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Passage Two

Being a man has always been dangerous. There are about 105 males born for every 100 females, but this ratio drops to near balance at the age of maturity, and among 70-year-olds there are twice as many women as men. But the great universal of male mortality is being changed. Now boy babies survive almost as well as girls do. This means that, for the first time, there will be an excess of boys in those crucial years when they are searching for a mate. More important, another chance for natural selection has been removed. Fifty years ago, the chance of a baby (particularly a boy baby) surviving depended on its weight. A kilogram too light or too heavy meant almost certain death. Today it makes almost no difference. Since much of the variation is due to genes, one more agent of evolution has gone.

There is another way to commit evolutionary suicide: stay alive, but have fewer children. Few people are as fertile as in the past. Except in some religious communities, very few women have 15 children. Nowadays the number of births, like the age of death, has become average. Most of us have roughly the same number of offspring. Again, differences between people and the opportunity for natural selection to take advantage of it have diminished.Indiashows what is happening. The country offers wealth for a few in the great cites and poverty for the remaining tribal peoples. The grand mediocrity of today everyone being the same in survival and number of offspring means that natural selection has lost 80% of its power in upper-middle-class Indian compared with other tribes.

For us, this means that evolution is over; the biological Utopia has arrived. Strangely, it has involved little physical change. No other species fills so many places in nature. But in the past 100,000 years--even the past 100 years--our lives have been transformed but our bodies have not. We did not evolve, because machines and society did it for us. Darwin had a phrase to describe those ignorant of evolution; they "look at an organic being as a savage looks at a ship, as at something wholly beyond his comprehension". No doubt we will remember a 20th century way of life beyond comprehension for its ugliness. But however amazed our descendants may be at how far from Utopia we were, they will look just like us.

57. What used to be the danger of a man according to the first paragraph?

A) Lake of mates. B) A defective gene.

C) A fierce competition. D) A lower survival rate.

58. The word "diminished" (Para. 2) probably means" ______."

A) decreased B) increased C) changed D) gone away

59. What does the example ofIndiaillustrate?

A) Wealth people tend to have fewer children than poor people.

B) The upper class population is 80% smaller than that of the tribes.

C) Natural selection hardly works among the rich and the poor.

D)Indiais one of the countries with a very high birth rate.

60. The author argues that our bodies have stopped evolving because ______.

A) life has been improved by technological advance

B) the number of female babies has been declining

C) the difference between wealth and poverty is disappearing

D) our species has reached the highest stage of evolution

61. Which of the following is most probably the best title for the passage?

A) Human Evolution Going Nowhere.

B) Sex Ratio Changes in Human Evolution.

C) Ways of Continuing Man's Evolution.

D) The Evolutionary Future of Nature.

答案解析

57--61 DACAA

57.细节题。文章第一段第二句话指出每100个女婴出生就会有105个男婴出生，但男女比例在成年后就接近平衡，而70岁的老年人中女性的人数是男性的两倍。这说明男性曾面临低成活率的问题，故正确答案为D项

58.词义判断题。文章第二段指出，对人类进化不利的另一个因素是现在出生的人口比以前少，而且人们拥有的后代人数几乎相等，因此人与人之间的差异缩小了，大自然利用这种差异进行优胜劣汰的机会都减少了。所以diminished是“减少”的意思，故正确答案为A项。

59.细节推断题。文章第二段以印度人为例说明到现在印度人的存活率和后代人数都基本上没有差异，这使自然选择无法分辨好坏，从而很难在有钱人和穷人之间进行物竞天择。因此，正确答案为C项。

60.细节推断题。文章第三段第四和第五句提到近一百年来我们的生活发生了巨大的变化，而我们的身体没有任何变化，因为机器和社会替我们做了进化该做的事。因此可以推断人类停止进化的原因是技术进步改善了人类的生活并帮助人类不断适应环境的变化，故正确答案为A项。

61.主旨题。文章的第一段中作者指出婴儿成活率的提高妨碍了优胜劣汰。文章第二段中作者明确提出人类新生人口的减少和拥有相同数量后代的趋势进一步使自然选择失去了效力。第三段开始作者就提出进化对我们来说已经结束了。技术和社会的发展使人类的进化失去了必要性。纵观全文，作者认为“人类进化已经无路可走”的观点十分清楚。故正确答案为A项。