LECTURES IN BIOLOGICAL SCIENCES 



The skull of Proconsul is sufficiently different from the skull of 

 living pongids that several investigators assign it to a separate 

 subfamily. It is enough for our purposes to assume Proconsul 

 represents one of several sorts of hominoids living in the Mio- 

 cene and that one of these phyla was, in fact, ancestral to mod- 

 ern man. 



The pelvis of Proconsul is unknown and the hind-limb is 

 represented only by fragments. The rich fauna and flora as- 

 sociated with Proconsul suggests this Miocene hominoid occu- 

 pied a region containing both open savannah with grass and 

 low shrubs and scattered forests with large trees and an abun- 

 dance of vines. The ecological setting gives additional evidence 

 that Proconsul was an able climber of trees as well as an adept 

 ground runner. 



Australopithecus is the first known primate with upright, 

 bipedal locomotion. This conclusion is supported by the ana- 

 tomical evidence from pelvic remains of five different individ- 

 uals, plus fragments of leg and foot bones. The general mor- 

 phology of the australopithecine pelvis and leg resembles modern 

 man in those features which make his upright, bipedal posture 

 possible. The way the australopithecine head was mounted 

 atop the spinal column gives further indirect evidence of a man- 

 like, bipedal locomotor habit. 



There are some detailed features of full human bipedalism 

 not found in Australopithecus. It may be that these South 

 African near-men did not possess the anatomical equipment to 

 sustain a ten-mile run in pursuit of an eland after the fashion 

 of a modern Bushman. These locomotor parts are fully de- 

 veloped in Pithecanthropus from Java and Peiping, whose leg 

 bones are within the range of variation of Homo. 



By the opening of the Pleistocene a million years ago, man's 

 ancestors were fully bipedal with free hands which could be, 

 and were, used to handle tools. We will see that this was a 

 master adaptation demanding other adaptations leading to man's 

 capacity to be like the primates who read this. If I were more 

 poetic, I would say something here about near-men standing 

 with their soft underbellies exposed to the saber-like canines 

 and claws of vicious carnivores or to the saber-like canines and 

 nails of vicious baboons, defending themselves, alter a group 



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