life121 chapter 43

46) The use of DDT as an insecticide in the United States has been outlawed since 1971, yet is still a problem for certain top-level carnivores in the United States. Which of the following choices best explains this apparent incongruity? A) DDT is still used for mosquito control in tropical countries, and certain migratory predators can be affected by a seasonal biomagnification. B) DDT is persistent in the environment, and all of the pre-1971 DDT is still available in toxic form to poison top-level carnivores. C) Pre-1971 DDT has been deposited in certain habitats, particularly wetlands and estuaries, so predators in these ecosystems are vulnerable to biomagnifications of DDT. D) Whereas most DDT-susceptible species have become resistant to persistent DDT, others are still vulnerable. E) All of the options are correct.

A) DDT is still used for mosquito control in tropical countries, and certain migratory predators can be affected by a seasonal biomagnification.

14) What is the biological significance of genetic diversity between populations? A) Genes for adaptive traits to local conditions make microevolution possible. B) The population that is most fit would survive by competitive exclusion. C) Genetic diversity allows for species stability by preventing speciation. D) Isolated populations become more fit. E) Diseases and parasites are not spread between separated populations

A) Genes for adaptive traits to local conditions make microevolution possible.

8) According to the U.S. Endangered Species Act (ESA), the difference between an endangered species and a threatened one is that A) an endangered species is closer to extinction. B) a threatened species is closer to extinction. C) threatened species are endangered species outside the U.S. borders. D) endangered species are mainly tropical. E) only endangered species are vertebrates.

A) an endangered species is closer to extinction.

40) As the climate changes because of global warming, species' ranges of plants in the Northern Hemisphere may move northward, using effective reproductive adaptations to disperse their seeds. The trees that are most likely to avoid extinction in such an environment are those that A) have seeds that are easily dispersed by wind or animals. B) have thin seed coats. C) produce well-provisioned seeds. D) have seeds that become viable only after a forest fire. E) disperse many seeds in close proximity to the parent tree

A) have seeds that are easily dispersed by wind or animals.

18) Of the following ecosystem types, which have been impacted the most by humans? A) wetland and riparian B) open and benthic ocean C) desert and high alpine D) taiga and second-growth forests E) tundra and arctic

A) wetland and riparian

42) Which of the following investigations would shed the most light on the future distribution of organisms in temperate regions that are faced with climate change? A) Remove, to the mineral soil, all of the organisms from an experimental plot and monitor the colonization of the area over time in terms of both species diversity and abundance. B) Look at the climatic changes that occurred since the last ice age and how species redistributed as glaciers melted, then make predictions on future distribution in species based on past trends. C) Compare and contrast the flora and fauna of warm/cold/dry/wet climates to shed light on how they evolved to be suited to their present-day environment. D) Quantify the impact of humankind's activities on present-day populations of threatened and endangered species to assess the rate of extirpation and extinction. E) There is no scientific investigation that can help make predictions on the future distribution of organisms.

B) Look at the climatic changes that occurred since the last ice age and how species redistributed as glaciers melted, then make predictions on future distribution in species based on past trends

44) What is the biggest problem with selecting a site for a preserve? A) There is always a conflict about use of land set aside for preservation. B) Making a proper selection is difficult because the current environmental conditions of almost any site may change in the future because of climate change or other factors. C) Keystone species are difficult to identify in potential preserve sites. D) Only lands that are not useful to human activities are available for preserves. E) Most of the best sites are inaccessible by land transportation, so making roads to them is often prohibitively expensive.

B) Making a proper selection is difficult because the current environmental conditions of almost any site may change in the future because of climate change or other factors.

7) Which of the following terms includes all of the others? A) species diversity B) biodiversity C) genetic diversity D) ecosystem diversity E) species richness

B) biodiversity

16) Overexploitation encourages extinction and is most likely to affect A) animals that occupy a broad ecological niche. B) large animals with low intrinsic reproductive rates. C) most organisms that live in the oceans. D) terrestrial organisms more than aquatic organisms. E) edge-adapted species.

B) large animals with low intrinsic reproductive rate

11) The most serious consequence of a decrease in global biodiversity would be the A) increase in global warming and thinning of the ozone layer. B) potential loss of ecosystem services on which people depend. C) increase in the abundance and diversity of edge-adapted species. D) loss of sources of genetic diversity to preserve endangered species. E) loss of species for use as crops.

B) potential loss of ecosystem services on which people depend

41) If global warming continues at its present rate, which biomes will likely take the place of the coniferous forest (taiga)? A) tundra and polar ice B) temperate broadleaf forest and grassland C) desert and chaparral D) tropical forest and savanna E) chaparral and temperate broadleaf forest

B) temperate broadleaf forest and grassland

19) The introduction of the brown tree snake in the 1940s to the island of Guam has resulted in A) eradication of non-native rats and other undesirable/pest species. B) the extirpation of many of the island's bird and reptile species. C) a good lesson in biological control. D) a new species of hybrids from crossbreeding with a native snake species. E) its failure to compete with native species and its quick elimination from the island.

B) the extirpation of many of the island's bird and reptile species.

22) Which of the following species was driven to extinction by overexploitation by hunters/fishermen? A) African elephant B) the great auk C) North American bluefin tuna D) flying foxes E) American bison

B) the great auk

47) Agricultural lands frequently require nutrient augmentation because A) nitrogen-fixing bacteria are not as plentiful in agricultural soils because of the use of pesticides. B) the nutrients that become the biomass of plants are not cycled back to the soil on lands where they are harvested. C) land that is available for agriculture tends to be nutrient-poor. D) grains raised for feeding livestock must be fortified, and thus require additional nutrients. E) cultivation of agricultural land inhibits the decomposition of organic matter.

B) the nutrients that become the biomass of plants are not cycled back to the soil on lands where they are harvested.

2) Invasive species are introduced by humans to new geographic locations and A) are successful in colonizing a novel area. B) spread because they encounter none of their natural predators. C) All of the choices are correct. D) can outcompete and displace native species for biotic and abiotic resources. E) are usually considered pests by ecologists.

C) All of the choices are correct.

4) Extinction is a natural phenomenon. It is estimated that 99% of all species that ever lived are now extinct. Why then do we say that we are now experiencing an extinction (loss of biodiversity) crisis? A) Humans are ethically responsible for protecting endangered species. B) Scientists have finally identified most of the species on Earth and are thus able to quantify the number of species becoming extinct. C) The current rate of extinction is high and human activities threaten biodiversity at all levels. D) Humans have greater medical needs than at any other time in history, and many potential medicinal compounds are being lost as plant species become extinct. E) Most biodiversity hot spots have been destroyed by recent ecological disasters

C) The current rate of extinction is high and human activities threaten biodiversity at all levels.

50) What causes extremely high levels of toxic chemicals in fish-eating birds? A) depletion of ozone layer B) acid precipitation C) biological magnification D) greenhouse effect E) eutrophication

C) biological magnification

9) What term did E. O. Wilson coin for our innate appreciation of wild environments and living organisms? A) bioremediation B) bioethics C) biophilia D) biophobia E) landscape ecology

C) biophilia

3) Estimates of current rates of extinction A) indicate that we have reached a state of stable equilibrium in which speciation rates equal extinction rates. B) suggest that one-half of all animal and plant species may be gone by the year 2100. C) indicate that rates may be greater than the mass extinctions at the close of the Cretaceous period. D) indicate that only 1% of all of the species that have ever lived on Earth are still alive. E) suggest that rates of extinction have decreased globally.

C) indicate that rates may be greater than the mass extinctions at the close of the Cretaceous period.

6) Although extinction is a natural process, current extinctions are of concern to environmentalists because A) more animals than ever before are going extinct. B) most current extinctions are caused by introduced species. C) the rate of extinction is higher than background extinction rates. D) current extinction is primarily affecting plant diversity. E) None of the options are correct.

C) the rate of extinction is higher than background extinction rates.

39) The success with which plants extend their range northward following glacial retreat is best determined by A) whether there is simultaneous migration of herbivores. B) their tolerance to shade. C) their seed dispersal rate. D) their size. E) their growth rate

C) their seed dispersal rate

1) Which of the following ecological locations has the greatest species diversity? A) tundra B) deciduous forests C) tropical rain forest D) grasslands E) islands

C) tropical rain forest

13) According to most conservation biologists, the single greatest threat to global biodiversity is A) chemical pollution of water and air. B) stratospheric ozone depletion. C) overexploitation of certain species. D) alteration or destruction of the physical habitat. E) global climate change resulting from a variety of human activities.

D) alteration or destruction of the physical habitat.

48) Which of the following refers to the reflecting and absorption of infrared radiation by atmospheric methane, carbon dioxide, and water? A) depletion of ozone layer B) acid precipitation C) biological magnification D) greenhouse effect E) eutrophication

D) greenhouse effect

12) Which of the following is the most direct threat to biodiversity? A) increased levels of atmospheric carbon dioxide B) the depletion of the ozone layer C) overexploitation of selected species D) habitat destruction E) zoned reserves

D) habitat destruction

5) Which of the following provides the best evidence of a biodiversity crisis? A) the incursion of a non-native species B) increasing pollution levels C) decrease in regional productivity D) high rate of extinction E) climate change

D) high rate of extinction

20) Which of the following examples poses the greatest potential threat to biodiversity? A) replanting, after a clear cut, a monoculture of Douglas fir trees on land that consisted of oldgrowth Douglas fir, western cedar, and western hemlock B) allowing previously used farmland to go fallow and begin to fill in with weeds and then shrubs and saplings C) trapping and relocating large predators, such as mountain lions, that pose a threat as they move into areas of relatively dense human populations D) importing an Asian insect into the United States to control a weed that competes with staple crops E) releasing sterilized rainbow trout to boost the sport fishing of a river system that contains native brook trout

D) importing an Asian insect into the United States to control a weed that competes with staple crops

17) How might the extinction of some Pacific Island bats called "flying foxes" threaten the survival of over 75% of the tree species in those islands? A) wetland and riparian B) open and benthic ocean C) desert and high alpine D) taiga and second-growth forests E) tundra and arctic

D) taiga and second-growth forests

45) What is a critical load? A) the amount of nutrient augmentation necessary to bring a depleted habitat back to its former level B) the level of a given toxin in an ecosystem that is lethal to 50% of the species present C) the maximum abundance level of a particular species, beyond which additional numbers will degrade a habitat D) the amount of added nutrient that can be absorbed by plants without damaging ecosystem integrity E) the number of predators an ecosystem can support that effectively culls prey populations to healthy levels

D) the amount of added nutrient that can be absorbed by plants without damaging ecosystem integrity

49) What is caused by excessive nutrient runoff into aquatic ecosystems? A) depletion of ozone layer B) acid precipitation C) biological magnification D) greenhouse effect E) eutrophication

E) eutrophication

21) Which of the following is a type of research in which a conservation biologist would be involved? A) reestablishing whooping cranes in their former breeding grounds in North Dakota B) studying species diversity and interaction in the Florida Everglades, past and present C) studying the population ecology of grizzly bears in Yellowstone National Park D) determining the effects of hunting white-tailed deer in Vermont E) All of the options are correct.

E) All of the options are correct

43) Burning fossil fuels releases oxides of sulfur and nitrogen. These air pollutants can be responsible for A) the death of fish in lakes. B) precipitation with a pH as low as 3.0. C) calcium deficiency in soils. D) direct damage to plants by leaching nutrients from the leaves. E) All of the options are correct.

E) All of the options are correct

10) We should care about loss in biodiversity in the populations of other species because of A) biophilia. B) potential loss of medicines and other products yet undiscovered from threatened species. C) potential loss of genes, some of which may code for proteins useful to humans. D) the risk to global ecological stability. E) All of the options are correct

E) All of the options are correct.

15) Introduced species can have deleterious effects on biological communities by A) preying on native species. B) competing with native species for food or light. C) displacing native species. D) competing with native species for space or breeding/nesting habitat. E) All of the options are correct.

E) All of the options are correct.