A Biology Seminar was held on Monday, March 6, 2017 on the Fairleigh Dickinson University, Florham campus. It was given by Anna J. Ragni, MA. She is a Ph.D. candidate of the Richard Gilder Graduate School at the American Museum of Natural History.
The following notes were taken and submitted by Biology student Jillian Salvodon.
The topic of the seminar was “The Evolution of Hominin Bipedalism”.
- This topic observes the evolution of locomotion in primates, specifically humans, can help to explain how our ancestors evolved their locomotion to bipedalism.
- Human beings are the only primates that have obligate bipedalism locomotion, meaning that we can only walk on two legs; any other way of moving from point A to point B would be uncomfortable.
- In our obligate bipedalism, our walking cycle consists of a heel-strike, then a stance phase on one foot, then the push off with the big toes, and a swinging phase of the leg, and then this process is repeated.
- Different bones in the human body can be compared to the bones of our relatives, such as chimpanzees, to observe how our bones are structured differently to support our obligate bipedalism. Some of these differences are in the spine, which in humans, it is s-shaped and vertical to support our vertebrae so it does not absorb a lot of shock pressure, while in chimpanzees their spine is at almost a 45 degree angle and is straight. Their arms and legs can also be observed, because in chimpanzees they are approximately the same size. In humans our legs are longer than our arms, because we want to cover the longest amount of distance in the shortest amount of time. There are many other ways to observe these differences.
- In our relation to our ancestors, if a skeletal structure is found, and there is a least one distinct trait that shows bipedalism, the skeleton can be classified as a hominin. Many scientists argue the degree of bipedalism by skeletal structures.
- Many skeletal structures that could have been the missing links between our ancestors could have been lost to the savanna hypothesis, which the idea that the fossilization of the skeleton was not preserved due to environmental conditions.
- There are also other ideas as to why humans evolved into obligate bipedalism, such as the thermoregulatory hypothesis, which is that we are upright to avoid having a large surface area of our bodies to the sun, and the increased convection of wind. Another idea as to why we evolved this way is for endurance running. This provides an increase of hunting tactics, such as handling tools with hands or being able to see the prey from further distances.