Human Distinctives

Slide 74 of 109

Modern humans have extremely large brains, which requires a large amount of energy to operate. In the fossil record, brain size increased slightly among successively younger species of Australopithecines, although many Australopithecine skulls have brain capacities no larger than those of chimpanzees. (1, 2). However, brain capacities expanded abruptly with the appearance of Homo, but within early Homo remained at about half the size of Homo sapiens for almost a million years. The fossil record indicates an accumulation of relatively rapid shifts in successive species, and certainly not any kind of gradualistic changes.

The next 12 slides will examine bipedalism among the hominids to see if it fits any kind of evolutionary theory.

References

1. Dean Falk. 1998. Hominid brain evolution: looks can be deceiving. Science 280: 1714

2. Conroy, G.C., G.W. Weber, H. Seidler, P.V. Tobias, A. Kane, and B. Brunsden. 1998. Endocranial capacity in an early hominid cranium from Sterkfontein, South Africa. Science 280: 1730-1731.