The Making of Species 



may indirectly be responsible for characteristics 

 which in themselves are injurious to the in- 

 dividual. This is probably the case as regards 

 the decorative plumage of some male birds. 

 The phenomenon of correlation was recognised 

 by Darwin, and has, we believe, played an 

 important part in the making of species. We 

 shall deal more fully with the subject in a later 

 chapter. 



5. An oft-urged objection to the theory of natural 

 selection, and one which weighed very strongly 

 with Huxley, is that breeders have hitherto not 

 succeeded in breeding a variety which is infertile 

 with the parent species. If, Huxley asked, 

 breeders cannot produce such a thing, how 

 can we say we consider it proved that natural 

 selection produces new species in nature ? This 

 objection, however, loses much of its force in 

 view of the fact that many perfectly distinct 

 species are quite fertile when bred together. We 

 shall recur to this in Chapter IV. 



6. The fact that palaeontology has hitherto failed 

 to yield links connecting many existing species is 

 a classical objection to the theory of the origin 

 of species by gradual evolution. 



Wallace states this objection as follows, on 

 page 376 of his Darwinism : " Many of the 

 gaps that still remain are so vast that it seems 

 incredible to these writers that they could ever 

 have been filled up by a close succession of 



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