ANTH Notes IV PDF

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Adam Hamilton Dr. Sezgin ANTH 1102 September 27, 2016

1) Bipedalism is defined as a terrestrial locomotion where an organism stands up right and walks on its two legs. The most critical trait to have for a bipedal walker is maintaining balance. This means that there must be a vertebra, and most importantly it must be centered with the pelvis. Our mystery skeleton has both of the qualities, a vertebra and one that is centered with the pelvis. Other bones that appear in our mystery skeleton that may show that it was a bipedal walker include a sacrum and a femur. Each one of these bones may benefit in helping to prove that our mystery skeleton was bipedal. The sacrum is large triangular shaped bone that is connected to the vertebrae. Based on the curve of the Sacrum allows us to know if the organism was bipedal. The more of a curve the bone has, shows how the weight on the body was dispersed. Our mystery skeleton shows a curved but somewhat smaller sacrum. Never the less it is still curved giving evidence of bipedal locomotion. The femur is another important bone to show existents of bipedalism. The femur holds the weight of the torso, and based on the shape of the end of the bones we can tell how they were attached to pelvis. With this information we could then tell if the individual stood upright or not. The femur in our mystery skeleton show signs of an upright walker.

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2) Having the bones of the arms and legs could also be used to determine bipedalism but may not always be as reliable unless the full length of the arm is known. Most primates that are either quadrupedal or arboreal have longer arms relative to their legs. This is because these primates used knuckle-walking locomotion, such as chimpanzees. Most bipedals have longer legs than arms. Based from the picture of the chimp skeleton their structure is more curved than that of the human skeleton and our mystery skeleton. Compared to the human skeleton you can easily tell that the chimp’s arms are relatively longer than its legs allowing it to walk on its knuckles. The chimps innominate is also obviously larger compared to the mystery skeleton and the humans. This shape and size difference is compensated for the chimps because of their bent use of locomotive.

3) Primates who use bipedalism locomotion have distinct different traits in their hands and feet from those who use other forms of locomotion. Humans have the most distinctive feet since only the lower limbs are used for forward motion. This use of forward motion means that the foot structure must provide for the way of movement. This is why the structure of a humans foot is different that of an apes. For example, a human’s foot does not have as wide of a gap between the hallux and their other toes, also the heel bone is more stout in humans. The hands also tell a lot about the locomotion of primates. Human’s fingers are much flatter than that of an arboreal primate, simply because arboreal primate’s hands adapt to climbing trees and walking on their knuckles. Unfortunately we cannot use the

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bones of the hands or feet of our mystery fossil simply because the bones of the hands or feet are not present.

4) The pelvic bone plays a critical part when it comes to bipedalism. In primates that use bipedal locomotion the pelvic bone support and balance the weight of the torso. The shape and size of the pelvic differ from that of apes and other arboreal primates. The modern human hip bone has larger hip joints and larger pelvic outlet this is what allows humans to have the balance they need to walk upright.

5) The average height of modern humans varies upon gender. For females the average height is 5 feet and 3 inches. For males the average height is 5 feet and 9 inches. Chimpanzees for males and females have an average height of 2.68 feet. Knowing the height of the mystery fossil is very important to know what the fossil represents. Height is considered an adaptation for primates. Data suggest that increasing body size means a greater reliance on animal food resources, and increased range size in the brain.

6) Dr. Sezgin’s hypothesis that the mysterious skeleton was an upright walker is correct. There is enough evidence to back up the hypothesis to be true. The mysterious skeleton obtains bone structures that only a bipedal walker would have. We can see the distinct differences in the shape of the pelvis from a quadruped and biped. The legs on the “Mystery Skeleton” are longer than quadrupeds would be and the sizes of its arms are too small to use quadrupedal

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locomotion. All of the bones showed in the “Mystery Skeleton” show that it is a bipedal walker.

7) From my research gathered, I conclude that the “Mystery Skeleton” lived about 3

million years ago, and can be classified as Australopithecus afarensis and belongs to the genus Australopithecus. I researched the skeletal bones that where visible in our mystery skeleton and it turns out that our skeleton happens to be a primate by the name of Lucy. Based on this source, http://www.history.com/news/famedlucy-fossils-discovered-in-ethiopia-40-years-ago, I was able to obtain the information I needed to solve who our skeleton was.

Bibliography “Main.” Main. N.p., 23 Jan. 2012. Web. 02 Mar. 2016

Hamilton 5 Kappleman, John. “About Lucy.” Elucy. N.p. Wed. 02 Mar. 2016. O’Neil, Dennis. “Early Hominin Evolution: Analysis of Early Hominids.” Early Hominin Evolution: Analysis of Early Hominids. N.p., 2002. Web. 02 Mar.2016....