Question 1

A species of bird is critically endangered, and its habitat is rapidly disappearing.A conservationist committed to preventing the extinction of this species would be most likely to undertake which type of program in the short term?

Accepted Answer

A)  A tourism program to promote the bird species 
B)  A program to pass a national law to save both the bird and its habitat 
C)  An education program to teach people the importance of the bird species 
D)  A captive breeding program to buy time while the bird's habitat is restored 
E)  A program to protect the bird from invasive species

Question 2

Each country that participates in CITES issues a permit for the sale of all legal wildlife or plant species.Species listed by CITES are not permitted.At trade sites, merchandise is counted and checked to ensure its legality.In this way, the CITES agreement helps limit illegal trade in endangered species.What recent factor in elephant conservation has made enforcement of the CITES agreement less useful?

Accepted Answer

A)  Elephants are now being killed so people can sell ivory to fund conservation efforts. 
B)  Legal or sanctioned ivory is now mixed with poached ivory and cannot be distinguished. 
C)  Elephants are no longer endangered, so CITES is no longer needed. 
D)  Elephants from all countries can now be legally sold, so CITES is no longer useful. 
E)  Elephant poaching is no longer a problem, so CITES is no longer needed.

Question 3

When it was established, the U.S.Forest Service instituted a "no fire" policy; they attempted to prevent forest fires and to quickly and completely suppress fires if they started.Their stated purpose was to protect the nation's timber supply.In the 1970s, they reversed this policy and now let some fires burn, especially those that start naturally.In some cases, they even start fires, a process called "controlled burning." What factor caused the Forest Service's reversal of policy on fires?

Accepted Answer

A)  Recognition that periodic disturbance by fire helps maintain forests 
B)  Lack of money and resources to fight all forest fires 
C)  Recognition that it was impossible to suppress all fires 
D)  Recognition that controlled burning would speed up the growth rate of trees 
E)  Need to increase the amount of forest floor litter

Question 4

Extinctions, such as the extinction of the heath hen on Martha's Vineyard, Massachusetts, occur at the population or species level.But factors at other levels can be instrumental in causing an extinction.Which factor in the heath hens' extinction operated at the community level of diversity rather than the population level?

Accepted Answer

A)  Fire 
B)  Hard winter 
C)  Influx of predators 
D)  Poultry disease 
E)  Demographic stochasticity

Question 5

Plume hunting in the late 1800s to supply feather decorations for hats and clothing was responsible for the depletion and even extinction of many types of birds in the United States.This activity was an example of loss of biodiversity due to

Accepted Answer

A)  fragmentation. 
B)  edge effect. 
C)  invasion. 
D)  habitat degradation. 
E)  overharvesting.

Question 6

Many native pollinators in Hawaii were driven extinct by non-native species.Now, many beautiful native Hawaiian flowers are pollinated by the Japanese white-eye bird.At first, Japanese white-eyes coexisted with native birds, but recently their numbers have increased in old-growth forests, leaving native birds too little to eat and threatening their survival.Today, the Japanese white-eye could best be classified as

Accepted Answer

A)  both introduced and invasive. 
B)  invasive, but not introduced. 
C)  introduced, but not invasive. 
D)  both pathogenic and invasive. 
E)  both pathogenic and introduced.

Question 7

Refer to the figure.  The figure illustrates three ecological principles considered in the establishment of protected areas.Briefly explain why the characteristics in the "better" column (larger reserves, buffer zones, and habitat corridors) are considered superior to their opposites in terms of supporting viable populations and ecosystem services.

Accepted Answer

The answer of Refer to the figure.  The figure...

Question 8

In the eastern United States, 28 species of migratory birds are nesting earlier in the spring than they did several decades ago, and northeastern birds that winter in the southern United States are returning north 13 days earlier than they did a century ago.These changes are most likely due to

Accepted Answer

A)  rising temperatures due to climate change. 
B)  rapid genetic changes in the birds' behavior. 
C)  loss of habitat in the southern United States. 
D)  rapid adaptation to cooler, more northern climates. 
E)  new habitats opening up in more northern areas.

Question 9

Wild orca populations face many threats from humans.Sea World bred captive orcas from the 1980s until 2016.In captivity, orcas had their first calves much younger (8 years old) than wild orcas (14.9 years old).Captives were highly inbred and had a high number of stillbirths.Calves were later bred by artificial insemination.Suppose, in the future, orcas become endangered and the species must be saved through captive breeding and release.Based on this information, what factor or factors might limit the success of such a program?

Accepted Answer

The answer of Wild orca populations face many threats from...

Question 10

Which situation would be considered an example of habitat degradation, as opposed to habitat loss or destruction?

Accepted Answer

A)  Clearing land for agriculture 
B)  Clearing land to expand a city 
C)  Allowing land to be abandoned and badly eroded 
D)  Building a copper mine and leaving mine tailings in place 
E)  Building a hydroelectric dam and flooding the upstream area

Question 11

A conservation group is debating the benefits of working specifically on the protection of an endangered species versus establishing a protected area that encompasses the habitat of that species.Which benefit would be provided only by the protected area option?

Accepted Answer

A)  The protection and maintenance of multiple species 
B)  The assurance that the endangered species would be saved 
C)  The assurance that multiple endangered species would be saved 
D)  The reintroduction of the endangered species into other habitats 
E)  The prevention of invasion by exotic or undesirable species

Question 12

Introduced from Asia more than 5,000 years ago, dingoes (wild dogs) are now considered an "honorary native species" in Australia.They are the largest predators in the country.Like wolves, they hunt in packs and can bring down prey the size of buffaloes.Where dingoes are scarce, foxes and cats have caused the extinction of 20 mammals and threaten many more.Where more dingoes are present, fox and cat numbers are low, and mammal populations are protected.But farmers want to eradicate dingoes, which sometimes prey on sheep.Which would likely happen to the ecosystem if dingoes were removed?

Accepted Answer

A)  Foxes and cats would both be top predators, and the ecosystem would stabilize. 
B)  Foxes and cats would both be top predators, and more species would go extinct. 
C)  Foxes and cats would vie for top predator status; the winner would stabilize the ecosystem. 
D)  The ecosystem would be unstable because sheep would overpopulate it. 
E)  The ecosystem would become more diverse because dingoes would not be removing organisms.

Question 13

Edge effects are often damaging to the biodiversity of the original habitat because they

Accepted Answer

A)  increase pollution in the original habitat. 
B)  increase the amount of living space in the original habitat. 
C)  result in habitats more similar to the new habitat than to the original one. 
D)  result in habitats more similar to the original habitat than to the new one. 
E)  decrease competition among species in the original habitat.

Question 14

Genetic drift, leading to inbreeding depression, combined with demographic stochasticity can threaten biodiversity because it results in a smaller _______.

Accepted Answer

The answer of Genetic drift, leading to inbreeding depression, combined...

Question 15

One way ecologists try to estimate the effect of habitat loss on the rate of extinctions is by applying a concept from island biogeography known as the _______ relationship.

Accepted Answer

The answer of One way ecologists try to estimate the...

Question 16

Refer to the figure.  From the map, determine the locations in the world where overfishing is the most serious problem.Which continents or regions show high, moderate, and low exploitation? Why are the exploited areas close to continents?

Accepted Answer

The answer of Refer to the figure.  From the...

Question 17

Michigan scientists are trying to save the endangered Kirtland's warbler, a small songbird that breeds only in even-aged stands of jack pine.They have replanted stands of jack pine and used prescribed burning to develop stands of the middle-aged trees the warblers prefer.Which ecological concept is being used to aid this restoration ecology project?

Accepted Answer

A)  Use of periodic disturbances to stimulate plant germination 
B)  Restoring biodiversity by reintroducing native animals 
C)  Control of predators to make a safe environment for the warblers 
D)  Use of vegetation to prevent erosion 
E)  Restoration of original native habitat

Question 18

In the past 20 to 50 years, many plants have reacted to rising temperatures by blooming earlier in the spring.Early flowering is particularly associated with insect-pollinated plants.Which would be the most likely result if insect pollinators did not also emerge earlier, or if their emergence did not coincide with flowering?

Accepted Answer

A)  Other insects would pollinate the early-flowering plants. 
B)  Pollination of some plants would decrease or not occur. 
C)  Early-blooming plants would reproduce without pollination. 
D)  Both plant and pollinator would go extinct within a few years. 
E)  Plants would respond by flowering later the following year.

Question 19

Deaths of individuals in a population could lead to genetic drift, inbreeding, and demographic stochasticity.This in turn reduces genetic diversity and fitness, which results in a smaller effective population size.This leads to a spiraling population decline known as a(n) _______.

Accepted Answer

The answer of Deaths of individuals in a population could...

Question 20

Developers are building ten new homes on a parcel of land of one habitat type.Local zoning regulations require that they leave some of the land in its natural condition to conserve native species.They can set aside either one large plot or five small separated plots.The total amount of conserved area is the same in either case.Which choice, if either, would be best for maintaining biodiversity, and why?

Accepted Answer

A)  Either choice; the total conserved area would be the same. 
B)  Five small plots; they would reduce the likelihood that an outside threat could eradicate a species. 
C)  Five small plots; they would allow for multiple populations of each species. 
D)  One large plot; it would support larger populations and have fewer edge effects. 
E)  One large plot; it would support more types of human recreational activity.

Exam 58: A Changing Biosphere