Bipedalism Hypothesis

Along with a big brain, opposable thumbs, bipedalism is one of the characteristics that makes the human species unique. The dictionary defines bipedalism as “a condition of using two feet for standing or walking”. Walking on two legs allowed our ancestors to see better, have freed up hands, and eventually become erect. Bipedalism is one of the initial driving force of the human evolution.
It is still being debated to on exactly when did the ancestor of our species began to walk on two legs. One hypothesis relies on a 6-7 million year old skull of Sahelanthropus tchadensis. The skull was discovered in the Djurab Desert in Chad. Since only the skull was discovered, it is still unclear on how Sahelanthropus tchadensis fits in our evolutionary
Owen Lovejoy is known in the scientific community for his reconstruction work on Lucy’s remains. He is a functional anatomist at Kent State University. Lovejoy hypothesized that bipedalism may have influenced male provisioning in our species. Walking on two legs meant our bipedal ancestors couldn’t carry their offsprings on their backs the way quadrupedal hominids do; instead, they have to carry their offsprings in their arms until they are weaned. Having full hands meant that their mate must provide food and protection. This probably resulted in monogamous relationships between mates until the offsprings are weaned. Bipedalism might have been the catalyst that transitioned our species from R-reproductive strategist towards K-reproductive strategists. R-reproductive strategy is characterized by large quantity of offsprings, little care for offsprings, fast maturation and short lived. In contrast, K-reproductive strategy is characterized by lower quantity of offsprings, more care for offsprings, longer maturation stage and long lived. Though our evolutionary relatives, the chimps, are facultative bipeds and can carry food in their hands while using biped locomotion for a short period of time, it is very energy consuming. It’s very energy consuming for them because they lacked the pelvic and lower body structure to walk energy efficiently that is present in hominoids with obligated bipedalism. Lovejoy’s hypothesis suggests that bipedalism may have increased offspring survivorship and the species reproductive fitness through by increasing efficiency in male