14 EVOLUTION AND GENETICS 



which have made possible the modern development of the 

 science. 



Darwin's early training included the study of medicine at Edin- 

 burgh and preparation for the ministry at Christ's College, Cam- 

 bridge. During the three years at the latter place he became in- 

 terested in science, and when H. M. S. Beagle was devoted to an 

 expedition from the years 1831 to 1836, he accompanied the survey 

 party as naturalist. His account of this period, under the title 

 The Voyage of the Beagle, shows a remarkable capacity for observa- 

 tion of facts of great variety. Much of the time the ship was 

 absent from England was spent in South America, but the brief 

 stop which Darwin was enabled to make at the Galapagos Islands 

 seems to have been a particularly productive part of the trip. The 

 remarkable conditions prevailing in these islands, recently brought 

 to the attention of the world in inimitable style in Beebe's Gala- 

 pagos, World\ End, appear to have been a stimulus to his inquiring 

 mind, and later to have furnished him with valuable data in con- 

 nection with his work on evolution, although he did not begin his 

 first notebook on the development of species until 1837. 



After returning to England, Darwin devoted himself to his 

 scientific investigations. Although he was financially well able to 

 do this, he was handicapped for the rest of his life by ill health, and 

 was forced to limit his periods of work to less than two hours each. 

 His first idea of natural selection came as a result of reading 

 Malthus on Population, a work which set forth the part played by 

 overproduction and the consequent struggle for existence in the 

 human race. This was destined to disclose to him the idea of the 

 survival, under similar conditions in the organic world, of those 

 individuals best fitted for life under the existing conditions, and 

 the destruction of those less favored. With the aid of his own ex- 

 tensive knowledge of variation in organisms he was al)le to formu- 

 late the theory which has carried the name natural selection or 

 survival of the fittest. Darwin records that he first set down this 

 theory in June, 1842, and later extended it in 1844, but it was not 

 until 1858 that it was finally made public under circumstances 

 which are a fine example of individual generosity. During the 

 year 1858 Alfred Russel Wallace (1822-1913), as a result of reading 

 the same work which had given Darwin his first idea of natural 

 selection, conceived a theory of the origin of species which was 

 identical with that of his countryman. He communicated his 



