NA TURA L SEL E CTION 



29 



nal stocks from which they were derived. 1 Our domestic 

 chickens have been much modified from the jungle fowl, 

 their ancestor. Sheep, cattle, hogs, canary birds, pigeons, 

 and other kinds of domesticated animals show similar 

 modifications of the original stock. Among plants we 

 have more numerous instances; for example, most of our 

 garden vegetables, the many varieties of the cabbage 

 (Plates 5-8), the several sorts of potatoes, peas, lettuce, 

 etc. (Plate 9). Other instances are furnished by the numer- 

 ous kinds of roses, chrysanthemums, pansies, tulips, sweet- 

 peas, asters, hollyhocks, dahlias (Plates 10 and 1 1 ), and a host 

 of others of our common flowers which show many varieties. 

 Now, as just stated, the methods used by breeders to 

 produce these varieties of the different species of domestic 

 animals and plants are closely similar to the chief method 

 adopted by nature in the evolution of natural species. The 

 breeder, whether of plants or animals, finding in his stock an 

 individual or several individuals which show some desirable 

 quality, chooses these individuals to breed from, and when, 

 among their offspring, he finds some in which the useful 

 quality is especially pronounced, these again are chosen for 

 breedino- The desired character can be intensified bv choos- 



<J _/ 



ing, generation after generation, those individuals in which 

 it is most strongly developed, and rejecting the others. The 

 breeder rejects the individuals in which the important quality 

 is weakly developed. So also does nature in the process of 

 natural selection. The resemblance between the two pro- 

 cesses is very close, and the results are similar. In the case 

 of natural selection we tret modification of the orio-inal stock 



o o 



1 It is probable that domestic horses have been derived from several wild 

 species. 



