THE ORGANIC TENDENCY 193 



so; this may be admitted without discounting in 

 the least the high valuation which we place upon 

 unselfish work. 



Certainly the exercise of intelligence with respect 

 to biological necessities leads to the preservation 

 of that which exists in the species and not, in it- 

 self, to change. But fortunately for evolution, the 

 environment is an inevitable and perpetual source 

 of change; the organism cannot secure exactly the 

 same materials at all times nor is it always subject 

 to the same stimuli. Successive generations cannot 

 always live under the same conditions. Individ- 

 uals in nature must take what they can get, as a 

 result of availability in the environment and ability 

 on the part of the organism. Opportunism is a fact 

 in nature. Nothing goes to waste, for as surely as 

 a bit of food is found in a vacant space, some organ- 

 ism will find in it an opportunity for the release 

 of some pressure in its existing mode of life, and a 

 new step in evolution is accomplished. 



The effects of environmental conditions are va- 

 rious. An organism may have to migrate if crowded 

 in one region, or it may have to climb or burrow or 

 run because of the activities of its associates. It 

 may go south because the climate has grown colder, 

 or raise a thicker coat of fur for the same reason. 

 Always it does what is most certain to provide 

 for its needs, within its inherently possible re- 

 sponses, or perishes, and since its own activities 



