I02 WHAT EVOLUTION IS 



habits are most diverse. Were these 

 met with in nature, the zoologist 

 would unhesitatingly assign many of 

 them to separate species or even 

 distinct genera. What is true of 

 pigeons is also true of other domesti- 

 cated animals such as dogs, horses, 

 swine, cattle, and the like. 



In considering evolution Darwin 

 first set for himself the task of ac- 

 counting for the origin of domesti- 

 cated stocks. He found that when 

 the breeder wished to develop a par- 

 ticular feature, such as an excessive 

 covering of feathers on the leg and 

 foot of a pigeon, he watched his stock 

 closely and chose for breeding pur- 

 poses those individuals that showed 

 evidences of the trait he sought. By 

 this method of selection applied to 

 one generation after another, he 

 gradually arrived at a stock in which 

 the given feature was as pronounced 



