For years, anecdotal evidence from around the world indicated that amp

For years, anecdotal evidence from around the world indicated that amphibians were under siege, especially in the Caribbean. Finally, proof of this hypothesis is available, thanks to the concerted, Internet-based effort of scientists involved with the Global Amphibian Assessment.

Amphibians have a unique vulnerability to environmental changes thanks to their permeable skin and their need of specific habitats to allow their metamorphosis from larva to adult. Studies indicate that they are at risk due to global climatic change, reduction in the ozone layer leading to an increased exposure to ultraviolet rays, interference with migratory pathways, drainage of wetlands, pollution by pesticides, erosion and sedimentation, and exposure to unknown pathogens thanks to the introduction of nonnative species. In other words, human progress is responsible for the losses this population is suffering.

Scientists have long considered amphibians a barometer of environmental health. In areas where amphibians are declining precipitously, environmental degradation is thought to be a major cause. Amphibians are not adaptable. They must have clean water in which to lay their eggs. They must have clean air to breathe after they grow to adulthood. Their “double life” as aquatic and land-dwelling animals means that they are at risk of a double dose of pollutants and other hazards.

The Global Amphibian Assessment concluded that nearly one-third of the world’s amphibian species are under immediate threat of extinction. Nearly half of all species are declining in population. The largest numbers of threatened species are in Colombia, Mexico, and Ecuador, but the highest percentages of threatened species are in the Caribbean. In Haiti, for example, 9 out of 10 species of amphibians are threatened. In Jamaica, it’s 8 out of 10, and in Puerto Rico, 7 out of 10.

Certainly, this is a disaster for amphibians, but scientists rush to point out that it may be equally a disaster for the rest of us on Earth. Even recent pandemics among amphibians may be caused by global changes. True, amphibians are ultrasensitive to such changes, but can reptiles, fish, birds, and mammals be far behind?

Which of the following most accurately summarizes the main point of the passage?

(A)  The extinction of amphibians is due to global warming.
(B)  Amphibians really are a barometer of environmental health.
(C)  Only equatorial amphibians are currently under siege.
(D)  Amphibians’ “double life” on land and in water may end up saving them.
(E)  Pandemics among amphibians are evident in South America.


The passage implies that the Global Amphibian Assessment has done science a favor by

(A)  setting forth a hypothesis that connects the environment to species decline
(B)  eliminating the need to study the connection between extinction and environment
(C)  refuting a contention that had existed purely through anecdotal evidence
(D)  collecting data to prove something that was previously just a hypothesis
(E)  recovering and rehabilitating species that had previously faced extinction


The author’s point in the first paragraph that amphibians are especially at risk in the Caribbean is best supported by evidence presented in which paragraph?

(A)  2
(B)  3
(C)  4
(D)  5
(E)  none of the above


The author’s purpose in the third paragraph is to

(A)  provide background on the assessment study
(B)  explain why amphibians are especially vulnerable
(C)  list types of amphibians that are most at risk
(D)  present examples of dangers from around the world
(E)  suggest an action plan for scientists and nature lovers