cherry, olive, coconut, and walnut). An aggregate fruit (e.g., blackberry and raspberry) consists of a mass of small drupes (drupelets), each of which developed from a separate ovary of a single flower. A multiple fruit (e.g., pineapple and mulberry) develops from the ovaries of many flowers growing in a cluster. Accessory fruits contain tissue derived from plant parts other than the ovary; the strawberry is actually a number of tiny achenes (miscalled seeds) outside a central pulpy pith that is the enlarged receptacle or base of the flower. The core of the pineapple is also receptacle (stem) tissue. The best-known accessory fruit is the pome (e.g., apple and pear), in which the fleshy edible portion is swollen stem tissue and the true fruit is the central core. Fruit Growth Terms :
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Bud development – On temperate-zone woody plants, buds typically develop midsummer of the previous year. An exception is on summer flowering shrubs, where the buds develop on the current season’s wood. Pollination – Transfer of pollen from the male flower to the stigma of the female flower. Fertilization – Union of the pollen grain from the male flower with the egg cell in the female flower. Seed A seed (mature ovule) is a miniature plant with a protective cover in a suspended state of development. Most seeds contain a built-in food supply called endosperm (orchid is an exception). The endosperm can be made up of proteins, carbohydrates or fats. Seed Structure Seeds of monocots and dicots differ in structure and method of emergence. Monocot Seed : Parts and Functions Seed coat – Formed from the wall of the embryo sack (mother tissue) Endosperm – Food supply containing 3 sets of chromosomes (2 from the mother and 1 from the father) Embryo – Immature plant Cotyledon – Seed leaf Plumule – Shoot Radicle – Root Dicot Seed : Parts and Functions Seed coat – Formed from embryo sack wall and endosperm tissue (During development, the endosperm stops dividing and is absorbed into the embryonic tissues.) Embryo – Immature plant Cotyledon – Food storing seed leaf Plumule – Shoot Hypocotyl – Stem Radicle – Root
Cross-section of a monocot seed ( corn )
Cross-section of dicot seed ( bean )
Root System The roots are the beginning of the vascular system pipeline that moves water and minerals from the soil up to the leaves and fruits. Roots anchor and support plants. To function, roots must have adequate levels of soil oxygen. Soil compaction or waterlogged soil reduces soil oxygen levels, kills roots and lead to a shallow root system. Root Structure : Epidermis – The outer layer of cells Root hairs – Absorptive unicellular extensions of epidermal cells of a root. These tiny, hair-like structures function as the major site of
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water and mineral uptake. Root hairs are extremely delicate and subject to desiccation. Root hairs are easily destroyed in transplanting. Cortex – Primary tissues of a root bound on the outside by the epidermis and on the inside by the endodermis. In a carrot, the cortex becomes a storage organ. Endodermis – A single layer of cells in a root that separates the cortex tissues from the pericycle. Pericycle – A layer of cells immediately inside the endodermis. Branch roots arise from the pericycle. Vascular system : Phloem tissue conducts products of photosynthesis from leaves throughout plant including down the roots. Xylem tissue conducts water and minerals up from the roots up through the plant. Zone of Maturation - Pipeline section of the roots, conducting water and nutrients from the root hairs up to the stems. Zone of elongation –Area where new cells are enlarging.
Cross-section of root
lateral view of root
Meristematic zone : Root tip meristem – Region of cell division that supports root elongation, found at the root tips just behind the root cap. Root cap – A thimble-shaped group of thick-walled cells at the root tip serves as a “hard hat” to push though soil. The root cap protects the tender meristem tissues. Types of Roots : Fibrous – Profusely branched roots that occupy a large volume of shallow soil around a plant's base (petunias, beans, peas). Taproot – Main, downward- growing root with limited branching, where soils permit (carrots, beets, radishes). Combination –In nursery production the taproot of young plants (like oaks) is cut, forcing a fibrous growth pattern. This has a significant impact on the plant’s ability to survive transplanting. Adventitious roots - arise at an unexpected place. For example, the brace roots on corn and the short whitish bumps along a tomato stem are adventitious roots. Aerial roots - arise from above-ground stem tissues. Aerial roots support the vine on English ivy and poison ivy. Lateral root – Side root Sinker roots - make a sharp dive into deeper soils, following soil cracks where oxygen is available. Sinker roots are common on some tree species. Storage or Tuberous root – Enlarged roots that serve as storage organs. (Canadian thistle, morning glory, sweet potato, dahlia).
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Exercise : Identify the word that is being described by the given statement. _______________1. the part of the plant that makes food _______________2. It is the colorful part of the plant that attracts bees and other insects. _______________3. conducts water and dissolved minerals from the roots to all other parts of the plants _______________4. It is the actual agent of dispersal in most flowering plants. _______________5. the hard protective covering of the seed
Lesson 8.2:
Plant Growth and Development
Objectives: 1. To describe the difference between photosynthesis, respiration, and transpiration 2. To differentiate light reaction from dark reaction 3. To identify the factors needed in food production by plants Major plant functions that are the basics for plant growth and development are photosynthesis, respiration, and transpiration. Photosynthesis One of the major differences between plants and animals on earth is the ability of plants to internally manufacture their own food. To produce food for itself a plant requires energy from sunlight, carbon dioxide from the air and water from the soil. If any of these ingredients is lacking, photosynthesis, or food production, will stop. If any factor is removed for a long period of time, the plant will die. Photosynthesis literally means "to put together with light." Any green plant tissue is capable of photosynthesis. Chloroplasts in these cells contain the green pigment called chlorophyll which traps the light energy. However leaves are generally the site of most food production due to their special structure. The internal tissue (mesophyll l) contains cells with abundant chloroplasts in an arrangement that allows easy movement of water and air. The protective upper and lower epidermis (skin) layers of the leaf include many stomata that are openings in the leaf formed by two specialized guard cells on either side. Guard cells regulate movement of the gases, (i.e. CO2 into and O2 and H2O out of the leaf), involved in photosynthesis. The lower epidermis of the leaf normally contains the largest percentage of stomata. Photosynthesis is the process of turning the energy of sunlight into chemical energy from the raw products of CO 2 and H2O. This process is necessary to sustain nearly all forms of life. Photosynthesis is divided in to two separate reactions known as the light and dark reactions.
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light
Carbon Dioxide + Water
light
Sugar + Oxygen
6CO2 + 6H2O C6H12O6 + 6O2 (Photosynthesis Reaction) Light Reaction Light reaction takes place when light is present but the dark reaction does not require light. The whole process is begun by light reacting with pigments in the leaf causing the splitting of water molecules. This is called photolysis or the Hill Reaction which is not completely understood. Three products are produced in this reaction. Electrons from the hydrogen molecules and remaining H + ions are used to form two separate energy storage molecules. The air we breathe is from the remaining oxygen portion of H2O. The carbon dioxide molecules are transformed into sugars during the dark reaction using the energy that was formed during the light reaction. Dark Reaction This reaction does not require light. This part of the photosynthetic process is called the Calvin Cycle. With one cycle of this reaction 3 carbon atoms are fixed or placed in a sugar molecule. This pathway is called C-3 photosynthesis. This is the way that most dicots or broadleaf plants make sugars during the dark reaction. The disadvantage of this process is that oxygen competes with CO 2 for a binding site during the dark reaction. Sometimes sugars are not formed, but energy is still expended to complete the cycle. This is called photorespiration. Another dark reaction pathway is called C-4 photosynthesis because 4 carbons are fixed or placed in a sugar molecule each time the cycle is completed. The dark reaction of C-4 photosynthesis occurs inside of specialized parts of leaf cells in the leaf called the bundle sheath, which exclude the presence of O2. Because there is no oxygen present photorespiration does not occur. The C-4 photosynthetic pathway is what occurs in most monocots or grasses. This is a more efficient pathway and allows grasses to grow faster than broadleaf plants. Crassulacean acid metabolism or CAM photosynthesis is the dark reaction type found in many cactus, succulents, bromeliads, and orchids as well as a few other plants. CAM photosynthesis is similar to C-4 photosynthesis. However, CAM plants open their stomata only during the night to collect CO2, when air temperatures are cooler, thus conserving water because of reduced transpiration. The CO2 is converted into malic acid and then converted back to CO 2 during the day when light is present, thus producing sugars, while the stomata are closed and greatly reducing water loss.
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Plants convert the energy from light into simple sugars, such as glucose. This food may be converted back to water and carbon dioxide, releasing the stored energy through a process called respiration. This energy is required for growth in nearly all organisms. Simple sugars are also converted to other sugars and starches ( carbohydrates ) which may be transported to the stems and roots for use or storage, or they may be used as building blocks for more complex structures like oils, pigments, etc. Photosynthesis is dependent on the availability of light. As sunlight increases in intensity photosynthesis increases. Water plays an important role in photosynthesis in several ways. First, it maintains a plant's turgor or the firmness or fullness of plant tissue. Water pressure or turgor is needed in plant cells to maintain shape and ensure cell growth. Second, water is split into hydrogen and oxygen by the energy of the sun that has been absorbed by the chlorophyll in the plant leaves. The oxygen is released into the atmosphere and the hydrogen is used in manufacturing carbohydrates. Third, water dissolves minerals from the soil and transports them up from the roots and throughout the plant, where they serve as raw materials in the growth of new plant tissues. Water is pulled through the plant by evaporation of water through the leaves (transpiration). Respiration Carbohydrates made during photosynthesis are of value to the plant when they are converted into energy. This energy is used in the process of building new tissues. The chemical process by which sugars and starches produced by photosynthesis are converted into energy is called respiration. It is similar to the burning of wood or coal to produce heat or energy. This process in cells is shown most simply as:
C6H12O6 + 6O2 Sugar + Oxygen
6CO2 + 6H2O + Energy Carbon Dioxide + Water
( Respiration Reaction ) This equation is precisely the opposite of that used to illustrate photosynthesis, although more is involved than just reversing the reaction. However, it is appropriate to relate photosynthesis to a building process, while respiration is a breaking-down process. . Unlike photosynthesis, respiration occurs at night as well as during the day. Respiration occurs in all life forms and in all cells. The release of accumulated carbon dioxide and the uptake of oxygen occurs at the cell level. In plants there is simple diffusion into the open spaces within the leaf and exchange occurs through the stomata. Transpiration Transpiration is the process by which a plant loses water, primarily through leaf stomata. Transpiration is a necessary process that involves the use of about 90% of the water that enters the plant through the roots. The other 10% of the water is used in chemical re-actions and in plant tissues. Transpiration is necessary for mineral transport from the soil to the plant for the cooling of the plant through evaporation, to move sugars and plant chemicals, and for the maintenance of turgor pressure. The
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amount of water lost from the plant depends on several environmental factors such as temperature, humidity and wind or air movement. An increase in temperature or air movement decreases relative humidity and causes the guard cells in the leaf to shrink, opening the stomata and increasing the rate of transpiration. REVIEW TEST: Identify the word being described by the given statement. _______________1. the loss of water vapor through the stomata of leaves _______________2. the reverse of photosynthesis _______________3. by-product of photosynthesis _______________4. the green pigment of leaf that traps the solar energy _______________5. used for the exchange of gases to and from the leaf _______________6. the products of respiration reaction _______________7. _______________8. energy from light is converted into what compound by plants _______________9. also known as Calvin Cycle ______________10. the transfer of pollen from the male flower to the stigma of the female flower
CHAPTER 9: THE PROCESS OF EVOLUTION Lesson 9.1:
Evidence of Evolution
Objectives: 1. To cite evidences that support evolution 2. To explain how populations of organisms have changed and continue to change over time What Is Evolution? Biological evolution is genetic change in a population from one generation to another. The speed and direction of change is variable with different species lines and at different times. Continuous evolution over many generations can result in the development of new varieties and species. Likewise, failure to evolve in response to environmental changes can, and often does, lead to extinction. The result of the massive amount of evidence for biological evolution accumulated over the last two centuries can safely conclude that evolution has occurred and continues to occur. All life forms, including
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humans, evolved from earlier species, and all still living species of organisms continue to evolve today. Evidence of Evolution The evidence for evolution has primarily come from sources like fossil record of change in earlier species, homologies, DNA and protein, the chemical and anatomical similarities or related life forms, the geographic dis-tribution of related species, and the recorded genetic changes in living organisms over many generations. Fossil Record Remains of animals and plants founding sedimentary rock deposits give us an indisputable record of past changes through vast periods of time. This evidence attests to the fact that there has been a tremendous variety of living things. Some extinct species had traits that were transitional between major groups of organisms. Their existence confirms that species are not fixed but can evolve. Geological strata containing into other species over time. The an evolutionary sequence of evidence also shows fossils that what have appeared to be gaps in the fossil record are due to incomplete data collection. The more that we learn about the evolution of specific species lines, the more that these so-called gaps or "missing links in the chain of evolution" are filled with transitional fossil specimens. One of the first of these gaps to be filled was between small bipedal dinosaurs and birds. Just two years after Darwin published On the Origin of Species, a 150-145 mil-lion year old fossil of Archaeopteryx was found in southern Germany. It had jaws with teeth and a long bony tail like dinosaurs, broad wings and feathers like birds, and skeletal features of both. This discovery verified the assumption that birds had reptilian ancestor.
Archaeopteryx fossil
Archaeopteryx recreation
Archaeopteryx tail feathers
Since the discovery of Archaeopteryx, there have been many other crucial evolutionary gaps filled in the fossil record. Perhaps, the most important one, from our human perspective, was that between apes and our own species. Since the 1920's, there have been literally hundreds of well-dated intermediate fossils found in Africa that were transitional species leading from apes to humans over the last 6-7 million years. The fossil record also provides abundant evidence that the complex animals and plants of today were preceded by earlier simple ones. In addition, it shows that multicelled organisms evolved only after the first single-celled ones. This fits the predictions of evolutionary theory. Homology Evolutionary theory predicts that related organisms will share similarities that are derived from common ancestors. Similar characteristics due to relatedness are known as homologies. Homologies can be revealed by comparing the anatomies of different
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living things, looking at cellular similarities and differences, studying embryological development, and studying vestigial structures within individual organisms. If evolution has occurred, there should be many anatomical similarities among varieties and species that have diverged from a common ancestor. Those species with the most recent common ancestor should share the most traits. For instance, the many anatomical similarities of wolves, dogs, and other members of the genus Canis are due to the fact that they are descended from the same ancient canine species and still share 99.8% of their genes. Wolves and dogs also share similarities with foxes, indicating a slightly more distant ancestor with them.
In the following photos of plants, the leaves are quite different from the "normal" leaves we envision.
Each leaf has a very different shape and function, yet all are homologous structures, derived from a common ancestral form. The pitcher plant and Venus' flytrap use leaves to trap and digest insects. The bright red leaves of the poinsettia look like flower petals. The cactus leaves are modified into small spines which reduce water loss and can protect the cactus from herbivory. Genetics One of the strongest evidences for common descent comes from the study of gene sequences. Comparative sequence analysis examines the relationship between the DNA sequences of different species, producing several lines of evidence that confirm Darwin's original hypothesis of common descent. If the hypothesis of common descent is true, then species that share a common ancestor inherited that ancestor's DNA sequence, as well as mutations unique to that ancestor. More closely related species
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have a greater fraction of identical sequence and shared substitutions compared to more distantly related species. The simplest and most powerful evidence is provided by phylogenetic reconstruction. Such reconstructions, especially when done using slowly evolving protein sequences, are often quite robust and can be used to reconstruct a great deal of the evolutionary history of modern organisms (and even in some instances of the evolutionary history of extinct organisms, such as the recovered gene sequences of mammoths or Neanderthals). These reconstructed phylogenies recapitulate the relationships established through morphological and biochemical studies. The most detailed reconstructions have been performed on the basis of the mitochondrial genomes shared by all eukaryotic organisms, which are short and easy to sequence; the broadest reconstructions have been performed either using the sequences of a few very ancient proteins or by using ribosomal RNA sequence. DNA sequencing Comparison of the DNA sequences allows organisms to be grouped by sequence similarity, and the resulting phylogenetic trees are typically congruent with traditional taxonomy, and are often used to strengthen or correct taxonomic classifications. Sequence comparison is considered a mea-sure robust enough to correct erroneous assumptions in the phylogenetic tree in instances where other evidence is scarce. For example, neutral human DNA sequences are approximately 1.2% divergent (based on substitutions) from those of their nearest genetic relative, the chimpanzee, 1.6% from gorillas, and 6.6% from baboons. Genetic sequence evidence thus allows inference and quantification of gene-tic relatedness between humans and other apes. The sequence of the 16S ribosomal RNA gene, a vital gene encoding a part of the ribosome, was used to find the broad phylogenetic relationships between all extant life. The analysis , originally done by Carl Woese, resulted in the three-domain system, arguing for two major splits in the early evolution of life. The first split led to modern Bacteria and the subsequent split led to modern Archaea and Eukaryotes. Some DNA sequences are shared by very different organisms. It has been predicted by the theory of evolution that the differences in such DNA sequences between two organisms should roughly resemble both the biological difference between them according to their anatomy and the time that had passed since these two organisms have separated in the course of evolution, as seen in fossil evidence. The rate of accumulating such changes should be low for some sequences, namely those that code for critical RNA or proteins, and high for others that code for less critical RNA or proteins; but for every specific sequence, the rate of change should be roughly constant over time. These results have been experimentally confirmed. Two examples are DNA sequences coding for rRNA, which is highly conserved, and DNA sequences coding for fibrino peptides (amino acid chains that are discarded during the formation of fibrin), which are highly non-conserved. Proteins The proteomic evidence also supports the universal ancestry of life. Vital proteins, such as the ribosome, DNA polymerase, and RNA polymerase, are found in everything from the most primitive bacteria to the most complex mammals. The core part of the protein is conserved across all lineages of life, serving similar functions. Higher organisms have evolved additional protein subunits, largely affecting the regulation and protein-protein interaction of the core. Other overarching similarities between all lineages of extant organisms, such as DNA, RNA, amino acids, and the lipid bilayer, give support
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to the theory of common descent. Phylogenetic analyses of protein sequences from various organisms produce similar trees of relationship between all organisms. The chirality of DNA, RNA, and amino acids is conserved across all known life. As there is no functional advantage to right- or left-handed molecular chirality, the simplest hypothesis is that the choice was made randomly by early organisms and passed on to all extant life through common descent. Further evidence for reconstructing ancestral lineages comes from junk DNA such as pseudogenes, "dead" genes that steadily accumulate mutations. Evolutionary developmental biology and embryonic development Evolutionary developmental biology is the biological field that compares the developmental process of different organisms to determine ancestral relationships between species. A large variety of organism's genomes contain a small fraction of genes that control the organisms development. Hox genes are an example of these types of nearly universal genes in organisms pointing to an origin of common ancestry. Embryological evidence comes from the development of organisms at the embryological level with the comparison of different organisms embryos similarity. Remains of ancestral traits often appear and disappear in different stages of the embryological development process. Examples include such as hair growth and loss (lanugo) during human development; development and degeneration of a yolk sac; terrestrial frogs and salamanders passing through the larval stage within the egg—with features of typically aquatic larvae—but hatch ready for life on land; and the appearance of gill-like structures (pharyngeal arch) in vertebrate embryo development. Note that in fish, the arches continue to develop as branchial arches while in humans, for example, they give rise to a variety of structures within the head and neck. Chemical and Anatomical Similarities Living things on earth are fundamentally similar in the way that their basic anatomical structures develop and in their chemical compositions. No matter whether they are simple single-celled protozoa or highly complex organisms with billions of cells, they all begin as single cells that reproduce themselves by similar division processes. After a limited life span, they also all grow old and die. All living things on earth share the ability to create complex molecules out of carbon and a few other elements. In fact, 99% of the proteins, carbohydrates, fats, and other molecules of living things are made from only 6 of the 92 most common elements. This is not a mere coincidence. All plants and animals receive their specific characteristics from their parents by inheriting particular combinations of genes. Molecular biologists have discovered that genes are, in fact, segments of DNA molecules in our cells.
(section of a DNA molecule)
(simple protein molecule)
These segments of DNA contain chemically coded recipes for creating proteins by linking together particular amino acids in specific sequences.
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All of the tens of thousands of types of proteins in living things are mostly made of only 20 kinds of amino acids. Despite the great diversity of life on our planet, the simple language of the DNA code is the same for all living things. This is evidence of the fundamental molecular unity of life. In addition to molecular similarities, most living things are alike in that they either get the energy needed for growth, repair, and reproduction directly from sunlight, by photosynthesis or they get it indirectly by consuming green plants and other organisms that eat plants. Many groups of species share the same types of body structures because they inherited them from a common ancestor that had them. This is the case with the vertebrates, which are the animals that have internal skeletons. The arms of humans, the forelegs of dogs and cats, the wings of birds, and the flippers of whales and seals all have the same types of bones (humerus, radius, and ulna) because they have retained these traits of their shared common ancient vertebrate ancestor. All of these major chemical and anatomical similarities between living things can be most logically ac- counted for by assuming that they either share a common ancestry or they came into existence as a result of similar natural processes. These facts make it difficult to accept a theory of special and independent creation of different species. Geographic Distribution of Related Species Another clue to patterns of past evolution is found in the natural geographic distribution of related species. It is clear that major isolated land areas and island groups often evolved their own distinct plant and animal communities. For instance, before humans arrived 60-40,000 years ago, Australia had more than 100 species of kangaroos, koalas, and other marsupials but none of the more advanced terrestrial placental mammals such as dogs, cats, bears, horses. Land mammals were entirely absent from the even more isolated islands that make up Hawaii and New Zealand. Each of these places had a great number of plant, insect, and bird species that were found nowhere else in the world. The most likely explanation for the existence of Australia's, New Zealand's, and Hawaii's mostly unique biotic environments is that the life forms in these areas have been evolving in isolation from the rest of the world for millions of years. Genetic Changes Over Generations The earth's environments are constantly changing, usually in subtle and complex ways. When the changes are so great as to go beyond what most members of a population of organisms can tolerate, widespread death occurs. As Charles Darwin observed, however, not all individuals always perish. Fortunately, natural populations have genetic diversity. Those individuals whose characteristics allow them to survive an environmental crisis likely will be the only ones able to reproduce. Subsequently, their traits will be more common in the next generation--evolution of the population will have occurred. This process of natural selection resulting in evolution can be easily demonstrated over a 24 hour period in a laboratory Petri dish of bacteria living in a nutrient medium. When a lethal dose of antibiotic is added, there will be a mass die-off. However, a few of the bacteria usually are immune and survive. The next generation is mostly immune because they have inherited immunity from the survivors. That is the
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case with the purple bacteria in the Petri dishes shown below--the bacteria population has evolved. This same phenomenon of bacteria evolution actions occurs in our own bodies at times when an antibiotic drug is unable to completely eliminate a bacterial infection. That is the reason that medical doctors are sometimes hesitant to recommend an antibiotic for their patients and insist that the full dosage be used even if the symptoms of ill-ness go away. They do not want to allow any potentially antibiotic resistant bacteria to survive.
speeded up by human
Species that mature and reproduce large numbers in a short amount of time have a potential for very fast evolutionary changes. Insects and microorganisms. Often evolve at such rapid rates that our actions to combat them quickly lose their effectiveness. We must constantly develop new pesticides, antibiotics, and other measures in an ever escalating bio-logical arms race with these creatures. Unfortunately, there are a few kinds of insects and microbes that are now significantly or completely resistant to our counter measures, and some of these species are responsible for devastating crop losses and deadly diseases. Evidence from selection Examples for the evidence for evolution often stem from direct observation of natural selection in the field and the laboratory. This section is unique in that it provides a narrower context concerning the process of selection. All of the examples provided prior to this have described the evidence that evolution has occurred, but has not provided the major underlying mechanism: natural selection. This section explicitly provides evidence that natural selection occurs, has been replicated artificially, and can be replicated in laboratory experiments. Scientists have observed and documented a multitude of events where natural selection is in action. The most well known examples are antibiotic resistance in the medical field along with better-known laboratory experiments documenting evolution's occurrence. Natural selection is tantamount to common descent in that long-term occurrence and selection pressures can lead to the diversity of life on earth as found today. All adaptations—documented and undocumented changes concerned—are caused by natural selection (and a few other minor processes). It is well established that, "...natural selection is a ubiquitous part of speciation...", therefore; henceforth, examples of natural selection and speciation will often interdepend or correspond with one another. The examples below are only a small fraction of the actual experiments and observations. Artificial selection and experimental evolution Artificial selection Artificial selection demonstrates the diversity that can exist among organisms that share a relatively recent common ancestor. In artificial selection, one species is bred selectively at each generation, allowing only those organisms that exhibit desired
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characteristics to repro-duce. These characteristics become increasingly well deve-loped in successive generations. Artificial selection was successful long before science discovered the genetic basis. Examples of artificial selection include dog breed-ing, genetically modified food, flower breeding, and the cultivation of foods such as wild cabbage and others. Experimental evolution Experimental evolution uses controlled experiments to test hypotheses and theories of evolution. In one early example, William Dallinger set up an experiment shortly before 1880, subjecting microbes to heat with the aim of forcing adaptive changes. His experiment ran for around seven years, and his published results were acclaimed, but he did not resume the experiment after the apparatus failed. Evolution Of Man The modern theory concerning the evolution of man proposes that humans and apes derive from an apelike ancestor that lived on earth a few million years ago. The theory states that man, through a combination of environmental and genetic factors, emerged as species to produce the variety of ethnicities seen today, while modern apes evolved on a separate evolutionary pathway. Perhaps the most famous proponent of evolutionary theory is Charles Darwin (1809-82) who authored The Origin of Species (1859) to describe his theory of evolution. It was based largely on observations which he made during his 5-year voyage around the world aboard the HMS Beagle (1831-36). Since then, mankind's origin has generally been explained from an evolutionary perspective. Moreover, the theory of man's evolution has been and continues to be modified as new findings are discovered, revisions to the theory are adopted, and earlier concepts proven incorrect are discarded.
The Chihuahua mix and Great Dane illustrate the range of sizes among dog breeds
Exercise: Identify the word being described by the given statement. ______________1. the remains of once living animals or plants ______________2. the gaps in the fossil records ______________3. He is the Father of evolution. ______________4. the existence of shared ancestry between a pair of structures, or genes, in different taxa 91different kinds of living organisms are ______________5. the process by which thought to have developed and diversified from earlier forms during the history of the earth
Lesson 9.2
The Origin and Extinction of Species
Objectives: 1. To state the theories on the origin of life 2. To cite the causes of extinction of species 3. To recognize the system of classification of organisms Theories on the origin of life Several attempts have been made from time to time to explain the origin of life on earth. As a result, there are several theories which offer their own explanation on the possible mechanism of origin of life. Following are some of them:
Theory of Special Creation According to this theory, all the different forms of life that occur today on planet earth, have been created by God, the almighty. This idea is found in the ancient scriptures of almost every religion. According to Hindu mythology, Lord Brahma, the God of Creation, created the living world in accordance to his wish. According to the Christian belief, God created this universe, plants, animals and human beings in about six natural days. The Sikh mythology says that all forms of life including human beings came into being with a single word of God. Special creation theory believes that the things have not undergone any significant change since their creation. The theory of Special Creation was purely a religious concept, acceptable only on the basis of faith. It has no scientific basis. Theory of Spontaneous Generation ( Abiogenesis ) This theory assumed that living organisms could arise suddenly and spontaneously from any kind of non-living matter. One of the firm believers in spontaneous generation was Aristotle, the Greek philosopher (384-322 BC).He believed that dead leaves falling from a tree into a pond would transform into fishes and those falling on soil would transform into worms and insects. He also held that some insects develop from morning dew and rotting manure. Egyptians believed that mud of the Nile river could spontaneously give rise to many forms of life. The idea of spontaneous generation was
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popular almost till seventeenth century. Many scientists like Descartes, Galileo and Helmont supported this idea. The theory of Spontaneous Generation was disproved in the course of time due to the experiment conducted by Fransisco Redi, (1665), Spallanzani (1765) and later by Louis Pasteur (1864) in his famous Swan neck experiment. This theory was disapproved, as scientists gave definite proof that life comes from pre-existing life. Theory of Catastrophism It is simply a modification of the theory of Special Creation. It states that there have been several creations of life by God, each preceded by a catastrophe resulting from some kind of geological disturbance. According to this theory, since each catastrophe completely destroyed the existing life, each new creation consisted of life form different from that of previous ones. A French scientist Georges Cuvier (1769-1832) and Orbigney (1802 to 1837) were the main supporters of this theory. Cosmozoic Theory (Theory of Panspermia) According to this theory, life has reached this planet Earth from other heavenly bodies such as meteorites, in the form of highly resistance spores of some organisms. This idea was proposed by Richter in 1865 and supported by Arrhenius (1908) and other contemporary scientists. The theory did not gain any support. This theory lacks evidence, hence it was discarded. Theory of Chemical Evolution This theory is also known as Materialistic Theory or Physicochemical Theory. According this theory, Origin of life on earth is the result of a slow and gradual process of chemical evolution that probably occurred about 3.8 billion years ago. This theory was proposed independently by two scientists A.I.Oparin, a Russian scientist in 1923 and J.B.S Haldane, an English scientist, in 1928. According to this theory ; - Spontaneous generation of life, under the present environmental conditions is not possible. - Earth's surface and atmosphere during the first billion years of existence, were radically different from that of today's conditions. - The primitive earth's atmosphere was a reducing type of atmosphere and not oxidizing type. - The first life arose from a collection of chemical substances through a progressive series of chemical reactions. - Solar radiation, heat radiated by earth and lighting must have been the chief energy source for these chemical reactions. Organic Evolution Speciation stretches back over3.5 billion years during which life has existed on earth. It is thought to occur in multiple ways such as slowly, steadily and gradually overtime or rapidly from one long static state to another. Evolution (also known as biological or organic evolution) is the change over time in one or more inherited traits found in populations of organisms. Inherited traits are particular distinguishing characteristics, including anatomical, biochemical or behavioral characteristics, that are
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passed on from one generation to the next. Evolution has led to the diversification of all living organisms, which are described by Charles Darwin as “endless forms most beautiful and most wonderful”. Principles of Evolution I. The Theory of Inheritance of Acquired Characteristics (by Jean Lamarck : 1809 ) Modifications acquired during one’s lifetime are inherited by the next generation, ex. giraffes acquired a long neck slowly over time as each generation of giraffe stretched its neck slightly longer in trying to reach leaves high in trees. At first glance this theory is deceptively close to Darwin’s theory (both include the concept that evolution produces life forms adapted to their environments) but the inheritance of acquired characteristics implies that the organism itself in response to environmental pressures can control the direction of change. Unfortunately, there have been no discoveries of any such mechanism of change. II. The Theory of Evolution by means of Natural Selection Charles Darwin and Alfred Russel Wallace proposed the Theory of Natural Selection independently which is strikingly similar. Darwin worked hard for decades to gather data to support this theory , thus, most of the credits have been given to him. Darwin's theory of evolution is based on key facts and the inferences drawn from them. Darwin’s process of natural selection has four components. 1. Variation. Organisms (within populations) exhibit individual variation in appearance and behavior. These variations may involve body size, hair color, facial markings, voice properties, or number of offspring. On the other hand, some traits show little to no variation among individuals—for example, number of eyes in vertebrates. 2. Inheritance. Some traits are consistently passed on from parent to offspring. Such traits are heritable, whereas other traits are strongly influenced by environmental conditions and show weak heritability. 3. High rate of population growth. Most populations have more offspring each year than local resources can support leading to a struggle for resources. Each generation experiences substantial mortality. 4. Differential survival and reproduction. Individuals possessing traits well suited for the struggle for local resources will contribute more offspring to the next generation.
Beak variations in finches Darwin
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Evolution of the horse family
Observed in the Galapagos Island
From one generation to the next, the struggle for resources (what Darwin called the “struggle for existence”) will favor individuals with some variations over others and thereby change the frequency of traits within the population. This process is natural selection. The traits that confer an advantage to those individuals who leave more offspring are called adaptations. In order for natural selection to operate on a trait, the trait must possess heritable variation and must confer an advantage in the competition for resources. If one of these requirements does not occur, then the trait does not experience natural selection. (We now know that such traits may change by other evolutionary mechanisms that have been discovered since Darwin’s time.) What is Extinction ? Extinction is the end of an organism or of a group of organisms (taxon), normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. Many factors are driving an unprecedented rate of extinction of plant and animal species worldwide. Although extinction is a natural process, the rate at which current extinction is taking place is clearly not, and all scientific evidence indicates that the activities of man- kind are the primary engine behind most recent and present extinction events Major causes of extinction Habitat Loss Destructive change to environments or landscapes, either through natural phenomena (such as floods, volcanoes, hurricanes etc.), or human processes (such as construction, deforestation, changing land use for agriculture, artificial land drainage etc.), is the single greatest threat to the biodiversity of Planet Earth, and the greatest cause of extinction in our world. When a plant or an animal does not have a habitat, and cannot adapt to a different environment, it will become extinct. Unregulated or Illegal Killing, Hunting or Poaching Hunting and poaching rare plants and animals is a human cause of extinction that may represent a major, or dominant factor in the decline of certain species, particularly those that are endemic to a small geographic area, or have a small or slowregenerating population overall. Unfortunately, across the world, various socio-economic factors drive hunting and poaching of endangered plant and animal species, and where this occurs at unregulated, unsustainable levels, vulnerable species may be pushed towards extinction. Although regulations and legislation may exist at a national or international level, often sufficient infrastructure, awareness or resources are in place for any effective impact. Sometimes killing of endangered plants and animals is due to ignorance or
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misconceived stereotypes, as is often the case of bats, snakes and arachnids that are commonly, but incorrectly perceived to be aggressive or necessarily dangerous. Introduced Species The introduction of plant and animal species that are not endemic to a given locality is both a natural and human process that often has disastrous knock-on consequences for local biota, often including extinction of native taxa. Introduction of species that are not native to a given area may occur through regular dispersal processes over short geographic distances. Artificial or accidental introduction of nonnative plant and animal species occurs much more commonly, particularly as humans travel more extensively and frequently across the globe. Seeds are rapidly transported by humans on their clothes and shoes, and or rats on board ships. Both natural and anthropogenic introduction of non native plant or animal taxa may profoundly upsets the balance of the local ecosystem of a given locality and push the most vulnerable native taxa towards extinction, particularly those that are endemic to a small geographic area, or have a small or slow-regenerating population overall. Pollution Pollution may be a natural or human cause of extinction, and can take many forms. Natural pollution events may result from cataclysmic geographic processes (volcanic eruptions, floods, earthquakes, etc.), or from over-population of ecosystems by specific species (red tide) or other processes. Natural pollution events commonly cause local extinction events, but rarely are sufficiently wide scale to cause complete extinction of significant numbers of plant and animal taxa. Human pollution can take many forms, but usually arises when toxic substances are dumped, either advertently or inadvertently, into biologically diverse areas of our planet. Anthropogenic pollution may have knock-on consequences, for example, eutrophication. Large scale anthropogenic pollution events (i.e. oil spills) may have the scope to cause the complete extinction of plant and animal taxa, particularly those that are endemic to a small geographic area, or have a small or slow-regenerating population overall. Pollution may impact entire ecosystems, including humans. For example, the pesticide DDT, which was used against arthropods up until the 1970s, but causes catastrophic impacts at all ecological levels, from the water and soil, through water feeders, ground arthropods, predators, and humans. Competition On going evolutionary processes are driven by competition, and over (usually) long periods of time, plant and animal taxa that are unable to adapt may be out competed and naturally displaced from their habitat, and pushed towards extinction. Disease The spread of disease may be both a natural and human factor behind extinction. Naturally occurring diseases that afflict specific plant or animal taxa may be inadvertently spread by humans with disastrous consequences, for example, Dutch elm disease, which is a fungal disease of elm trees spread by the elm bark beetle. Although believed to be originally native to Asia, the disease has been accidentally introduced into North America and Europe, where it has devastated native populations of elms which had not had the opportunity to evolve resistance.
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Effects of ancient humans Human beings have been affecting the environment for a very long time. Early humans burned woodland to clear it and make way for grassland. They also made spears and used them to hunt more efficiently. Some scientists believe that some recent mass extinctions took place because of the actions of ancient humans. One example is the extinction of Australian megafauna, or very large animals, that took place approximately 40 000 years ago . This mass extinction coincided almost exactly with the arrival of the Australian Indigenous peoples, who would have found the slow-moving megafauna easy prey. Another example is the mass extinction that occurred between 10 000 and 25 000 years ago in North America. Here, too, a large portion of the native mega- fauna was wiped out around the same time that human beings appeared. Climate Change The biodiverse Earth can't keep up with the rapid changes in temperature and climate. The species are not used to severe weather conditions and long seasons, or a changing chemical make-up of their surroundings. As more species die, it is only making it more difficult for the survivors to find food. The warmer climates we are used to present-day are perfect for diseases and epidemics to thrive. Present day destruction Today, animals are disappearing from the world at an alarming rate. That rate is continuing to grow. Some scientists believe that by 2050, extinction rates will be between 1000 and 10 000 times above the background rate of extinction (the rate of extinction due to evolution). This is happening because the human population is expanding very quickly. As more humans are born, the population needs more food. This means that more land is cleared for farming. More resources are also needed for manufacturing and building homes, so more lumber and minerals are taken from the Earth. Introduced species, if left unchecked, continue to damage ecosystems. Pollution from more and more factories, cars and power plants also harm ecosystems. There are many government protections in place to prevent over-hunting, but many of these are not always followed. Unless drastic changes are made, more species will become extinct due to human intervention. Changes in Sea Levels or Currents The changes in sea levels and currents is a result, in part, of the melting freshwater. The denser, saltier water sinks and forms the currents that marine life depends on. Ocean floor spreading and rising also affects sea level. A small rise in the ocean floor can displace a lot of water onto land that is all ready occupied. The gases from the volcanic activity can also be absorbed by the water, thus changing the chemical composition, making it unsuitable for some life. Spread of Invasive Species Invasive species invade foreign territory. They use resources that the other species depend on. Once competition gets too great, the survival of the fittest plan will begin, and one of the species, usually the natural one, will die off. Cosmic Radiation Cosmic Radiation is radiation being emitted from outer space and the Sun. It is hypothesized that being exposed to too much cosmic radiation can mutate genes, which
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can potentially weaken a species' gene pool in the future. Since the radiation comes from space and the Sun, it is extremely difficult to avoid the radiation. Present day destruction Today, animals are disappearing from the world at an alarming rate. That rate is continuing to grow. Some scientists believe that by 2050, extinction rates will be between 1000 and 10 000 times above the background rate of extinction (the rate of extinction due to evolution). This is happening because the human population is expanding very quickly. As more humans are born, the population needs more food. This means that more land is cleared for farming. More resources are also needed for manufacturing and building homes, so more lumber and minerals are taken from the Earth. Introduced species, if left unchecked, continue to damage ecosystems. Pollution from more and more factories, cars and power plants also harm ecosystems. There are many government protections in place to prevent over-hunting, but many of these are not always followed. Unless drastic changes are made, more species will become extinct due to human intervention. Tracing evolutionary relationships In order to find out the evolutionary relationships among organisms, we have to look for their common features. Different organisms would have common features if they are inherited from a common ancestor. Comparative anatomy The study of body parts of animals of a particular group shows how apparently dissimilar animals have quite similar anatomical structures. For example , the forelimbs of man, cat, whale and bat are made up of the same skeletal elements. They have been modified to suit the environmental conditions in which these animals live. These organs are functionally dissimilar but structurally similar. Such organs are called homologous organs. The anatomical similarity points to the existence of a common ancestor from which these organisms have evolved. However, though the wings of a bat and the wings of a bird look similar, they are anatomically dissimilar. Such organs are called analogous organs. Comparative embryology A comparative study of the stages of the embryonic development of animals reveals that in their early stages they were very similar. These embryonic stages reflect their ancestry. The embryological stages of an organism give us an idea about the stages of its evolution. For example, when we study the human embryo, we find that at a certain stage it has gills. This suggests that fish is one of the earliest ancestors in the evolution of mammals including human beings. Classification of Organisms In order to make sense of the diversity of organisms, it is necessary to group similar organisms together and organize these groups in a non-overlapping hierarchical arrangement. The classification of organisms into a hierarchy of groups, namely, kingdoms, phyla (or divisions), classes, orders, families, genera and species, is based
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on their similarities and differences. Classification shows how closely organisms are related with respect to evolution. It is based on the assumption that each organism has descended from its ancestral type with some modification Taxonomy is the science of biological classification. The basic taxonomic group is the species, which is defined in terms of either sexual reproduction or general similarity. Morphological, physiological, metabolic, ecological, gene-tic, and molecular characteristics are all useful in taxonomy because they reflect the organization and activity of the genome. Nucleic acid structure is probably the best indicator of relatedness because nucleic acids are either the genetic material itself or the products of gene transcription. Classification is the arrangement of organisms into groups or taxa. It is based on any analysis of possible evolutionary relationships (phylogenetic or phyletic classification) or on overall similarity (phenetic classification). Linnaeus, Carolus (late 1700s) system of classification according to similarity: Carolus Linnaeus developed a system of classification of every known organism up to that time. This system is based on creating and differentiating groups in terms of structural (and other) similarities and differences. Linnaeus also invented binomial nomenclature to keep track of group members. That is the use of Genus and species names for all the organisms, e.g. Home sapiens or humans. Systematics is the study of the diversity of organisms and their evolutionary relationships. The main goal of systematics is the discovery and codification of phylogenetic relationships between organisms. Taxon (pl. taxa), A taxon is a phylogenetic grouping of organisms. There are two related processes in taxonomy. Taxonomy is the science concerned with the identification, classification, nomenclature of organisms. Identification is the practical side of taxonomy, the process of determining that a particular (organism) belongs to a recognized taxon. Nomenclature is the branch of taxonomy concerned with the assignment of names to taxonomic groups in agreement with published rules. Hierarchical classification . The full description of a given organism's place among all the world's organisms does not end with its binomial designation. There exists a hierarchy of designations only the last of which describe genera and species denomination. A category in any rank unites groups in the level below it based on shared properties. The major designations, listed in terms of increasing specificity, include: domain – kingdom – phylum – class – order – family – genus – species.
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Sample of Classification Scheme of Organisms CHAPTER TEST: Identify the word being described by the given phrase or sentence. ______________1. It is the theory that states that living things come from non-living things. ______________2. a system for naming and organizing things, especially plants and animals, into groups that share similar qualities ______________3. the name of the book of Charles Darwin about evolution through natural selection ______________4. Other than Charles Darwin, who was the other scientist who worked on the theory of evolution through natural selection ? ______________5. It is an evolutive process that leads to the disappearance of a species or a population. ______________6. It also known as biological evolution. ______________7. This system of classification creates and differentiates groups in terms of structural similarities and differences. ______________8. the scientific name for human ______________9. the highest level of biological classification _____________10. the lowest taxonomic category
Activity : Simulate the natural formation of fossils using plaster of Paris.
CHAPTER 10: INTERACTION AND INTERDEPENDENCE Lesson 10.1:
THE PRINCIPLES OF ECOSYSTEM
Objectives : 1. To describe the principle of ecosystem 2. To identify the components of ecosystem 3. To cite examples of terrestrial and aquatic ecosystem Ecology is the branch of science that deals with the relationship and interactions between organisms and their environment, including other organisms. Ecology includes
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not only how living things interact with each other, but how they interact with their physical environment: things such as climate, water, and soil. Biodiversity is the variety of all life forms on earth - the different plants, animals and micro-organisms and the ecosystems of which they are a part. Ecosystem An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment (things like air, water and mineral soil), interacting as a system. These biotic and abiotic components are regarded as linked together through nutrient cycles and energy flows. As ecosystems are defined by the network of interactions among organisms, and between organisms and their environment, they can be of any size but usually encompass specific, limited spaces. There are two primary types of ecosystems: Natural ecosystems: Natural ecosystems may be terrestrial ( meaning desert, forest , or meadow) or aquatic, ( pond ,river, or lake). A natural ecosystem is a biological environment that is found in nature (e.g. a forest) rather than created or altered by man.
Artificial ecosystems: Humans have modified some ecosystems for their own benefit. These are artificial ecosystems. They can be terrestrial (crop fields and gardens) or aquatic (aquariums, dams, and manmade ponds).
There are two main components that exist in an ecosystem: the abiotic and biotic components. The abiotic components of any ecosystem are the properties of the environment; the biotic components are the life forms that occupy a given ecosystem. Abiotic Components Abiotic components of an ecosystem consist of the nonorganic aspects of the environment that determine what life forms can thrive. Examples of abiotic components are temperature, average humidity, topography and natural disturbances. Temperature varies by latitude; locations near the equator are warmer than are locations near the poles or the temperate zones. Humidity influences the amount of water and moisture in the air and soil, which, in turn, affect rainfall. Topography is the layout of the land in terms of elevation. Natural disturbances include tsunamis, lightning storms, hurricanes and forest fires. Biotic Components The biotic components of an ecosystem are the life forms that inhabit it. The life forms of an ecosystem aid in the transfer and cycle of energy. They are grouped in terms of the means they use to get energy. Producers such as plants produce their own energy without consuming other life forms; plants gain their energy from conducting photosynthesis via sunlight. Consumers exist on the next level of the food chain. There are three main types of consumers: herbivores, carnivores and omnivores. Herbivores feed on plants, carnivores get their food by eating other carnivores or herbivores, and omnivores can digest both plant and animal tissue. Decomposers , like fungi and
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bacteria ,are organisms that break down dead or decaying organisms, and in doing so, they carry out the natural process of decomposition. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrients for growth and development. Ecosystems are controlled both by external and internal factors : External factors such as climate, the parent material that forms the soil, and topography control the overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem. Other external factors include time and potential biota. Ecosystems are dynamic entities—invariably, they are subject to periodic disturbances and are in the process of recovering from some past disturbance . Ecosystems in similar environments that are located in different parts of the world can have very different characteristics simply because they contain different species. The introduction of non-native species can cause substantial shifts in ecosystem function. Internal factors not only control ecosystem processes but are also controlled by them and are often subject to feedback loops. While the resource inputs are generally controlled by external processes like climate and parent material, the availability of these resources within the ecosystem is controlled by internal factors like decomposition, root competition or shading. Other internal factors include disturbance, succession and the types of species present. Although humans exist and operate within ecosystems, their cumulative effects are large enough to influence external factors like climate. Processes of Ecosystems The figure on the side, with the plants, zebra, lion, and so forth, illustrates the two main ideas about how ecosystems function: ecosystems have energy flows and ecosystems cycle materials. These two processes are linked, but they are not quite the same. Energy that enters the biological system as light energy, or photons, is transformed into chemical energy in organic molecules by cellular processes including photosynthesis and respiration, and ultimately is converted to heat Energy flow and energy. This energy is dissipated, meaning it is lost to material cycle the system as heat; once it is lost it cannot be re-cycled. Without the continued input of solar energy, biological systems would quickly shut down. Thus the earth is an open system with respect to energy. Elements such as carbon , nitrogen, or phosphorus enter living organisms in a variety of ways. Plants obtain elements from the surrounding atmosphere, water, or soils. Animals may also obtain elements directly from the physical environment, but usually they obtain these mainly as a consequence of consuming other organisms. These materials are transformed biochemically within the bodies of organisms, but sooner or later, due to excretion or decomposition, they are returned to an inorganic state. Often bacteria complete this process ,through the process called decomposition or mineralization. During decomposition these materials are not destroyed or lost, so the earth is a closed system with respect to elements (with the exception of a meteorite entering the system now and then). The elements are cycled endlessly between their biotic and abiotic states within ecosystems. Those elements whose supply tends to limit biological
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activity are called nutrients. Interaction Biotic components and abiotic components of an eco-system interact with and affect one another. If the temperature of an area decreases, the life existing there must adapt to it. Global warming, or the worldwide increase in temperature due to the greenhouse effect, will speed up the metabolism rates of most organisms. Metabolic rate increases with temperature because the nutrient molecules in the body are more likely to contact and react with one another when excited by heat. Accordingly, tropical ectothermic - cold-blooded-organisms could experience increased metabolic rates from an increase of as little as 5 oC because their internal temperature is almost entirely dependent on external temperature. To adapt to these circumstances, cold-blooded life forms could reside in the shade and not actively search for food during daylight hours when the sun is at its brightest.
Different Types of Ecosystems There are essentially two kinds of ecosystems; Aquatic and Terrestrial. Any other subecosystem falls under one of these two headings. Terrestrial Ecosystems Terrestrial ecosystems can be found anywhere apart from heavily saturated places. They are broadly classed into: The Forest Ecosystems They are the ecosystems in which an abundance of flora, or plants, is seen so they have a big number of organisms which live in relatively small space. Therefore, in forest ecosystems the density of living organisms is quite high. A small change in this ecosystem could affect the whole balance, effectively bringing down the whole ecosystem. They are further divided into: Tropical evergreen forest: These are tropical forests that receive a mean rainfall of 80 for every 400 inches annually. The forests are characterized by dense vegetation which comprises tall trees at different heights. Each level is shelter to different types of animals. Tropical deciduous forest: There, shrubs and dense bushes rule along with a broad selection of trees. The type of forest is found in quite a few parts of the world while a large variety of fauna and flora are found there.
Temperate evergreen forest: Those have quite a few number of trees as mosses and ferns make up for them. Trees have developed spiked leaves in order to minimize transpiration.
Temperate deciduous forest: The forest is located in the moist temperate places that have sufficient rainfall. Summers and winters are clearly defined and the trees shed the leaves during the winter months.
Taiga: Situated just before the arctic regions, the taiga is defined by evergreen conifers. As the temperature is below zero for almost half a year, the remainder of the months, it buzzes with migratory birds and insects.
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The Desert Ecosystems Desert ecosystems are located in regions that receive an annual rainfall less than 25. They occupy about 17 percent of all the land on our planet. Due to the extremely high temperature, low water availability and intense sunlight, fauna and flora are scarce and poorly developed. The vegetation is mainly shrubs, bushes, few grasses and rare trees. The stems and leaves of the plants are modified in order to conserve water as much as possible. The best known desert ones are the succulents such as the spiny leaved cacti. The animal organisms include insects, birds, camels, reptiles all of which are adapted to the desert conditions. The Grassland Ecosystem Grasslands are located in both the tropical and temperate regions of the world though the ecosystems vary slightly. The area mainly comprises grasses with a little number of trees and shrubs. The main vegetation includes grasses, plants and legumes that belong to the composite family. A lot of grazing animals, insectivores and herbivores inhabit the grasslands. The two main kinds of grasslands ecosystems are: 1. Savanna: The tropical grasslands are dry seasonally and have few individual trees. They support a large number of predators and grazers. 2. Prairies: It is temperate grassland, completely devoid of large shrubs and trees. Prairies could be categorized as mixed grass, tall grass and short grass prairies. The Mountain Ecosystem Mountain land provides a scattered and diverse array of habitats where a large number of animals and plants can be found . At the higher altitudes, the harsh environmental conditions normally prevail, and only the treeless alpine vegetation can survive. The animals that live there have thick fur coats for prevention from cold and hibernation in the winter months. Lower slopes are commonly covered with coniferous forests. Aquatic Ecosystems The aquatic ecosystem is the ecosystem found in a body of water. It encompasses aquatic flora, fauna and water properties, as well. There are two main types of aquatic ecosystem- Marine and Freshwater. The Marine Ecosystem Marine ecosystems are the biggest ecosystems, which cover around 71% of Earth's surface and contain 97% of out planet's water. Water in Marine ecosystems features in high amounts minerals and salts dissolved in them. The different divisions of the marine ecosystem are: Oceanic: A relatively shallow part of oceans which lies on the continental shelf. Profundal: deep or bottom water.
Benthic Bottom substrates.
Inter-tidal: The place between low and high tides.
Estuaries
Coral reefs
Salt marshes
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Hydrothermal vents where chemosynthetic bacteria make up the food base.
Many kinds of organisms live in marine ecosystems: the brown algae, corals, cephalopods, echinoderms, dinoflagellates and sharks. The Freshwater Ecosystem Contrary to the Marine ecosystems, the freshwater ecosystem covers only 0.8% of Earth's surface and contains 0.009% of the total water. Three basic kinds of freshwater ecosystems exist: Lentic: Slow-moving or till water like pools, lakes or ponds. Lotic: Fast-moving water such as streams and rivers.
Wetlands: Places in which the soil is inundated or saturated for some lengthy period of time.
The ecosystems are habitats to reptiles, amphibians and around 41% of the world’s fish species. The faster moving turbulent waters typically contain a greater concentrations of dissolved oxygen, supporting greater biodiversity than slow moving waters in pools. Review Questions : Identify the word being described by the given statement. _______________1. It refers to the non-living things in the ecosystem. _______________2. It refers to all the living things in an area and the way they affect each other and the environment. _______________3. These are organisms that break down dead or decaying organisms. _______________4. These are organisms in an ecosystem that produce biomass from inorganic compounds. _______________5. the ultimate source of energy for most communities of living things
Lesson 10.2:
BIOTIC POTENTIAL AND ENVIRONMENTAL RESISTANCE
Objectives : 1. To identify the limiting factors of population 2. To explain biotic potential
Population It is a group of organisms of the same species living in an area at the same time. Birth rate is the ratio of total live births to total population in a specified community or area over a specified period of time. The birthrate is often expressed as the number of live births per 1,000 of the population per year.
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Death rate is the ratio of total deaths to total population in a specified community or area over a specified period of time. The death rate is often expressed as the number of deaths per 1,000 of the population per year. Also called fatality rate. Population Density It is a measurement of population per unit area or unit volume; it is a quantity of type number density. It is frequently applied to living organisms, and most of the time to humans. Environmental resistance Environmental resistance is the limiting effect of environmental conditions on the numerical growth of a population. Environmental resistance factors are things that limit the growth of a population. They lower the chances for reproduction, affect the health of organisms, and raise the death rate in the population. They include biotic factors like predators, disease, competition, and lack of food, as well as abiotic factors like fire, flood, temperature, wrong amount of sunshine ,and drought.
Environmental Resistance Factors Food supply As the population increases, the food supply, or the supply of another necessary resource , may decrease. When necessary resources, such as food , decrease, some individuals will die. Overall, the population cannot reproduce at the same rate, so the birth rates drop. This will cause the population growth rate to decrease. Competition When populations become crowded, organisms compete for food,water, space, sunlight and other essentials. Predation Populations in nature are often controlled by predation. The regulation of a population by predation takes place within a predator-prey relationship, one of the bestknown mechanism of population control. Parasitism and Disease Parasites and disease can limit the growth of a population. A parasite lives in or on another organism (the host) and consequently harms it. Natural disasters
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Natural disasters such as droughts, floods, hurricanes, and fires, can all influence whatever populations are in the area at the time. Not only do these occurrences kill individuals in all populations, they also disrupt the availability of resources for survivors. Biotic Potential The biotic potential of a population is how well a species is able to survive. While environmental resistance acts like a hill pushing back against population growth, biotic potential is what urges a population to grow. Biotic potential has to do with how well a species can survive, including how well adapted it is to the environment and its rate of reproduction. Some species produce a lot of young very often (while others produce fewer babies less often), but invest a lot of energy raising and protecting them. So while the biotic potential of a species causes the population to increase, environmental resistance keeps it from increasing relentlessly. When the population is small, environmental resistance factors are, well, not as big of a factor. There may be plenty of resources around so the population can keep growing quickly. It's kind of like pushing a piece of gravel uphill rather than a boulder. But, as competition get stiffer and resources start to become limited, population growth starts to slow.
Review Questions : 1. Explain the relationship between population and food supply. 2. Give 5 factors that limit the growth of population and write a brief explanation.
Lesson 10.3:
EFFECTS OF HUMAN ACTIVITIES TO THE NATURAL ECOSYSTEM
Objectives : 1. To identify the activities of man that affect the natural ecosystem 2. To cite measures on how to prevent human activities from damaging the ecosystem Human survival depends on the health of the ecosystem. An ecosystem is comprised of communities of plants, animals and other organisms in a particular area that interact with each other and their surrounding environment. Both living and nonliving things are considered part of an ecosystem. Humans threaten ecosystems by producing waste and disposing them improperly, damaging habitats by logging forests, planting crops, construction of dams, conversion of agricultural lands into housing projects, using chemical base pesticides and fertilizers, and removing too many species without giving the ecosystem time to naturally regenerate. Human activities that affect natural ecosystem
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1. Introduction of Invasive Species Invasive species are brought on by transporting species either intentionally or accidentally from other areas of the world. This can be devastating to existing species as invasive species are introduced on a time scale much more quickly than typically would happen with evolution over longer time periods. This can include outcompeting native species in the ecosystem, leading to the decline or extinction of local species, and overpopulation as these invasive species may not have any predators in this new ecosystem. 2. Overexploitation Overexploitation is a major threat to ecosystems and therefore sustainability. It is the consumption of a natural resource at a rate greater than that natural resource can maintain itself.
Overhunting When humans overhunt key predators such as lions, tigers and bears, they remove the very animals that keep plant consumers in balance and prevent overgrazing. A healthy ecosystem has a balance of predators and prey that naturally cycle through life and death sequences. Over-hunting often results in ecosystem species imbalance and environmental stress.
Overfishing Humans also practice commercial overfishing , where massive fishing nets result in “bycatch,” in which unwanted fish are caught in nets and then thrown away. Bycatch results in the death of one million sharks annually. Large weights and heavy metal rollers that are used with the commercial fishing nets also drag along the bottom of the ocean, destroying anything in their path including fragile coral reefs.
Overgrazing It occurs when plants are exposed to intensive grazing for extended periods of time , or without sufficient recovery periods. It reduces the usefulness, productivity, and biodiversity of the land and is one cause of desertification and erosion.
Illegal logging Illegal logging contributes to deforestation, degrades forest environments, reduces biodiversity, and contributes to green gas emissions.
Continuous cropping Continuous cropping refers to a system in which certain crops are ‘‘replanted” in soils that had previously supported the same or similar plant species. Because of limited arable land sand expansive populations, continuous cropping systems are commonly practiced in the production of grain crops and cash crops. However, long-term continuous cropping usually leads to plant growth inhibition and serious soil-borne diseases. Continuous cropping can lead
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to soil exhaustion, erosion and low productivity if soil and nutrients conservation practices are not adopted. Excess fertilizers can be washed off by rain into bodies of water that could cause pollution 3. Pollution Vehicles, trains and planes emit toxic gases that include carcinogenic particles and irritants, creating air pollution. Humans have also dumped large amounts of pesticides, such as organophosphates, onto crops that migrate into groundwater and bodies of water, poisoning ecosystems. Plants and animals die from exposure to pollutants such as excess nutrients from chemical fertilizers and other harmful chemicals. Pollution is increasing around the world and results in loss of biodiversity causing severe damage to self-sustaining ecosystems. 4. Habitat destruction Deforestation Humans have always cut down trees throughout history. The world’s rainforests are being destroyed resulting in vegetation degradation, nutrient imbalance, flooding and animal displacement. Trees act as a natural air filter in the carbon cycle by taking in carbon dioxide and releasing oxygen, so deforestation contributes to global warming.
Kaingin System Kaingin system is the cutting down and burning of trees and plant growth in an area for cultivation purposes. Kaingin is a Filipino word that means clearing. Known as swidden farming in other countries, it is a traditional but destructive agricultural system practiced in many parts of the globe.
Land Conversion Through urban development, the continued rapid construction of road systems and buildings has changed the Earth's natural surface, removing soil nutrients, surface vegetation and trees that filter the air and equalize the carbon cycle. Urbanization also displaces animals and increases environmental pollution from vehicles and factories. A system of highways also causes migratory obstacles for animals and replaces native plants with impermeable concrete, resulting in habitat destruction. This practice of human construction continues at a rapid pace, leading to urban sprawl, where cities are essentially forever expanding outside the traditional inner-city limits.
THE EARTH SAVERS TEN COMMANDMENTS FOR SUSTAINABLE DEVELOPMENT 1. Thou shalt not throw garbage along canals, creeks or rivers. 2. Thou shalt not resort to destructive and illegal methods of fishing. 3. Thou shalt not resort to open burning methods to dispose your drug waste. 4. Thou shalt improve and maintain your care and vehicles in good running. 5. Thou shalt not smoke cigars and cigarettes . 6. Thou shalt minimize if not put to stop the use of CFC products. 7. Thou shalt not waste energy and water. 8. Thou shalt plant more trees and nurture them. 9. Thou shalt protect endangered species of plants and animals. 10.Thou shalt minimize if not totally stop the use of farm chemicals.
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CHAPTER TEST : Identify the word being described by the given statement. _______________1. tropical grasslands, with few trees, and good for grazers _______________2. It means contamination with pollutants. _______________3. It is the ratio of total live births to total population in a specified area over a specified period of time. _______________4. a kind of ecosystem found in bodies of water _______________5. It is an organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host's expense. _______________6. It is a measurement of population per unit area. _______________7. It is the cutting down and burning of trees for clearing purposes. _______________8. Fatality rate is also known as ________. _______________9. It is the light energy that enters the biological system. ______________10. factors that limit the growth of a population
Activity : Make a miniature manmade terrestrial or aquatic ecosystem
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