The Source 



of Variability 



Life has developed into an amazing array of types, 

 ranging from bacteria to elephants, with millions of 

 other kinds around and between. To produce such 

 an array, a tremendous amount of genetic character 

 A change had to occur, so much that at first thought 



^ I one would expect to find our natural species literally 



evolving before our eyes from one generation to an- 

 other. Yet, here we encounter another of the many 

 apparent paradoxes of nature, for we find that the 

 streams of life have an orderliness and stability akin 

 to those of the cell. Examination of parents and off- 

 spring discloses only few and small differences be- 

 tween them, and a museum specimen 200 years old 

 will match character for character a freshly caught 

 specimen of the same species. 



A closer scrutiny of numerous progeny or large 

 samples shows that small variations do occur in a 

 surprising variety of characters. Occasionally a 



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