Ecosystems Study Guide
Name:______________________
1. How do humans obtain nitrogen and carbon cycle?
2. How do humans add to the nitrogen and carbon cycle?
3. How do humans artificially impact the nitrogen and carbon cycles?
4. What role do bacteria have in the Nitrogen cycle?
5. What role do plant have in the nitrogen and carbon cycle?
6. Contrast abiotic and biotic factors in an ecosystem and provide examples for each.
7. What is biomagnification and provide an example?
8. How are the terms bioaccumulation and biomagnification related?
SEE BACK FOR MORE QUESTIONS
Ecosystems Study Guide
Name:______________________
1. How do humans obtain nitrogen and carbon cycle?
2. How do humans add to the nitrogen and carbon cycle?
3. How do humans artificially impact the nitrogen and carbon cycles?
4. What role do bacteria have in the Nitrogen cycle?
5. What role do plant have in the nitrogen and carbon cycle?
6. Contrast abiotic and biotic factors in an ecosystem and provide examples for each.
7. What is biomagnification and provide an example?
8. How are the terms bioaccumulation and biomagnification related?
SEE BACK FOR MORE QUESTIONS
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Sun
9. List 1 food chain from the food web above and label the trophic levels (primary producer, primary consumer,
secondary consumer, tertiary consumer)
10. What happens to the amount of energy as it moves up the trophic levels? How does this affect the size of
populations at each trophic level?
11. What is the difference between an herbivore, omnivore and carnivore?
12. What are decomposers role in an ecosystem? Where could you add them to the food web?
13. What is the source of energy for all food webs?
14. What would happen if the population of deer in the food web above was hunted to extinction? What would be
some unintended consequences?
Sun
9. List 1 food chain from the food web above and label the trophic levels (primary producer, primary consumer,
secondary consumer, tertiary consumer)
10. What happens to the amount of energy as it moves up the trophic levels? How does this affect the size of
populations at each trophic level?
11. What is the difference between an herbivore, omnivore and carnivore?
12. What are decomposers role in an ecosystem? Where could you add them to the food web?
13. What is the source of energy for all food webs?
14. What would happen if the population of deer in the food web above was hunted to extinction? What would be
some unintended consequences?
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Ecosystems Study Guide
ANSWER KEY
1. How do humans obtain nitrogen and carbon cycle?
Humans obtain nitrogen and carbon from their food (plants and animals)
2. How do humans add to the nitrogen and carbon cycle?
Carbon – exhaling and decomposition (death)
Nitrogen – pee and decomposition (death)
3. How do humans artificially impact the nitrogen and carbon cycles?
Carbon – burning fossil fuels (cars, factories, power plants), cutting down trees, flash burning
Nitrogen – Fertilizers from farming, lawns, etc
4. What role do bacteria have in the Nitrogen cycle?
Nitrifying bacteria “fix” or absorb nitrogen from the atmosphere so that plants can use it.
5. What role do plants have in the nitrogen and carbon cycle?
Carbon – plants absorb CO2 from the atmosphere to use for photosynthesis.
Nitrogen – plants contain nitrogen. This is passed on to the animals that eat them.
6. Contrast abiotic and biotic factors in an ecosystem and provide examples for each.
Abiotic (non-living) – chemicals, rocks, oceans, mountains, water, sunlight, viruses, weather etc
Biotic (living) – animals, plants, decomposers, bacteria, relationships (competition, symbiosis, predation)
7. What is biomagnification and provide an example?
Biomagnification is the build up of toxins as you move up the trophic levels and concentrates at the top. An
example is the Orcas (PCBs) or dolphins (DDT). It can lead to death, cancer, poor reproduction, etc.
8. How are the terms bioaccumulation and biomagnification related?
Bioaccumulation occurs on an individual level (in you) while biomagnification occurs throughout an entire
food web (ecosystem).
15. List 1 food chain from the food web above and label the trophic levels (primary producer, primary
consumer, secondary consumer, tertiary consumer).
Grass (producer) -> grasshopper (primary consumer) -> coyote (secondary consumer) -> cougar (tertiary)
16. What happens to the amount of energy as it moves up the trophic levels? How does this affect the size of
populations at each trophic level?
Only 10% of energy transfers to the next trophic level. This means fewer numbers of animals can be
supported the higher up the trophic levels the energy moves.
17. What is the difference between an herbivore, omnivore and carnivore?
Herbivore (eats plants), carnivore (eats animals), omnivore (eats both)
18. What are decomposers role in an ecosystem? Where could you add them to the food web?
Decomposers break down dead matter (plants and animals) and release nutrients back to the soil.
19. What is the source of energy for all food webs?
The sun!
20. What would happen if the population of deer in the food web above was hunted to extinction? What would
be some unintended consequences?
The grass population would increase, causing primary consumers (grass hoppers and prairie dogs) to
increase. Coyotes would increase but cougars would DECREASE.
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