1. Ecosystems: What Are They and How Do They Work?
Chapter 4-1 & 4-2
Ecosystems:
What Are They and
How Do They Work?

2. QUESTION OF THE DAY What would be an example of a parasite?
Ticks feeding on a deer
Startlings displacing bluebirds from nesting sites
Bees consuming nectar and carrying pollen from one flower to another
Moss growing on a tree trunk

3. THE NATURE OF ECOLOGY Ecology is a study of connections in nature.
How organisms interact with one another (biotic) and with their nonliving (abiotic) environment.
Figure 3.2
Natural capital: levels of organization of matter in nature. Ecology focuses on five of these levels.
Figure 3-2

4. Organisms and Species
Organisms, the different forms of life on earth, can be classified into different species based on certain characteristics.
Figure 3.3
Natural capital: breakdown of the earth’s 1.4 million known species. Scientists estimate that there are 4 million to 100 million species.
Figure 3-3

5. Populations, Communities, and Ecosystems
Members of a species interact in groups called populations.
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.

6. Populations
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.
Figure 3-4

7. Populations Genetic diversity
In most natural populations individuals vary slightly in their genetic makeup.
Figure 3-5

8. Visualizing an Ecosystem
biosphere
ecosystem
community
population
organism

9. THE EARTH’S LIFE SUPPORT SYSTEMS
The biosphere consists of several physical layers that contain:
Air
Water
Soil
Minerals
Life
Figure 3.6
Natural capital: general structure of the earth.
Figure 3-6

10. The Earth’s Components
Atmosphere
Membrane of air around the planet.
Stratosphere
Lower portion contains ozone to filter out most of the sun’s harmful UV radiation.
Hydrosphere
All the earth’s water: liquid, ice, water vapor
Lithosphere
The earth’s crust and upper mantle.

11. The Biosphere
Biosphere: the space where organisms live and interact. It includes
Most of the Hydrosphere
Parts of the lower atmosphere
Parts of the upper lithosphere

12. What Sustains Life on Earth?
1. Solar energy
2. The cycling of matter
3. Gravity
sustain the earth’s life.
Figure 3.7
Natural capital: life on the earth depends on the flow of energy (wavy arrows) from the sun through the biosphere and back into space, the cycling of crucial elements (solid arrows around ovals), and gravity, which keeps atmospheric gases from escaping into space and helps recycle nutrients through air, water, soil, and organisms. This simplified model depicts only a few of the many cycling elements.
Figure 3-7

13. The Effect of Solar Energy on the Earth
Solar energy flowing through the biosphere
1. Warms the atmosphere
2. Evaporates and
recycles water
3. Generates winds and
4. Supports plant growth.
Figure 3.8
Solar capital: flow of energy to and from the earth.
Figure 3-8

14. Ecosystem inputs nutrients cycle inputs energy nutrients
biosphere
energy flows through
constant input of energy
nutrients cycle
Matter cannot
be created or destroyed
Don’t forget the laws of Physics!
nutrients can only cycle
inputs
energy
nutrients

15. Generalized Nutrient cycling
consumers
consumers
consumers
producers
decomposers
decomposers
nutrients ENTER FOOD CHAIN = made available to producers
nutrients made available to producers
return to abiotic reservoir
Decomposition connects all trophic levels
abiotic reservoir
abiotic reservoir
geologic processes
geologic processes

16. Summary 1. What do ecologists study?
Interactions among organisms, populations, communities, ecosystems, and the biosphere.
2. How does a population differ from a community? Example
3. What is an ecosystem? A community of different species interacting with each other and with their nonliving environment of matter and energy. All of the earth’s diverse ecosystems comprise the biosphere.
4. What are the interconnected spherical layers make up the earth’s life-support system?
5. How does solar energy sustain life?

17. Ecosystems Components
Chapter 4-3
Ecosystems Components

18. QUESTION OF THE DAY All forms of water make up the lithosphere
atmosphere
hydrosphere
tranosphere
biosphere

19. ECOSYSTEM COMPONENTS Life exists on land systems called Biomes
Ex. deserts, forests, and grasslands
Aquatic life zones in freshwater and ocean.
Ex. coral reefs, coastal estuaries, deep ocean
Figure 3.9
Natural capital: major biomes found along the 39th parallel across the United States. The differences reflect changes in climate, mainly differences in average annual precipitation and temperature.

20. ECOSYSTEM COMPONENTS
Major biomes found along the 39th parallel across the United States
What causes the differences?
Figure 3.9
Natural capital: major biomes found along the 39th parallel across the United States. The differences reflect changes in climate, mainly differences in average annual precipitation and temperature.
Figure 3-9

21. Components of Ecosystems
Abiotic: non-living living components
Ex.
Biotic: living components.
Figure 3.10
Natural capital: major components of an ecosystem in a field
Figure 3-10

22. Factors That Limit Population Growth
Availability of matter and energy resources can limit the number of organisms in a population. Ex.
Figure 3.11
Natural capital: range of tolerance for a population of organisms, such as fish, to an abiotic environmental factor—in this case, temperature. These restrictions keep particular species from taking over an ecosystem by keeping their population size in check.
dissolved oxygen (DO) content in the water or by the salinity.
Figure 3-11

23. Factors That Limit Population Growth
The physical conditions of the environment can limit the distribution of a species.
i.e.
Figure 3.12
The physical conditions of the environment can limit the distribution of a species. The green area shows the current range of sugar maple trees in eastern North America. (Data from U.S. Department of Agriculture)
Figure 3-12

24. Major Biological Components
Autotrophs (self-feeders): make their own food from compounds in the environment
Consumers (heterotrophs): feed on other organisms or their remains.
Natural ecosystems produce little waste or no waste. In nature, waste becomes food.

25. Producers: Basic Source of All Food
Most producers capture sunlight to produce carbohydrates by photosynthesis:
Chemosynthesis:
Some organisms such as deep ocean bacteria draw energy from hydrothermal vents and produce carbohydrates from hydrogen sulfide (H2S) gas .

26. Photosynthesis: A Closer Look
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.
Figure 3.A
Simplified overview of photosynthesis. In this process, 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, such as glucose, and oxygen.
Figure 3-A

27. Consumers
Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains.
Herbivores
Primary consumers that eat producers
Carnivores
Secondary consumers eat primary consumers
Third and higher level consumers: carnivores that eat carnivores.
Omnivores
Feed on both plant and animals.

28. Role of Decomposers and Detritivores
Detritivores: Insects or other scavengers that feed on wastes or dead bodies.
They leave some parts and their feces that are converted to energy by the decomposers.
Improve the nutritional value and the texture of the soil
Millipedes, earthworms and slugs feed on dead plants and animals
Decomposers:
Recycle nutrients in ecosystems.
Help in the process of decay by converting what is left by the detritivores
Bacteria and fungi
Figure 3.13
Natural capital: various scavengers (detritivores) and decomposers (mostly fungi and bacteria) can “feed on” or digest parts of a log and eventually convert its complex organic chemicals into simpler inorganic nutrients that can be taken up by producers.
Figure 3-13

29. Decomposers and Detrivores
Figure 3.13
Natural capital: various scavengers (detritivores) and decomposers (mostly fungi and bacteria) can “feed on” or digest parts of a log and eventually convert its complex organic chemicals into simpler inorganic nutrients that can be taken up by producers.
Figure 3-13

30. 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
This is usually done through aerobic respiration.
The opposite of photosynthesis

31. Aerobic and Anaerobic Respiration: Getting Energy for Survival
Anaerobic respiration or fermentation:
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:
Methane gas
Ethyl alcohol
Acetic acid
Hydrogen sulfide

32. Two Secrets of Survival: Energy Flow and Matter Recycle
An ecosystem survives by a combination of
Energy flow and
Matter recycling
Figure 3.14
Natural capital: the main structural components of an ecosystem (energy, chemicals, and organisms). Matter recycling and the flow of energy—first from the sun, then through organisms, and finally into the environment as low-quality heat—links these components.
Figure 3-14

33. BIODIVERSITY
Functional diversity: biological & chemical processes necessary for life
Genetic Diversity: variety of genetic material within a species or population
Species Diversity: the number of species present in different habitats.
Ecological Diversity: the variety of terrestrial & aquatic ecosystems in an area or on the earth.
Figure 3-15

34. BIODIVERSITY
Figure 3-15

35. Biodiversity Loss and Species Extinction: Remember HIPPO
H for habitat destruction and degradation
I for invasive species
P for pollution
P for human population growth
O for overexploitation

36. Why Should We Care About Biodiversity?
Biodiversity provides us with:
Natural Resources (food water, wood, energy, and medicines)
Natural Services (air and water purification, soil fertility, waste disposal, pest control)
Aesthetic pleasure

37. Solutions Goals, strategies and tactics for protecting biodiversity.
Species approach
Ecosystem Approach
Figure 3.16
Solutions: goals, strategies, and tactics for protecting biodiversity.
Figure 3-16

38. SUMMARY 1. Why do limiting factors affect species’ range?
2. What are the two major biological components of ecosystems?
3. How are the roles of decomposers and detritivores related?
4. What are the four kinds of biodiversity?
5. What are the causes of biodiversity loss and species extinction?
The limiting factor principle states that too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are at or near the optimum range of tolerance.

39. Energy Flow in Ecosystems & Primary Productivity Energy Flow
Chapter 4-4 & 4-5
Energy Flow in Ecosystems
&
Primary Productivity
Energy Flow

40. ENERGY FLOW IN ECOSYSTEMS
Figure 3.17
Natural capital: a food chain. The arrows show how chemical energy in food flows through various trophic levels in energy transfers; most of the energy is degraded to heat, in accordance with the second law of thermodynamics.
Food chains and webs show how eaters, the eaten, and the decomposed are connected to one another in an ecosystem.
Figure 3-17

41. Food Webs
Trophic levels are interconnected within a more complicated food web.
What is the purpose of a food web?
Figure 3.18
Natural capital: a greatly simplified food web in the Antarctic. Many more participants in the web, including an array of decomposer organisms, are not depicted here.
Figure 3-18

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

43. 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.
% energy transferred:
Where does the majority of energy go?
How does this effect the # of organisms found in each trophic level?
Figure 3.19
Natural capital: generalized pyramid of energy flow showing the decrease in usable energy available at each succeeding trophic level in a food chain or web. In nature, ecological efficiency varies from 2% to 40%, with 10% efficiency being common. This model assumes a 10% ecological efficiency (90% loss in usable energy to the environment, in the form of low-quality heat) with each transfer from one trophic level to another. QUESTION: Why is it a scientific error to call this a pyramid of energy?
Figure 3-19

44. Productivity of Producers: The Rate Is Crucial
Gross primary production (GPP)
Rate at which an ecosystem’s producers convert solar energy into chemical energy as biomass.
Which areas have the greatest GPP?
Figure 3.20
Natural capital: gross primary productivity across the continental United States based on remote satellite data. The differences roughly correlate with variations in moisture and soil types. (NASA’s Earth Observatory)
Figure 3-20

45. Net Primary Production (NPP)
NPP = GPP – R
Rate at which producers use photosynthesis to store energy minus the rate at which they use some of this energy through respiration (R).
Figure 3.21
Natural capital: distinction between gross primary productivity and net primary productivity. A plant uses some of its gross primary productivity to survive through respiration. The remaining energy is available to consumers.
Figure 3-21

46. Figure 3.22
Natural capital: estimated annual average net primary productivity per unit of area in major life zones and ecosystems, expressed as kilocalories of energy produced per square meter per year (kcal/m2/yr). QUESTION: What are nature’s three most productive and three least productive systems? (Data from Communities and Ecosystems, 2nd ed., by R. H. Whittaker, New York: Macmillan)
What are nature’s three most productive and three least productive systems?
Figure 3-22

47. Chapter 4-4 /4-5 Summary 1. Food Chains: 2. Food Webs
3. 1st Law of Thermodynamics
4. 2nd Law of Thermodynamics
5. Efficiency of Energy Flow
6. Pyramid of Energy
7. Pyramid of Biomass
8. Gross Primary Productivity
9. Net Primary Productivity

48. Matter Cycling in Ecosystems Matter & Energy Transfer
Chapter 4-7
Matter Cycling in Ecosystems
Matter & Energy Transfer

49. MATTER CYCLING IN ECOSYSTEMS
Nutrient Cycles: Global Recycling
Global Cycles recycle nutrients through the earth’s air, land, water, and living organisms.
Nutrients are the elements and compounds that organisms need to live, grow, and reproduce.
Biogeochemical cycles move these substances through air, water, soil, rock and living organisms.

50. Background on Biogeochemical cycles
Earth system has four parts
Atmosphere
Hydrosphere
Lithosphere
Biosphere
Biogeochemical cycles: The chemical interactions (cycles) that exist between the atmosphere, hydrosphere, lithosphere, and biosphere.
Abiotic (physio-chemical) and biotic processes drive these cycles

51. Commonalities of the Cycles
Each nutrient typically exists in different parts of the Earth System
There are
‘Pools’ or reservoirs
Fluxes in and out of pools
Chemical or biochemical transformations
Transformations (or processes)
Help to move nutrients between parts of the earth’s system
Can lead to positive & negative consequences

52. Examples of Transformations/Processes
Carbon cycle: Organic compounds to CO2 (processes: respiration, decomposition, or fire)
Carbon cycle: CO2 to organic compounds (process: photosynthesis)
Nitrogen cycle: N2 to NO3 (atmospheric nitrogen to plant utilizable nitrate) (process: N-fixation)
Nitrogen cycle: N2 to NH3 (plant utilizable ammonia) (process: Haber-Bosch Industrial N-fixation)
Water cycle: Liquid water to water vapor (process: evaporation and transpiration)
Water cycle: Water vapor to liquid water (process: condensation)

53. The Water Cycle Figure 3-26 Figure 3.26
Natural capital: simplified model of the hydrologic cycle.
Figure 3-26

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

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

56. The Carbon Cycle: Part of Nature’s Thermostat
Figure 3.27
Natural capital: simplified model of the global carbon cycle. Carbon moves through both marine ecosystems (left side) and terrestrial ecosystems (right side). Carbon reservoirs are shown as boxes; processes that change one form of carbon to another are shown in unboxed print. QUESTION: What are three ways in which your lifestyle directly or indirectly affects the carbon cycle? (From Cecie Starr, Biology: Concepts and Applications, 4th ed., Pacific Grove, Calif.: Brooks/Cole, © 2000)
Figure 3-27

57. Carbon Cycle
5000

58. Effects of Human Activities on Carbon Cycle
We alter the carbon cycle by adding excess CO2 to the atmosphere through:
Burning fossil fuels.
Ex.
Clearing vegetation faster than it is replaced.
Figure 3.28
Natural capital degradation: human interference in the global carbon cycle from carbon dioxide emissions when fossil fuels are burned and forests are cleared, 1850 to 2006 and projections to 2030 (dashed lines). (Data from UN Environment Programme, British Petroleum, International Energy Agency, and U.S. Department of Energy)
Figure 3-28

59. The Nitrogen Cycle: Bacteria in Action
Figure 3.29
Natural capital: simplified model of the nitrogen cycle in a terrestrial ecosystem. Nitrogen reservoirs are shown as boxes; processes changing one form of nitrogen to another are shown in unboxed print. QUESTION: What are three ways in which your lifestyle directly or indirectly affects the nitrogen cycle? (Adapted from Cecie Starr, Biology: Today and Tomorrow, Brooks/Cole © 2005)
Figure 3-29

60. Nitrogen Cycle

61. Forms of Nitrogen (N2) N2 - inert gas, 78% of the atmosphere
NO, N20, NO2 - other gases of nitrogen, not directly biologically important. Part of the gases found in smog.
NO3- (nitrate) and NH4+ (ammonium) -- ionic forms of nitrogen that are biologically usable.

62. Forms & Sources of Biologically Available Nitrogen (N2)
For Plants
NO3- (nitrate)
NH4+ (ammonium)
Sources: N-fixation by plants (N2 to NH3 and N2 to NO3), lightening, bacteria decomposition of organic N (amino acids & proteins)
For Animals
Organic forms: amino acids and proteins (from plants or other animals)

63. Losses of Nitrogen from system
In bogs, lakes (places of low oxygen), NO3- is converted to N2 by bacteria (get their oxygen from the NO3)
Volatilization of NH4+ (urea) to ammonia gas (NH3) - warm, dry conditions.
Leaching of NO3- (nitrate)
Erosion
Fire (combustion)

64. Pneumonic Device
FIX A
N N
A P
A A
D N

65. Nitrogen Cycle: Key Points
Nitrogen is in the atmosphere as N2 (78%)
N2 is an inert gas and cannot be used by plants or animals
N2 can be converted to a usable form via
Lightening
N-fixing plants and cyanobacteria
Industrial process (energy intensive)
Nitrogen limits plant growth
Nitrogen is easily lost from biological systems

66. Effects of Human Activities on the Nitrogen Cycle
We alter the nitrogen cycle by:
Adding gases that contribute to acid rain.
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.
Releasing nitrogen into the troposphere through deforestation.

67. Effects of Human Activities on the Nitrogen Cycle
Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined.
Figure 3.30
Natural capital degradation: human interference in the global nitrogen cycle. Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined. (Data from UN Environment Programme, UN Food and Agriculture Organization, and U.S. Department of Agriculture)
Figure 3-30

68. The Phosphorous Cycle Figure 3-31 Figure 3.31
Natural capital: simplified model of the phosphorus cycle. Phosphorus reservoirs are shown as boxes; processes that change one form of phosphorus to another are shown in unboxed print. QUESTION: What are three ways in which your lifestyle directly or indirectly affects the phosphorus cycle? (From Cecie Starr and Ralph Taggart, Biology: The Unity and Diversity of Life, 9th ed., Belmont, Calif.: Wadsworth © 2001)
Figure 3-31

69. Effects of Human Activities on the Phosphorous Cycle
We remove large amounts of phosphate from the earth to make fertilizer.
We reduce phosphorous in tropical soils by clearing forests.
We add excess phosphates to aquatic systems from runoff of animal wastes and fertilizers.

70. The Sulfur Cycle Figure 3-32 Figure 3.32
Natural capital: simplified model of the sulfur cycle. The movement of sulfur compounds in living organisms is shown in green, blue in aquatic systems, and orange in the atmosphere. QUESTION: What are three ways in which your lifestyle directly or indirectly affects the sulfur cycle?
Figure 3-32

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

73. Chapter 4-7 Summary
1. Biogeochemical cycles nutrients through air, water, soil, rock and living organisms.
2. Human activities impact the cycle
3. Water (hydrologic) cycle
4. Carbon cycle
5. Nitrogen Cycle
6. Phosphorus Cycle
7. Sulfur Cycle

74. Chapter 4-6
Soils

75. SOIL: A RENEWABLE RESOURCE
Soil is a slowly renewed resource that provides most of the nutrients needed for plant growth and also helps purify water.
Soil formation begins when bedrock is broken down by physical, chemical and biological processes called weathering.
Mature soils, or soils that have developed over a long time are arranged in a series of horizontal layers called soil horizons.

76. SOIL: A RENEWABLE RESOURCE
Figure 3-23

77. Wood sorrel Oak tree Organic debris builds up Lords and ladies
Dog violet
Rock
fragments
Grasses and
small shrubs
Earthworm
Millipede
Fern
Moss and
lichen
Honey
fungus
O horizon
Mole
Leaf litter
A horizon
Topsoil
B horizon
Bedrock
Subsoil
Immature soil
Regolith
Young soil
C horizon
Figure 3.23
Natural capital: soil formation and generalized soil profile. Horizons, or layers, vary in number, composition, and thickness, depending on the type of soil. (Used by permission of Macmillan Publishing Company from Derek Elsom, Earth, New York: Macmillan, Copyright © 1992 by Marshall Editions Developments Limited)
Pseudoscorpion
Mite
Parent
material
Nematode
Root system
Actinomycetes
Red Earth
Mite
Fungus
Mature soil
Bacteria
Springtail
Fig. 3-23, p. 68

78. Layers in Mature Soils
Infiltration: the downward movement of water through soil.
Leaching: dissolving of minerals and organic matter in upper layers carrying them to lower layers.
The soil type determines the degree of infiltration and leaching.

79. Soil Profiles of the Principal Terrestrial Soil Types
Figure 3-24

80. Desert Soil (hot, dry climate) Grassland Soil semiarid climate)
Mosaic of closely packed pebbles, boulders
Weak humus-mineral mixture
Alkaline,
dark,
and rich
in humus
Dry, brown to reddish-brown with variable accumulations of clay, calcium and carbonate, and soluble salts
Figure 3.24
Natural capital: soil profiles of the principal soil types typically found in five types of terrestrial ecosystems.
Clay, calcium compounds
Desert Soil
(hot, dry climate)
Grassland Soil
semiarid climate)
Fig. 3-24a, p. 69

81. Tropical Rain Forest Soil (humid, tropical climate)
Acidic
light-colored humus
Figure 3.24
Natural capital: soil profiles of the principal soil types typically found in five types of terrestrial ecosystems.
Iron and aluminum compounds mixed with clay
Tropical Rain Forest Soil
(humid, tropical climate)
Fig. 3-24b, p. 69

82. Deciduous Forest Soil (humid, mild climate)
Forest litter leaf mold
Humus-mineral mixture
Light, grayish-brown, silt loam
Figure 3.24
Natural capital: soil profiles of the principal soil types typically found in five types of terrestrial ecosystems.
Dark brown firm clay
Deciduous Forest Soil
(humid, mild climate)
Fig. 3-24b, p. 69

83. Coniferous Forest Soil
Acid litter and humus
Light-colored and acidic
Figure 3.24
Natural capital: soil profiles of the principal soil types typically found in five types of terrestrial ecosystems.
Humus and iron and aluminum compounds
Coniferous Forest Soil
(humid, cold climate)
Fig. 3-24b, p. 69

84. Some Soil Properties
Soils vary in the size of the particles they contain, the amount of space between these particles, and how rapidly water flows through them.
Figure 3-25

85. Sand Silt Clay 0.05–2 mm diameter 0.002–0.05 mm diameter
less than mm
Diameter
Water
Water
Figure 3.25
Natural capital: the size, shape, and degree of clumping of soil particles determine the number and volume of spaces for air and water within a soil. Soils with more pore spaces (left) contain more air and are more permeable to water than soils with fewer pores (right).
High permeability
Low permeability
Fig. 3-25, p. 70

86. HOW DO ECOLOGISTS LEARN ABOUT ECOSYSTEMS?
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
Remote Sensing
Ecologists also use controlled indoor and outdoor chambers to study ecosystems

87. Geographic Information Systems (GIS)
A GIS organizes, stores, and analyzes complex data collected over broad geographic areas.
Allows the simultaneous overlay of many layers of data.
Figure 3-33

88. USDA Forest Service Private owner 1 Habitat type
Critical nesting site locations
USDA Forest Service
USDA
Forest Service
Private
owner 1
Private owner 2
Topography
Habitat type
Forest
Wetland
Lake
Figure 3.33
Geographic information systems (GISs) provide the computer technology for organizing, storing, and analyzing complex data collected over broad geographic areas. They enable scientists to overlay many layers of data (such as soils, topography, distribution of endangered populations, and land protection status).
Grassland
Real world
Fig. 3-33, p. 79

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

90. Identify and inventory variables Obtain baseline data on variables
Define objectives
Systems
Measurement
Identify and inventory variables
Obtain baseline data on variables
Make statistical analysis of
relationships among variables
Data
Analysis
Determine significant interactions
System
Modeling
Objectives Construct mathematical model
describing interactions among
variables
Figure 3.34
Major stages of systems analysis. (Modified data from Charles Southwick)
Run the model on a computer,
with values entered for different
Variables
System
Simulation
System
Optimization
Evaluate best ways to achieve
objectives
Fig. 3-34, p. 80

91. Importance of Baseline Ecological Data
We need baseline data on the world’s 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).