Question 1

Over several years, a natural prairie area is broken into smaller and smaller fragments to provide more land for agriculture.As this occurs, the remaining natural prairie becomes more subject to changing biodiversity due to greater _______.

Accepted Answer

The answer of Over several years, a natural prairie area...

Question 2

Cheetah populations around the world have very low effective population sizes and low genetic diversity.Relate these factors to the concept of an "extinction vortex," and explain how this concept might apply to future cheetah populations.

Accepted Answer

The answer of Cheetah populations around the world have very...

Question 3

Species are affected by rising temperatures, rising ocean acidity, and increased storms primarily as a result of

Accepted Answer

A)  habitat loss and degradation. 
B)  behavioral changes in animals. 
C)  unknown causes. 
D)  human-caused climate change. 
E)  natural climate change.

Question 4

Which process would not be considered an example of restoration ecology?

Accepted Answer

A)  Removing restrictions on fires from an area that depends on periodic fires to germinate trees 
B)  Removing polluted soil from an old industrial site and planting it with native vegetation 
C)  Introducing wolves to an area from which they had previously been exterminated 
D)  Abandoning an agricultural field and allowing it to undergo succession on its own 
E)  Planting grasses to trap soil and sediment, speeding the return of a dredged coastal area to wetland status

Question 5

In Sumatra, Indonesia, tiger populations are decreasing because of severe poaching and habitat fragmentation.Several groups, including the U.S.Fish and Wildlife Service, are cooperating to try to limit poaching.Over 2 years, they made 63 reports of illegal hunting, trading, smuggling, or possession of tigers or tiger parts, leading to 35 arrests or confiscations.In what way do such activities most likely protect or enhance endangered species?

Accepted Answer

A)  They eliminate poachers from the area. 
B)  They improve habitat for remaining tigers. 
C)  They stop all trade in tigers and tiger parts. 
D)  They make tigers safer by eliminating the demand for them. 
E)  They help prevent further reductions in breeding populations of tigers.

Question 6

Which factor would scientists consider evidence that humans are causing the current mass extinction?

Accepted Answer

A)  The extinction rate is lower than extinction rates from natural causes. 
B)  We can count the number of species currently going extinct. 
C)  Megafauna on all continents began to go extinct shortly after humans arrived. 
D)  Mass extinctions have occurred throughout history. 
E)  The extinctions are occurring only in regions densely populated by humans.

Question 7

Refer to the graphs.  The graphs illustrate edge effects on bird populations in a forest environment that has been fragmented.Bird populations are compromised when their nests host eggs of cowbirds, which live in forest edge habitats.Explain what the graphs show about the effects of forest edge environments on nesting success.What factors related to human activity tend to increase edge effects?

Accepted Answer

The answer of Refer to the graphs.  The graphs...

Question 8

Twenty percent of all humans depend on fish as their primary protein source.The United Nations Food and Agriculture Organization (FAO) states that 70 percent of all marine fisheries are now either fully exploited or depleted.Since the mid-1990s, commercial populations of cod, hake, haddock, and flounder have declined by up to 95 percent.Many UN members are calling for action to solve this problem.Which action would be most likely to reverse the trend of declining fish populations?

Accepted Answer

A)  Developing more effective fishing technology 
B)  Removing regulations on fishery catches 
C)  Having fisheries switch to new fish species 
D)  Fertilizing oceans to produce more food for fish stocks 
E)  Setting stricter catch limits, to allow fish stocks to recover

Question 9

Refer to the figure.  According to the figure, which statement best describes the changes undergone by plant communities in the past 9,000 years (9 ka)?

Accepted Answer

A)  Boreal forests and forest tundra are moving southward. 
B)  Prairie is beginning to overtake southeast forest. 
C)  Most forests are becoming mixed forests. 
D)  Northern forests are tending to move southward. 
E)  Southern forests are tending to move northward.

Question 10

Refer to the table.  According to the table, during the past several decades, plants have begun to show earlier flowering and leaf unfolding, butterflies have appeared earlier, and animals show earlier breeding and migration dates.How do these changes provide evidence for climate change?

Accepted Answer

A)  They represent examples of species having unusual reactions to climate change. 
B)  They represent ways in which organisms are failing to adapt to the changing climate. 
C)  They correlate with temperature variations, which lead to random organism responses. 
D)  They correlate with temperature decline, which leads to spring beginning later. 
E)  They correlate with temperature rise, which leads to spring beginning earlier.

Question 11

Elephants on Africa's Serengeti plains eat small trees, such as acacia, by knocking them over and uprooting them.This behavior keeps the region a grassland rather than a forest or woodland.The grassland sustains large grazers such as antelopes, wildebeests, and zebras, and small mice and shrews.These in turn feed predators such as lions and hyenas.Because of their position in this ecosystem, elephants can be considered a(n)

Accepted Answer

A)  top predator. 
B)  keystone species. 
C)  foundation species. 
D)  autotroph. 
E)  exotic species.

Question 12

Unusually warm waters in the Caribbean caused mass coral bleaching events in 1998, 2005, and 2014F1F1F1S1F1F1F102016 (an unprecedented 3-year barrage of record-breaking temperatures).As many as 80F1F1F1S1F1F1F1090 percent of corals were damaged, many died, and more are expected to die.Temperature spikes during these years occurred because of El Niño effects, but the bleaching and its devastating effects on coral were likely worsened by ongoing

Accepted Answer

A)  natural predation loss. 
B)  overharvesting. 
C)  habitat loss and degradation. 
D)  climate change. 
E)  vandalism of reefs by humans.

Question 13

Possible changes in species as a result of climate change include all of the following except

Accepted Answer

A)  earlier breeding, flowering, or emergence. 
B)  earlier migration. 
C)  reduced growth and reproductive rates. 
D)  lower effective population sizes. 
E)  increased species richness.

Question 14

A semitropical coastal region is undergoing development, and there are plans to destroy a local mangrove swamp to allow offshore oil development in the area.The mangrove swamp is highly diverse and serves as a nursery for many marine organisms, including some of economic value.It also buffers the city from storm surges.You are asked to speak to the city council about the proposed project.Briefly summarize the types of biodiversity-related losses that are likely to occur if the swamp is destroyed during oil development.Include both economic and noneconomic impacts.

Accepted Answer

The answer of A semitropical coastal region is undergoing development,...

Question 15

Australia's Lord Howe Island stick insect was believed to have become extinct about 1930.Accidentally introduced mice and rats were thought to have eliminated it from its only known habitat.The enormous 12-cm-long insect was rediscovered in 2001 when scientists found 24 individuals living underneath a single shrub on the world's tallest volcanic sea stack, an extremely isolated islet in the Pacific called Ball's Pyramid.This set of facts exemplifies that

Accepted Answer

A)  extinction cannot be easily confirmed. 
B)  extinction can be reversible. 
C)  extinction can be easily confirmed. 
D)  this species is at low risk of extinction. 
E)  extinction can occur for reasons other than human impacts.

Question 16

Which of these would not be considered a part of the illegal wildlife trade?

Accepted Answer

A)  Buying a tiger skin from a tiger shot in an Indian reserve 
B)  Selling a horn from the endangered white rhinoceros 
C)  Buying goldfish from a breeder 
D)  Buying endangered Banggai cardinalfish collected in Indonesia 
E)  Poaching elephants for their ivory

Question 17

The rate of extinctions that occurred normally throughout history, when mass extinction events were not occurring, is called the _______.

Accepted Answer

The answer of The rate of extinctions that occurred normally...

Question 18

Blue whales and humpback whales were both greatly overharvested before commercial whaling was banned in 1986.Humpbacks are making a comeback, but blue whale populations remain very low.The most likely reason for this is that blue whales

Accepted Answer

A)  have lower reproductive rates. 
B)  have higher reproductive rates. 
C)  are smaller than humpback whales. 
D)  suffer from more severe habitat loss. 
E)  are keystone species in marine communities.

Question 19

The brown tree snake, which arrived on Guam in air cargo after World War II, is now found at high densities on the island and has caused the extinction of 15 species of land birds.The brown tree snake can best be described as a(n) _______ species.

Accepted Answer

The answer of The brown tree snake, which arrived on...

Question 20

A non-native mosquito species moves north into the United States, carrying with it a viral disease that affects humans.Epidemiologists, who track disease outbreaks, want to predict both the spread of the disease in humans and how serious its effect will be.Given that it is a new (introduced) virus, how will its effect likely compare with that of a viral disease spread by a native mosquito?

Accepted Answer

A)  It should be no different, since both diseases are carried by mosquitoes. 
B)  It should cause a less serious disease, since it is not adapted to the area. 
C)  It should cause a less serious disease, since there are fewer of the new mosquitoes. 
D)  It should cause a more serious disease, since it will spread faster than a native virus. 
E)  It should cause a more serious disease, since no humans are adapted to it.

Exam 58: A Changing Biosphere