ASPECTS OF KINETIC EVOLUTION 36 1 



continues, but there is, nevertheless, a very wide and very 

 practical divergence of opinion regarding the nature and causes 

 of the evolutionary process. In the study of this question 

 it becomes important to realize that the evolutionary condition 

 of cultural species differs from that of wild types because of 

 the much greater degree of inbreeding to which the former 

 are commonly subjected. 



The constitution of species has a practical bearing upon agri- 

 culture, not because the domesticated plants and animals have 

 not been studied from an evolutionary standpoint, but for the 

 very opposite reason, that they have been considered too exclu- 

 sively, so that the important differences existing between them 

 and wild species have been overlooked. Ideas drawn from 

 domesticated varieties have been projected into nature at large, 

 and this made it only the more impossible to appreciate the fact 

 that grave differences exist between wild and domesticated 

 groups of organisms. 



Evolutionary science has gained much from the study of do- 

 mesticated plants and animals, and may gain still more in the 

 future. The objection is only to the use of such studies and 

 results as an exclusive basis of interpretation of the facts of 

 nature. All that happens in domestication may also happen in 

 nature, for domestication is, after all, only a department of 

 nature. It does not follow, however, that nature is fully mir- 

 rored in domestication; the mirror is too small. It shows us 

 only the conditions in which constructive evolution does not 

 take place, even in nature. 



The recognition of the fact that evolution is a phenomenon 

 depending upon the specific constitution of living matter has 

 been delayed, no doubt, by the difficulties which have been en- 

 countered in the field of taxonomy. In the recent decades nat- 

 uralists have faltered in the task of nomenclature set by Lin- 

 naeus. To merely describe and give names to the millions of 

 evolutionary unit groups of organisms which occupy the sur- 

 face of our planet is a work much too vast for the present re- 

 sources of science. The temptation of weariness has been to 

 shorten it by passing over the apparently useless redundancy 

 of slightly different groups, or by declaring that all is vanity of 



