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From < The proper study of mankind> 摘自《经济学人》 Dec 20th 2005

Not all of his contemporaries agree with Dr Ambrose about Toba's effect on humanity. The eruption certainly happened, but there is less consensus about his suggestion that it helped form the basis for what are now known as humanity's racial divisions, by breaking Homo sapiens into small groups whose random physical quirks were preserved in different places. The idea is not, however, absurd.It is based on a piece of evolutionary theory called the founder effect, which shows how the isolation of small populations from larger ones can accelerate evolutionary change, because a small population's average characteristics are likely to differ from those of the larger group from which it is drawn.Like much evolutionary theory, this is just applied common sense. But only recently has such common sense been applied systematically to areas of anthropology that have traditionally ignored it and sometimes resisted it. The result, when combined with new techniques of genetic analysis, has been a revolution in the understanding of humanity's past.

new words

consensus     n 一致，合意
The two parties have reached a consensus。
这两个政党达成一致意见。
Homo Sapiens    智人（现代人的学名）
quirk     n 古怪的行为

≡参考答案：≡

火山爆发确实发生了。Ambrose博士认为，爆发把“智人”分成了小群体，并把他们的随机肢体行为保存在不同地点，这是目前被称之为“人类种族区分”理论的基础。然而与Ambrose博士看法一致的很少。 这种观点的基础是一个名为“创建者效应”的进化理论，该理论表明把小群人从大群体中隔离出去如何能加速进化。小群体的一般特征很可能与大的群体不同，因而得出上述理论。