1. 3-2 What Are the Major Components of an Ecosystem?
Concept 3-2 Some organisms produce the nutrients they need, others get their nutrients by consuming other organisms, and some recycle nutrients back to producers by decomposing the wastes and remains of organisms.

2. Ecologists Study Interactions in Nature
Ecology is a key component of environmental science
the study of how organisms interact with ________________ and their ________________ environment
Organism - ___________________ living being
Populations - ____________ of the same species
Communities – populations of _____________ species
Ecosystems – community plus its ______________ environment
Biosphere – parts of the planet where _________ is found
one another
non-living
individual
groups
interacting
non-living
life

3. Biosphere Ecosystem Community Population Organism Cell Molecule Atom
Parts of the earth's air,water, and soil where life is found
Ecosystem
A community of different species interacting with one another and with their nonliving environment of matter and energy
Community
Populations of different species living in a particular place, and potentially interacting with each other
Population
A group of individuals of the same species living in a particular place
Organism
An individual living being
Cell
The fundamental structural and functional unit of life
Molecule
Chemical combination of two or more atoms of the same or different elements
Water
Smallest unit of a chemical element that exhibits its chemical properties
Atom
Stepped Art
Hydrogen
Oxygen
Fig. 3-5, p. 58

4. Ecosystems Have Living and Nonliving Components
The nonliving components of an ecosystem are called _______________ factors
Water
Air
Nutrients
Rocks
Heat
Solar energy
The living and ____________________ components of an ecosystem are called _____________ factors
Includes plants, animals, microbes, and all organisms
abiotic
once living
biotic

5. What are some of the abiotic factors shown in this diagram? CO2 O2
precipitation
minerals
Figure 3.6: Key living and nonliving components of an ecosystem in a field are shown in this diagram.
water
Fig. 3-6, p. 59

6. Producers and Consumers Are the Living Components of Ecosystems (1)
Ecologists assign every type of organism in an ecosystem to a feeding level, or ____________ level
Producers, autotrophs - ____________________
Photosynthesis:
6CO2 + 6H2O + sunlight → C6H12O6 + 6O2
(glucose)
energy rich carbohydrate
Chemosynthesis – process through which specialized _____________ living in deep-sea hydrothermal vents use __________________ energy to convert simple inorganic compounds into more complex nutrient compounds
trophic
“self-feeder”
bacteria
geothermal

7. Producers Green plants (photosynthesis) Algae (photosynthesis)
Figure 3.7: Some producers live on land, such as this large tree and other plants in an Amazon rain forest (Core Case study) in Brazil (left). Others, such as green algae (right), live in water.
Algae
(photosynthesis)
Fig. 3-7a, p. 59

8. Producers Phytoplankton in the sea (photosynthesis) Chemosynthetic
Figure 3.7: Some producers live on land, such as this large tree and other plants in an Amazon rain forest (Core Case study) in Brazil (left). Others, such as green algae (right), live in water.
Chemosynthetic
bacteria
Fig. 3-7a, p. 59

9. Producers and Consumers Are the Living Components of Ecosystems (1)
Consumers, heterotrophs - ___________________
Primary consumers - ___________________
Eat plants (or other producers)
Examples: giraffes, caterpillars, and zooplankton
Secondary consumers – eat ____________________
Examples: lions, spiders, small fish
Tertiary consumers – eat other __________________
Examples: hawks, killer whales
Omnivores – eat ________ plants and animals
Examples: humans, pigs, rats
“other-feeders”
herbivores
herbivores
Carnivores
both

10. Consumers Primary consumer - herbivore Secondary consumer - carnivore
Figure 3.8: The giraffe (left) feeding on the leaves of a tree is an herbivore. The lions (right) are carnivores feeding on the dead body of a giraffe that they have killed.
Fig. 3-8a, p. 60

11. Producers and Consumers Are the Living Components of Ecosystems (2)
Decomposers
Consumers that release _____________ from the wastes or remains of plants or animals
Return those nutrients back to the soil for producers to use
Example: Bacteria and fungi
Detritivores (detritus feeders)
Feed on ___________ bodies of other organisms
Examples: Earthworms and vultures
nutrients
dead

12. Decomposer
Figure 3.9: This saddle fungus feeding on a dead tree (left) is a decomposer. Three vultures and two Marabou storks (right), classified as detritivores, are eating the carcass of an animal that was killed by other animals.
Fig. 3-9a, p. 61

13. Detritivores and Decomposers
Detritivores and decomposers ________________ nutrients,
so there is very little waste of nutrients in nature
recycle
Figure 3.10: Various 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.
Fig. 3-10, p. 61

14. Producers and Consumers Are the Living Components of Ecosystems (3)
Once organisms obtain glucose (or other organic nutrient) …they ALL break it down to obtain the energy stored in its __________ _______________
Aerobic respiration
Using _______________ to turn glucose back to carbon dioxide and water
Anaerobic respiration = ___________________
Breaks down glucose in the ______________ of oxygen
End products…carbon compounds such as methane or acetic acid
chemical
bonds
oxygen
C6H12O6 + 6O2 → 6CO2 + 6H2O + ENERGY
fermentation
absence

15. Energy Flow and Nutrient Cycling
Ecosystems and the biosphere are sustained through…
_______________flow of energy from sun
Nutrient _______________ of key materials
one-way
cycling

16. Ecosystem Components High quality energy is either used or
converted to…?
heat
Nutrients
eventually return
to the soil and
producers through
the work of…?
Figure 3.11: Natural capital.
This diagram shows the main structural components of an ecosystem (energy, chemicals, and organisms). Nutrient cycling and the flow of energy—first from the sun, then through organisms, and finally into the environment as low-quality heat—link these components.
decomposers
Fig. 3-11, p. 62

17. 3-3 What Happens to Energy in an Ecosystem?
Concept 3-3 As energy flows through ecosystems in food chains and webs, the amount of chemical energy available to organisms at each succeeding feeding level decreases.

18. Energy Flows Through Ecosystems in Food Chains and Food Webs
A sequence of organisms, each which serves as ___________ or ___________ for the next, is called a ______________________
Different feeding levels are called _____________ levels
Every use and transfer of energy involves a loss of _______________________ energy to the environment as _____________
Food web
Network of ______________ food chains
food
energy
food chain
trophic
high-quality
heat
interconnected

19. A Food Chain
Figure 3.12: This diagram illustrates a food chain. The arrows show how the chemical energy in nutrients flows through various trophic levels in energy transfers; most of the energy is degraded to heat, in accordance with the second law of thermodynamics (see Chapter 2, p. 47). Question: Think about what you ate for breakfast. At what level or levels on a food chain were you eating?
Fig. 3-12, p. 63

20. A Food Web
Figure 3.13: This diagram illustrates a greatly simplified food web in the southern hemisphere. The shaded middle area shows a simple food chain. Its participants interact in feeding relationships to form the more complex food web shown here. Many more participants in the web, including an array of decomposer and detritus feeder organisms, are not shown here. Question: Can you imagine a food web of which you are a part? Try drawing a simple diagram of it.
Fig. 3-13, p. 64

21. Usable Energy Decreases with Each Link in a Food Chain or Web
Each trophic level in a food chain has a certain amount of biomass…dry ______________ of all organic matter of a given trophic level in a food chain or food web
Biomass ___________________ as you move through a food chain because high-quality energy is lost
Pyramid of energy flow
__________ of energy lost with each transfer
Less _____________ ____________ available to organisms at each succeeding level
weight
decreases
90%
chemical
energy

22. Pyramid of Energy Flow
Figure 3.14: This model is a generalized pyramid of energy flow that shows the decrease in usable chemical energy available at each succeeding trophic level in a food chain or web. The model assumes that with each transfer from one trophic level to another, there is a 90% loss in usable energy to the environment in the form of low-quality heat. (Calories and joules are used to measure energy. 1 kilocalorie = 1,000 calories = 4,184 joules.) Question: Why is a vegetarian diet more energy efficient than a meat-based diet?
Fig. 3-14, p. 65

23. Some Ecosystems Produce Plant Matter Faster Than Others Do
The biomass in a particular ecosystem is determined by how much solar energy its producers can _____________ and store and how ____________ they can do so
Gross primary productivity (GPP)
________ at which an ecosystem’s producers convert solar energy to chemical energy and biomass
Measured in terms of energy production per unit area over a given time span….._______________
capture
quickly
Rate
kcal/m2/year
“photosynthesis”

24. Some Ecosystems Produce Plant Matter Faster Than Others Do
Net primary productivity (NPP)
Rate at which an ecosystem’s producers convert solar energy to chemical energy, __________ the rate at which producers _________ energy for aerobic respiration
GPP = ___________________
NPP = the money you have left over to spend after you have paid your ___________ expenses
Clothes, transportation, food, supplies
minus
use
“photosynthesis - respiration”
paychecks
work

25. Estimated Annual Average NPP in Major Life Zones and Ecosystems
Figure 3.15: The estimated annual average net primary productivity in major life zones and ecosystems is expressed in this graph 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 R. H. Whittaker, Communities and Ecosystems, 2nd ed., New York: Macmillan, 1975)
What will happen to the NPP of a forest if its trees are cut down?
It will decrease
Fig. 3-15, p. 66

26. Review Questions 1. Which term describes interacting populations?
Organisms
Community
Ecosystem
Biosphere

27. Review Questions
2. Which organism below is acting as primary consumer?
Caterpillar

28. Review Questions 3. Why are the decomposers important?
They are recycling nutrients

29. Review Questions
4. Is energy being recycled? 5. Where does the energy come from? no
Sun (perpetual)

30. Review Questions 6. What is the difference between GPP and NPP?
GPP – rate that producers can capture and store energy
NPP – rate of energy capture minus rate of use for aerobic respiration