Human Evolution. (n.d.). Retrieved June 04, 2020, from https://humanevolutionb36.weebly.com/
This week in our Human Evolution class we focused a lot on Bipedalism. Bipedalism is a form of locomotion that involves walking on two legs/limbs. Skeletal evidence for bipedalism can be vast, but when trying to apply this evidence to our past ancestor (in order to determine human evolution) it can be hard because we have very few bones that will be found.
The main evidence of bipedalism in which I will focus on is the postcranial evidence of spinal curvatures. I chose this specific evidence because I watched a video lecture called “Early Hominin Body Form” by Carol Ward. Ward was talking about spinal curvatures of early hominins vs great apes. In this video, she states that spinal curvatures are distinctive for humans and they not seen in animals such as the chimp. This means that bipedalism could have something to do with our spinal curvatures. Later on, in the lecture, Carol Ward goes on to talk about how one can notice spinal curvatures since Australopithecus afarensis. This got me interested in the topic.
I decided to do more research on this topic overall and remembered an article that I had read for class. Within this article, it had a chart that stated in obligate biped the “s-curve is due to pressure on the spine from bipedalism” (Lumbar Lordosis, n.d.). This s-curve (lumbar lordosis) is the spinal curvature that we have been discussing. Like mentioned, in healthy humans, we tend to have an anterior curvature of the vertebral column and this curvature is believed to be important functionally for bipedal locomotion. Why is it important? Well according to C.A.R.T.A., it serves to move one's center of gravity allowing for the upright posture to function with more ease (Lumbar Lordosis, n.d.). Something to remember about spinal curvatures is that it is not present at birth. Why is this? Well as an infant we are not exposed to gravities pressure from walking upright. This happens later on in life when we begin to stand and walk, thus, adopting bipedal locomotion (Wagner, et al., 2012).
I am going to attach an article that I think is interesting to read for more information on this topic along with the Carol Ward video discussed above. I think it is important to understand skeletal evidence for bipedalism for the reasons easily known: The more information we know the easier (hopefully) it will be for anthropologist to determine which skeletons found from our past belongs to the Hominin ancestral line.
Citations:
Lumbar Lordosis. (n.d.). Retrieved June 04, 2020, from https://carta.anthropogeny.org/moca/topics/lumbar-lordosis
Wagner, H., Liebetrau, A., Schinowski, D., Wulf, T., & de Lussanet, M. H. (2012). Spinal lordosis optimizes the requirements for a stable erect posture. Theoretical biology & medical modelling, 9, 13. https://doi.org/10.1186/1742-4682-9-13
ooh..nice find on that Wagner et al piece. Very interesting piece here. Spinal column adapation is really impt and as Ward points out it isn't talked about as much. It is interesting to think about how we can look at the shape of the vertebrare and then use that to talk about the body form in general!
ReplyDeleteThinking about it now, I see why it would not be present at birth, especially since an infant's bones are weak and composed of cartilage as it hardens. It is fascinating that these gravity pressures help us to develop our way of walking upright, so to speak. I wonder how maybe people who slouch when they walk or sit at a young age if gravity affects their spine curves and if it is permanent.
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