March 1, 2012
World Civilizations 101- Dr. James LePree
“Lucy and Ardi: Beginning of Human Origins”
Many people often consider our first milestone in life to be our first step. It is the beginning of many important developments as an individual. It was also the beginning of our development as a species. Dr. Donald Johanson and Dr. Tim White discovered two of the most amazing specimens that would be the stepping-stones to the beginning of evolutionary development. Australopithecus Afarensis (Lucy) and Ardipithecus Ramidus (Ardi) were the first fossils found in Africa that showed signs of early evolutionary development that is connected to Homo sapiens in the evolutionary tree. Lucy and Ardi are important to our evolutionary development because they were the first fossils to show upright walking as their primary locomotion.
American paleoanthropologist, Dr. Donald Johanson, led the team that discovered Australopithecus Afarensis in 1974 at Hadar in the Awash Valley in Ethiopia. The discovery of Lucy was very significant, which was because the skeleton showed evidence of a small skull that resembled that of an ape and of bipedal upright walking that is akin to that of humans. Lucy is dated back to about 3.2 million years ago. Lucy’s species survived for over 900,000 years, which is over four times as long as our own species has been around. A. Afarensis, which are similar to chimpanzees, grew rapidly after birth and reached adulthood earlier than modern day humans. Lucy was about the age of 11-12 years old but the formation of all of her teeth showed that he was fully matured for her species unlike modern day humans were that isn’t reach till later years (Johanson The Quest for Human Origins). This meant Lucy’s species had a shorter period of growing up than modern humans have today. A. Afarensis had both ape-like and human characteristics such as ape-like faces, which is described as flat nosed and sloping lower jaw that juts out underneath the braincase. Also Lucy had a small brain that was about 13 fluid ounces and 400 cubic centimeters, which is about one third the size of a modern human brain. They also had long, strong arms with curves fingers most likely adapted for climbing trees to hide the land animals that would attack them and also picking fruit from up in the trees. They also had small canine teeth that resembled early humans and most importantly had a body that stood on two legs and regularly walked upright. This was one of the most important features of A. afarensis because their adaptations for living both in the trees and on the ground helped them survive for almost a million years as the climate and environment changed (Johanson The Quest for Human Origins).
Twenty years after the discovery of Lucy, Dr. Timothy White led a team into Middle Awash area of the Ethiopia where he discovered the first fossils of the second biggest discovery since Lucy. Ardipithecus Ramidus was uncovered in over 100 fossil specimens in the Awash area. At the time of the discovery, the genus Australopithecus was scientifically well established, so White devised the genus name Ardipithecus to distinguish this new genus from Lucy’s species. In 2009, scientists formally announce and published the findings of a partial skeleton nicknamed “Ardi”. Ardi is estimated to be about 4.4 millions years old. Tim White and his team found bits and pieces of Ardi’s skeleton, which were heavily damaged due to erosion, and the pressure of geology. Ardi’s skull was flat with loping lower jaw that juts out underneath the braincase similar to Lucy. The pelvis of Ardi after being reconstructed from a crushed specimen, suggested that even though it was not as tall as the apes it showed similarities. Also it showed adaptations that combined tree climbing and bipedal activity. White and his colleagues that worked on Ardi suggested that Ardi was a female that was a bit large. She was about 1.2 meters tall and about 50 kilos, which...
Cited: 1. Leakey, Mary D. Discoveries at Laetoli.
Proceedings of the Geological Association. 92(2), 81, 82
2. Lucy’s Legacy: The Quest for Human Origins
5. Lovejoy, C. Owen. The Pelvis and Femur of Ardipithecus Ramidus: The Emergence of Upright Walking.
Vol. 326 no. 5949 pp. 71, 71e1-71e6
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