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| 文章出处： 发布时间：2006-05-10 |
Passage Two
Coincident with concerns about the acceleration loss of species and habitats has been a growing appreciation of the importance of biological diversity, the number of species in a particular ecosystem, to the health of the Earth and human well-being. Much has been written about the diversity of terrestrial organisms, particularly the exceptionally rich life associated with tropical rainforest habitats. Relatively little has been said, however, about diversity of life in the sea even though coral reef systems are comparable to rain forests in terms of richness of life.
An alien exploring Earth would probably give priority to the planet’s dominant, most distinctive feature—the ocean. Humans have a bias toward land that sometimes gets in the way of truly examining global issues. Seen from far away, it is easy to realize that landmasses occupy only one-third of the Earth’s surface. Given that two-thirds of the Earth surface is water and that marine life lives at all levels of the ocean, the total three-dimensional living space of the ocean is perhaps 100 times greater than that of land and contains more than 90 percent of all life on Earth even though the ocean has fewer distinct species.
The fact that half of the known species are thought to inhabit the world’s rain forest does not seem surprising, considering the huge numbers of insects that comprise the bulk of the species. One scientist found many different species of ants in just one tree from a rain forest. While every species is different from every other species, their genetic makeup constrains them to be insects and to share similar characteristics with 750,000 species of insects. If basic, broad categories such as phyla and classes are given more emphasis than differentiating between species, then the greatest diversity of life is unquestionably the sea. Nearly every major type of plant and animal has some representation there.
To appreciate fully the diversity and abundance of life in the sea, it helps to think small. Every spoonful of ocean water contains life, on the order of 100 to 100,000 bacterial cells plus assorted microscopic plants and animals, including larvae of organisms ranging from sponges and corals to starfish and clams and much more.
36. What is the main point of the passage?
A. Humans are destroying thousands of species.
B. There are thousands of insect species.
C. The sea is even richer in life than the rain forests.
D. Coral reefs are similar to rain forests.
37. Why does the author compare rain forests and coral reefs in Paragraph 1?
A. They are approximately the same size.
B. They share many similar species.
C. Most of their inhabitants require water.
D. Both have many different forms of life.
38. The passage suggests that most rain forest species are ______.
A. insects
B. bacteria
C. mammals
D. birds
39. The word “assorted” at the end of the passage probably means ______.
A. mixed
B. numerous
C. interesting
D. accumulated
40. Which of the following conclusions is supported by the passage?
A. Ocean life is highly adaptive.
B. More attention needs to be paid to preserving ocean species and habitats.
C. Ocean life is primarily composed of plants.
D. The sea is highly resistant to the damage done by pollutants.
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