Deck 56: Conservation Biology and Global Change

Question 1

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.

Answer 1

C

Question 2

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.

Answer 2

A

Question 3

Which of the following statements regarding extinction is (are)correct?
I)Only a small percentage of species is immune from extinction.
II)Extinction occurs whether humans interfere or not.
III)Extinctions can even be caused indirectly by humans.

A)only I
B)only II
C)only III
D)only II and III

Answer 3

D

Question 4

To better comprehend the magnitude of current extinctions,it will be necessary to

A)monitor atmospheric carbon dioxide levels more closely.
B)differentiate between plant extinction and animal extinction numbers.
C)focus on identifying more species of mammals and birds.
D)identify more of the yet unknown species of organisms on Earth.
E)use the average extinction rates of vertebrates as a baseline.

Question 5

Which of the following ecological locations has the greatest species diversity?

A)tundra
B)deciduous forests
C)tropics
D)grasslands
E)islands

Question 6

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.

Question 7

With regard to the destruction of tropical forests,the focus is often on biodiversity and the impact to these ecosystems.What is a direct benefit to humans that helps explain why these forests need to be preserved?

A)This diversity could contain undocumented insect species.
B)Natural and undisturbed areas are important wildlife habitats.
C)The diversity could contain novel drugs for consumers.
D)The plant diversity provides shade, which lowers global warming.

Question 8

Which of the following groups is most threatened by global extinctions?

A)mammals
B)birds
C)fish
D)amphibians
E)plants

Question 9

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

Question 10

If all individuals in the last remaining population of a particular bird species were all highly related,which type of diversity would be of greatest concern when planning to keep the species from going extinct?
I)genetic diversity
II)species diversity
III)ecosystem diversity

A)only I
B)only II
C)only III
D)only II and III

Question 11

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.

Question 12

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

Question 13

We should care about loss in biodiversity in other species because of
I) potential loss of medicines and other products yet undiscovered from threatened species.
II) potential loss of genes,some of which may code for proteins useful to humans.
III)the risk to global ecological stability.

A)only I
B)only II
C)only II and III
D)I, II, and III

Question 14

Which of the following terms includes all of the others?

A)species diversity
B)biodiversity
C)genetic diversity
D)ecosystem diversity
E)species richness

Question 15

What is the estimated number of extant species on Earth?

A)1000 to 50 000
B)50 000 to 150 000
C)500 000 to 1 000 000
D)10 000 000 to 100 000 000
E)5 billion to 10 billion

Question 16

Which of the following ecological locations has the greatest species diversity?

A)deciduous forests
B)tropical rain forest
C)grasslands
D)islands

Question 17

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 source of genetic diversity to preserve endangered species.
E)loss of species for "bioprospecting."

Question 18

Philippe Bouchet and colleagues conducted a massive survey of marine molluscs on the west coast of New Caledonia.Twenty percent of the species found were represented by a single specimen.What does that suggest about the diversity of molluscs in this area?

A)The west coast of New Caledonia is not an appropriate habitat for molluscs.
B)Many of the species from this 20 percent are probably rare.
C)They were not sampling uniformly throughout the area.
D)Many of the species from this 20 percent are most likely just dispersing through the area.

Question 19

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

Question 20

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 unusually high.
D)current extinction is primarily affecting plant diversity.
E)None of the options are correct.

Question 21

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.

Question 22

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 old-growth 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

Question 23

Review the formula for effective population size.Imagine a population of 1000 small rodents.Of these,300 are breeding females,300 are breeding males,and 400 are nonbreeding juveniles.What is the effective population size?

A)1000
B)1200
C)600
D)400
E)300

Question 24

According to the small-population approach,what would be the best strategy for saving a population that is in an extinction vortex?

A)determining the minimum viable population size by taking into account the effective population size
B)establishing a nature reserve to protect its habitat
C)introducing individuals from other populations to increase genetic variation
D)determining and remedying the cause of its decline
E)reducing the population size of its predators and competitors

Question 25

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.

Question 26

Which of the following pairs is incorrectly matched?

A)rosy periwinkle - medicinal plant that inhibits cancer cell growth
B)extirpation - local extinction
C)acid rain/precipitation - rain, snow, sleet with a pH < 6
D)extinction vortex - processes that result in smaller and smaller population size until all individuals die
E)effective population size - based on the breeding potential of a population

Question 27

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)The bats eat the insects that harm competitor plants.
B)The bats consume the fruit including the seeds that would disrupt the trees' reproductive cycle.
C)The bats roost in the trees and fertilize soil around the trees with their nitrogen-rich droppings.
D)The bats pollinate the trees and disperse seeds.
E)The bats pierce the fruit, which allows the seeds to germinate.

Question 28

Small populations are most vulnerable to ________ and ________.

A)inbreeding, genetic drift
B)inbreeding, disease
C)genetic drift, heterozygosity
D)loss of variation, small mate choice
E)loss of adaptability, heterozygosity

Question 29

Which of the following conditions is the most likely indicator of a population in an extinction vortex?

A)The population is geographically divided into smaller populations.
B)The species in question is found only in small pockets of its former range.
C)The effective population size of the species falls below 500.
D)Genetic measurements indicate a loss of genetic variation over time.
E)The population is no longer connected by corridors.

Question 30

The greatest cause of the biodiversity crisis,the one which includes all of the others,is

A)pollution.
B)global warming.
C)habitat destruction.
D)introduced species.
E)human overpopulation.

Question 31

Researchers have been studying a rare population of eighty-seven voles in an isolated area.Ten voles from a larger population were added to this isolated population.Besides having ten additional animals,what benefits are there to importing individuals?

A)Additional animals from a distant population will likely bring genetic diversity and reduce inbreeding depression.
B)Additional animals will bring additional competition and could hurt the population.
C)Additional animals would increase beneficial genetic drift.
D)There is no benefit other than increasing the overall population size.

Question 32

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.

Question 33

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 population ecology of grizzly bears in Yellowstone National Park
D)determining the effects of hunting white-tailed deer in Vermont
E)determining the effect of protection programs on the recovery of the North Atlantic cod fishery

Question 34

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.

Question 35

The following statements are correct,with the exception of:

A)Cloning techniques, such as the one used to create "Dolly" are being used to try and resurrect extinct species.
B)Although the cloning process resulted in the birth of a Pyrenean ibex, the ibex died shortly after birth.
C)Preservation of species will no longer be necessary once scientists can resurrect species.
D)Resurrecting species does not get around the issue of genetic diversity.
E)all of the above

Question 36

Modern conservation biology increasingly aims at

A)protecting federally listed endangered species.
B)lobbying for strict enforcement of the U.S. Endangered Species Act.
C)sustaining biodiversity of entire ecosystems and communities.
D)maintaining genetic diversity in all species.
E)saving as much habitat as possible from development and exploitation.

Question 37

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.

Question 38

If the sex ratio in a population is significantly different from 50:50,then which of the following will always be true?

A)The population will enter the extinction vortex.
B)The genetic variation in the population will increase over time.
C)The genetic variation in the population will decrease over time.
D)The effective population size will be greater than the actual population size.
E)The effective population size will be less than the actual population size.

Question 39

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

Question 40

Which of the following life history traits can potentially influence effective population size (Ne)?

A)maturation age
B)genetic relatedness among individuals in a population
C)family and population size
D)gene flow between geographically separated populations
E)All of the options are correct.

Question 41

A land developer and several ecologists are discussing how a parcel of private land should be developed while saving twenty hectares as natural habitat.The land developer suggests that the twenty hectares be divided into twenty separate one-hectare areas.The ecologists suggest that it would be better to have one intact parcel of twenty hectares.What is the significance of these different arrangements of the twenty hectares?

A)There really is no difference; they should both work equally well.
B)The isolated hectare plots increase the ability of individuals to disperse from one habitat to another.
C)The isolated plots are more vulnerable to edge effects.
D)The large plot will create more inbreeding in many species.

Question 42

How are movement corridors potentially harmful to certain species?

A)They increase inbreeding.
B)They promote dispersion.
C)They spread disease and parasites.
D)They increase genetic diversity.
E)They allow seasonal migration.

Question 43

The word triage originated during World War I and was first used by French doctors in prioritizing patients based on the severity of their wounds,because there were more wounded soldiers in need of urgent care than there were resources to treat them.Conservation biologists have to make similar determinations with degraded ecosystems.Which of the following is the most important consideration when it comes to managing for maintenance of biodiversity?

A)identifying large, high-profile vertebrates first, because steps to saving them would be most recognized by the public
B)determining which species is most important for conserving biodiversity as a whole
C)replanting suitable habitat for fauna
D)assessing the economic costs and the gains for society
E)maintaining optimum size of all populations in the ecosystem

Question 44

On Easter Island,data show that it was once covered by massive palm trees.How can an ecosystem collapse from removal of just one species of large tree?
I)Without large trees,soil erosion increases and reduces productivity.
II)Species of plants needing shade no longer have it.
III)Large trees are habitats for many species.

A)only I
B)only II
C)only III
D)I, II, and III

Question 45

Key goals of zoned reserves include all of the following,except

A)provide a stable economy for people living in the area
B)protect wildlife
C)practice sustainable agriculture
D)promote ecotourism
E)remove all human presence and activity

Question 46

The primary difference between the small-population approach (S-PA)and the declining-population approach (D-PA)to biodiversity recovery is

A)S-PA is interested in bolstering the genetic diversity of a threatened population rather than the environmental factors that caused the population's decline.
B)S-PA kicks in for conservation biologists when population numbers fall below 500.
C)D-PA would likely involve bringing together individuals from scattered small populations to interbreed in order to promote genetic diversity.
D)S-PA would investigate and eliminate all of the human impacts on the habitat of the species being studied for recovery.
E)D-PA would use recently collected population data to calculate an extinction vortex.

Question 47

The long-term problem with red-cockaded woodpecker habitat intervention in the southwest United States is

A)the only habitat that can support their recovery is large tracts of mature southern pine forest.
B)the mature pine forests in which they live cannot ever be subjected to forest fire.
C)all of the appropriate red-cockaded woodpecker habitat has already been logged or converted to agricultural land.
D)the social organization of the red-cockaded woodpecker precludes the dispersal of reproductive individuals.
E)what habitat remains for the red-cockaded woodpecker does not contain trees suitable for nest-cavity construction.

Question 48

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

Question 49

How is habitat fragmentation related to biodiversity loss?

A)Less carbon dioxide is absorbed by plants in fragmented habitats.
B)In fragmented habitats, more soil erosion takes place.
C)Populations of organisms in fragments are smaller and, thus, more susceptible to extinction.
D)Animals are forced out of smaller habitat fragments.
E)Fragments generate silt that negatively affects sensitive river and stream organisms.

Question 50

Managing southwestern forests specifically for the red-cockaded woodpecker

A)was wholeheartedly supported by the timber extraction industry.
B)contributed to greater abundance and diversity of other forest bird species.
C)caused other species of songbird to decline.
D)involved strict fire suppression measures.
E)involved the creation of fragmented forest habitat.

Question 51

Which of the following is true about the current research regarding forest fragmentation?

A)Fragmented forests support a greater biodiversity because they result in the combination of forest-edge species and forest-interior species.
B)Fragmented forests support a lesser biodiversity because the forested-adapted species leave, and only the edge and open-field species can occupy fragmented forests.
C)Fragmented forests are the goal of conservation biologists who design wildlife preserves.
D)Harvesting timber that results in forest fragmentation results in less soil erosion.
E)The disturbance of timber extraction causes the species diversity to increase because of the new habitats created.

Question 52

Relatively small geographic areas with high concentrations of endemic species and a large number of endangered and threatened species are known as

A)endemic sinks.
B)critical communities.
C)biodiversity hot spots.
D)endemic metapopulations.
E)bottlenecks.

Question 53

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 currently the environmental conditions of almost any site change so quickly.
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.

Question 54

Cowbirds utilize fragmented forests effectively by

A)feeding on the fruits of shrubs that tend to grow at the forest/open-field interface.
B)parasitizing the nests of forest birds, and feeding on open-field insects.
C)roosting in forest trees, and nesting in grassy fields.
D)outcompeting other songbird species in fragmented communities.
E)using forest cover to escape from predators in their normal grassland habitat.

Question 55

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

Question 56

Which of the following is a (are)potential disadvantage(s)of movement corridors for wildlife?

A)reduce wildlife-vehicle collisions
B)route for spread of parasites/disease
C)promote dispersal and reduce inbreeding
D)potential increase in predation along corridor
E)B and D

Question 57

Which of the following is consistent with forest fragmentation research?

A)Productivity is the same in both fragmented forests and forest interiors.
B)Edge communities consistently have low species diversity.
C)Forest-interior species show declines in small patch communities.
D)New-edge species that migrate in do not seem to compete with forest species and often increase biodiversity in fragmented forests.
E)Species diversity is always lower in fragmented forests when compared to forest interiors in the same region.

Question 58

Which of the following criteria have to be met for a species to qualify as invasive?

A)endemic to the area, spreads rapidly, and displaces foreign species
B)introduced to a new area, spreads rapidly, and displaces native species
C)introduced to a new area, spreads rapidly, and displaces other invasive species
D)endemic to the area, spreads slowly, and displaces native species

Question 59

Biodiversity hot spots are not necessarily the best choice for nature preserves because

A)hot spots are situated in remote areas not accessible to wildlife viewers.
B)their ecological importance makes land purchase very expensive.
C)a hot spot for one group of organisms may not be a hot spot for another group.
D)hot spots are designated by abiotic factors present, not biotic factors.
E)designated hot spots change on a daily basis.

Question 60

Which of the following is true about "hot spots"?

A)One-third of all species on Earth occupy less than 1.5% of Earth's land area (hot spots).
B)All of the plants and animals containing genes that may be useful to humankind are located in Earth's hot spots.
C)Around 75% of all of the undiscovered species of organisms live in ecological hot spots.
D)As conservation measures improve over the next ten years, hot spots will likely disappear.
E)The hot spots that are in most dire need of remediation are located in the tundra.

Question 61

Which of the following nations has become a world leader in the establishment of zoned reserves?

A)Costa Rica
B)Canada
C)China
D)United States
E)Mexico

Question 62

Based on what you know about ecosystem stability and the information provided in the graph,which community (A-E)would likely support the most biodiversity?

A)A
B)B
C)C
D)D
E)E

Question 63

For the following questions,match the statement with the appropriate term/phrase.
This 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

Question 64

The main goal of sustainable development is to

A)involve more countries in conservation efforts.
B)use only natural resources in the construction of new buildings.
C)use natural resources such that they do not decline over time.
D)reevaluate and re-implement management plans over time.

Question 65

Why are changes in the global carbon cycle important?
I)Burning reduces available carbon for primary producers and,therefore,primary consumers.
II)Deforestation and suburbanization reduce an area's net primary productivity.
III)Increasing atmospheric concentrations of carbon dioxide could alter Earth's climate.
IV)By using fossil fuels we are destroying a nonrenewable resource.

A)only I and III
B)only II and IV
C)only II, III, and IV
D)only I, II, III, and IV

Question 66

For the following questions,match the statement with the appropriate term/phrase.
This causes an increase in the intensity of UV radiation reaching Earth.

A)depletion of ozone layer
B)acid precipitation
C)biological magnification
D)greenhouse effect
E)eutrophication

Question 67

For the following questions,match the statement with the appropriate term/phrase.
This term 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

Question 68

Use the following figure to answer the questions below.

Study the information above about quail habitats.Which of these represents the best quail habitat in terms of fragmentation and edge?

A)A
B)B
C)C
D)D
E)E

Question 69

If the nestlings of flycatchers are to benefit from the shift in peak caterpillar season from June 3,1980 to May 15,2000,in which direction should the May 25,2000 peak bird hatching date move?

A)to the left so it corresponds to the mean date of arrival in 2000
B)to the left so it corresponds with the new peak caterpillar season in 2000
C)to the right so there is no overlap in the May 15 and May 25 (year 2000)curves
D)no movement is necessary because the caterpillars grow slowly so the nestlings will have enough food to eat
E)no movement is necessary because herbicides can be used to kill the vegetation the caterpillars feed on and therefore the peak hatching time of caterpillars will move to the right from May 15 to May 25, 2000

Question 70

Use the graph and information provided in the paragraph below to answer the following questions.
Flycatcher birds that migrate from Africa to Europe feed their nestlings a diet that is almost exclusively moth caterpillars.The graph below shows the mean dates of arrival,bird hatching,and peak caterpillar season for the years 1980 and 2000.

Why were ecologists concerned about the shift in the peak caterpillar season from June 3,1980,to May 15,2000?

A)The caterpillars would have eaten much of the foliage of the trees where flycatchers would have nested, rendering their nests more open to predation.
B)The earlier hatching of caterpillars would compete with other insect larval forms which the flycatchers would also use to feed their young.
C)The 2000 flycatcher nestlings would miss the peak caterpillar season and might not be as well fed.
D)The flycatchers would have to migrate sooner to match their brood-rearing to the time of peak caterpillar season.
E)Pesticides, which have a negative effect on the ecosystem, would have to be used to control the earlier outbreak of caterpillar hatching.

Question 71

The biggest challenge that Costa Rica will likely face in its dedication to conservation and restoration in the future is

A)the pressures of its growing population.
B)its small size (as a country), which may not be able to maintain large enough reserves.
C)the potential for disturbance of sensitive species in reserves by ecotourists.
D)spread of disease and parasites via corridors from neighboring countries.
E)the large number of Costa Rican species already in the extinction vortex.

Question 72

Atmospheric carbon dioxide has risen dramatically during the past century.Some global implications of climate change include all the following,with the exception of

A)shifting of ecosystems towards the poles.
B)insect pest outbreaks.
C)faster rate of ice melt in the north and slower rate of ice melt in the south.
D)some species are unable to disperse or adapt fast enough to changing conditions.
E)current agricultural land may become unsuitable for agriculture.

Question 73

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.

Question 74

Use the following figure to answer the questions below.

Study the information above about quail habitats.Assuming that only one quail can occupy a habitat where all cover requirements are met,what is the maximum number of quail that could inhabit any of the hypothetical plots shown?

A)1
B)2
C)4
D)6
E)9

Question 75

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.

Question 76

Elevated carbon dioxide levels have been shown to contribute to the greenhouse effect,resulting in an increase in mean global temperature.Ecosystems where the largest warming has already occurred include snow-covered northern coniferous forests,tundra,and arctic sea ice habitats.Which statement best explains how the elimination of ice-covered ecosystems affects the rise or fall in global temperature?

A)Melting ice releases dissolved ozone gas, which adds to the greenhouse effect.
B)More reflective surfaces of ice are replaced with darker, more absorptive surfaces, thereby contributing to the warming trend.
C)Large-scale ice melts actually contribute toward lowering global temperatures by decreasing salinity of the oceans.
D)Carbon dioxide levels are lowered as a result of greater volume of water to accommodate greater dissolved gas.

Question 77

Eutrophication is often caused by excess limiting nutrient runoff from agricultural fields into aquatic ecosystems.This results in massive algal blooms,which eventually die and decompose,ultimately depleting the dissolved oxygen and killing large numbers of fish and other aquatic organism.Predict which of the following human actions would best address the problem of eutrophication near agricultural areas?

A)After each eutrophication event, remove the dead fish and invertebrates to place on agricultural fields instead of fertilizer.
B)Determine which limiting nutrient is responsible for the algal bloom and use other fertilizers to apply to crops.
C)Remove the algae before it dies and decomposes to prevent eutrophication from occurring.
D)Determine critical nutrient loads required for certain crops and do not exceed this amount during fertilizer application.

Question 78

For the following questions,match the statement with the appropriate term/phrase.
This 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

Question 79

Use the graph and information provided in the paragraph below to answer the following questions.
Flycatcher birds that migrate from Africa to Europe feed their nestlings a diet that is almost exclusively moth caterpillars.The graph below shows the mean dates of arrival,bird hatching,and peak caterpillar season for the years 1980 and 2000.

The shift in the peak of caterpillar season is most likely due to

A)pesticide use.
B)earlier migration returns of flycatchers.
C)an innate change in the biological clock of the caterpillars.
D)global warming.
E)acid precipitation in Europe.

Question 80

Burning fossil fuels releases oxides of sulphur 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.