CHAPTER XXV 

 THE HUMAN BACKGROUND 



The process of evolution has its outcome in personalities who 

 have discerned its magnificent sweep. — Thomson. 



As the culmination of our survey of the continuity of life, it is 

 important to consider briefly what is known in regard to human 

 origins — to bring Man more specifically into relationship with 

 the evolutionary process and to appreciate his affiliations as evi- 

 denced by the ancestral strands that persist in his fabric. 



Although the general recognition of Man's place in nature has 

 but recently been attained, more than two thousand years ago 

 Aristotle placed him at the summit of animal creation, emphasiz- 

 ing his God-like nature, but withal regarding him as only the 

 highest point of the Scale of Nature. Linnaeus, the founder of 

 our modern method of classification, during the middle of the 

 eighteenth century placed Man in the order Primates of the class 

 Mammalia, a position he has since held. (Figs. 288, 296.) 



A. The Prehuman Lineage 



The order Primates to-day comprises three suborders: the Le- 

 muroidea, or Lemurs; the Tarsioidea, or Tarsiers; and the 

 Anthropoidea, or Monkeys, Apes, and Man. Most of the charac- 

 ters which distinguish them from the other groups of Mammals 

 represent adaptations to a tree-dwelling life: adaptations for 

 climbing, for subsisting on a simple and plentiful food supply, and 

 for taking advantage of changing environmental conditions by a 

 bigger and better brain. (Figs. 93, 272.) 



The Anthropoidea, in which our interest centers, are widely 

 distributed throughout the tropical regions of both hemispheres, 

 and although those of the eastern and western hemispheres doubt- 

 less were derived from the same original stock, they have followed 

 somewhat different though, in general, parallel evolutionary paths 

 since their origin more than fifty million years ago, early in the Age 

 of Mammals. 



The Old World branch of the Anthropoidea is of especial im- 



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