The Making of Species 



which afforded a plausible explanation of what 

 they believed to have occurred. 



Hence the rapturous welcome accorded to the 

 theory of natural selection by the more pro- 

 gressive biologists. 



Another point in Darwin's favour was the 

 delightful simplicity of his hypothesis. Nothing 

 could be more enticingly probable. It is based 

 on the unassailable facts of variation, heredity, 

 and the tendency of animals to multiply in 

 numbers. Everybody knows that the breeder 

 can fix varieties by careful breeding. Darwin 

 had simply to show that there is in nature some- 

 thing to take the part played among domesticated 

 animals by the human breeder. This he was 

 able to do. As the numbers of species remain 

 stationary, it is evident that only a small portion 

 of the animals that are born can reach maturity. 

 A child can see that the individuals most likely 

 to survive are those best adapted to the circum- 

 stances of their life. Even as the breeder weeds 

 out of his stock the creatures not suited to his 

 purpose, so in nature do the unfit perish in the 

 everlasting struggle for existence. 



In nature there is a selection corresponding to 

 that of the breeder. 



It is useless to deny the existence of this selec- 

 tion in nature, this natural selection. The only 

 disputable point is whether such selection can 

 do all that Darwin demanded of it. 



4 



