32 SOCIAL EVOLUTION 



secuihig- mates, or at any rate less robust mates, would 

 have fewer progeny and eventually their line would die 

 out. There were also combats between rival males for 

 the possession of females as well as the preferential 

 mating' ^vhere the female chooses or seems to choose. 

 There is little reason to doubt the effect of selection 

 where there is combat among males. For when the 

 younger or weaker candidates are killed, or expelled 

 from the herd, or left unmated, there is discriminate 

 elimination, the progeny inherit the strong constitutions 

 of ilicir parents. But as to preferential mating, the 

 theory has broken down rather badly under criticism 

 since T)ar^nn's time." 



Tlicrc is one oilier point of considerable importance 

 wliicli must he discussed ])efore we can understand the 

 I'cal si.uiiilicaiK'e of natural selection. It is the alleged 

 inheritance of acquired characters. The athlete has 

 larger and more developed muscles than the average 

 man. Do his chiklt'en inherit larger and more developed 

 muscles? ^Mau}^ years ago the naturalist Lamarck ad- 

 vanced a theory that modifications induced in the struc- 

 ture of the parent by adaptation to its surroundings 

 were inlierited by the offspring. His classic illustration 

 of this theory was the giraife. The entire frame of the 

 giraffe has been adapted to support an enormously long 

 neck wliicli is of use to the animal in reaching the foliage 

 of trees. Lamarck thought that the ancestors of the 

 giraffe had ordinary necks but had increased the length 

 of them through many successive generations by con- 

 stantly strctcirnig to reach high foliage. Moreover, when 

 the neck became so long as to require for its sujiport 

 special changes in the general form of the animal, these 



7 'HinnmoTi & rioddos, op. ell., p. 172. 



