The birth of a child is a miracle for the world; a baby crawling on his own is a huge achievement; a child taking his first steps is a historic moment in human evolution. A human being is able to endure many changes, social and environmental, adapting their skills and abilities along the way. The most notable adaptation for humans is the ability to walk upright on two feet, rather than crawl on all fours. When a child masters the mechanics of bipedalism, it is a significant moment in his or her life. This precise moment dates back millions of years, when bipedalism began to emerge in early hominids. It is unclear when it originated, although the fossil record leads us to believe that it began five to ten million years ago. As with the formation of the Earth, there are many controversial theories regarding bipedalism. A common point in these existing theories concludes that bipedalism has become one of the most significant traits distinguishing humans from non-human primates and other animals. Examining the general phenomenon of bipedalism and the location of its earliest occurrences contributes to the discussion detailing why bipedalism is a significant time in human evolution, making a clear distinction between man and primate. The origin of bipedalism is certainly not accurate, but having fossil evidence and making connections in the environment in which they were discovered can improve the accuracy of when and where they originated. “Our early ancestors and some of their contemporary primates thus encountered a variety of environments – the forest/open space ecotone… as well as changes over time – and so underwent selection for the ability to cope with a mixed environment of increasing variability." (Park, 210). The... center of the card... weighs twice as much as the flexors." (Du Brul, 207). Du Brul argues that humans have all of their upper body weight resting on the extensors of our postcranial construction. Furthermore, the human body has certain proportions to balance on our two legs of humans are longer than our arms, while quadrupeds possess longer arms than legs primate, humans are set up to adapt to the locomotives of bipedalism. As a result, “humans have bipedal vertebrae.” Furthermore, Lewin describes a “debate centered on the anatomy of the pelvis and the shape of the hands and feet and on the amount of weight that the joints must support on two limbs instead of four” (Lewin, 1433) Both Du Burl and Lewin both have the same theoretical approach to bipedalism and its correlation with the human body.