FORMS OF SeivECTION. 



199 



organisms better adapted than their rivals of|the same intergenerant 

 to the natural laws and conditions of the environment, or to the nat- 

 ural constitution of the species to which they belong. The former I 

 call rational selection and the latter adaptational selection. Under the 

 former I place artificial [prudential] and institutional selection, and 

 under the latter I place processes as unlike as natural selection and 

 sexual selection. This classification does not, however, seem to me 

 so important or so fundamental and clearly definable as that which 

 rests on the fact that some forms of selection depend on the relations 

 in which organisms stand to the environment, while others depend on 

 the relations in which the members of the same species stand to each 

 other. It may here be noted that artificial selection is the exclusive 

 generation of those that are better fitted to the rational environment, 

 through the failure to propagate of those that are less fitted. The 

 effect is the same whether the failure to propagate is through lack of 

 adaptation to human purposes or through lack of adaptation to the 

 unreasoning environment. 



The following table of the forms of selection will, I think, be a help in 

 maintaining these and other distinctions. 



Forms of Selection. 



