2021年10月14日雅思阅读真题+题目+答案：The value of research into mite harvestmen

2021年10月14日雅思阅读真题+题目+答案：The value of research into mite harvestmen

Few people have heard of the mite harvestman, and fewer still would recognize it at close range. The insect is a relative of the far more familiar daddy longlegs. But its legs are stubby rather than long, and its body is only as big as a sesame seed. To find mite harvestmen, scientists go to dark, humid forests and sift through the leaf litter. The animals respond by turning motionless, making them impossible for even a trained eye to pick out.’ They look like grains of dirt.’ said Gonzalo Giribet, an invertebrate biologist at Harvard University.

Dr Giribet and his colleagues have spent six years searching for mite harvestmen on five continents. The animals have an extraordinary story to tell they carry a record of hundreds of millions of years of geological history, chronicling the journeys that continents have made around the Earth. The Earth’s landmasses have slowly collided and broken apart again several times, carrying animals and plants with them. These species have provided clues to the continents’ paths.

The notion of continental drift originally came from such clues. In 1911, the German scientist Alfred Wegener was struck by the fact that fossils of similar animals and plants could be found on either side of the Atlantic. The ocean was too big for the species to have traveled across it on their own. Wegener speculated correctly, as it turned out that the surrounding continents had originally been welded together in a single landmass, which he called Pangea.

Continental drift, or plate tectonics as it is scientifically known, helped move species around the world. Armadillos and their relatives are found in South America and Africa today because their ancestors evolved when the continents were joined. When South America and North America connected a few million years ago, armadillos spread north, too.

Biogeographers can learn clues about continental drift by comparing related species. However, they must also recognize cases where species have spread for other reasons, such as by crossing great stretches of water. The island of Hawaii, for example, was home to a giant flightless goose that has become extinct. Studies on DNA extracted from its bones show that it evolved from the Canada goose. Having colonized Hawaii, it branched off from that species, losing its ability to fly. This evolution occurred half a million years ago, when geologists estimate that Hawaii emerged from the Pacific.

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QUESTIONS 1-6

Choose the correct letter A, B, C or D.

Write the correct letter in boxes 1-6 on your answer sheet.

1. Why is it difficult to find mite harvestmen?

A they are too small to see with naked eye.

B they can easily be confused with daddy longlegs.

C they are hard to distinguish from their surroundings.

D they do not exist in large numbers in any one place.

2. Why are mile harvestmen of interest to Dr Giribet and his colleagues?

A they have been studied far less than most other species.

B they show the effects of climate on the evolution of animals.

C they have an unusual relationship with plants and other animals.

D they provide evidence relating to a field of study other than insects.

3. What factor contributed to Wegener’s idea that present-day continents used to form a single landmass?

A changes in the level of the ocean

B the distance that species could travel

C the lack of certain fossils on one side of the Atlantic

D similarities in living conditions on both sides of the Atlantic

4. What point is made by the reference to armadillos?

A regions have both separated and become connected.

B certain animals could travel longer distances than others.

C the oldest species of animals are likely to be found in Africa.

D there is a tendency for animals to spread in a particular direction.

5. Which of the following is stated in the fifth paragraph?

A Hawaii is a habitat that cannot support large birds.

B Hawaii is an attractive habitat for certain species of birds.

C flightless birds are more likely to become extinct than others.

D the Hawaiian goose became flightless after it had reached Hawaii.

6. Why is evidence from cockroached of limited value?

A they spread too fast.

B they multiply too quickly.

C they are found in too few places.

D they have divided into too many species.

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