ASPECTS OF KINETIC EVOLUTION 20J 



ment and the causing of evolution by selection, assumptions 

 which rest in turn on the still more general and obviously 

 erroneous assumption that species are normally uniform and 

 stationary, whereas they are neither. It will some day be 

 reckoned as one of the paradoxical incidents of biological history 

 that this static theory, which is simply a relic of pre-Darwinian 

 doctrine of special creation, should have been cherished most 

 jealously by the ultra-materialistic school of biology. 



ENVIRONMENTAL ADJUSTMENT ANALOGOUS TO LOCOMOTION. 



The power of locomotion is a very important adaptive char- 

 acter of organisms because it gives great freedom of choice of 

 environment. The hippopotamus, for example, is an aquatic 

 animal, but the brief nocturnal excursions to the grassy river- 

 bank or to the neighboring rice farm keep the huge bulk alive. 

 Being animals ourselves and accustomed to use our powers of 

 locomotion to change our environments, we fail to appreciate 

 this form of adaptation and view with much wonder the fact 

 that organic types have other means of dealing with environ- 

 mental problems. 



Unable to change their environments, they have the alterna- 

 tive power of changing their characters and of behaving in dif- 

 ferent ways in different environments. Some of the most 

 striking instances of this kind are afforded by a series of plants 

 (belonging to diverse and unrelated natural families) which can 

 live either in water or on land, and which have two sets of char- 

 acters appropriate to the alternative habitats. On land they have 

 the characters of other land plants, in water the characters of 

 other aquatics. The mystery is that they can change from the 

 one to the other. Some have imagined that if we could find out 

 how this change is accomplished we would have penetrated to 

 the causes of evolutionary changes in general. The analogy 

 between locomotion and environmental adjustment has been 

 overlooked, along with the probability that both these methods 

 of adjustment have been attained by the same evolutionary 

 processes. They are finished products and not merely charac- 

 ters in the making. 



The elasticity of muscular tissues is onlv one of the many 



