596 GENETICS AND EVOLUTION 



rabbits and no carnivorous enemies on the island and the rabbits mul- 

 tipHed at an amazing rate. In 400 years they became quite different from 

 the ancestral European stock; they were only half as large, had a different 

 color pattern, and were more nocturnal animals. Most miportant, they 

 could not produce offspring when bred with members of the European 

 species. They were, in fact, a new species of rabbit. 



296. Development of Ideas about Evolution 



The idea that the present forms of life have arisen from earlier, 

 simpler ones was far from new when Charles Darwin published The 

 Origin of Species in 1859. The oldest speculations about evolution are 

 found in the writings of certain Greek philosophers, Thales (624-548 

 B.C.), Anaximander (588-524 b.c), Empedocles (495-435 b.c.) and Epi- 

 curus (341-270 B.C.). The spirit of this age of Greek philosophy was 

 somewhat similar to that of our own age, for simple, natural causes were 

 sought to explain all phenomena. Since they knew very little biology, 

 however, their ideas about evolution were extremely vague and can 

 scarcely be said to foreshadow our present theory of organic evolution. 

 Aristotle (384-322 b.c), who was a great biologist as well as a philosopher, 

 knew a great deal about animals and plants and wrote detailed, accurate 

 descriptions of many of them. He observed that organisms could be 

 arranged in graded series from lower to higher, and drew the correct 

 inference that one evolved from the other. However, he had the meta- 

 physical belief that the gradual evolution of living things occurred be- 

 cause nature strives to change from the simple and imperfect to the more 

 complex and perfect. An evolutionary explanation of the origin of plants 

 and animals was given by the Roman poet Lucretius (99-55 b.c.) in his 

 poem De Rerum Natura. 



With the Renaissance, interest in the natural sciences quickened 

 and the increasing knowledge of the many kinds of animals led more 

 and more scientists to consider the concept of evolution favorably. 

 Among these were Hooke (1635-1703), Ray (1627-1705), Buffon (1707- 

 1788), Erasmus Darwin (1731-1802) and Lamarck (1744-1829). Even be- 

 fore the Renaissance men had discovered shells, teeth, bones and other 

 parts of animals buried in the ground. Some of these corresponded to 

 parts of familiar, living animals, but others were strangely unlike any 

 known form. Many of the objects found in rocks high in the mountains, 

 far from the sea, resembled parts of marine animals. In the fifteenth 

 century, the versatile artist and scientist, Leonardo da Vinci, gave the 

 correct explanation of these curious finds, and gradually his conclusion, 

 that they were the remains of animals that had existed at one time but 

 had become extinct, was accepted. This evidence of former life suggested 

 to some people the theory of catastrophism— the idea that a succession of 

 catastrophes, fires and floods, have periodically destroyed all living 

 things, followed each time by the origin of new and higher types by acts 

 of special creation. 



Three Englishmen in the eighteenth and early nineteenth centuries 

 laid the foundations of modern geology, and by their careful, cogent 



