托福阅读真题+题目+答案：Industrialized Moths

托福阅读真题+题目+答案：Industrialized Moths

When most people think of evolution, they imagine slow, incremental changes in a population of plants or animals. But evolutionary changes can also appear suddenly. This is illustrated by the most famous example of natural selection at work- the changing coloration of the peppered moth (Biston betularia ). The story of this population of light-colored moths that turned dark and then light again in response to environmental change is an elegant example of Darwinian evolution at work. What happened to the peppered moth reminds us how easily populations can adapt to new conditions in times of environmental stress.

1.According to paragraph 1, what popular idea about evolution did the changing coloration of peppered moths prove wrong?

O That evolution occurs through natural selection

O That evolution occurs in times of environmental stress

O That there are elegant examples of Darwinian evolution

O That evolution occurs very slowly

The peppered moth, easily recognizable by its distinctive off-white wings peppered with black specks, is common in England, where its preferred daytime environment is light-grey-lichen-covered trees. The species, which includes a variety of color gradations from dark to light, has always been popular with insect collectors because it's easy to preserve and because the specimens generally maintain their color after death. Before 1850, most of the specimens netted by English collectors were a speckled light grey-roughly the color of the lichens (organisms that often cover the bark on trees). But then the collectors noticed a change: increasingly, the moths they captured had dark wings, and many of them were almost totally black. British entomologists (scientists who study insects) were fascinated by this rapid change in the peppered moth population, especially when they realized that it was almost entirely restricted to polluted industrial areas. They began to realize that what they were seeing was the process of evolution through natural selection.

Because the light grey moths resembled the lichens on the trees, they were relatively safe from their main daytime predators, birds. But the darker moths were easy to see, and this disadvantage limited the percentage of genes for dark coloration in the peppered moth gene pool. When, in the mid-nineteenth century, industrial pollution in England began turning the lichen on the tree trunks black, the darker moths were suddenly protected while the light-colored moths became vulnerable. As more and more dark moths survived, the gene pool shifted toward darker coloration. Similar examples of industrial melanism, a darkening in color linked to a rise in industrialization, were identified in Europe, Japan, the United States, and Canada.

2.Which of the following statements most accurately describes the relationship of paragraph 3 to paragraph 2 ?

O Paragraph 2 describes a phenomenon, and paragraph 3 provides an explanation for the phenomenon.

O Paragraph 2 presents a theory, and paragraph 3 provides different examples in support of the theory.

O Paragraph 2 describes the typical behavior of a species, and paragraph 3 explains how the behavior affects the predators of the species.

O Paragraph 2 discusses the advantages of the dark coloration of one species of moth, and paragraph 3 discusses its disadvantages.

3.The word “ulnerable” in the passage is closest in meaning to

O less healthy

O visible

O at risk

O less common

4.According to paragraph 3, why was the percentage of light-colored moths relatively high before 1850?

O Light-colored moths had genes that allowed them to reproduce faster than dark-colored moths could.

O Light-colored moths were less visible to birds during the day than dark-colored moths were.

O Light-colored moths typically spent less time on lichens during the day than darker-colored moths did.

O Light- colored moths were better protected from industrial pollutants than dark-colored moths were.

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