There’s no question that variation in size and shape has conferred selective advantages over the course of evolutionary time. One of the most obvious examples is the long neck and legs of the giraffe, which allow it to snatch foliage that is unreachable by vertically challenged competitors. The variable beak shapes and sizes of Darwin’s finches represent the diverse tool set that evolved when only certain food sources became available. And the appearance of the opposable thumb, a simple change in hand shape, undoubtedly influenced the course of human history.
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