ASPECTS OF KINETIC EVOLUTION 3 19 



inducing adaptation under the kinetic theory than under the 

 purely selective doctrine of Darwinism, because in kinetic evo- 

 lution a much wider range of characters can be expected to 

 reach a sufficient development to render them of selective im- 

 portance. Under a logical static theory, only those characters 

 could be developed which have selective value from their first 

 inception. 



METHODS OF PRESERVING NEW CHARACTERS. 



The great weight given to the various forms of selection, 

 isolation, and environmental influence as factors of evolution 

 have been determined largely by the belief that new characters 

 or variations could not be preserved unless they were in some 

 way separated from the unmodified parental type. This opinion 

 has been supported largely by the fact that many of the varia- 

 tions which have been taken for examples of normal evolution- 

 ary motion have been in reality more or less abnormal results 

 of the condition of inbreeding common in our domesticated 

 varieties of plants and animals. The prepotency of the un- 

 selected wild type has been insisted upon, as well as the swamp- 

 ing effects of intercrossing, when the characters of the carefully 

 selected variety fade away into those of the unspecialized 

 parental form without leaving any apparent result. Neverthe- 

 less, the fact seems to be that new characters are prepotent, not 

 of necessity over the whole taxonomic species to which the 

 individual may belong, but at least in the particular variety or 

 group and in the particular stage of interbreeding in which the 

 variation appears. The recognition of the prepotency of new 

 variations makes it obvious that the preservation and continued 

 evolution of new characters does not involve the necessity of 

 isolating the new form or the extinction of the old, after a period 

 of struggle for existence. 



Mechanical theories of evolution have centered largely about 

 this question of acquiring characters, but it is still more impor- 

 tant to know how characters are preserved after having been 

 acquired. Organisms appear to acquire some characters from 

 the environment, but it does not follow that the characters are 

 also preserved by the environment, or even that the characters 



