EVOLUTION AS A NATURAL PROCKSS L33 



its immediate purpose of giving a natural oxi)lanatiuii 

 of how evolution may be partly accounted for. 



Before proceeding to the post-Danvinian investiga- 

 tions that have done so much to amplify the account 

 of natural evolution, let us consider the contnustod 

 explanation given by Lamarck and his followers. As 

 we have stated earlier, Lamarckianism is th e namo give n 

 to the dof>tnnpJji/i.t rnnH^(if>"^^^^ Ot her tiiaiMliosc dug 



^to_^^iingenital fact or^may enter in to t|if> |n>i-if-'^v '}( 

 a species/^ahd may add themselves t oth()se_iil ready 

 > gorn[?rrft TJ~?T?rj^ 



^sgecies. Let us take the giralTe' and its long neck 

 as a concrete example. The great length of this 

 part is obviously an adaptive character, enabling the 

 animal to browse upon the softer leafy slioots of shrubs 

 and trees. Th-'j vertebral column of the neck comj)rises 

 just the same number of bones that are present in the 

 short-neckeJ relatives of this form, so that we are 

 justified m accepting as a fact the evolution of the 

 giraffe's long neck by the lengthening of each one of 

 originally shorter vertebrcT. The Lamarckian exj)lana- 

 tion of this fact would be that the earliest forms in 

 the ancestry of the giraffe as such stretched their necks 

 as they fed, and that this peculiar function with its 

 correlated structural modification became habitual. 

 The slight increase brought about by any single in- 

 dividual would be inherited and transmitted to the 

 giraffes of the next generation; in other words, an 

 individually acquired character would be inherited. 

 The young giraffes of this next generation would 



