Biology | Answers to Review Questions

Author Dr. George B. Johnson, Washington University
Author Dr. Peter H. Raven, Missouri Botanical Gardens & Washington University
Contributor Dr. Susan Singer, Carleton College
Contributor Dr. Jonathan Losos, Washington University

Answers to Review Questions

Chapter 31 (p. 646)

1. There are many areas where conservation is important. However, Madagascar, tropical rain forests of the eastern Himalayas, South Africa, California, and Australia as well as other climate areas are the "conservation hot spots."

2. Diverse biological communities are of vital importance to maintaining a healthy ecosystem, and the chemical quality of water, buffering ecosystems against floods, soil quality conservation, and absorbing pollution.

3. Factors contributing to the extinction rate in a particular location are overexploitation, introduced species, disruption of ecological relationships, loss of genetic variability, and habitat loss or fragmentation.

4. Loss of genetic variability results in serious inbreeding with all of the problems characteristic of inbreeding.

5. Introducing members of other populations to breed with the genetically poor population, as was done with the Illinois prairie chickens, can enrich gene pools.

6. Keystone species play a key role in a community. Many other species depend upon them for seed dispersal or pollination, as a part of the food chain, or for predation.

7. Some species simply require a large area of habitat to survive. Territorial species may require large territories. Large areas may allow for more habitat diversity and for development of a more complex community.

8. Captive breeding has had some notable successes and in many cases is the only alternative. It is important that the products of captive breeding be released into a situation where they can thrive. They must be released into an environment free of factors that lead to extinction.

9. Introduced species tend to radiate from the point of introduction rather rapidly. The sooner they are removed, the less widespread their destruction will be.