CHAPTER XXX 

 EVOLUTION AND HEREDITY 



"It has been a Proteus from the first; changefulness is its most abiding 

 quality; in short, the essence of the creature is its innate creativeness." 

 THOMSON AND GEDDES. 



In the past various theories have been held in regard to 

 the origin and descent of animals. Some scholars have sup- 

 ported the idea of (1) special creation (i.e., that all species 

 of animals were originally created as they now are), but since 

 Lamarck and Darwin there have been an increasing number 

 of those who believe (2) that living types of animals did 

 not originate as they are today but have been transformed 

 while descending from remote ancestors. The evolution 

 theory, then, supports the principle of " descent with modi- 

 fication" as opposed to that of special creation. 



Among scientific men evolution is no longer on trial, but 

 is accepted as a fact. Throughout this book such a point 

 of view has been taken for granted and it may now be well 

 to examine more critically the facts and theories on which 

 present ideas of evolution rest. In this connection there 

 should be no confusion between what is known and what is 

 believed that there has been an evolution scientists do not 

 doubt, but there has been, and is, much difference of 

 opinion as to why and how changes have taken place. After 

 accepting the (1) facts, and evolutionist must still puzzle 

 over the (2) means by which new species have come into 

 being, and why there is (3) adaptation to the environmental 

 conditions in which animals live. 



EVIDENCES OF EVOLUTION 



Palaeontology and Geographic Distribution. As was 

 stated in the last chapter, the earliest stages of the earth's 



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