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CHAPTER VI. 



THE GROWTH OF THE "ORIGIN OF SPECIES "-(1837-58). 



In dealing with this subject in his " Autobiography," 

 Darwin tells us of his reflections whilst on the voyage 

 of the Beagle, and here mentions another observation 

 which deeply impressed him in addition to those which 

 he again repeats, on the relation between the living 

 and the dead in the same area and on the productions 

 of the Galapagos Archipelago — viz. " the manner in 

 which closely allied animals replace one another in 

 proceeding southwards over the continent " (of South 

 America). On the theory of separate creation the 

 existence of such representative species received no 

 explanation, although it became perfectly intelligible 

 on the theory that a single species may be modified 

 into distinct, although nearly related, species in the 

 course of its range over a wide geographical area. 

 Here, too, the evidence is in favour of evolution simply, 

 and does not point to any cause of evolution. 



He also implies that even at this time he regarded 

 the beautiful adaptations or contrivances of nature 

 by which organisms are fitted to their habits of life — 

 " for instance, a wood-pecker or a tree-frog to climb 

 trees, or a seed for dispersal by hooks or plumes " — as 

 the most striking and important phenomena of the 

 organic world, and the one great difficulty in the path 



