n 



INDIVIDUALS AND SPECIES 



The species problem has had a place in most 

 studies of evolution, in addition to the numerous 

 discussions in which it has occupied the center of 

 the stage. Fortunately it has been so thoroughly 

 handled that the usual points need scarcely be 

 considered in detail; a few characteristics alone 

 will be adequate for our needs. 



The many recorded attempts to reach an agree- 

 ment on the distinctive characteristics of species 

 as biological units have said, as a rule, one of two 

 things: that the species is a natural entity,^ or 

 that only individuals exist in nature and the species 

 is merely a concept for human convenience. ^ We 

 gain nothing by pursuing the inquiry. If entity 

 means to the individual a material object which 

 can be perceived, then obviously he will take the 

 latter point of view, but if the broader idea of 

 reality permitted by the accepted meaning of the 

 word satisfies him, then nothing need prevent his 



1 Powers, J. H., Am. Nat, Vol. XLIII, pp. 598-610, 1909; Bateson, Wm., 

 Problems of Genetics, pp. 16, 21, 1913; Lindsey, A. W., Denison U. Bull., 

 Jn. Sci. Lab., Vol. xx, pp. 289-305, 1924. 



2 Montgomery, T. H., Proc. Acad. Nat. Sci. Phil., 1902, p. 193; Bessey, 

 Chas. E., et al.. Am. Nat., Vol. XLII, p. 218 et seq., 1908; Williston, S. W., 

 Am. Nat., Vol. XLII, p. 187, 1908. 



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