Upright walking is very old, and came long before modern humans evolved big brains.We share a common ancestor with chimpanzees. The human skull is relatively flat but the chimps skull sticks out in front. A. afarensis live about 3 million years ago half way between chimps and humans. Human's Foramen magnum is in the center of the skull, and its larger to. The chimps is more in the back of the skull and it is smaller. One theory was that we stood up to use/make stone tools but big brains and stone tools didn't appear until a million years ago after bipedality. Another theory by C. Lovejoy was that we stood up on 2 legs to carry food to our mates, taking care of offspring and learning new behaviors which lead to a more developed brain. Another theory was that we stood up to cross the hot savanna to get to the forests or to get over the streams. However, none of these and more theories have bean proven to be true because they are difficult to test.
No comments:
Post a Comment