ADAPTATION 325 



and between them and their environment. It is the work of 

 Providence whose foresight extends to every minute detail of 

 creation. Cuvier actively combated all attempts to explain 

 life as the result of evolutionary processes and this attitude is 

 reflected in his conception of adaptation. Such a dogmatic 

 view of life finds little support in scientific circles today. 



Lamarck also believed in the reality of adaptation, but his 

 interpretation was entirely different from Cuvier's. These men 

 were contemporaries and on opposite sides on the question of 

 evolution. Lamarck emphasized the importance of environ- 

 ment in shaping the development of adaptive features. To him 

 the organism is plastic with reference to environmental influences, 

 and is always responding to environmental stimuli, the stimulus 

 and response gradually bringing about a state of adaptation in 

 the organism. Environment induces needs, needs induce habits, 

 and the use and disuse of organs play prominent parts in giving 

 directions to adaptation. Useful organs improve with use, 

 useless ones degenerate and finally disappear. According to 

 Lamarck, adaptation is an a posteriori fact. Organs are created 

 by function. Lamarck assumed further that the effects of use 

 and disuse are inherited, the inheritance of acquired characters 

 becoming the immediate cause of the evolution of new species 

 from old. He offered no proof of the inheritance of acquired 

 characters, i.e., characters acquired by the organism as the 

 result of special training, education, or experience directly due to 

 environmental influences; and proof is still lacking, yet the idea 

 that organisms are molded more or less by environmental factors 

 is one that today is given serious consideration in the problem 

 of adaptation and evolution. The main value of Lamarck's 

 writings on this subject lies in calling attention to the probable 

 importance of environment in developing adaptive conditions in 

 the organism. 



Charles Darwin, in building up his theory of evolution by nat- 

 ural selection, used variations as the basis of adaptation. Those 

 individuals whose variations best fit them for the struggle for 

 existence survive, the others perish. The survival of the fittest 

 is the survival of the best adapted. Adaptation is recognized as 

 a real condition. The adaptation begins as a chance variation, 

 the environment determining whether or not the variation will 

 survive.- Darwin did not throw any light on the origin and 



