ADAPTATION TO ENVIRONMENT 25 



pecker for insects in the bark of a tree, in the light- 

 ning-like dash of a lizard to cover under a rock, in 

 the stealthy advance of a snake upon a bird's nest, in 

 the scream of an eagle overhead, we have vivid glimpses 

 of nature showing her teeth, of the tragic side of life, 

 which, because it is familiar to us, seems right and 

 beautiful and placid. 



Everywhere something is pursuing and something 

 is escaping another creature. It is a constant drama 

 of getting food and of seeking to escape being made 

 food, evolving in the conflict structures fitted to accom- 

 plish both reactions. Everywhere the strong prey 

 upon the weak, the swift upon the slow, the clever 

 upon the stupid ; and the weak, the slow, the stupid 

 retaliate by evolving mechanisms of defense, which 

 more or less adequately repel or render futile the op- 

 pressor's attack. For each must live, and those al- 

 ready living have proved their right to existence- by a 

 more or less complete adaptation to their environment. 

 The result of this twofold conflict between living beings 

 is to evolve the manifold structures and functions - 

 teeth, claws, skin, color, fur, feathers, horns, tusks, 

 wily instincts, strength, stealth, deceit and humility - 

 which make up character in the animal world. Accord- 

 ing to the nature and number of each being's enemies 

 has its own special mechanism been evolved, dis- 

 tinguishing it from its fellows and enabling it to get a 

 living in its particular environment. 



The survival of any organism implies that it is pro- 

 tected against adverse climate, against starvation 

 and against annihilation by enemies, in order that it 

 may live and produce offspring. In each instance, 



