ADAPTATION 953 



to survive which are able to react advantageously. Thus in the course of 

 time it is to be expected that the plants that are congenitally unfit and 

 the plants that react disadvantageously will largely be eliminated. Only 

 occasionally would there survive plants with structures that are slightly 

 disadvantageous. Somewhat more abundant might be the number 

 of plants with indifferent or with only slightly useful structures. Many 

 more individuals are born than have a chance to live, since severe physi- 

 cal conditions and crowding by other plants cause the elimination of the 

 unfit and the survival of the fit; consequently advantageous structures 

 must ultimately dominate, whatever the nature of the primitive struc- 

 tures. Such an explanation of the predominance of advantageous struc- 

 tures seems far more tenable than does the theory of origin through 

 adaptation. 



