The diagram demonstrates the distinction between an ancestor’s and a contemprorary human’s skeletal systems’ alterations.
Overall, Australopithecus afarensis is much bigger than Homo erectus, because otheir structure is intended for distant walk and tree climbing. while Homo erectus’ physical structure is thin and aimed to endurance running.
Initally, while Homo erectus’ head is balanced, Australophithecus afarensis can not stabilize it, cause of the size. High and narrow shoulder impeded austalophithecus afarensis leaving no space between head and neck, however, in contrast, Homo erectus has low and wide shoulders. As it is illustrated in inner part of the systems, Australophithecus afarensis has much wider chest rather than Homom erectus’ typical narrow chest. The same is with waist, that is wider than modified human’s skeleton system. Moving on to the arms, while afensis’ armes are lengthen, which is intended for climbing, Homo erectus’ forearm is short, that extends distinction between two ancestors.
Since Australophithecus afarensis’ body structure is inherently large, femoral neck correspondigly is longer, and obviously, Homo erectus has short one. Even though Homo erectus’ upper body is smaller in many aspects, its’ body has larger hips, knee and ankle joints. The down part of body is much superior on the whole, because it is amed to be enduring in running.