If some individuals have a trait that allows them to better compete in a given environment, then they are more likely to survive into adulthood and produce offspring. And the offspring are likely to carry the same trait.

The organism acts, and has evolved, to further the interests of its genes.

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The idea of evolution by natural selection - as per 'The Origin of Species', by Charles Darwin:

If during the long course of ages and under varying conditions of life, organic beings vary at all in the several parts of their organization, and I think this cannot be disputed; if there be, owing to the high geometric powers of increase of each species, at some age, season, or year, a severe struggle for life, and this certainly cannot be disputed; then, considering the infinite complexity of the relations of all organic beings to each other and to their conditions of existence, causing an infinite diversity in structure, constitution, and habits, to be advantageous to them, I think it would be a most extraordinary fact if no variation ever had occurred useful to each being's own welfare, in the same way as so many variations have occurred useful to man.

But if variations useful to any organic being do occur, assuredly individuals thus characterized will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance they will tend to produce offspring similarly characterized. This principle of preservation, I have called, for the sake of brevity, Natural Selection.


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Success by mutual cooperation is explained in 'Darwin's Blind Spot', by Frank Ryan.

Besides the law of mutual struggle there is in Nature the law of mutual aid, which, for the progressive evolution of the species, is far more important than the law of mutual contest.

The intimate cooperation...

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‘The Origin of Wealth’, by Eric Beinhocker puts evolution into an economic context:

We are accustomed to thinking of evolution in a biological context, but modern evolutionary theory views evolution as something much more general.

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