Exam 58: A Changing Biosphere

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 _______.

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.

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

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

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?

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

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?

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?

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)?

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?

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)

Unusually warm waters in the Caribbean caused mass coral bleaching events in 1998, 2005, and 20142016 (an unprecedented 3-year barrage of record-breaking temperatures).As many as 8090 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

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

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.

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

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

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

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

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.

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?