In The Beginning: We Were Made To Stand Upright

The Bare Outline of Bipedal Beginnings

Humans are the only primate habitual, obligate, bipedal on the planet. And not only can we walk, but we can launch ourselves completely off the ground and run. It is important to note that running is a one legged exercise. Only one limb is in contact with the ground at any time. This has implications for both energetics, efficiency, and the type of injuries that we end up with in the present.

How did we get here? The middle part of the story is that there seems to be a relationship between tree apes and those of us who ended up on the ground. Our structure is homologous, yet different in many respects. In becoming the first runners the fossil and bone evidence seems to be that we first stood upright before our skull and brain enlarged. Australopithecus has a small skull, yet seems built for bipedal movement.  Some feel that Australopithecus could not run, and that it’s bipedal locomotion was a shuffling gait. Remnants of the apes remained, particularly the long upper limbs and curved fingers. Changes occurred in the feet. The great (first) toe and first metatarsal moved closer to the rest of the toes and was no longer opposable like the thumb. The limbs functioned better nearly straight. The pelvis changed and the spine changed to allow for limb connections. The knees could extend fully and lock.  The spine changed both with curves to better position the center of gravity and to allow for the new way in which the skull was oriented to allow for an upright head with eyes looking forward.

Following the development of upright posture, we had two free hands that could be used to carry tools, hunting implements, or food. We could move about fairly efficiently on the ground. We could range far in order to find food. Chimps and apes do not have a wide hunting range to gather food. As we ranged about, we found non-plant sources of protein. This enhanced the development of those built to use the protein, and allowed for eventually the development of a larger brain. This in turn led to the development of the genus homo, including Homo Erectus and later Homo Habilis.

The control of fire, and the use of fire for cooking made for easy to digest protein sources and richer, more calorie dense food. Some feel that the socialization that may have arisen around the ritual of cooking and meals helped enriched humans both culturally and socially. No food fights or no food!

As we developed more and more complex, those with larger brains, and skulls to hold them needed to be born through a larger pelvis. Eventually the pelvis enlarged in two different ways, Neandertal in width and our branch of hominids in an anterior – posterior direction.

Shortly we’ll take a look at the first runners. These first runners had larger gluteal muscles, a longer Achilles tendon, and even developed a bit of an arch along with toes that were all in line. Our knees could lock out. We already could look straight ahead and move on two limbs. As we became obligate bipeds we could no longer climb trees as well as those that came earlier.  I expect to have more details with recommended readings and references on my main web site. And of course, follow up here. To quote Charles Darwin in The Origin of Species: “To treat this subject at all properly, a long catalogue of dry facts should be given; but these I shall reserve for my future work.”