Chapter 38 Answers – Flashcards
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The loss of biodiversity is one of the greatest challenges facing humanity. Humans are contributing significantly to this loss by _____.
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damaging the biosphere
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Which of the following is an example of a major threat to biodiversity?
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extensive fishing reducing populations of Laurentian North Atlantic cod
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3. Incorrect To control mosquitoes that help transmit malaria, swamps in malaria-infected regions were frequently sprayed with DDT. In one particular ecosystem, mosquitoes were eaten by mosquito fish, which in turn were eaten by kingfisher birds. If the mosquitoes had 0.2 ppm of DDT in their systems, what concentration of DDT would we expect to find in the kingfishers?
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20.0 ppm
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The average global temperature has risen _____°C in the last 100 years.
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0.8
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Which of the following significantly contributes to the greenhouse effect and global warming?
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the purchase of large vehicles that have poor gas mileage
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An important consequence of global warming is _____.
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changes in the distribution of terrestrial biomes
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The great tit population in Oxford, England, has responded to climate change by _____.
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laying its eggs earlier
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The Mauna Kea silversword was brought to near extinction by _____.
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overgrazing by sheep and goats
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Which of the following has proved to be most helpful in managing landscapes that have been highly fragmented?
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creating movement corridors
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What is an important concern that many ecologists have about areas designated as hot spots?
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Hot spots are important areas of species diversity, but there are other important areas of Earth that should not be forgotten.
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The greatest challenge facing the zoned reserve system of Costa Rica is _____.
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an expanding human population
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If wolves were eliminated from Yellowstone National Park, we would expect that _____.
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grasses will be shorter
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Steeply declining populations of waterfowl, destruction of largemouth bass populations, and reduction of bald eagle nesting sites near the Kissimmee River in Florida were caused by _____.
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a U.S. Army Corps of Engineers project that canalized the Kissimmee River and drained marshlands
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In order to succeed, sustainable development will require _____.
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political commitment and cooperation of nations
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Extinction is a naturally occurring phenomenon. Scientists now worry more about extinctions because _____.
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humans are altering trophic structure, energy flow, chemical cycling, and natural disturbances
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According to the International Union for Conservation of Nature (IUCN), which of the following has the largest percentage of species that are threatened?
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amphibians
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In addition to endangered species, the U.S. Endangered Species Act provides protection for _____.
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threatened species
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The major cause of extinction of species today is _____.
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habitat destruction
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The species most at risk of extinction due to habitat destruction are those _____.
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with small, limited geographic ranges
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Why is the ozone layer important?
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It protects Earth from ultraviolet radiation.
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Why does biological magnification occur?
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Although biomass decreases with increasing trophic level, the amount of toxin remains the same.
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The signature effect of increasing greenhouse gases in the atmosphere is _____.
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global warming
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In the past 100 years, global temperatures have risen about _____.
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0.8°C
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The two major contributors to the increase in atmospheric carbon dioxide levels are _____.
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fossil fuel combustion and deforestation
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Global warming is having a significant effect on _____.
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the distribution of terrestrial biomes
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It may be possible for some organisms to cope with global climate change by _____.
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phenotypic plasticity
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The study and protection of biological diversity is _____.
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conservation biology
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When a population is fragmented into smaller subpopulations, it may _____.
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experience genetic drift
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The survival of fragmented populations often depends on the movement of individuals through _____.
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corridors
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Regions with high concentrations of species, especially species that are endangered or threatened, are referred to as _____.
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biodiversity hot spots
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Hot spots, such as rain forests and dry shrublands, which make up less than _____ of Earth's land surface, are home to about _____ of all plant and vertebrate species.
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1.5% ... 33%
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Species found in only one place on Earth are _____ species.
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endemic
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The "zoned reserve" concept of landscape management calls for _____.
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protected areas to be surrounded by transitional areas
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An initiative that attempts to preserve the web of life in connected areas of the Rocky Mountains of Canada and the northern United States is called the _____.
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Y2Y
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_____ is the science of facilitating the return of a degraded ecosystem to a more natural condition.
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Restoration ecology
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When commercial fishermen agree to catch less fish than they can so that the fish population will not be put in danger of extinction, the fishermen can be said to be practicing _____.
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sustainable development
