WHAT EVOLUTION IS 113 



5. DARWINISM CRITICIZED 



In discussing Darwinism or natural 

 selection from a critical standpoint 

 we may begin by inquiring w^hether 

 there is any evidence that this process 

 is an actual occurrence in nature. To 

 answer such a question, one would 

 naturally turn to conditions where 

 organisms are subjected to severe 

 and unusual strain. Some years ago 

 Bumpus studied the effects of a 

 severe winter storm on sparrows. 

 As a result of a heavy sleet many 

 birds were brought close to death. A 

 large number of these spent birds 

 were collected, and of the total col- 

 lection, 64 died and J2 revived. Do 

 the members of these two groups 

 thus naturally established dift'er, or 

 are they essentially the same? A 

 statistical study of the two sets of 



