THE EVOLUTIONARY CONCEPT 339 



and when he was only twenty-two years old, Darwin accepted the 

 unsalaried position of naturalist on board the British cruiser Beagle, 

 which had been detailed to spend 5 years in making oceanographic charts 

 for the British admiralty. Most of this period was spent in mapping the 

 harbors and coastal waters of South America, and Darwin took full 

 advantage of his unusual opportunity to study the fauna, flora, and 

 geology of this continent- All the way from Brazil to Patagonia and thence 

 up the west coast to Chile, he made extensive collections and recorded 

 his observations, both along the coast and on long trips inland. Later, the 

 ship spent some time at the Galapagos Islands, some 600 miles due west 

 of Ecuador in the Pacific, and then returned around the world to England. 



It was his detailed observations of the animal and plant life of South 

 America, especially of the distribution of species on this continent and 

 in the Galapagos Islands, that first convinced Darwin of the inadequacy 

 of the doctrine of special creation and started him on the search for a 

 satisfactory substitute. Returning from the voyage in 1836, he occupied 

 himself with publishing reports on his observations and in bringing out a 

 number of zoological researches that established his reputation as a 

 first-rate biologist. Most of all he strove to find an acceptable explana- 

 tion of the diversity of organisms and the peculiarities of their distribu- 

 tion over the face of the earth. 



In Darwin's own words: 



On my return home in the autumn of 1836 I immediately began to prepare my 

 journal [of the voyage of the Beagle] for publication, and then saw how many 

 facts indicated the common descent of species. ... In July (1837) I opened my 

 first notebook for facts in relation to the origin of species, about which I had long 

 reflected, and never ceased working for the next twenty j^ears. . . . Had been 

 greatly struck from about the month of March on character of South American 

 fossils, and species on Galapagos Archipelago. These facts (especially latter) 

 origin of all my views. . . . 



In October (1838), that is fifteen months after I had begun my systematic 

 inquiry, I happened to read for amusement Malthus on Population, and being well 

 prepared to appreciate the struggle for existence which everywhere goes on, from 

 long-continued observation of the habits of animals and plants, it at once struck 

 me that under these circumstances favorable variations would tend to be pre- 

 served, and unfavorable ones to be destroyed. The result of this would be the 

 origin of new species. Here then I had at last got a theory by which to work. 



Malthus had attempted to show that most of the social and economic 

 ills of society come from too high a reproductive rate in man relative to 

 available resources. This concept furnished Darwin with the clue to many 

 of the questions that had been puzzling him and served as the starting 

 point for his theory of natural selection. 



