218 EEV. J. T. GULICK ON DIVEEGENT EVOLUTION 



fundamental distinction is between segregation produced by the 

 purpose of man, which I call 



Eational Segregation, in its two forms : 

 Aetieicial Segregation, 

 Institutional Segregation, 



and that produced by nature outside of man, which I call 

 Eesponsive Segregation ; 



while any of these forms of Segregation may be intensified by 

 Independent transformation through the principles of Diversity 

 of Selection, Diversity of Use, or Diversity of Direct Effects of 

 the Environment ; and the combined action of Segregation witt 

 these and other principles of transformation I call 



Intensive Segregation. 



In the other classification, the fundamental distinction is be- 

 tween segregation arising from the relations in which the organism 

 stands to the environment, which I call 



Environal Segregation, 



and segregation arising from the relations in which the members 

 of the same species stand to each other, which I call 



Reflexive Segregation ; 



while any form of segregation belonging to either of these classes 

 may be enhanced by one or more of the forms of Intension, and 

 thus present what I call 



Intensive Segregation. 



The Eeeects oe Segregation. 



The effects of Segregation can be studied to advantage in the 

 vast experience that has been accumulated in the domestication 

 of plants and animals. 



Artificial Segregation is caused by the relations in which the 

 organism stands to the rational environment, that is to the 

 purposes of man. In other words. Artificial Segregation is the 

 rational form of Environal Segregation. Though the bearing of 

 Segregation on the evolution of species in a state of nature has 

 been for the most part overlooked, its eftects have been quite 

 familiar to the breeder of domestic races. 



