CHAPTER LXXII 



EVOLUTION OF ANIMALS 



Two conceptions of the universe in which we hve have been held. 

 One was that it is a static universe created some 6000 years ago, with the 

 character it now has, and that it has remained in that condition ever 

 since. This, however, is contrary to facts easily secured by careful 

 observation and is untenable in the light of modern scientific knowledge. 

 Changes are now seen to be taking place everywhere and there is ample 

 evidence that this has always been the case. It is also clear that the 

 history of the earth has involved unnumbered ages. Animals and plants 

 no longer appear to us as organisms created in the beginning with exactly 

 the same character they have today but as having the characters they now 

 possess in consequence of gradual changes which have come about 

 through the ages that have passed. So the second conception— that 

 the universe is ever changing and progressing — now prevails. This 

 progressive change is called evolution. Certain theories of the origin of 

 life were stated early in the text, but organic evolution, which is the 

 evolutionary conception applied to living things, concerns itself only with 

 the changes which have ensued in living things since life first appeared. 



585. History of Evolution. — For the beginnings of the concept of 

 evolution it is necessary to go back to the time of the early Greek philoso- 

 phers. In striving to explain the nature of the universe the idea of evolu- 

 tion suggested itself to them, though they had no data by which to test it. 

 Anaximander (611-547 b.c.) presented the idea of an actual change in 

 hving organisms, including a change from aquatic to terrestrial life. 

 He even included man in his theory, Empedocles (495-435 b.c.) has 

 been called the father of evolution. He believed both in spontaneous 

 generation and in the gradual development of different types of organisms. 

 In a crude way he also expressed ideas of competition between organisms 

 and of natural selection, or the survival of the most fit. Aristotle (384- 

 322 B.C.) did not accept the idea of the survival of the fittest but he did 

 believe in the development of organisms from a primordial living slime, 

 and he suggested a sequence of animal types forecasting a phylogenetic 

 series such as is accepted today. He also believed in heredity and recog- 

 nized evidences of relationship in rudimentary organs. 



Throughout the Dark Ages no progress was made, but even during 

 this period there were theologians, including Augustine (353-430 a.d.) 



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