570 EVOLUTION 



additional fitness that any of the individuals pf each generation 

 may happen to develop, and in this way new species are gradually 

 built lip. 



Darwin's explanation may be summarized as follows: (1) plants 

 and animals vary in all directions and as a result no two individ- 

 uals are exactly ahke in their ability to compete for space, food, 

 etc.; (2) of the numerous individuals that come into the world, 

 there is space and food for only a few and this results in an 

 immense struggle for the necessities of life in which many indi- 

 viduals perish; (3) those that survive are the individuals which 

 have the variations that best adapt them to secure the necessities 

 of life and to defend themselves against enemies; (4) whatever is 

 gained in each generation in the way of better adaptations to 

 environment, heredity preserves until useful variations become 

 so prominent and general in a group of individuals as to be 

 distinguishing features of new species. 



Darwin not only drew his conclusions from observations but 

 also from experiments. He brought under cultivation a number 

 of wild plants and by selecting the variants was able in a few 

 generations to obtain individuals strikingly different from the 

 original wild forms. He found that a character could be built up 

 through artificial selection and thought the same was done in 

 nature by the process of natural selection. 



Opposition to the theory of natural selection. — Naturally, of 

 course, the Church at first opposed the theory of natural selection 

 because it contradicted the literal interpretation of the Book of 

 Genesis. The Church thought it attributed too little to the 

 Creator. Eventually the Church has come to see that the idea 

 of evolution is a no less dignified conception of the Creator than 

 is the idea of Special Creation. 



One of the greatest objections to the theory is that Darwin 

 assumes that variations in general are hereditary and more recent 

 investigations have shown that most variations are not hereditary 

 and consequently cannot be gradually built up through heredity 

 into characters as Darwin assumed. Only such variations as 

 mutations and those exceptional fluctuating variations that 

 depend upon something inherited can become permanent 

 characters. 



Through centuries of artificial selection, plant and animal 

 breeders have been "able to change the type considerably, but have 



