Evolution of the Colors of North American Land Birds
The book Evolution of the Colors of North American Land Birds was written by author Charles Augustus Keeler Here you can read free online of Evolution of the Colors of North American Land Birds book, rate and share your impressions in comments. If you don't know what to write, just answer the question: Why is Evolution of the Colors of North American Land Birds a good or bad book?
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He freely grants that Mr. Wallace has proved that some specific characters are useful, but insists that this is not sufficient to prove that all points of specific difference are so. The theory of * xxi, pp. 59-80. EVOLUTION OF THE COLORS OF BLRDS. 119 natural selection is based upon the assumption that cer- tain characters are useful, but we are not justified in arguing from this that all characters have been devel- oped by natural selection and are therefore useful. Darwin himself freely conc...eded the inutility of many characters, and, as Mr. Romanes says, " there is positive evidence to show that the slight changes of form and colour which chiefly serve to distinguish allied species are often due to what Mr. Darwin calls 'the direct action of external conditions, ' such as changes of food, climate, etc. , as well as to mere independent variation on isolated areas, and in some of our domesticated pro- ductions, etc. ; and in none of these cases do the specific changes which result present a meaning of any kind.
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