THE SEXES AND SEXUAL SELECTION. 9 



established and enhanced as secondary sexual characters of the 

 species. The process by which the possessors of the fortunate 

 excellencies of beauty and strength outbid or overcome their 

 less endowed competitors, he termed "sexual selection." It is 

 only fair, however, to state Mr Darwin's case by direct 

 quotation. 



Sexual selection " depends on the advantage which certain 

 individuals have over others of the same sex and species solely 

 in respect of reproduction." ... In cases where " the males 

 have acquired their present structure, not from being better 

 fitted to survive in the struggle for existence, but from having 

 gained an advantage over other males, and from having trans- 

 mitted this advantage to their male oifspring alone, sexual 

 selection must have come into action." ... "A slight degree 

 of variability, leading to some advantage, however slight, in 

 reiterated deadly contests, would suffice for the work of sexual 

 selection." ... So too, on the other hand, the females " have, 

 by a long selection of the more attractive males, added to their 

 beauty or other attractive qualities." ..." If any man can in 

 a short time give elegant carriage and beauty to his bantams, 

 according to his standard of beauty, I can see no reason to 

 doubt that female birds, by selecting during thousands of 

 generations the most melodious or beautiful males, according 

 to their standard of beauty, might produce a marked effect." 

 ... "To sum up on the means through which, as far as we 

 can judge, sexual selection has led to the development of 

 secondary sexual characters. It has been shown that the 

 largest number of vigorous offspring will be reared from the 

 pairing of the strongest and best-armed males, victorious in 

 contests over other males, with the most vigorous and best- 

 nourished females, which are the first to breed in the spring. 

 If such females select the more attractive, and at the same 

 time vigorous males, they will rear a larger number of offspring 

 than the retarded females, which must pair with the less 

 vigorous and less attractive males. So it will be if the more 

 vigorous males select the more attractive, and at the same time 

 healthy and vigorous females; and this will especially hold 

 good if the male defends the female, and aids in providing 

 food for the young. The advantage thus gained by the more 

 vigorous pairs in rearing a larger number of offspring, has 

 apparently sufficed to render sexual selection efficient." 

 Another sentence from Darwin's first statement of his position 



