84 DOMESTICATED ANIMALS AND PLANTS 



killed off, and the fleetest would go scot free. On the other 

 hand, the fleetest wolves would be best fed and the laggards 

 would die of hunger. In this way both species would develop 

 high speed and great wariness, and this development would pro- 

 gress further and further as the competition grew keener with 

 each passing generation. The horse has almost certainly come 

 up through a similar experience in ages past. 



Effect of selection upon the individual. This effect is two- 

 fold. First of all, it sharpens the wits of the individual if he 

 has any, and develops to the utmost whatever faculties he may 

 possess. If by this he is able to withstand the competition, he is 

 in every way the better for it. 



If, however, as generally happens where the selective process 

 is severe, it is only the few that are able to withstand, then the 

 masses will go down in the struggle ; so that the total effects 

 of selection may be said to be hard upon all but the few individ- 

 uals, and its chief advantage is to the race as a whole. 



Selection good for the species that can endure it. By this we 

 mean that if a number of individuals sufficient to keep up the 

 population are able to meet the demands of selection, then the 

 species will rapidly progress ; and up to this point the more 

 severe the selection the better for the race. This is an impor- 

 tant distinction in all evolution that should never be forgotten, 

 for it is only when undergoing severe selection that species 

 change much in their characters from generation to generation. 



Next to sudden calamity the greatest misfortune that can 

 happen to a species or a race is a long succession of easy times, 

 when the whole population settles down to a dead level of inac- 

 tivity. Then are the days of extinction imminent, for matters 

 will not always run in an accustomed rut, and when the days of 

 sudden and unaccustomed changes come, they are likely to find 

 things unprepared. 



Selection fatal to a race that cannot endure its hardships. 

 It matters little to the race what happens to individuals, so long 

 as a sufficient number prosper. It is vital, however, that a 



