Factors in the Evolution to Bipedalism

766 WordsJul 10, 20184 Pages
The evolution of the human species has significantly changed during the course of evolution to what is now the modern day Homo sapiens. Some of the changes that have occurred through the evolution are bipedalism, changes in body features such as brow ridges, and an increase in brain capacity. Bipedalism is a form of locomotion that is on two feet and is the one factor that separates humans from other forms of hominoids. The first bipeds are believed to have lived in Africa between 5 and 8 million years ago. (Haviland et al. 2011, pg. 78). The evolution to bipedalism resulted in various anatomical changes. To be able to balance on two legs, the skull must be centered over the spinal column. As bipeds evolved, the foramen…show more content…
Heavy lifting causes a strain on the back and can lead to back problems. Other back problems such as scoliosis, herniated disks, and pinched nerves are all results of bipedalism. (Ackerman). The evolution to bipedalism resulted in the narrowing of the pelvis. This narrowing was necessary for locomotion, but it increased the difficulty of childbirth for women. In other primates, birth is relatively easy. Babies come through a straight birth canal and are born facing their mothers. The mother can pull the baby out during birth without causing injury to spine of the baby. The human female pelvis is now smaller and babies are forced to be born facing away from the mother. Assistance is needed during birth to prevent injury to the baby's spine. The birth canal is curved and there is barely enough room for the passing of the head and shoulders. (Ackerman). Three adaptive characteristics of early humans that are not present in modern humans are heavy brow ridges, sagittal crests, and facial prognathism. All of these characteristics were influenced by the change in diet of humans. Heavy brow ridges, or supraorbital ridges, are the bony ridges located above the eyes on primates. It is believed that early man had very pronounced brow ridges to reinforce the facial structure during chewing. As man evolved, their diets changed to softer foods
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