Sustaining the Variety of Life

1. Sustaining the Variety of Life 0 Current Issues in Biology, Volume 4 Scientific American

2. Sustaining the Variety of Life Concept Review • Extinction is a natural process. • The average lifetime of a species is roughly 1 million years. • This means that at natural or background rates, one in 1 million species is expected to become extinct each year. • Current rates of extinction are at least 100 times higher than this background rate

3. Sustaining the Variety of Life Concept Review • The elevated extinction rate is due to human activities that include • habitat destruction • introduction of exotic species • overharvesting • and in the future, global warming

4. Sustaining the Variety of Life Concept Review • Some species are much more vulnerable to extinction than others, and these species are geographically concentrated. • To sustain the variety of life, special places rich in threatened species must be identified and protected. • The intuitive notion that extinctions occur most often in areas where the most people live is wrong. • Extinctions occur most frequently where fronts of habitat destruction, especially deforestation, overlap concentrations of vulnerable species.

5. Sustaining the Variety of Life Concept Review • Probably one-half of the world’s species live in 25 mostly forested, tropical areas where human actions have removed > 70% of the natural vegetation. • These areas are hot spots for conservation efforts. • The laws of biogeography explain how species are distributed across the world.

6. Sustaining the Variety of Life Concept Review • Laws of Biogeography • Law 1. Most species’ ranges are very small; few are very large. • Law 2. Species with small ranges are locally scarce. • Law 3. The number of species found in a given area varies greatly and according to common factors. • Law 4. Species with small ranges are often geographically concentrated.

7. Sustaining the Variety of Life Concept Review • The costs of sustaining biodiversity are large, but so are the benefits. • The Millennium Ecosystems Assessment report has documented benefits that include food, water, fuel, climate regulation, and many other often undervalued services that are provided by healthy ecosystems. • There are many possible solutions to conserving biodiversity. • Ultimately, all solutions must benefit local human populations as well as endangered species.

8. Sustaining the Variety of Life Concept Review • How can biodiversity be conserved? • By encouraging conservation groups to purchase logging leases for sensitive tropical wilderness forests. • By providing economic alternatives to displaced poor people who now clear the majority of tropical forests. • By connecting now-fragmented forests through forest bridges.

9. Sustaining the Variety of Life Concept Review • How can biodiversity be conserved? • By promoting ecotourism to provide a cash incentive to local people to conserve the natural environment. • By allowing preserved forest tracts to be used as capital in the Kyoto carbon-trading system. • By promoting understanding of the economic benefits provided by intact ecosystems.

10. Sustaining the Variety of Life • Testing Your Comprehension At the background rate of extinction, one expects 1 in _________ species to become extinct each year. a) 10 b) 1,000 c) 10,000 d) 1,000,000

11. Sustaining the Variety of Life • Testing Your Comprehension At the background rate of extinction, one expects 1 in _________ species to become extinct each year. d) 1,000,000

12. Sustaining the Variety of Life • Testing Your Comprehension Probably of all species live in the world’s hot spots for biodiversity conservation. a) 1/10 b) 1/4 c) 1/2 d) 9/10

13. Sustaining the Variety of Life • Testing Your Comprehension Probably of all species live in the world’s hot spots for biodiversity conservation. c) 1/2

14. Sustaining the Variety of Life • Testing Your Comprehension The bulk of tropical forests are cleared by a) multinational logging companies b) nationally sponsored logging companies c) local logging companies d) displaced poor people

15. Sustaining the Variety of Life • Testing Your Comprehension The bulk of tropical forests are cleared by d) displaced poor people

16. Sustaining the Variety of Life • Testing Your Comprehension The Millennium Ecosystems Assessment report a) lists economic benefits provided by ecosystems b) focuses exclusively on ecotourism c) provides a plan for sustainable tropical forest logging d) argues against acceptance of the Kyoto Treaty

17. Sustaining the Variety of Life • Testing Your Comprehension The Millennium Ecosystems Assessment report a) lists economic benefits provided by ecosystems

18. Strongly Agree Strongly Disagree A. D. C. B. E. Sustaining the Variety of Life • Biology and Society It is vitally important that we protect each and every species.

19. Strongly Agree Strongly Disagree A. D. C. B. E. Sustaining the Variety of Life • Biology and Society Since biodiversity is a global resource, binding decisions about biodiversity conservation must be made internationally.

20. Sustaining the Variety of Life • Thinking About Science The biogeographic laws state that 1) Most species’ ranges are very small; few are very large; 2) Species with small ranges are locally scarce; 3) The number of species found in a given area varies greatly and according to common factors; and 4) Species with small ranges are often geographically concentrated. Which of these laws imply that a small number of bird species contributes a disproportionately large number of individuals to the world’s bird population? a) Laws 1 and 2 b) Laws 2 and 3 c) Laws 3 and 4 d) Laws 1 and 4

21. Sustaining the Variety of Life • Thinking About Science The biogeographic laws state that 1) Most species’ ranges are very small; few are very large; 2) Species with small ranges are locally scarce; 3) The number of species found in a given area varies greatly and according to common factors; and 4) Species with small ranges are often geographically concentrated. Which of these laws imply that a small number of bird species contributes a disproportionately large number of individuals to the world’s bird population? a) Laws 1 and 2

22. Sustaining the Variety of Life • Interpreting Data and Graphs The biogeographic laws state that 1) Most species’ ranges are very small; 2) Species with small ranges are locally scarce; 3) The number of species found in a given area varies greatly and according to common factors; and 4) Species with small ranges are often geographically concentrated. Which law(s) is/are supported by the figure? a) Law 1 b) Law 2 c) Law 3 d) Law 4

23. Sustaining the Variety of Life • Interpreting Data and Graphs The biogeographic laws state that 1) Most species’ ranges are very small; 2) Species with small ranges are locally scarce; 3) The number of species found in a given area varies greatly and according to common factors; and 4) Species with small ranges are often geographically concentrated. Which law(s) is/are supported by the figure? c) Law 3 d) Law 4

24. Sustaining the Variety of Life • Interpreting Data and Graphs Which of the following regions has the largest area of remaining habitat? a) West Africa b) South-Central China c) Tropical Andes d) Central Chile

25. Sustaining the Variety of Life • Interpreting Data and Graphs Which of the following regions has the largest area of remaining habitat? c) Tropical Andes