CREATION BY EVOLUTION 



common than large ones. Dozens of different faint grada- 

 tions in the color of the eye have appeared. Physiological 

 changes so slight that they can be perceived only after long 

 experimental study have been noted in great numbers. Every 

 feature of the animal has thus become modified in many 

 different ways. Hundreds of diverse races of Drosophila 

 have taken origin from the original one; and many of these 

 are more diverse than what have been called different species 

 in this genus. 



We do not yet understand the causes of these changes; 

 we do not know how they are produced. An immense deal 

 remains to be learned about them. But our ignorance must 

 not be allowed to obscure the great, the essential fact that 

 appears in these attempts to see evolution in progress — the 

 fact of actual change. Remember that there are two opposite 

 doctrines. One holds that the constitution of organisms 

 is permanent; that they were created as they are and do not 

 change. The other, the doctrine of evolution, holds that the 

 hereditary constitution slowly changes as generations pass; 

 that a single race differentiates in the course of time into 

 diverse ones; that from one stock many are produced. The 

 critical observations that have been made on these minute 

 living organisms through the passage of generations sub- 

 stantiates this theory; they do change and differentiate into 

 diverse races as generations pass. The facts observed are 

 what the doctrine of evolution demands, not what the 

 opposed theory demands. 



REFERENCES 



Note: A full, illustrated account of the studies of evolutionary 

 change in Difjiugia is given in an article entitled "Heredity, Varia- 

 tion, and the Results of Selection in the Uniparental Reproduction 

 of Difjiugia corona," by H. S. Jennings, published in Genetics, 

 vol. 1, 1916, pp. AQl-'blA. A comparative account of these 



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