Deck 57: Conservation Biology

Question 1

Why might captive-breeding programs that reintroduce species into natural environments fail

Answer 1

Captive-breeding programs may be limited in effectiveness in reintroducing species to their natural environments. Breeding captive species may increase the numbers of endangered species over time gradually, but it does not guarantee that these animals will survive in their original habitats. Having been bred under human-controlled settings, these animals, especially wild ones such as tigers, lions, and cheetahs, have not been exposed to the wildlife or fully used their instincts to survive. Thus, they are less likely to be adept at surviving and reproducing in nature, where they are under the constant threat of competition and predation by members of the same or other species.

Question 2

Which of the following statements about extinction is not correct

A)extinction is the permanent loss of a species
B)extinction is a natural biological process
C)once a species is extinct, it never reappears
D)human activities have little impact on extinctions
E)thousands of plant and animal species are currently threatened with extinction

Answer 2

Extinction and its rate of progress are caused by multiple factors. Human activities such as the introduction of invasive species, commercial hunting of endangered species, and habitat breakup all directly contribute to a rapidly declining biological diversity.
Thus, the correct answer is d
Extinction refers to the death or complete removal of an entire species, occurring when the last surviving member dies. This eliminates (a).
While human interference accelerates the rate of extinction, it is still a natural biological process. Human activities only propagate the rate of extinction, not initialize it; this means (b) is incorrect.
Choice (c) is incorrect because, as mentioned earlier, extinction is the permanent loss of a species. This implies it is not reversible.
There are 34,000 plant species that are currently threatened with extinction as listed by the IUCN, with many more endangered animal and plant species that have yet to be identified. This eliminates choice (e).

Question 3

Conservation biologists often say that their discipline is less about biology than it is about economics and human decision-making. What do you think they mean

Answer 3

Conservation biology is the study of how humans influence organisms and biological diversity. Conservation biologists are primarily concerned with trying to save species from extinction by limiting the negative human activities and promoting behaviors that contribute to preserving natural habitats and breeding captive species. Conservation biologists do little scientific or technical work in seeking to protect biological diversity. Instead, they qualify how human decisions and presence have contributed to the decline of species, such as hunting and habitat fragmentation. In response to the human economics behind extinction, they seek to restore natural habitats destroyed by humans and prevent future disturbances through in situ and ex situ conservation methods.

Question 4

An endangered species

A)is severely reduced in number
B)is in imminent danger of becoming extinct throughout all or a significant part of its range
C)usually does not have reduced genetic variability
D)is not in danger of extinction in the foreseeable future
E)a and b

Question 5

A more descriptive name for Homo sapiens is Homo dangerous. Explain this specific epithet, given what you have learned in this chapter.

Question 6

The most important reason for declining biological diversity is

A)air pollution
B)introduction of foreign (invasive)species
C)habitat destruction and fragmentation
D)illegal commercial hunting
E)commercial harvesting

Question 7

EVOLUTION LINK. Because new species will eventually evolve to replace those that humans are driving to extinction, why is declining biological diversity such a threat

Question 8

Habitat corridors

A)surround a given habitat
B)cut through a continuous habitat, producing an edge effect
C)vary in width depending on the species they are designed to protect
D)are an important strategy of ex situ conservation
E)have been widely adopted by restoration ecologists

Question 9

EVOLUTION LINK. Biologists have wondered how introduced species that would probably have limited genetic variation (due to the founder effect)survive and adapt so successfully that they become invasive. Part of the answer may be that invasive species are the result of multiple introductions instead of a single one. Explain how multiple introductions from a species' native area to an introduced area could increase that species' invasion success.

Question 10

In situ conservation

A)includes breeding captive species in zoos
B)includes seed storage of genetically diverse crops
C)concentrates on preserving biological diversity in the wild
D)focuses exclusively on large, charismatic animals
E)a and b

Question 11

EVOLUTION LINK. Conservation biologists have altered the evolution of salmon populations in captive-breeding programs. Wild female salmon tend to produce fewer large eggs because the large eggs contain more nutrients for the offspring, giving each individual a greater chance to survive. After just a few generations, however, captive-bred females now lay greater numbers of small eggs. Suggest a possible adaptive advantage for many small eggs in the captive-bred environment. What would you predict regarding the reproductive success of captive-bred females released in the wild

Question 12

Restoration ecology

A)is the study of how humans impact organisms
B)returns a degraded environment as close as possible to its former state
C)is an example of ex situ conservation
D)has been used to successfully reverse the decline in amphibian populations
E)is an important provision of the Endangered Species Act

Question 13

ANALYZING DATA. Study the graph, which shows the combined effects of various factors on biological diversity in 12 different terrestrial and aquatic ecosystems. Which factor is most important overall Why do you think that climate change andincreasing atmospheric CO 2 are represented as separate factors What is nitrogen pollution (Adapted from Sala, O. E. et al. Science, Vol. 287, 2000.)

Question 14

Which of the following is linked to the decline of amphibian populations

A)agricultural chemicals
B)increased UV radiation
C)infectious diseases
D)global climate change
E)all of the preceding

Question 15

SCIENCE, TECHNOLOGY, AND SOCIETY. If you were given the task of developing a policy for the United States to deal with global climate change during the next 50 years, what would you propose Explain your answer.

Question 16

About 60% of tropical rainforest deforestation is the result of

A)commercial logging
B)cattle ranching
C)hydroelectric dams
D)mining
E)subsistence agriculture

Question 17

Which of the following gases contributes to both climate change and thinning of the ozone layer

A)CO 2
B)CH 4
C)surface O 3
D)CFCs
E)N 2 O

Question 18

Climate change occurs because

A)carbon dioxide and other greenhouse gases react chemically to produce excess heat
B)Earth has too many greenhouses and other glassed buildings
C)volcanic eruptions produce large quantities of sulfur and other greenhouse gases
D)carbon dioxide and other greenhouse gases trap infrared radiation in the atmosphere
E)carbon dioxide and other greenhouse gases allow excess heat to pass out of the atmosphere

Question 19

What gas is a human-made pollutant in the lower (surface)atmosphere but a natural and beneficial gas in the stratosphere

A)CO 2
B)CH 4
C)O 3
D)CFCs
E)N 2 O

Question 20

Where is stratospheric ozone depletion most pronounced

A)over Antarctica
B)over the equator
C)over South America
D)over North America and Europe
E)over Alaska and Siberia.