INHERITANCE, VARIATION AND SELECTION. 41 



all animal life, from the largest whale down to the microscopic 

 unicellular organism, is descended from some primordial form, and 

 consequently that all animals (and all plants, for that matter) are 

 more or less closely related. 



KINDS OF SELECTION. 



This process of selecting particular animals or particular plants 

 from which to produce another generation of animals or plants 

 is what is known as "selection." When selection is practiced by 

 man it is called artificial selection, and when that selection has a 

 definite object in view and is carried out with the intention of 

 securing definite results, it becomes methodical selection. It is 

 through the methodical selection and preservation of desirable 

 variations that we have obtained our improved breeds of animals 

 and varieties of plants. So perfect have become the methods of 

 selection that it is said that a breeder can, in a few generations, 

 produce any particular form of animal desired. 



During the early history of man, and at the present time among 

 savage and barbarous people, there is a process of selection that 

 is not methodical but depends upon whim, pleasure, or convenience, 

 and consequently is called unconscious selection. Because the man, 

 having to kill an animal, kills the less pleasing or useful and retains 

 the one that pleases his fancy, unconscious selection improves the 

 breed subjected to it though the improvement is not so rapid as 

 with methodical selection. 



In a state of nature, very many more young are produced than 

 can possibly survive to reproduce. If there were not a constant 

 elimination of individuals, even the slowest breeding animals would 

 soon overrun the surface of the earth. This elimination occurs 

 through struggles for food during periods of scarcity, contests 



