Nature Sketches 

 in Temperate America 



I. EVOLUTION AND NATURAL SELECTION 



IT is my purpose to confine this brief historical sketch to 

 some of the salient features of the theory of natural 

 selection as applied to organic life. I shall attempt to 

 show the presumed process by which organisms have 

 changed and become modified into what are termed species. 

 In so doing, I have stated some of the opinions of the 

 principal workers in this field of biological science. Before 

 the time of Linnaeus the grouping of animals and plants 

 was not founded upon any useful scientific plan, and it remained 

 for him to bring forth system out of chaos. The system which 

 he introduced comprised the grouping of animals according 

 to their resemblance, both in external appearance and anatomi- 

 cal structure. This laid the foundation of systematic arrange- 

 ment of animals which grouped them into class, order, genus, 

 species, and variety. Until recently the majority of natural- 

 ists believed that species were unchangeable productions and 

 had been separately designed and created. On the other hand, 

 some of the earlier naturalists believed that species underwent 

 modification and that the existing forms of life were the 

 descendants of preexisting forms. ^ 



Passing over the allusions made to the subject by the earlier 

 classical writers, we find that Lamarck was the first whose 

 conclusions on the subject excited much attention. In his 

 published views in 1809 he upholds the doctrine that all species, 

 including man, are descendants from other species. He was 

 the first who aroused attention to the probability of all change 

 in the organic as well as the inorganic world being the result 

 of natural causes, and not miraculous interposition. With 

 respect to the means by which modification of animals was 



* In this epitomized sketch I have borrowed freely from Darwin and the 

 various other writers cited in the text. 



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