Xo. :><)()] DAHW1X AX!) MCTATIOX THKORY 



4. There results competition for what subsistence there 

 is, or, as it is otherwise called, a struggle for life. 



5. Since out of all the variations that occur in the 

 constitutions or characters of organisms some must 

 happen to be in directions to give their possessors an 

 advantage, or advantages, in procuring the means of 

 existence, as compared with other individuals of the same 

 class, some of the new-born animals and plants are best 

 adapted to their surroundings or "conditions of life." 



6. These best-adapted forms ("the fittest") will win 

 in the struggle for life and are figuratively said to be 

 selected ; the unfit will in the end be exterminated. The 

 result is the origination (evolution) of new classes of 

 organisms out of the old ones and their substitution for 

 the earlier classes or groups. 



Not one of these factors was originally discovered by 

 Darwin, but he first discerned their interrelations and 

 bound them together by a consistent and convincing phi- 

 losophy. He, for example, was not the earliest observer 

 of progressive change in the organizations and external 

 characters of animals and plants, but no one before him 

 had had the insight to perceive that this changeability 

 was the manifestation of a force great enough to burst 

 the artificial limits placed about the groups called species 

 and varieties and to enable them to transform themselves 

 into other groups better adapted to the changing environ- 

 ment. Before Darwin's time every one. of course, had 

 ocular demonstration of the fact that there were differ- 

 ences between individuals and that descendants were not 

 in every respect like their ancestors. There was uni- 

 versal belief, however, that these variations never ex- 

 ceeded certain narrow boundaries built round species 

 like inviolable walls. Curiously enough, Darwin, who 

 first broke down these boundaries, took the same indi- 

 vidual variations as the principal foundations of his 

 selection theory. He assumed— for he admitted that it 

 could not be proved for any particular case— that these 

 small differences, which ordinarily fluctuate about a cer- 



