CHAPTER VI 

 ARTIFICIAL SELECTION 



We can command Nature only by obeying her laws. This prin- 

 ciple is true even in regard to the astonishing changes which are super- 

 induced in the qualities of certain animals and plants in domestication 

 and in gardens. — Lyell. 



Varieties are the product of fixed laws, never of chance. With a 

 knowledge of these laws we can improve the products of nature, by 

 employing nature's forces in ameliorating old or producing new species 

 and varieties better adapted to our necessities and taptes. Breeding 

 to a fixed line will produce fixed results. There is no e\'idence of 

 any hmit in the production of variation through artificial selection; 

 especially if preceded by crossing. — Luther Burbank. 



The name Selection has been long used for the process by 

 which breeds or races of domestic animals or plants have been 

 formed in the past, and for the process by which the skill- 

 ful breeder can develop new forms at will. This latter proc- 

 ess, called by Youatt "the magician's wand," by wdiich the 

 breeder can summon up any form of animal which may meet 

 his needs or please his fancy, has been especially designated as 

 Artificial Selection. By it we have derived all of our famil- 

 iar hosts of varieties of domesticated animals and plants. The 

 similar process in nature was accordingly designated by Darwin, 

 Natural Selection. It refers to the development or increase 

 of traits adaptive or advantageous in the life of a species, 

 through the survival for reproduction of a greater proportion of 

 individuals possessing the characters in question than of those 

 w^hich do not. In any race, it is the individual w^hich succeeds 

 in reaching maturity which determines the future of the race. 

 The qualities of the multitude which die prematurely are 

 naturally not repeated in heredity. In general, the forms pro- 



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