Chapter 3: the Biosphere

Chapter 3: The Biosphere

1. What is ecology? ______

2. What does the biosphere contain? ______

3. Why do ecologists worry about the events and organisms that range in complexity from an individual to the entire biosphere? ______

4. Complete the following table

Level Definition Species

A group of individuals that belong to the same species and live in the same area. Community

Ecosystem

A group of ecosystems that have the same climate and dominant communities.

5. What is the highest level of organization that ecologists study? ______

6. What are the three basic approaches scientists use to conduct modern ecological experiments?

a. ______b. ______c. ______

7. Why might an ecologist set up an artificial environment in a laboratory? ______8. Why are many ecological phenomena difficult to study? ______

9. Why do ecologists make models? ______

10. What is at the core of every organism’s interaction with the environment? ______

11. What source of energy do organisms use if they don’t use the sun’s energy? ______

12. What are autotrophs? ______

13. Why are autotrophs also called producers? ______

14. What do autotrophs do during photosynthesis (What do they take in and what do they produce)? ______

15. For each of the following, write which kind of autotroph is the main producer.

a. Land: ______

b. Upper layers of ocean: ______

c. Tidal flats and salt marshes: ______

16. What is chemosynthesis? ______17. Where do bacteria that carry out chemosynthesis live? ______

18. Heterotrophs are also called ______.

19. Plant and animal remains and other dead matter are collectively called ______.

20. Complete the table about types of heterotrophs.

Type Definition Examples Herbivore Cows, Rabbits

Eats Animals

Omnivore Humans, bears, crows

Detritivore

Decomposer

21. How does energy flow through an ecosystem? ______

22. Complete the following table.

Relationship Description Food Chain

Food Web

23. What does a food web link together? ______

24. What is a trophic level? ______

25. In a food web, what organisms make up the first trophic level? ______26. What does a consumer in a good chain depend on for energy? ______

27. What is an ecological pyramid? ______

28. Why is it that only part of the energy stored in one trophic level is passed on to the next level? ______

29. What is biomass? ______

30. What does a biomass pyramid represent? ______

31. What does a pyramid of numbers show? ______

32. Why can each trophic level support only about one tenth the amount of living tissue of the level below it? ______

33. With the rest of the space below, draw an energy pyramid with 4 trophic levels. You are to show the main source of the energy for the pyramid, how much energy is available for each of the 4 trophic levels, and also label the four trophic levels correctly.