464 Evolution and Adaptation 



form or another. This idea will remain, I think, a most 

 important contribution to the theory of evolution. We may- 

 sum up our position categorically in the following statements: 



Animals and plants are not changed in this or in that part 

 in order to become better adjusted to a given environment, 

 as the Darwinian theory postulates. Species exist that are 

 in some respects very poorly adapted to the environment in 

 which they must live. If competition were as severe as the 

 selection theory assumes, this imperfection would not exist. 



In other cases a structure may be more perfect than the 

 requirements of selection demand. We must admit, there- 

 fore, that we cannot measure the organic world by the meas- 

 ure of utility alone. If it be granted that selection is not a 

 moulding force in the organic world, we can more easily 

 understand how both less perfection and greater perfection 

 may be present than the demands of survival require. 



If we suppose that new mutations and " definitely " in- 

 herited variations suddenly appear, some of which will find 

 an environment to which they are more or less well fitted, 

 we can see how evolution may have gone on without assum- 

 ing new species have been formed through a process of 

 competition. Nature's supreme test is survival. She makes 

 new forms to bring them to this test through mutation, and 

 does not remodel old forms through a process of individual 

 selection. 



