EVOLUTION DEFINED 5 



A process of orderly mutation is observed not only in living 

 things but in inanimate objects as well. The features of the 

 surface of the earth pass through a slow process of unrolling 

 from primitive chaos to the diversified earth of to-day. Mani- 

 festly we cannot imagine a homogeneous earth which could 

 forever retain its homogeneous condition. At least our universe 

 and our earth have not done so. A cooling earth must lose 

 its perfect rotundity, its surface must become diversified, its 

 relation to the sun must cause its equator to differ from its 

 poles. A single homogeneous form of life on this earth could 

 not remain uniform because it would be thrown under varying 

 conditions. It could not be the same under the tropical sun as 

 under the arctic cold, and the individuals adapted to either 

 would tend to reproduce individuals likewise adapted. There 

 must, then, exist in all things a " tendency " to become special- 

 ized and differentiated. In accordance with this tendency, it is 

 conceived that nebulous masses have been concentrated into 

 planets and the generalized creatures of geologic time have been 

 succeeded by variant and specialized forms, their lineal de- 

 scendants. 



The universal formula of the process of evolution is com- 

 pactly stated by Herbert Spencer in these famous words: 



"Evolution is a continuous change from indefinite incoherent 

 homogeneity to a definite coherent heterogeneity of structure and 

 function, through successive differentiations and integrations. In 

 its physical aspect evolution is further an integration of matter with 

 concomitant dissipation of motion." 



This formula applies more or less to all forms of orderly 

 change, that is, change due to a persistent cause, a continuous 

 force. Thus solar systems are conceivably formed from nebulae. 

 Thus continents and mountain chains, islands and river basins 

 are shaped. Thus organisms are derived from parent organisms. 

 Thus all the variant chemical elements may have been (hypo- 

 thetically) derived through influences as yet not even imagined, 

 from the unknown and probably unknowable primitive element, 

 protyl. The general movement is from the simple to the 

 complex, from the homogeneous to the heterogeneous, from 

 the inexperienced to the experienced, from the undivided to 

 the divided, from the inchoate to the integrated. Whatever 

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