The Evolution of Man j 285 



lopithecus, one of our earliest upright ancestors, had a brain volume 

 of 450 to 600 CO (about that of a large ape). The cranial capacity 

 of H. erectus bridges the gap between the largest great apes and 

 modern man, the smallest skull on record having a capacity of 775 

 cc, and the largest, 1,200 cc, well within the range of present H. 

 sapiens. The Java men tended to have a slightly smaller brain than 

 Peking men. Modern men (Homo sapiens) average about 1,450 cc. 

 Because of the physical limitations on pelvic expansion in anthro- 

 poid females, most of the growth resulting in large brain size is 

 postnatal. This great postnatal growth in skull capacity results in a 

 very long period of helplessness in the infants of the larger-skulled 

 forms, creating a mother-offspring relationship that has left a con- 

 siderable mark upon our present-day culture. 



In summary, then, man owes many of his most characteristic 

 features to an ancestral sojourn in the trees. It is responsible for the 

 well-developed association centers of his brain and the skillful 

 manipulating devices on his forelimbs. It also gave him his family 

 association with its year-round sexuality and mother-offspring rela- 

 tionship. All these were instrumental in the development of culture, 

 which will be considered next. 



CULTURE 



At one time it was commonly thought that man's large brain made 

 it possible for him to invent culture. It now seems that possibly the 

 reverse was true. The earliest presumed ancestors (or near ances- 

 tors) of modern man, the Australopithecines, were erect, tool-mak- 

 ing creatures with brains not differing appreciably in size from those 

 of modern-day anthropoid apes. The evidence indicates that the 

 Australopithecines were animals of the plains and that they were 

 primarily vegetarian. There is also evidence that their diet was sup- 

 plemented somewhat with the meat of small animals. Little is 

 known about the tools used by these protohumans, but it seems 

 unlikely that they could have left the shelter of the forests before 

 they acquired a reasonable security by employing rocks and clubs in 

 their own defense. A variety of stone tools found in association with 

 the latest Australopithecine discovery [Zinjanthropus) removes any 

 reasonable doubt that Australopithecines made and used tools. This 

 association is prima facie evidence that Australopithecines had at 

 least a rudimentary culture. 



There can be little doubt that an ape-brained anthropoid, quite 

 possibly our own direct ancestor, was the possessor of a complex 



