1 



The Expansion 

 of Evolutionary 

 Concepts 



From the earliest times of his recorded history, man 

 has searched for an explanation of the earth, the 

 things on it, the universe surrounding it, how they 

 were formed, and the mechanisms they represent. 

 Over the years he has had many notable successes, 

 culminated in the last two centuries by the formula- 

 tion of the theory of organic evolution. According 

 to this theory, the present life on our planet has 

 evolved from primeval ancestors by a process of 

 change, and the direction of change has been chan- 

 nelled by an automatic interaction of organism and 

 environment called natural selection. 



Concepts of evolution began and evolved with 

 the increasing development of modern fields of 

 science. The first serious suggestions that present- 

 day forms of life arose by a process of change from 

 earlier prototypes were made in the middle and 

 latter part of the eighteenth century. The French 



