2014年7月6日托福阅读真题P3+题目+答案：Sociality in Animals

2014年7月6日托福阅读真题P3+题目+答案：Sociality in Animals

Social insects represent the high point of invertebrate evolution. Some species live in communities of millions, coordinating their building and foraging, their reproduction, and their offspring care. Yet sociality is found in only a few species of insects, and is rare among vertebrates as well: wildebeest (large antelope) and lions are the exception rather than the rule. Nearly all fish, amphibians, reptiles, birds, and mammals are solitary, except when courting and mating. Birds and mammals usually rear their young, but year-round family groups are almost unknown, though they are intensely studied where they do exist. The same is true for insects.

1. According to paragraph 1, which of the following is true of sociality among animal species?

A.Sociality is much more common among invertebrates than among vertebrates.

B.Very few animals are considered social because most spend the majority of their lives alone.

C.An animal group must contain more than one family unit for the species to be considered social.

D.All animals that rear their young are considered to be social.

答案：B

We know, or think we know, that social groups are good. Wolves are better predators when they hunt in packs, and pigeons escape from falcons far more often when feeding in flocks. Group building projects—the dams beavers build to block a body of water that provides them with relative safety from predators and the lodges they build for shelter, for instance—can provide a high level of protection and comfort. Why, then, are social species so very rare? In fact, living socially presents inevitable problems that transcend habitat needs so that only when these costs are offset by corresponding benefits is group living a plus.

2. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

A.Group living allows some animals to transcend problems of habitat.

B.Group living is only advantageous when benefits outweigh inevitable problems.

C.Problems resulting from living socially extend beyond the habitat.

D.It is difficult to determine whether the benefits of social living offset its costs.

答案：B

The most obvious cost is competition. All the members of a species share the same habitat; when they live together, they are trying to eat the same food and occupy the same nesting sites. In general, there is far less competition away from a group, and selection should favor any individual who (all things being equal) sets off on its own, leaving the members of its group behind to compete among themselves for limited resources. Another difficulty is that concentrations of individuals facilitate disease and parasite transmission. On the whole, social animals carry more parasites and species-specific diseases than do solitary animals. Parasites and diseases diminish the strength and limit the growth of animals, and among highly social creatures, epidemics can devastate whole populations. Distemper (a viral disease) has been known to wipe out entire colonies of seals, for instance. So the penalty of social life is potentially huge.

3. What does paragraph 3 say about the relationship between natural selection and animals that live apart from other members of their species?

A. Natural selection does not favor living apart because individuals are unable to obtain resources equal to those of group members.

B.Natural selection does not favor living apart because of the intense competition for resources among individuals apart from a group.

C.Natural selection favors living apart because individuals are unlikely to attract the attention of predators.

D.Natural selection favors living apart because group living increases competition for limited resources of food and nesting sites.

答案：D 

4. The word "devastate " in the passage is closest in meaning to

A.alter

B.spread to

C.destroy

D.involve

答案：C 

5. In paragraph 3, why does the author mention distemper and its effect on seals?

A.To explain why sociality is now relatively rare in seals

B.To prove that parasites prevent animals from growing healthy and strong

C.To show how easily social animals transmit potentially deadly diseases

D.To provide an example of a species-specific disease that affects solitary animals

答案：C 

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