Chapter 38

Which of these statements best describes what conservation biologists mean by the "the rapid loss of biodiversity"? a. Introduced species, such as starlings and zebra mussels, have rapidly expanded their ranges. b. Harvests of marine fishes, such as cod and bluefin tuna, are declining. c. The current species extinction rate is as much as 100 times greater than at any time in the past 100,000 years. d. Many potential medicines are being lost as plant species become extinct.

Which of the following is characteristic of endemic species? a. They are often found in biodiversity hot spots. b. They are distributed widely in the biosphere. c. They require edges between ecosystems. d. They are often keystone species whose presence helps to structure a community.

Ospreys and other top predators are most severely affected by pesticides such as PCBs because they a. are especially sensitive to chemicals. b. have very long life spans. c. store the pesticides in their tissues. d. consume prey in which pesticides are concentrated.

Movement corridors art a. the routes taken by migratory animals. b. strips or clumps of habitat that connect isolated fragment of habitat. c. landscapes that include several different ecosystems. d. edges, or boundaries, between ecosystems.

With limited resources, conservation biologists need to prioritize their efforts. Of the following choices, which should receive the greatest attention for the goal of conserving biodiversity? a. a commercially important species b. all endangered vertebrate species c. a declining keystone species in a community d. all endangered species

Which of the following statements about protected areas is not correct? a. We now protect \(25 \%\) of the land areas of the planet. b. National parks are only one type of protected area. c. Most reserves are smaller in size than the ranges of some of the species they are meant to protect. d. Management of protected areas must coordinate with the management of lands outside the protected zone.

What are the three levels of biological diversity? Explain how human activities threaten each of these levels.

What are "greenhouse gases"? Why are they important to life on earth?

What are the causes and possible consequences of climate change? Why is international cooperation necessary if we are to solve this problem?

The human-generated increase in greenhouse gases (see Module 38.3 ) provides many opportunities to study the effects of climate change. For example, snowshoe hares are adapted to the climate of their habitat in the taiga of the high mountains and northern regions of North America. One adaptation is seasonal changes in fur color-a white winter coat that turns brown in the spring-that camouflage hares from a long list of predators. These color changes are triggered by day length. As increasing spring temperatures cause earlier snow melt in the taiga, biologists have observed many white hares sitting on brown earth. Suggest how this natural experiment could be used to investigate the effects of climate change on populations and communities in the taiga ecosystem (assume historical data are available).

The price of energy does not reflect its real costs. What kinds of hidden environmental costs are not reflected in the price of fossil fuels? How are these costs paid, and by whom? Do you think these costs could or should be figured into the price of oil? How might that be done?

5\. Until recently, response to environmental problems has been fragmented -an antipollut ion law here, incentives for recycling there. Meanwhile, the problems of the gap between rich and poor nations, diminishing resources, and pollution continue to grow. Now people and governments are starting to envision a sustainable society. The Worldwatch Institute, a respected environmental monitoring organization, estimates that we must reach sustainability by the year 2030 to avoid economic and environmental disaster. To get there, we must begin shaping a sustainable society during this decade. In what ways is our present system not sustainable? What might a more sustainable \(\$ 0\). ciety be like? Do you think a sustainable society is an achievable goal? Why or why not? What is the alternative? What might you do to work toward sustainability? What are the major roadblocks to achieving sustainability? How would your life be different in a sustainable society? answers to all questions can be found in Appendix \(4 .\).