On Our Own Two Feet

On our two feet

by Stephen Whitt

Odyssey: Adventures in Science

Article Summary:

Our way of walking is very unique and rare. We can balance our whole body on our 2 feet. But the question is how we started and when we started walking on our two feet?

Up right walking is very old, it started even before modern humans evolved. Lets take a look at 3 very different skulls, the first skull is a chimpanzees skull.Chimpanzees are NOT our ancestors, but we do share one ancestor that lived almost 6 million year ago. This is why when you come across a chimps and a humans skull, you can see many differences right away. The humans face is quite flat, but a chimps face sticks out. Also the human scalp is much bigger than a chimps. A rounded vault is something that makes the human skull different from any other animal. Another skull we will add is of Australopithacus afarensis, it is the same  species as Lucie. It looks a lot like a chimps skull in some ways. The face also sticks out, and the scalp is not as big. When you sum it up,  A.afarensis skull relates more to a chimp than to human.

If you flip over all 3 skulls, "at the back of each skull, you will see a hole named forum magnum." This permits the chimps spinal cord to join with its brain. Chimps walk on all four legs and that is why the angle of their spine is up slightly, but sometimes can be straight up and down. The angle of the foreman magnum is backward and downward to let the spinal cord attach to the skull. The foreman magnum on humans doesn't angle backward and downward like on chimpanzees. “Its horizontal, and the hole is at the bottom of the skull. This shows that our spinal cord enters our skull from directly below.” This is essential as we walk on our own 2 feet, so our skull just balances on our neck and that doesn’t provide much neck muscles.  “The A.afarensis foreman magnum is horizontal and the bottom center of the skull.” Which means they also walk on 2 feet (Bipedal).  Walking on 2 feet is at least 3 million years old. It is very likely older than 6 million years, since other species also walked on 2 legs like the Orrorin tugenesis and many more.

C.Owen Lovejoy a scientist at Kent State university in Kent. He believes he knows the best theory for why we started up right walking. He said we started bipedalism to have our arms and hands free for carrying food to our friends and family. Some scientist don't agree with C.Owen Lovejoy. Some say we started walking up right to cross the dry and come to the wet, or to even swim in ancient seas.

So, what do you think, why did we stand on our 2 feet? Even with decades of active research, the truth is still hidden.

Whitt, Stephen. "On our two feet." Odyssey: Adventures in Science Oct. 2009: 26-28. Print