SIXTH LECTURE. 



-o-d^^oo- 



EVOLUTION AND HEREDITY. 



By henry FAIRFIELD OSBORN. 



I WANT especially to direct your attention to the rela- 

 tions between our present knowledge of the evolution 

 process and the problem of Heredity. The mere truth 

 of the origin and succession of life by evolution may now 

 be demonstrated in every branch of Biology, the argu- 

 ments from palaeontology, embryology, and morphology 

 being equally convincing, but the theory of the evolu- 

 tion process is inseparably connected with some theory of 

 inheritance. If new individuals were simply repetitions, 

 like coins struck from a species mint, there would, of 

 course, be no evolution possible, and we should perforce 

 return to the Miltonic conception of creation, at the 

 same time greatly reducing the number of difficulties 

 in the heredity problem. While in zoology the repeti- 

 tion phenomena are perhaps the most conspicuous, in 

 palaeontology, or, in other words, in the succession of life 

 in time, the variation phenomena are more striking, 

 and we come to realize that the how, why, and wdien of 

 the variations give zest to the study of the fossil series 

 and furnish the crucial test for any heredity hypothesis. 

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