T^atural Selection . 339 



Elhnination Selective and Indiscriminate 



The population tends to outrun the available food 

 supply and other essential conditions of living. There is 

 therefore an elimination of the superfluous which may be 

 conceived to correspond to the relative ineffectiveness of the 

 individuals in their struggle for life. Generally speaking, 

 the fitter in this struggle will survive. The late frost will 

 not kill all the individuals; those who can withstand frost 

 are here the fitter and survive. Where foxes pursue hares, not 

 all the hares are caught — the swifter ones escape. Con- 

 versely, not all of the foxes may get a meal — the slower ones 

 would perish. 



The struggle then affects every individual and results 

 on the one hand in a vast slaughter, and on the other hand, 

 in the survival of the superior. 



Darwin recognized that the survival was not always an 

 outcome of the struggle in any competitive sense. Vast 

 numbers of seeds and eggs and young plants and animals 

 are destroyed by their enemies as well as by changes in the 

 weather, utterly without discrimination as to relative adapta- 

 bility to living conditions. A whale will swallow a bushel 

 of floating animal life that happens to be in his path, and 

 the resulting destruction will fall like rain upon the just 

 and the unjust. With all of this indiscriminate destruction 

 of life the decision as to the ultimate survivors of each gen- 

 eration rests effectually, according to Darwin's views, upon 

 relative fitness. 



Natural Selection 



Nobody had ever questioned the effectiveness of arti- 

 ficial selection in improving varieties of plants and animals. 

 The practice has been widespread for at least two thousand 

 years. Darwin, in using the expression " natural selection " 

 recognized the essential differences between what happens 

 in nature and what happens under domestication. In the 



