Reciprocal altruistic behavior exists not only among organisms but also in the society, but it has been hard to explain the altruistic behavior of organisms to the classical natural selection theory.

互惠利他行为是生物有机体乃至人类社会普遍存在的一种现象，经典的自然选择学说难以解释生物有机体的这类行为。

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The complex and ever-changing society demands that we should satisfy the realistic needs in terms of our qualities and occupation selection.

复杂而多变的社会需求要求我们从自身素质和职业选择上满足现实需求。

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Students, we will step is a challenging and competitive society, "survival of the fittest in natural selection, survival of the fittest" is our survival environment.

同学们，我们将要跨入的是一个充满挑战和竞争的社会，“物竞天择，适者生存”将是我们的生存环境。

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The central aim of the Festival Fringe Society was not to have a selection process deciding who could or could not take part.

VOA: special.2009.08.05

Scientist Alfred Russel Wallace, who proposed the theory of evolution by natural selection with Charles Darwin, corresponded with the great and good of 19th Century society.

BBC: Search for Alfred Russel Wallace's 19th Century letters

As the American Judicature Society reported in 2009, more women nationwide reached the trial court bench through merit selection than through other method.

FORBES: Dim Prospects for Women Leaders in a Romney Administration