106 CALIFORNIA ACADEMY OF SCIENCES. 



group, it is called a variety. Species and varieties, then, 

 do not always represent real taxononiic values, for two 

 extreme varieties of one species may be morphologically 

 very much less alike than two closely allied species. It 

 all depends upon the accident of destruction of inter- 

 mediate forms. 



Having now clearly defined the nature of a species 

 and the relativity of its value, it is time to consider the 

 relation of evolution to species. The end of evolution 

 is the establishment of successively higher types. Pro- 

 gress must be orderly, and species are merely crystal- 

 lized forms of orderliness. If each individual were to 

 start off on its own indej)endent track there would be no 

 unity in nature. Organisms would not hold together, 

 and life as a whole would present no feature of ration- 

 ality. Real progress would be defeated, and evolution 

 would end in chaos. But in recognizing that species 

 are the indispensable instruments of orderly evolution, 

 is it necessarily implied that species are the outcome of 

 natural selection? This implication certainly does not 

 inevitably follow, even using the term natural selection 

 in its widest sense, and admitting it as an important 

 factor in evolution. 



Before considering this fundamental question as to 

 whether or not natural selection, aided, of course, by all 

 the factors of heredity and variation, can originate 

 species, it will be well to enquire what it is that natural 

 selection preserves — the individual or the species. Mr. 

 Romanes, in the Darwinian Theory* says: "Next, it 

 must be clearly understood that the life which it is the 

 object, so to speak, of natural selection to preserve, is 

 primarily the life of the species; not that of the indi- 

 vidual. Natural selection preserves the life of the 

 individual only in so far as this is conducive to that of 



* Darwin and After Darwin, i, pp. 264-265. 



