Adaptation and Natural Selection

Common Fallacies about Natural Selection

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Williams points out fallacies about natural selection and adaptation which may be found even in a text book on biology. This argument should be useful for the beginner, as well as for philosophers. He invites us to consider the following statement:

The white coat of the polar bear is necessary for the stalking of game in the snowy regions in which it lives. The whiteness was favored by selection because darker individuals were unable to survive.

What's wrong with this statement? Williams correct this as follows (correction indicated by red letters):

The white coat of the polar bear is advantageous for the stalking of game in the snowy regions in which it lives. The whiteness was favored by selection because darker individuals were unable to survive as well.

The statement must be corrected this way, because "necessity for survival" has nothing to do with natural selection, and natural selection is always a matter of comparison, "better or worse chances" for survival; thus even pink bears may be able to survive, even though their chances may not be as good as those of white bears!

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