作者:nahla Elsherbiny 17 年以前
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Species arose by common descent, as a result of divergence from a common stock.
The process by which favorable traits that are heritable become more common in successive generations of a population of reproducing organisms, and unfavorable traits that are heritable become less common.
The Beagle survey took five years, two-thirds of which Darwin spent on land. He carefully noted a rich variety of geological features, fossils and living organisms, and methodically collected an enormous number of specimens.This journey established him as a geologist.