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AP Biology Reading Guide for Chapter 37
Communities and Ecosystems
OK, there’s a LOT in this chapter – it contains many of the basic principles of Ecology that you should be
able to remember from Intro Biology.
Again, I recommend viewing Paul Anderson’s video that gives a 10-minutes overview of this chapter, at
http://www.bozemanscience.com/ecology. Go to the last video on the page, titled “Communities and
Ecosystems.”
Important concepts You Must Know: (advice from the text-prep experts!)
• The role of competitive exclusion in interspecific competition.
• The symbiotic relationships of parasitism, mutualism, and commensalism.
• The impact of keystone species on community structure.
• The difference between primary and secondary succession
1. Read the introduction to Ch. 37 and draw a diagram of the food web described. Aren't ecosystems awesome?!
2. Define “community” - how is this different from a "population"?
3. What happens when two species compete for the same resources?
4. Distinguish between Batesian and Mullerian mimicry (not in your text), and give an example of each.
5. Define and give two examples of mutualism.
6. Define and give two examples of commensalism
7. Distinguish between parasites and predators.
• Name several examples of adaptations that prey organisms have developed in order to avoid predation.
• Name several examples of plant adaptations to avoid being eaten by herbivores.
8. You should remember the terms producer, consumer, autotroph, heterotroph, food chain, and food web from 9th
grade biology. (If not, look them up now!) These fit into different trophic levels, depending on the exact structure of
the community in question.
What do the direction of the arrows indicate in a food web?
In the diagram below, label the boxes on the left with the following: (each color always gets the same label)
Producers
Primary consumers
Secondary consumers
Tertiary consumers
Notice how one organism can be two different things!!
Also label:
An autotroph
A heterotroph
An herbivore
A carnivore
An omnivore
An example of predation
An example of competition
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a.
b.
What are the trophic levels involved when a human eats a grilled cheese sandwich?
Where do detritivores and decomposers fit into this picture?
9. Create a 4-organism food chain that would be found in a desert. Identify the trophic level of each organism.
10. In an idealized food pyramid, what percent of energy is passed along from one level to the next? Why so little?
11. Distinguish between primary and secondary succession. Which type would occur if St. Andrew’s suddenly left
the area behind the library completely and totally alone? What do you predict the outcome would be? On a side
note, is a climax community “fixed” or “changeable”?
12. How do you characterize the dominant species? How is this different from the keystone species? Which is more
important in an ecosystem?
13. Speaking of which, what IS an ecosystem?
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14. See if you can label the diagram below. Hint:
blue = chemical cycling
red = energy flow
"The Sun"
15.Define “primary production”.
16. What limits the length of a food chain? How does this explain why eating meat is an ecological luxury for
humans?
17. Read about David Schindler's work on pg 759. What is eutrophication? Is it considered a “good thing” for a
lake environment?
18. Briefly outline the carbon cycle – write your answer, or draw the cycle.
19. Briefly outline the nitrogen cycle – write your answer, or draw the cycle.
20. Briefly outline the phosphorus cycle – write your answer, or draw the cycle.
21. Which biogeochemical cycle do you think humans have had the most impact on? Why?
22. EXTRA CREDIT: choose an invasive species NOT listed in your textbook and write a short (1-page) summary
of it – where it came from, how it got to the region it invaded, why it's invasive, current status, and what's being
done. Include references!!
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