Evolution 321 



plants and animals. The energy of this first life may have been derived 

 from simple ammonia compounds. Then as these organisms evolved 

 and became more complex, they were able to synthesize the more compli- 

 cated molecules which permitted more advanced forms to evolve. Thus 

 these first things were scarcely alive, and the transition from nonliving 

 to living was subtle. 



There have been many theories as to the exact nature of the first 

 living materials. The most widely accepted one is that they were hetero- 

 trophic organisms, that is. they depended upon other sources for their 

 energy. Another theory states that the first organisms were autotrophic, 

 that is, they were able to manufacture their own food from raw materials. 

 This latter theory had wide acceptance for a long time, but it must be 

 realized that any organism that synthesizes its energy sources is an 

 extremely complex one. The likelihood of its arising from nonliving 

 materials in light of our present information seems extremely improbable. 



At present there is no adequate explanation of the formation of 

 the first living material. The conditions bringing about its formation 

 may have occurred but once in the long history of the earth. Neverthe- 

 less life did appear, and once it had appeared, it rapidly diversified and 

 multiplied. 



DEVELOPMENT OF THE IDEA 



The name of "Darwin" is considered by most of us to be nearly 

 synonymous with the term "evolution." This is, of course, due to the 

 fact that he was the first man really to formulate the concept. The idea, 

 however, was not entirely his own: he owed much to many scientists 

 who had preceded him. Further, Wallace, working independently in 

 Malaysia, conceived the identical idea at about the same time as Darwin. 

 Moreover, as is so often the case with concepts which change the think- 

 ing of man, this one had been brewing for many centuries. 



In attempting to classify plants and animals, early naturalists were 

 often impressed with the relationships of the organisms to one another. 

 Linnaeus, the founder of our present method of classification, was a 

 firm believer in the fixity of species ; yet when his work is examined, it 

 is clear that he also was demonstrating evolution. 



Of the predecessors of Darwin, none stands out more clearly than 

 Buffon, a French scientist, who lived from 1707 to 1788. This versatile 

 biologist was impressed with the universality of nature, and in his con- 



