托福阅读真题+题目+答案：Amphibian Distribution and Abundance

托福阅读真题+题目+答案：Amphibian Distribution and Abundance

Amphibians are cold-blooded animals such as frogs, toads, and salamanders that develop from an immature form that breathes in water to an adult form that breathes in air. On a global and regional scale, the distribution and abundance of amphibians probably has little to do with biological interactions among species and a great deal to do with historical events and major features of landscape and climate. The global distribution and diversity of amphibian species is strongly affected by latitude. In both the Old World and New World, amphibians are far more diverse in the tropics than in temperate latitudes. This is not surprising, since the relatively constant temperatures and wet environments of tropical habitats are ideal for amphibians, especially those that lay eggs out of water. The diversity of amphibians is much higher in the New World tropics than in the Old World tropics. South America, for example, has nearly three times as many species of amphibians as does Africa, which is a much larger continent. In part this reflects the larger expanses of tropical forests in South America compared to tropical Africa, which has extensive grassland habitats. It also reflects the evolution of several large families of anurans (frogs and toads) in tropical South America into many different forms. Islands tend to have a much lower diversity of amphibians than do mainland habitats, even in the tropics, but species diversity increases with island size. Large tropical islands such as Borneo have high amphibian species diversity, whereas small tropical islands in the Caribbean have much smaller numbers of species.

In both the tropics and the temperate zone, amphibian diversity is strongly affected by rainfall. In North America, for example, amphibians are most diverse in the southern Appalachian Mountains and the southeastern Coastal Plain (flat lowlands along the Atlantic coast), both areas of high rainfall. A strong positive correlation or a high likelihood of interdependence between amphibian species diversity and rainfall is seen in other regions as well. ■Amphibian species diversity also is strongly affected by altitude. ■In North America, salamanders are more diverse in mountain habitats than in lowland habitats, but anurans are not.■In South America, the wet slopes of the Andes harbor the highest diversity of anuran species in the world. Mountain regions of Africa generally have fewer species of amphibians than do New World mountains, but nevertheless these areas often are rich in local species with limited altitudinal distributions.■

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托福阅读真题题目如下：

1.The word “ideal” in the passage is closest in meaning to

A.normal

B.perfect

C.comfortable

D.Healthy

正确的答案：B

2.According to paragraph 1, which of the following has the least amount of influence on the distribution and abundance of amphibians?

A.Major features of climate

B.Important aspects of landscape

C.Historical events

D.Biological interactions among species

正确的答案：D

3.The comparison between amphibian diversity in South America and amphibian diversity in Africa in paragraph 1 strongly suggests which of the following?

A.Species diversity for animals other than amphibians is generally also higher in South America than it is in Africa.

B.Amphibian diversity is increasing in South America, but it is decreasing in Africa.

C.Amphibian diversity is greater in tropical rain forests than it is in tropical grasslands.

D.The evolution of amphibians in many different forms was more extensive on large continents than it was on small continents.

正确的答案：C

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