適者生存

　　There is no exception to the rule that every organic being naturally increases at so high a rate, that, if not destroyed, the earth would soon be covered by the progeny of a single pair. Even slow-breeding man has doubled in twenty-five years, and at this rate, in less than a thousand years, there would literally not be standing room for his progeny.

　　The elephant is reckoned the slowest breeder of all known animals, and I have taken some pains to estimate its probable minimum rate of natural increase; it will be safest to assume that it begins breeding when thirty years old, and goes on breeding till ninety years old, bringing forth six young in the interval, and surviving till one hundred years old; if this be so, after a period of from 740 to 750 years there would be nearly nineteen million elephants alive descended from the first pair.

　　Can we doubt that individuals having any advantage, however slight, over others, would have the best chance of surviving and of procreating their kind? On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed. This preservation of favorable variations and the rejection of injurious variations, I call Natural Selection.

　　【參考譯文】

　　自然界中每一種有機物都以如此高的速率自然增長，如果沒有被破壞，地球很快就會被一對夫婦的后代所覆蓋。即使是緩慢的繁殖者在二十五年內(nèi)也翻了一番，以這種速度，在不到一千年的時間里，他的后代就沒有立足之地了。

　　大象估計所有已知的動物的繁殖速度最慢，我采取了一些痛苦，估計其最低的可能自然增長率;這將是安全的假設(shè)，它開始繁殖時三十歲，繼續(xù)飼養(yǎng)到九十歲，帶來了六年輕的間隔，并存活到一百歲;如果是這樣，經(jīng)過一段時間的740至750年將有近一千九百萬頭大象活著是第一對。

　　我們可以懷疑的人有優(yōu)勢，但是輕微的，別人，會有最好的'機會生存和繁衍的嗎?另一方面，我們可以確信，任何程度的傷害都會被嚴(yán)格摧毀。這種保留有利的變化和拒絕有害的變化，我稱之為自然選擇。

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