CHAPTER 11. 



THE EVOLUTION OF BIRDS. 



I The geographical distribution of the Charadriidse appears to indicate that the family 



I originated on the shores of the Arctic Ocean and the adjoining steppes and prairies. The 



chief factor in their subsequent dispersal and differentiation must have been Glacial Epochs ; 



but before entering upon the cause of differentiation, it is necessary to say a few words on 



the process itself. 



I propose to take for granted the truth of the statement, that the species of Charadriidae 

 existing at the present time are the modified descendants of a common ancestral species ; 

 that they were not specially created in the various localities where they are now found, but 

 have emigrated thither from a common centre. 



This theory, the theory of Evolution, was started as an hypothesis by Buffon, and defended 

 and modified by Lamarck and others, but was regarded by most scientific men as a wild 

 dream, until Darwin and Wallace, after years of patient accumulation of materials, over- 

 whelmed the learned world with such a vast array of facts, that with scarcely an exception 

 scientific men acknowledged their defeat, and the hypothesis of Evolution was raised to the 

 rank of a theory, as firmly based on facts as Newton's theory of Gravitation, or the undulatory 

 theory of Light. 



But when we admit that the exhaustive arguments in favour of the theory of Evolution, 

 propounded by Darwin in his remarkable book on the ' Origin of Species,' prove its truth, 

 so far as speculation on such remote events are capable of proof, we may at the same time 

 doubt whether Natural Selection be, in any sense, the cause of the Origin of Species. It 

 has probably played a very important part in the history of Evolution, but its role has been 

 that of increasing the rapidity with which the process of development has proceeded. 



Of itself it has probably been absolutely powerless to originate a species : the machinery 

 by which species have been evolved has been completely independent of Natural Selection, 

 and could have produced all the results which we call the evolution of species without its 

 aid, though the process would have been slow, had there been no struggle for life to increase 

 its pace. 



The great charm of Darwin's theory of Natural Selection is its simplicity. The theory 

 of Evolution by descent with modification had a great deal to recommend it ; but the 

 difficulty always presented itself, by what possible machinery could it be worked? To 



Truth of the 

 theorj' of 

 Evolution 

 assumed. 



Demon- 

 strated by 

 Darwin and 

 Wallace. 



Natural 

 Selection, 

 the guide, 

 not the cause 

 of Evolu- 

 tion. 



