CHAPTER 1 



EVOLUTION SEEN 



IN PERSPECTIVE 



Organic Evolution 



Evolution means change. We speak of the evolution of 

 the solar system, the evolution of the earth, the evolution of the airplane, 

 the evolution of the automobile. In such cases we are referrino to the 

 changes which have occurred in solar system, earth, airplane, or auto- 

 mobile. 



The evolution with which this book is concerned involves a special form 

 of the broader meaning of the term: organic evolution. This subdivision of 

 evolution deals with changes undergone by living things, plants and ani- 

 mals. For our purposes we may define organic evolution as the theory that 

 plants and animals now living are the modified descendants of somewhat 

 different plants and animals which lived in times past. These ancestors, in 

 their turn, are thought of as being the descendants of predecessors which 

 differed from them, and so on, step by step, back to a beginning shrouded 

 in mystery. 



In the above statement the words "modified descendants" deserve special 

 emphasis. The word "modified" refers to the element of change which we 

 have just mentioned as inherent in the whole idea of evolution. The word 

 "descendants" introduces an idea not present in the broader use of the 

 term "evolution." When we speak of the evolution of the automobile we 

 have reference to the changes occurring in the transition from the "horse- 

 less carriage" of a bygone era to the model currently advertised. We do 

 not think of the older automobiles as being the parents or ancestors of the 

 newer ones in any literal sense. Makers of automobiles learn from experi- 



1 



