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THE AMERICAN NATURALIST [Vol. LVI 



One does not imagine such a fauna as developing, even 

 through countless ages, great appreciation of beauty, or 

 of any of the aesthetic qualities of ''higher" animals. 

 The adaptations here are to resist the unfavorable in the 

 evironment, and still live. 



If a man walks in a tropical forest, he is amazed at the 

 abundance and variety of the life about him. He may see 

 a certain species of tree in one spot and not encounter 

 another like it for a mile. Meanwhile he has seen a hun- 

 dred other species of trees. What is the striking en- 

 vironmental factor in this forest? It is life itself! The 

 environment is favorable for so many systems of meta- 

 bolic activity that hundreds of kinds of animals are 

 ready to live in it— if they can find a place. Is there a 

 struggle ; is there adaptation ? Nowhere on the earth are 

 these responses to environment more striking. Most of 

 the struggles to live in the forest are competitions with 

 other living systems that are trying to continue to exist. 

 And the adaptations are not often for resisting, for eat- 

 ing, for resting. Think of all the animals in the tropical 

 forest— is there one that is radially symmetrical! Here 

 keen senses are at a premium. Life has always depended 

 upon seeing, hearing, feeling better than something else. 

 Lately it has come to depend upon thinking better than 

 something else. And the climax of adaptation in this 

 tropical forest has been the greatest thinker of the ages. 



A third generalization appears to be justified: Each 

 habitat, representing environment, limits the patterns of 

 the systems of activities that may persist from reactions 

 within it. The type of adaptation is set by the environ- 



Environment has a quality that any system of activi- 

 ties that attempts^ to live in it must respond to. This is 

 its changefulness. The paleontologists say that environ- 

 ment punishes too much adaptation by changing. I thhik 

 it is proper to say that the chief cause assigned for the 



i that ' ' attempts ' ' may be interpreted as teleologieal 

 sinfulness of it. If an organism does anything, it 



