2019年12月14日托福阅读真题+题目+答案：Beaks of Darwin' Finches

2019年12月14日托福阅读真题+题目+答案：Beaks of Darwin' Finches

In 1835, before he had developed his theory of evolution, Charles Darwin collected specimens of 13 previously unknown species of finches from the isolated Galapagos Islands. The Galapagos finches closely resembled a species of finches living on the mainland of South America, but each of the Galapagos species of finches had a differently shaped beak unique to it.His observations led Darwin to speculate that "from an original paucity of birds in this archipelago [the Galapagos Islands],one species has been taken and modified for different ends."This is the essence of Darwin's theory of evolution by natural selection:Birds with a particular beak shape survived and reproduced because their beak made them well adapted for using a particular food source. In this way one original species that came to Galapagos from the mainland ultimately evolved into 13 new species.

1.The word "speculate” in the passage is closest in meaning to

O claim

O hypothesize

O establish

O realize

The correspondence between the beaks of the 13 finch species and their food source immediately suggested to Darwin that evolution had shaped them. If his suggestion that the beak of an ancestral finch had been shaped by evolution is correct,then it ought to be possible to see the different species of finches acting out their evolutionary roles, each using their beaks to acquire their particular food specialty.The four species that crush seeds within their beaks, for example, should feed on different seeds, those with stouter beaks specializing in harder-to- crush seeds.

2.In paragraph 2, why does the author discuss the four finch species that crush seeds within their beaks?

O To suggest one way of testing Darwin's view that evolution determined the shape of finch beaks

O To emphasize that the finches with stouter beaks required a diet of larger seeds in order to survive in their island environment

O To argue that evolution may not have been the only factor in the shaping of finch beaks

O To explain why the other species observed by Darwin do not exist today

3.According to paragraph 2, which oft he following should be true if Darwin was right about the evolution of finch beaks?

O The four finch species that crush seeds should all feed on the Same seeds.

O Most finches should eventually have similarly shaped beaks.

O Finches with the stoutest beaks should feed on seeds that are the hardest to crush.

O Finches with stout beaks should have difficulty crushing seeds.

Many biologists visited the Galapagos after Darwin, but it was 100 years before any tried this key test of his hypothesis when the great naturalist David Lack finally set out to do this in 1938, observing the birds closely for a full five months, his observations seemed to contradict Darwin's proposal. Lack often observed many different species of finch feeding together on the same seeds. We now know that it was Lack's misfortune to study the birds during a wet year, when food was plentiful.' The finch's beak is of little importance in such flush times; small seeds are so abundant that birds of all species are able to get enough to eat.

4.What can be inferred from the discussion in paragraph 3 about Lack's research on finches?

O His research supported his belief that evolution influenced the feeding habits of finches.

O His observations indicated that finches that feed on small seeds have higher survival rates than finches that fed on large seeds.

O His observations would have confirmed Darwin's hypothesis about finch beaks if Lack had visited the Galapagos Islands during a dry year.

O His observations led him to conclude that climate greatly affected the feeding habits of finches as well as their beak sizes.

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