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Unformatted text preview: In past, biologists often spoke of evolved traits as serving "the good of the species," or even the stability of ecosystems; but there is no basis in evol. biology for supposing that natural selection favors any trait for that reason That's because selection acts via differential fitness of heritable variants, and this process works much more rapidly and effectively on variants that affect individual survival and reproduction than those that affect populations, species, or higher-level categories Thus, in most cases individual-level selection outpaces any higher-level selection To see why, consider example of population regulation discussed by Irons (pp 11-12) If population increases beyond the sustainable limits, it will overharvest its food, and perhaps crash to low levels or even go extinct So wouldn't natural selection favor populations that limit size to sustainable level?...
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- Fall '10