Exam 58: A Changing Biosphere

In 1900, there were about 100,000 cheetahs living in the wild, across Africa and Asia.Today, there are only 9,000 to 12,000 cheetahs remaining.These survivors are restricted to parts of eastern, central, and southwestern Africa, with a small portion (less than 200) in Iran.These changes suggest that the effective population size of cheetahs is currently

Throughout the Northern Hemisphere, plant species are blooming several weeks earlier than they did 50 years ago.Also, their insect pollinators are emerging and reproducing earlier, so they require earlier-blooming flowers to provide pollen and nectar.These changes in timing are most likely caused by

All species are affected by climate change, and some of them respond by moving their ranges poleward.Of the insects, birds, and trees contained in a given ecosystem, the _______ would likely be the slowest to move their ranges.

Groupers are large fish that act as top predators and keystone species in their coral reef habitats.They are preferentially harvested by fishermen.If overharvested, their decline would likely result in changes to the reef ecosystem and

Approximately 50 percent of current medicines either come from or are based on natural substances.Researchers also depend on natural biodiversity as a source of future medicines, foods, and energy.This potential use of biodiversity most directly relates to which aspect or value of biodiversity?

Suppose a highly virulent virus is found in chickens and several wild birds in the United States.It is new to the United States but has been seen a few times in isolated cases in African birds.Scientists think it might have arrived in the United States in a shipment of parrots, at least one of which was infected.In the United States, this virus would represent a(n)

A type of green seaweed known as "killer algae" was once native to the Indian and Pacific oceans but has escaped from aquariums in California, Japan, Australia, and Monaco.In the Mediterranean, it is replacing native algae and depriving native marine life of food and habitat.California eradicated the algae by using costly toxic chemicals.Would killer algae be considered invasive, or merely introduced? Why?

A city planning agency wants to restore an abandoned industrial area to its original natural state, including restoration of its original biodiversity.Based on methods typically used in restoration ecology, they would likely carry out all the following activities except

Which effort to preserve biodiversity would be classified as restoration ecology?

A landowner wants to control an invasive plant species.He analyzes the spread of the plant and realizes that the plant infestation has three areas: a highly infested core area, a middle area or "advancing front" that has fewer plants but is expanding, and an outlier area that has the lowest plant density.The landowner decides to focus his first control efforts on the outlier area.What is his likely rationale for this choice?

Kemp's ridley sea turtles nest along a single stretch of the Mexican coast in the Gulf of Mexico.In the 1940s, more than 100,000 turtles came ashore to nest in a single day.In the 1980s, only a few hundred were left, and now they are critically endangered.Initially, Kemp's ridleys were hunted for meat and particularly for their eggs, almost all of which were taken.Today, survivors are caught in fishing nets and threatened by pollution.This suggests that the major reason the Kemp's ridley sea turtle is critically endangered is

In 1989, CITES instituted a ban on trade in African elephant ivory but reversed the ban in several African countries in 2008.The main reason for reversing the ban was that

Scientists at the Woods Hole Oceanographic Institute tested marine organisms under different levels of atmospheric CO₂, which dissolves in the ocean to form carbonic acid.They tested organisms at today's level (400 ppm) and several higher CO₂ levels.At very high levels, the shells of clams, oysters, and some snails and urchins partially dissolved.However, crustaceans, including lobsters, crabs, and prawns, appeared to build more resilient skeletons.Which of the following do these results suggest about future marine ecosystems under higher CO₂ levels (more acidic oceans)?

Which is a major reason scientists are alarmed by the rapid and massive loss of amphibians?

Converting private agricultural land in northeastern Montana to a native prairie landscape is an example of _______.

Which of these actions is an example of ecological restoration?

The fungal pathogen Batrachochytrium dendrobatidis, or Bd, appears to be partly responsible for the worldwide decline in _______.

Ecologists often focus on protecting keystone species as a way of preserving endangered ecosystems.This is most likely because keystone species are the

The population of the California red-legged frog has been severely affected as its habitat has been drained, filled, and covered with housing developments, parking lots, and other urban structures.The best description of the type of pressure exerted on the frogs in this situation is

Refer to the map. The map shows the area of a large prairie restoration project currently underway in Montana.What ecological features does this location have that make it suitable for prairie restoration, as discussed in the text? What practical (as opposed to ecological) factors make this a feasible location?