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Chapter 3 Ecosystems: What Are They and How Do They Work?

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1 Chapter 3 Ecosystems: What Are They and How Do They Work?

2 Chapter Overview Questions What is ecology? What is ecology? What basic processes keep us and other organisms alive? What basic processes keep us and other organisms alive? What are the major components of an ecosystem? What are the major components of an ecosystem? What happens to energy in an ecosystem? What happens to energy in an ecosystem? What happens to matter in an ecosystem? What happens to matter in an ecosystem? How do scientists study ecosystems? How do scientists study ecosystems?

3 Core Case Study: Tropical Rain Forests Are Disappearing

4 Cover about 2% of the earths land surface Cover about 2% of the earths land surface Contain about 50% of the worlds known terrestrial plant and animal species Contain about 50% of the worlds known terrestrial plant and animal species Disruption will have three major harmful effects Disruption will have three major harmful effects Reduce biodiversity Reduce biodiversity Accelerate global warming Accelerate global warming Change regional weather patterns Change regional weather patterns

5 Natural Capital Degradation: Satellite Image of the Loss of Tropical Rain Forest Santa Cruz, Bolivia

6 THE NATURE OF ECOLOGY Ecology is a study of connections in nature. Ecology is a study of connections in nature. How organisms interact with one another and with their nonliving environment. How organisms interact with one another and with their nonliving environment. Put another way: Biotic & Abiotic Interactions Put another way: Biotic & Abiotic Interactions Next

7 Fig. 3-2, p. 51 Communities Subatomic Particles Atoms Molecules Protoplasm Cells Tissues Organs Organ systems Organisms Populations Communities Ecosystems Biosphere Earth Planets Solar systems Galaxies Universe Organisms Realm of ecology Ecosystems Biosphere

8 Organisms and Species Organisms, the different forms of life on earth, can be classified into different species based on certain characteristics. Organisms, the different forms of life on earth, can be classified into different species based on certain characteristics. Next

9 Insects 751,000 Other animals 281,000 Fungi 69,000 Prokaryotes 4,800 Plants 248,400 Protists 57,700 Known species 1,800,000

10 Have You Thanked the Insects Today? Many plant species depend on insects for pollination. Many plant species depend on insects for pollination. Insect can control other pest insects by eating them Insect can control other pest insects by eating them Figure 3-1

11 Core Case Study: Have You Thanked the Insects Today? …if all insects disappeared, humanity probably could not last more than a few months [E.O. Wilson, Biodiversity expert]. …if all insects disappeared, humanity probably could not last more than a few months [E.O. Wilson, Biodiversity expert]. Insects role in nature is part of the larger biological community in which they live. Insects role in nature is part of the larger biological community in which they live.

12 E.O. Wilson Worlds foremost authority on biodiversity

13 Case Study: Which Species Run the World? Multitudes of tiny microbes such as bacteria, protozoa, fungi, and yeast help keep us alive. Multitudes of tiny microbes such as bacteria, protozoa, fungi, and yeast help keep us alive. Harmful microbes are the minority. Harmful microbes are the minority. Soil bacteria convert nitrogen gas to a usable form for plants. Soil bacteria convert nitrogen gas to a usable form for plants. They help produce foods (bread, cheese, yogurt, beer, wine). They help produce foods (bread, cheese, yogurt, beer, wine). 90% of all living mass. (!) 90% of all living mass. (!) Helps purify water, provide oxygen, breakdown waste. Helps purify water, provide oxygen, breakdown waste. Lives beneficially in your body (intestines, nose). Lives beneficially in your body (intestines, nose).

14 Populations, Communities, and Ecosystems Members of a species interact in groups called populations. Members of a species interact in groups called populations. Populations of different species living and interacting in an area form a community. Populations of different species living and interacting in an area form a community. A community interacting with its physical environment of matter and energy is an ecosystem. A community interacting with its physical environment of matter and energy is an ecosystem.

15 Populations A population is a group of interacting individuals of the same species occupying a specific area. A population is a group of interacting individuals of the same species occupying a specific area. The space an individual or population normally occupies is its habitat. The space an individual or population normally occupies is its habitat. Figure 3-4 Monarch Butterflies

16 Populations Genetic diversity Genetic diversity In most natural populations individuals vary slightly in their genetic makeup. In most natural populations individuals vary slightly in their genetic makeup. Figure 3-5 Variation among one species of Caribbean snail!

17 THE EARTHS LIFE SUPPORT SYSTEMS The biosphere consists of several physical layers that contain: The biosphere consists of several physical layers that contain: sphere? sphere? Air Air Water Water Soil Soil MineralsMinerals Life Life Figure 3-6

18 Fig. 3-6, p. 54 Lithosphere (crust, top of upper mantle) Rock Soil Vegetation and animals Atmosphere Oceanic Crust Continental Crust Lithosphere Upper mantle Asthenosphere Lower mantle Mantle Core Biosphere Crust Crust (soil and rock) Biosphere (living and dead organisms) Hydrosphere (water) Atmosphere (air)

19 What Supports the Biosphere? Atmosphere Atmosphere Membrane of air around the planet. Membrane of air around the planet. Troposphere: lowest layer; we live in this! Troposphere: lowest layer; we live in this! Stratosphere: miles up Stratosphere: miles up Lower portion contains stratospheric ozone to filter out most of the suns harmful UV radiation.Lower portion contains stratospheric ozone to filter out most of the suns harmful UV radiation. Hydrosphere Hydrosphere All the earths water: liquid, ice, water vapor All the earths water: liquid, ice, water vapor Lithosphere Lithosphere The earths crust and upper mantle. The earths crust and upper mantle.

20 What Sustains Life on Earth? Solar energy, the cycling of matter, and gravity sustain the earths life. Solar energy, the cycling of matter, and gravity sustain the earths life. Figure 3-7

21 Fig. 3-7, p. 55 Nitrogen cycle Biosphere Heat in the environment Heat Phosphorus cycle Carbon cycle Oxygen cycle Water cycle

22 What Happens to Solar Energy Reaching the Earth? Solar energy flowing through the biosphere warms the atmosphere, evaporates and recycles water, generates winds and supports plant growth. Solar energy flowing through the biosphere warms the atmosphere, evaporates and recycles water, generates winds and supports plant growth. Figure 3-8

23 Fig. 3-8, p. 55 Absorbed by ozone Visible Light Absorbed by the earth Greenhouse effect UV radiation Solar radiation Energy in = Energy out Reflected by atmosphere (34% ) Radiated by atmosphere as heat (66%) Heat radiated by the earth Heat Troposphere Lower Stratosphere (ozone layer) 1 billionth of total solar energy reaches the earth!

24 ECOSYSTEM COMPONENTS Life exists on land systems called biomes and in freshwater aquatic and marine aquatic life zones. Life exists on land systems called biomes and in freshwater aquatic and marine aquatic life zones. Figure 3-9

25 Fig. 3-9, p –125 cm (40–50 in.) Coastal mountain ranges Sierra Nevada Mountains Great American Desert Coastal chaparral and scrub Coniferous forest Desert Coniferous forest Prairie grassland Deciduous forest 1,500 m (5,000 ft.) 3,000 m (10,000 ft.) 4,600 m (15,000 ft.) Average annual precipitation Mississippi River Valley Appalachian Mountains Great Plains Rocky Mountains below 25 cm (0–10 in.) 25–50 cm (10–20 in.) 50–75 cm (20–30 in.) 75–100 cm (30–40 in.) 39 th parallel transect across the USA

26 Nonliving and Living Components of Ecosystems Ecosystems consist of nonliving (abiotic) and living (biotic) components. Ecosystems consist of nonliving (abiotic) and living (biotic) components. Figure 3-10

27 Fig. 3-10, p. 57 Sun Oxygen (O 2 ) Carbon dioxide (CO 2 ) Secondary consumer (fox) Soil decomposers Primary consumer (rabbit) Precipitation Falling leaves and twigs Producer Producers Water

28 Factors That Limit Population Growth Availability of matter and energy resources can limit the number of organisms in a population. Availability of matter and energy resources can limit the number of organisms in a population. Figure 3-11

29 Fig. 3-11, p. 58 Zone of intolerance Optimum range Zone of physiological stress Zone of physiological stress Zone of intolerance TemperatureLowHigh No organisms Few organisms Upper limit of tolerance Population size Abundance of organisms Few organisms No organisms Lower limit of tolerance

30 Limiting Factor Principal Too much or too little of any one abiotic factor can limit or prevent the growth of a population, even if all other limiting factors are at or near the optimum range Figure 3-11

31 Factors That Limit Population Growth The physical and chemical conditions of the environment can limit the distribution of a species. The physical and chemical conditions of the environment can limit the distribution of a species. Figure 3-12

32 Fig. 3-12, p. 58 Sugar Maple Why does the sugar maple only grow in this range? CLIMATE is the most important factor that determines what biome grows in a particular area.

33 Limiting Factors Terrestrial Ecosystems: *Water *Major Soil nutrients *Temperature NH 3, NH 4 + NO 2 -, NO 3 - NO 2 -, NO 3 - PO 4 - K+K+K+K+ Aquatic Ecosystems: *Temperature *Sunlight *Dissolved O 2 DO *Nutrients (see above) *Salinity Physical or Chemical?

34 Producers: Basic Source of All Food Most producers capture sunlight to produce carbohydrates by photosynthesis: Most producers capture sunlight to produce carbohydrates by photosynthesis: Producers form the base of all food chains on earth, so the limiting factors that act upon producers are critical in determining what grows in a particular area.

35 Producers: Basic Source of All Food Photosynthesis: source of ALMOST ALL food Photosynthesis: source of ALMOST ALL food exceptionexception Chemosynthesis: Chemosynthesis: Sea Vent Community- Some organisms such as deep ocean bacteria draw energy from hydrothermal vents and produce carbohydrates from the chemical energy in hydrogen sulfide (H 2 S) gas. Sea Vent Community- Some organisms such as deep ocean bacteria draw energy from hydrothermal vents and produce carbohydrates from the chemical energy in hydrogen sulfide (H 2 S) gas. Some chemosynthetic bacteria are found in hot springs and geysers (as found in Yellowstone National Park) Some chemosynthetic bacteria are found in hot springs and geysers (as found in Yellowstone National Park)

36 Sea Vent Community Found in deep sea hydrothermal vents

37

38 Sea Vent Community- Tube Worms

39 Photosynthesis: A Closer Look Chlorophyll molecules in the chloroplasts of plant cells absorb solar energy. Chlorophyll molecules in the chloroplasts of plant cells absorb solar energy. This initiates a complex series of chemical reactions in which carbon dioxide and water are converted to sugars and oxygen. This initiates a complex series of chemical reactions in which carbon dioxide and water are converted to sugars and oxygen. Figure 3-A

40 Fig. 3-A, p. 59 Sun Chloroplast in leaf cell Light-dependent Reaction Light- independent reaction Chlorophyll Energy storage and release (ATP/ADP) Glucose H2OH2O Sunlight O2O2 CO 2 6CO H 2 OC 6 H 12 O O 2

41 Consumers: Eating and Recycling to Survive Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains. Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains. Herbivores Herbivores Primary consumers that eat producersPrimary consumers that eat producers Carnivores Carnivores Secondary consumers: Carnivores that eat primary consumersSecondary consumers: Carnivores that eat primary consumers Tertiary and higher level consumers: Carnivores that eat carnivores.Tertiary and higher level consumers: Carnivores that eat carnivores. Omnivores Omnivores Feed on both plant and animals.Feed on both plant and animals.

42 Decomposers and Detritovores Detritovores: Insects or other scavengers that feed on wastes or dead bodies. Detritovores: Insects or other scavengers that feed on wastes or dead bodies. Decomposers: Recycle nutrients in ecosystems. Decomposers: Recycle nutrients in ecosystems. Figure 3-13

43 Fig. 3-13, p. 61 Scavengers Powder broken down by decomposers into plant nutrients in soil Bark beetle engraving Decomposers Long- horned beetle holes Carpenter ant galleries Termite and carpenter ant work Dry rot fungus Wood reduced to powder Mushroom Time progression

44 Aerobic and Anaerobic Respiration: Getting Energy for Survival Organisms break down carbohydrates and other organic compounds in their cells to obtain the energy they need. Organisms break down carbohydrates and other organic compounds in their cells to obtain the energy they need. This is usually done through aerobic respiration. This is usually done through aerobic respiration. The opposite of photosynthesis The opposite of photosynthesis

45 Aerobic and Anaerobic Respiration: Getting Energy for Survival Anaerobic respiration or fermentation: Anaerobic respiration or fermentation: Some decomposers get energy by breaking down glucose (or other organic compounds) in the absence of oxygen. Some decomposers get energy by breaking down glucose (or other organic compounds) in the absence of oxygen. The end products vary based on the chemical reaction: The end products vary based on the chemical reaction: Methane gas- methanogens in our intestinesMethane gas- methanogens in our intestines Ethyl alcohol- yeast that make alcoholEthyl alcohol- yeast that make alcohol Acetic acid- bacteria that make vinegarAcetic acid- bacteria that make vinegar Hydrogen sulfide- bacteria in the salt marshHydrogen sulfide- bacteria in the salt marsh

46 Two Secrets of Survival: Energy Flow and Matter Recycle An ecosystem survives by a combination of energy flow and matter recycling. An ecosystem survives by a combination of energy flow and matter recycling. Figure 3-14

47 Fig. 3-14, p. 61 Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Heat Solar energy Consumers (herbivores, carnivores) Producers (plants) Decomposers (bacteria, fungi)

48 BIODIVERSITY Figure 3-15

49 ENERGY FLOW IN ECOSYSTEMS Food chains and webs show how eaters, the eaten, and the decomposed are connected to one another in an ecosystem. Food chains and webs show how eaters, the eaten, and the decomposed are connected to one another in an ecosystem. Next

50 Fig. 3-17, p. 64 Heat Detritivores (decomposers and detritus feeders) First Trophic Level Second Trophic Level Third Trophic Level Fourth Trophic Level Solar energy Producers (plants) Primary consumers (herbivores) Secondary consumers (carnivores) Tertiary consumers (top carnivores)

51 Food Webs Trophic levels are interconnected within a more complicated food web. Trophic levels are interconnected within a more complicated food web. Next

52 Fig. 3-18, p. 65 Humans Blue whaleSperm whale Crabeater seal Elephant seal Killer whale Leopard seal Adelie penguins Emperor penguin PetrelFish Squid Carnivorous plankton KrillHerbivorous plankton Phytoplankton

53 Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs In accordance with the 2 nd law of thermodynamics, there is a decrease in the amount of energy available to each succeeding organism in a food chain or web. In accordance with the 2 nd law of thermodynamics, there is a decrease in the amount of energy available to each succeeding organism in a food chain or web.

54 Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs Ecological efficiency: percentage of useable energy transferred as biomass from one trophic level to the next. Ecological efficiency: percentage of useable energy transferred as biomass from one trophic level to the next. Figure 3-19

55 Fig. 3-19, p. 66 Heat Decomposers Tertiary consumers (human) Producers (phytoplankton) Secondary consumers (perch) Primary consumers (zooplankton) ,000 10,000 Usable energy Available at Each tropic level (in kilocalories)

56 Productivity of Producers: The Rate Is Crucial Gross primary production (GPP) Gross primary production (GPP) Rate at which an ecosystems producers convert solar energy into chemical energy as biomass. Rate at which an ecosystems producers convert solar energy into chemical energy as biomass. Figure 3-20

57 Fig. 3-20, p. 66 Gross primary productivity (grams of carbon per square meter)

58 Net Primary Production (NPP) NPP = GPP – R NPP = GPP – R Rate at which producers use photosynthesis to store energy minus the rate at which they (the producers) use some of this energy through respiration (R). Rate at which producers use photosynthesis to store energy minus the rate at which they (the producers) use some of this energy through respiration (R). Figure 3-21

59 Fig. 3-21, p. 66 Photosynthesis Sun Net primary production (energy available to consumers) Growth and reproduction Respiration Energy lost and unavailable to consumers Gross primary production

60 What are natures three most productive and three least productive systems? What are natures three most productive and three least productive systems? Figure 3-22

61 Fig. 3-22, p. 67 Average net primary productivity (kcal/m 2 /yr) Open ocean Continental shelf Lakes and streams Estuaries Aquatic Ecosystems Extreme desert Desert scrub Tundra (arctic and alpine) Temperate grassland Woodland and shrubland Agricultural land Savanna North. coniferous forest Temperate forest Terrestrial Ecosystems Tropical rain forest Swamps and marshes

62 MATTER CYCLING IN ECOSYSTEMS Nutrient Cycles: Global Recycling Nutrient Cycles: Global Recycling Global Cycles recycle nutrients through the earths air, land, water, and living organisms. Global Cycles recycle nutrients through the earths air, land, water, and living organisms. C, H 2 O, S, N, P C, H 2 O, S, N, P Biogeochemical cycles move these substances through air, water, soil, rock and living organisms. Biogeochemical cycles move these substances through air, water, soil, rock and living organisms.

63 Characterizing Biogeochemical Cycles Where is Most of the Matter? Biogeochemical cycles are characterized by where the major reservoir of that compound or element is stored Water- On average, a water molecule stays in the ocean for 3,000 years, while it stays in the atmosphere only 9 days. Carbon- Most carbon is stored as dissolved carbonic acid in the ocean Nitrogen- atmospheric Phosphorous- sedimentary

64 Fig. 3-26, p. 72 Precipitation Transpiration Condensation Evaporation Ocean storage Transpiration from plants Precipitation to land Percolation: Groundwater movement (slow) Evaporation from land Evaporation from ocean Precipitation to ocean Infiltration Rain clouds Runoff Surface runoff (rapid) The Hydrologic Cycle

65 Waters Unique Properties There are strong forces of attraction between molecules of water (allows transpiration) There are strong forces of attraction between molecules of water (allows transpiration) Water exists as a liquid over a wide temperature range. Water exists as a liquid over a wide temperature range. Liquid water changes temperature slowly. Liquid water changes temperature slowly. It takes a large amount of energy for water to evaporate. It takes a large amount of energy for water to evaporate. Liquid water can dissolve a variety of compounds. Liquid water can dissolve a variety of compounds. Water expands when it freezes. Water expands when it freezes.

66 Effects of Human Activities on Water Cycle We alter the water cycle by: We alter the water cycle by: Withdrawing large amounts of freshwater. Withdrawing large amounts of freshwater. Clearing vegetation and eroding soils. Clearing vegetation and eroding soils. Polluting surface and underground water. Polluting surface and underground water. Contributing to climate change. Contributing to climate change.

67 The Carbon Cycle: Part of Natures Thermostat Figure 3-27

68 Effects of Human Activities on Carbon Cycle We alter the carbon cycle by adding excess CO 2 to the atmosphere through: We alter the carbon cycle by adding excess CO 2 to the atmosphere through: Burning fossil fuels. Burning fossil fuels. Clearing vegetation faster than it is replaced. Clearing vegetation faster than it is replaced. Figure 3-28

69 Fig. 3-28, p. 74 CO 2 emissions from fossil fuels (billion metric tons of carbon equivalent) Year Low projection High projection

70 The Nitrogen Cycle: Bacteria in Action Figure 3-29

71 Fig. 3-29, p. 75 Gaseous nitrogen (N 2 ) in atmosphere Ammonia, ammonium in soil Nitrogen-rich wastes, remains in soil Nitrate in soil Loss by leaching Loss by leaching Nitrite in soil Nitrification Ammonification Uptake by autotrophs Excretion, death, decomposition Loss by denitrification Food webs on land Fertilizers Nitrogen fixation

72 Effects of Human Activities on the Nitrogen Cycle We alter the nitrogen cycle by: We alter the nitrogen cycle by: Adding gases that contribute to acid rain. Adding gases that contribute to acid rain. Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone. Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone. Contaminating ground water from nitrate ions in inorganic fertilizers. Contaminating ground water from nitrate ions in inorganic fertilizers. Releasing nitrogen into the troposphere through deforestation. Releasing nitrogen into the troposphere through deforestation.

73 Effects of Human Activities on the Nitrogen Cycle Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined. Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined. Figure 3-30

74 Fig. 3-30, p. 76 Nitrogen fixation by natural processes Global nitrogen (N) fixation (trillion grams) Year

75 The Phosphorous Cycle Figure 3-31

76 Fig. 3-31, p. 77 Dissolved in Ocean Water Marine Sediments Rocks uplifting over geologic time settling out weathering sedimentation Land Food Webs Dissolved in Soil Water, Lakes, Rivers death, decomposition uptake by autotrophs agriculture leaching, runoff uptake by autotrophs excretion death, decomposition miningFertilizer weathering Guano Marine Food Webs

77 Effects of Human Activities on the Phosphorous Cycle We remove large amounts of phosphate from the earth to make fertilizer. We remove large amounts of phosphate from the earth to make fertilizer. It has been estimated that there is about 50 years of guano and phosphate rock remaining at current rates of removal by humans It has been estimated that there is about 50 years of guano and phosphate rock remaining at current rates of removal by humans We reduce phosphorous in tropical soils by clearing forests. We reduce phosphorous in tropical soils by clearing forests. We add excess phosphates to aquatic systems from runoff of animal wastes and fertilizers. We add excess phosphates to aquatic systems from runoff of animal wastes and fertilizers.

78 The Sulfur Cycle Figure 3-32

79 Fig. 3-32, p. 78 Hydrogen sulfide Sulfur Sulfate salts Decaying matter Animals Plants Ocean Industries Volcano Hydrogen sulfide Oxygen Dimethyl sulfide Ammonium sulfate Ammonia Acidic fog and precipitation Sulfuric acid Water Sulfur trioxide Sulfur dioxide Metallic sulfide deposits

80 Effects of Human Activities on the Sulfur Cycle We add sulfur dioxide to the atmosphere by: We add sulfur dioxide to the atmosphere by: Burning coal and oil Burning coal and oil Refining sulfur containing petroleum. Refining sulfur containing petroleum. Convert sulfur-containing metallic ores into free metals such as copper, lead, and zinc releasing sulfur dioxide into the environment. Convert sulfur-containing metallic ores into free metals such as copper, lead, and zinc releasing sulfur dioxide into the environment.

81 The Gaia Hypothesis: Is the Earth Alive? Some have proposed that the earths various forms of life control or at least influence its chemical cycles and other earth-sustaining processes. Some have proposed that the earths various forms of life control or at least influence its chemical cycles and other earth-sustaining processes. The strong Gaia hypothesis: life controls the earths life-sustaining processes. The strong Gaia hypothesis: life controls the earths life-sustaining processes. The weak Gaia hypothesis: life influences the earths life-sustaining processes. The weak Gaia hypothesis: life influences the earths life-sustaining processes.

82 HOW DO ECOLOGISTS LEARN ABOUT ECOSYSTEMS? Field Research- Going into the field Field Research- Going into the field Measuring and/or observations out in nature Measuring and/or observations out in nature UsuallyUsually Controlled experiments e.g. Hubbard Brooks Controlled experiments e.g. Hubbard Brooks RarelyRarely Lab Research Lab Research Controlled indoor & outdoor chambers Controlled indoor & outdoor chambers Systems Analysis/Modelling Systems Analysis/Modelling Feedback loops mathematically programmed Feedback loops mathematically programmed

83 Remote Sensing & GIS Ecologist go into ecosystems to observe, but also use remote sensors on aircraft and satellites to collect data and analyze geographic data in large databases. Ecologist go into ecosystems to observe, but also use remote sensors on aircraft and satellites to collect data and analyze geographic data in large databases. Geographic Information Systems (GIS) Geographic Information Systems (GIS) Remote Sensing Remote Sensing

84 Remote Sensing

85

86 The effect of building roads in a rainforest…

87 Geographic Information Systems (GIS) A GIS organizes, stores, and analyzes complex data collected over broad geographic areas. A GIS organizes, stores, and analyzes complex data collected over broad geographic areas. Allows the simultaneous overlay of many layers of data. Allows the simultaneous overlay of many layers of data. Next

88 Fig. 3-33, p. 79 Critical nesting site locations USDA Forest Service USDA Forest Service Private owner 1 Private owner 2 Topography Habitat type Lake Wetland Forest Grassland Real world

89 Systems Analysis Ecologists develop mathematical and other models to simulate the behavior of ecosystems. Ecologists develop mathematical and other models to simulate the behavior of ecosystems. Figure 3-34

90 Importance of Baseline Ecological Data We need baseline data on the worlds ecosystems so we can see how they are changing and develop effective strategies for preventing or slowing their degradation. We need baseline data on the worlds ecosystems so we can see how they are changing and develop effective strategies for preventing or slowing their degradation. Scientists have less than half of the basic ecological data needed to evaluate the status of ecosystems in the United Sates (Heinz Foundation 2002; Millennium Assessment 2005). Scientists have less than half of the basic ecological data needed to evaluate the status of ecosystems in the United Sates (Heinz Foundation 2002; Millennium Assessment 2005).


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