THE EVOLUTIOX OF MAN 209 



Like the more complete record of the development of the horse, 

 man's progress has Ijeen due to changing environment, range of 

 inherited possibilities and the interaction of the two. Unlike 

 the other animals, his development has involved a shift from 

 physical to mental modifications. Through his intelligence he is 

 now able to control to some degree one of the fundamental factors 

 of existence, environment, and on that biological foundation rests 

 his future. 



Summary. Man occupies a systematic position among the 

 highest mammals, the Primates. He is ordinarily included in a 

 separate family, the Hominidae. The anthropoid apes of the 

 family Simiidae are the nearest relatives of the human species and 

 so furnish the only indication to be found among existing species 

 of his probable origin. Structurally man and the apes are similar 

 but man differs in details associated with his intelligence, articu- 

 late speech, and erect posture. The arboreal habits of the apes 

 and their structural resemblance to man suggest that he may be 

 derived from arboreal ancestors, and a consideration of the effects 

 of arboreal life show that this may well be true. Descent from the 

 trees, which must have preceded the development of terrestrial 

 man, was favored by the climatic conditions of the time when 

 primitive man arose. Of these early creatures we have only scanty 

 records but they are sufficient to show that species existed which 

 were higher than the apes and lower than man, and that a gradual 

 transition occurred leading up to the structural characters of 

 modern man. Even the development of culture is indicated by 

 artefacts associated with the remains of extinct species of man. 



REFERENCES 



Haeckel, E., The Evolution of Man, 1905. 



Drummond, H., The Ascent of Man, 14th edition, 1911. 



Geikib, J., Antiquity of Man in Europe, 1914. 



Jones, F. W., Arboreal Man, 1916. 



OsBORN, H. F., Men of the Old Stone Age, 1916. 



Lull, R. S., Organic Evolution, 1917. 



Wilder, H. H., The Pedigree of the Human Race, 1926. 



OsBORN, H. F., "Recent Discoveries Relating to the Origin and Antiquity 

 of Man," Science LXV, 481-488, 1927. 



Gregory, Wm. K., "How Near is the Relationship of Man to the Chimpanzee- 

 Gorilla Stock?" Quarterly Review of Biology, II, 549-560, 1927. 



