THE HISTORY OF EVOLUTION 7 



and the survival of the fittest which persists even today as a logical 

 interpretation of some evohitionary proc(\sses. 



In spite of tlie vagueness of his theories, Enipcdocles therefore 

 dealt with logical ideas of evolution including th(^ gradual develop- 

 ment of existing species, the necessity for adaptation, competition 

 among organisms, and the extinction of less perfect creatures 

 which accompanies the persistence of those better fitted for life. 



Aristotle. Other Greeks contributed ideas likewise vaguely 

 suggestive of modern scientific beliefs, but Aristotle is generally 

 admitted to be the Outstanding thinker of the times. He worked 

 on the same basis as his predecessors, for they had accumulated no 

 dependable facts, but in spite of such limitations he expressed 

 most of the fundamental principles of evolution. Although this 

 phase of his work is of chief interest to us in such a study as this, 

 it is important for a full understanding of Aristotle's place in bio- 

 logical science to note that he did not limit himself to philosophical 

 considerations, but made extensive and in many cases accurate 

 observations of natural phenomena. At least one of his observa- 

 tions, that of parthenogenesis in the honey-bee, is commonly 

 credited to a scientist of the nineteenth century. In the science of 

 botany Theophrastus shares Aristotle's eminence as an accurate 

 and original observer. 



Aristotle's ideas in the field of evolution may be summed up as 

 follows : 



1. He believed in natural law as the source of evolutionary 

 change. 



2. He believed in intelligent design as the ultimate cause of all 

 nature. 



3. He did not accept the idea of survival of the fittest. 



4. He believed in the development of modern organisms from a 

 primordial soft mass of living substance, essentially as we believe 

 today. 



5. His works suggest a phylogenetic series such as we now recog- 

 nize in living organisms. 



6. He recognized rudimentary organs as an evidence of relation- 

 ship and the unity of groups of related forms. 



7. He believed in epigenesis in ontogeny. 



8. He recognized fundamental principles of heredity. 



9. He believed in prenatal influences and in the inheritance of 

 acquired characters, the former a fallacy and the latter still un- 

 proved. 



