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 was a bit large since that was the size of a male afarensis (Johanson The Quest for Human Origins).
Lastly a partial skeleton of Ardi combines human and other primate traits. Ardi moved in the trees using a grasping big toe, yet her pelvis was shorter and broader than an ape’s, indicating that she could walk bipedally. There were many pieces of evidence that proved Australopithecus afarensis to have been walking upright for thousands of years. Dr. Don Johanson brought up human like characteristics in Lucy’s bones that indicated she walked upright. One of Lucy’s most striking characteristics was her knee joint, which indicated that she normally moved by walking upright.
Her greater trochanter, however, was clearly derived, being short and human-like rather taller than the femoral head (Lovejoy). Another piece of evidence that proves Lucy walked upright was the formation of her pelvis. Her pelvis and leg bones were almost identical in function to those of modern humans, showing with certainty that these hominids had walked bipedally. The third piece of evidence that made it undoubtedly that Australopithecus afarensis walked upright was the footprints found at Laetoli in northern Tanzania.
In 1976, Mary Leakey discovered hominid footprints that was preserved in volcanic ash and unearthed 1978. “The Laetoli Footprints” and skeletal structure excavated showed clear evidence of bipedalism. Many believe the three individuals who made these footprints belonged to the species Australopithecus afarensis. The footprints demonstrated that Australopithecus afarensis walked upright habitually, as there were no knuckle or hand impressions found near the footprints. The footprints didn’t have the mobile big toe as the apes do; instead, they had an arch, which the typical modern humans have (Leakey 81-86).
After the discovery of Ardipithecus Ramidus, Tim White and Owen Lovejoy came up with many pieces of evidence that would place Ardi on the Human Evolutionary Tree. The femur and pelvis of Ardipithecus have characters that indicate both upright bipedal walking and movement in trees. Ardi’s pelvis was more primitive than Lucy’s but still contained characteristics to walk upright bipedally. Researchers say Ardi was a facultative biped (Lovejoy). That means Ardi was able to walk on two legs but only for a short period of time.
Donald Johanson said in “The Quest for Human Origins” that when moving on the ground Ardi would move bipedally, but when in the trees she was quadrupedal. Lastly Ardi had very large divergent great toe, which was probably used to climb trees. Using those feet to grasp on to the branches helped them stay out of the reach of the attackers on the ground and also climb to get fruit in the trees. Lucy and Ardi are two important specimens in history that helped us learn more about the past human origins. There were many differences and similarities between Ardi and Lucy.
The main and probably most obvious similarity was the ability to walk upright. This was probably the most important characteristic that connected Homo sapiens, Australopithecus Afarensis and Ardipithecus Ramidus together. Also another similarity was the formation of both pelvises. Lucy’s was more distinctively similar to the modern human but Ardi’s still contained characteristics that made it more human than ape. Something that Ardi and Lucy also had in common was that both walked bipedally on the ground, but when in the trees they were quadrupedal.
Being over a million years apart Lucy and Ardi also had some differences. Ardi was more primitive than Lucy in that she looked more like apes and had more characteristics of them. On the other hand Lucy was more developed than Ardi such as having a slightly bigger brain, having more human like anatomy when it came to the bones, and Australopithecus afarensis spent more of their days walking bipedally than in the trees. The discoveries of Australopithecus Afarensis and Ardipithecus Ramidus have changed the way we connect our human origins to the past. Dr.
Donald Johanson and Dr. Timothy White have brought to us these wonders that help us understand not exactly where our species come from but where some of our human origins and characteristics started. With the evidence presented, I can agree with the interpretations of Ardi and Lucy because through science and reasoning there isn’t any doubts and anyone can bring up. There may be many subtopic arguments about the theory of evolution but they all end up with the same conclusions that Lucy and Ardi is the first stepping-stone to connect our human origins to the evolutionary tree.
After Dr. Donald Johanson and Dr. Tim White discovered the two most amazing specimens that would happen to be the beginning of evolutionary development. Lucy and Ardi are important to our evolutionary development because they were the first fossils to show upright walking as their primary locomotion. After all the evidence that many anthropologist, archeologist, and paleoanthropologist discovered and examined to prove that Lucy and Ardi’s ability to walk upright is clear that they are ancestors in our human evolutionary tree.