Exercises

1.

Can the biosphere be considered an Earth system? How would that system be described?

2.

How do autotrophs differ from heterotrophs?

3.

What is metabolism?

4.

In what environments might you find extremophiles? Can humans live under extreme conditions?

5.

What is the difference between photosynthesis and respiration?

6.

Explain how life is related to water. What would happen if all the water on Earth turned to ice?

7.

Draw a diagram of a biogeochemical cycle. What are the inputs and outputs? What are the processes that power the cycle?

8.

Carbon is regarded as the starting point for all of life. What else is important?

9.

In the diagram shown in Figure 11.12, how many period boundaries of the geologic time scale are marked by mass extinctions? How many era boundaries are marked by mass extinctions?

10.

What controls the habitable zone around stars? Is Neptune in the habitable zone of our solar system?