Lucy Paper - Grade: A+++++ PDF

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Second Paper of Semester. Analysis of Lucy and evolution of man. Uses multiple resources....

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Dr. James Lepree World Civilizations 101 October 24, 2015

Controversy, has always existed in many different fields of science, but the most controversial field has recently been the field of paleoanthropology. The exact period of time when humans and apes branched off into different species, has long been the center of this controversy. In the years from 1967 to 1977, during an era now called “The Golden Decade,” some of the most redefining discoveries were made. These discoveries include several of Donald Johanson’s potent findings, such as the knee joint found in 1973 and the Australopithecus Afarensis in 1974. Johanson has believed both findings are clear pieces of evidence which refute the common claim at that the transition from human to ape has occurred fairly recently. Johanson’s belief was, however, challenged by some of the prominent paleoanthropologists of that time, including the likes of Mary and Richard Leakey. Through a close read and analysis of Johanson’s arguments, and the counter arguments of the Leakeys’ it is fairly certain that the Australopithecus Afarensis was bipedal and is the missing link between apes and humans. In 1973, while on his first field session in Hadar and kicking at what seemed like a “hippo rib,” Johanson stumbled upon a few bones (Johanson 155). Initially they believed the bones to be monkey bones, but as they “studied it, [they] realized that [they] had joined the femur and the tibia at an angle… They had gone that way naturally; that was the way they had to go” (Johanson 155). The bones had to be hominid, because “the monkey’s tibia and femur joined in a straight line. Almost against [his] will [he] began to picture in [his] mind the skeleton of a human being” (Johanson 155). All three pieces: the tibia, the femur, and the condyles, were “the

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same size and the same color. All three fitted perfectly. A rare find” (Johanson 155). “The angle at which the two bones connected is what convinced him it was hominid. In apes the connection would have been straight” (Johanson 156). When looking in the cross sectional view, the difference between the bones of a modern human knee joint, Johanson’s knee joint, and an apes knee joint is obvious. The knee joint of a modern human, and Johanson’s knee joint are both oval, while the ape joint is round (Johanson 156). Soon after excavating the knee joint, Johanson snuck into a nearby burial mound, and stole a femur from an old grave for comparison with the knee joint he had found. “Except for size, they were virtually identical” (Johanson 159). Using “bio-stratigraphic evidence… [it was] determined that the basalt layer was about 3 million years old. The knee joint was much deeper in the basalt layer, and therefore considerably older” (Johanson 162). A potassium argon test was also done and it yielded a 3-million year old date, with a “small but indeterminable error” (Johanson 200). To confirm his findings and interpretation, Johanson visited “C. Owen Lovejoy, a world authority on locomotion” (Johanson, 162). Lovejoy said that the knee joint “is adult… after examining it very carefully… My friend, he could walk upright. Explain to him what a hamburger was and he’d beat you to the nearest McDonald nine times out of ten” (Johanson 163). “Lovejoy [also] pointed out, the joint had all the hallmarks of a creature that moved around on two legs, not on all fours. Walking upright is something that only humans can do. And it needs a special kind of knee joint, one that can be locked straight (Lucy in Search of Human Origins). Lovejoy concluded that the knee joint was a “modern knee joint” and Johanson received the “confirmation of an expert” (Johanson 163). The following year, in 1974, while on his second field session, Johanson made two startling discoveries. Johanson’s first discovery was his finding of two seemingly hominid jaws.

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One jaw was that of a “hyena, an excellent find because carnivores are always rare” (Johanson 173). The other jaw was found in “two halves… [when put] together, they fitted perfectly to make a complete palate with every one of its teeth in position: a superb find” (Johanson 173). The jaws had characteristics of both humans and of apes. When looking at the canines, for example, they “held a hint of a more apelike condition” (Johanson 175). The size relationship of the molar and the incisors were similar to humans in that the molars were small relative to the incisors (Johanson 175). Johanson’s second discovery was Lucy. After deciding to catch up on the paperwork he had to do, Johanson “found [himself] under a strong compulsion to put off [his] paperwork and go surveying instead… the papers could wait. Gray and [Johanson} drove out of camp. Two hours later [they] found Lucy” (Johanson 180). Johanson found a “right proximal ulna… [an] occipital (skull) bone, a femur, some ribs, a pelvis, and the lower jaw… several hundred fragments of bone had been recovered, representing 40 percent of a single hominid skeleton (Lucy’s Story). Lucy was a “not more than three and a half feet tall, had a tiny brain, and yet walked erect. Its jaw was V-shaped, not as rounded in front as some of the other mandibles, and smaller than any of them. Furthermore, its first premolar had only a single cusp. The larger jaws had two-cusp premolars. Since the one-cusp condition is the more primitive and the two-cusp condition the more human, [Johanson} came to the tentative conclusion that Lucy was different form the larger-jawed type” (Johanson 180). While celebrating their find later that night, the song “Lucy in the Sky with Diamonds” kept on playing, so the skeleton was named Lucy (Lucy in Search of Human Origins). As for the name “Australopithecus Afarensis,” the second word comes from the name of the region where Lucy was found, “the Afar triangle” (Johanson 288).

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Hadar had not always been a hot place with “windless little gullies, and stifling canyons” (Johanson 151). “Even before Lucy's time, the climate of tropical Africa was changing. There were alternating seasons, wet and dry, and less rainfall overall. The dense forests were beginning to shrink. East of the Great Rift, the forests were replaced by open grasslands with scattered clumps of trees. Under these new conditions, some species died out entirely, and others took their place. New species of antelope were colonizing the forest edges. High in the trees, the ancestors of today's monkeys were on the increase. The monkeys' strategy is to produce a lot of young quickly. Their populations expanded rapidly at the expense of the apes, who reproduced much more slowly. Before long, the apes were in retreat, pushed out by the monkeys. The number of apes declined along with the shrinking forests. Except, that is, for one: Lucy, the ape that stood up” (Lucy in Search of Human Origins). “By keeping track of every fossil [they] find, [Johanson and his team] can map out a world totally different from Hadar today. The geologists can help [them], too. They sample ancient layers of the Earth that have been exposed in the Great Rift Valley. Geologist, Tesfaye Yemani, has discovered that Hadar was wet and forested millions of years ago…. There are several dry river[s] coming from the western mountain of Ethiopia, flowing to Awash River. The same thing was happening during the time of between four and three million years ago, except this, the river were flowing through very thick forests and not a desert like today…. At the time of our earliest ancestors, this place was lush and green. Back then, there were rivers and lakes with communities of animals living in and beside the water (Lucy in Search of Human Origins).” “It's potential is absolutely staggering. When walk[ing[] these gullies and valleys, [there are seen] tons of fossils eroding out of these ancient geological strata. There's almost no vegetation, so the seasonal rains do most of the work for [for the fossil finders], scouring the surface, uncovering buried fossils. There are bones of every imaginable

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creature, perfectly preserved in stone (Lucy in Search of Human Origins.” It is safe to say that different ecological conditions did exist throughout the history of Hadar dating millions of years back because of the variety of fossils which were found. All animals cannot live in the ecological environment, so to find a wide variety of fossils means that these animals must have been living there during different, and under different ecological conditions. Johanson’s claim that Lucy, a 3.6 million year old creature, had bipedal ability is central for his inclusion of her into the human family. Johanson’s claim is based mainly around the knee joint that was found. This knee joint Johanson uses to support his claim is the knee joint he found in 1973, found 2.5km away from where Lucy was found. Although the knee joint does not belong to Lucy, it was of a similar date, therefore validating Johanson’s claim. “There [it] was, an ape brained little creature with a pelvis and leg bones almost identical in function with those of humans” (Johanson 181). Lovejoy was the key figure in the analysis of the pieces of Lucy’s pelvis which were found. At a first glance, Lucy’s pelvis looked nothing like a human pelvis but rather like the pelvis of an ape (About the Reconstruction of Lucy Pelvis – Final Point). If one were to fit the pieces of Lucy’s pelvis looking for a perfect fit, you would notice her “hip bone flair like a chimps” (Lucy in Search of Human Origins). Lovejoy noticed that a part of her pelvis, where the ilium and sacrum met, had a deformity (About the Reconstruction of Lucy Pelvis – Final Point). To view Lucy’s pelvis without this deformity, Lovejoy created a model of Lucy’s pelvis, removed the deformity, and saw that without the deformity the pelvis looks like the exact replicate of a human pelvis (About the Reconstruction of Lucy Pelvis – Final Point). Lovejoy explains this deformity by saying that “[one part] of the pelvis was pressed so hard and so completely [on the other part] that it caused it to be broken in individual pieces which were then

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fused together then in later fossilization… [the bones] fit together so well that they’re in an anatomically impossible position” (Lucy in Search of Human Origins). Proof of the existence of human bipedal walkers dating back 3.6 million years ago, also exists in Laetoli, Tanzania. This proof is the footprints which were found by Mary Leakey in 1978. The footprints “found there [were] certainly one of the extraordinary cases of preservation and discovery in all of [paleo]anthropology” (Johanson 245) Sadiman, a volcano near the place where the footprints were found, was active millions of years ago. These footprints were made by “an imperfect walker; the prints indicated... shuffle[ing]…” and there was “some evidence of panic in the tracks, suggesting that the animals had been fleeing the eruption” (Johanson 246). As for what the footprints suggested about the anatomy of the walker’s foot was that the “external morphology is the same [as that of a modern human]. There is a well shaped modern heel with a strong arch and a good ball of the foot in front of it. The big toe is straight in line. It doesn’t stick out to the side like an ape toe or like the big toe in so many drawings you see of australopithecines in books” (Johanson 250). “The distribution of weight appears to be entirely human, first placed on the heel, then the lateral edge of the foot, and then on the ball and toes. The big toe is generally the most clearly defined and has often been dug into the ash for propulsion. Scuff marks in front of the toes are often present… The evidence for a fully upright free standing bipedal hominid gait during the Paleocene is indisputable; the Laetoli footprints have fully confirmed the work of those anatomists who reached this conclusion from the morphology of the fossil postcranial material” (Leakey 86). Unlike the reasons for whether Lucy was bipedal or not, the reasons for why she became bipedal cannot be established directly through an analysis of her bones. These reasons for why she walked bipedal lies in a deeper understanding of the ecological progression of Lucy’s

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environment. Hadar wasn’t always a desert, but rather a forest with rivers flowing through it. Progressively over time due to climate changes, there was a decline in forests and trees, forcing creatures to adapt new ways of life. In order for humans to be able to carry tools, they had to have hands to carry them and the only method of walking which allows for hands is for humans to walk in a bipedal fashion. “Lucy and her kind could still survive by walking across the grasslands to reach the clumps of trees where her food was found. And her hands were free to collect and carry the valuable food she found. This slight advantage was all she needed. While the other apes declined, Lucy and her kind flourished” (Lucy in Search of Human Origins). Maybe more important than the ecological progression of Hadar in Lucy’s ability to walk in a bipedal manner, has been the social structure. “An animal’s locomotor adaptation cannot be thoroughly understood unless its sexual strategy is also understood” (Johanson 321). Other bones have also been found, such as an ulna which is around 3-million years old, approximately the same age as Lucy’s ulna. What is unique about this ulna is that it is “nearly twice the size of Lucy's. And such substantial difference in body size really has important implications for behavior. These fossils suggest that some of Lucy's kind were much larger than others, nearly twice the size… Such enormous differences are seen today in mountain gorillas, and it's clearly related to their social life. This is a harem in which a single, large male controls a group of small females. The silver back male is almost twice the size of the females, and this leader of the group, he mates with each female in turn. He can easily control all the females. In this lush environment, they find all the food they need without wandering far. … Finding an arm bone twice as large as Lucy's raised the possibility that the new bone was from a large male, and that our ancestors fit the gorilla pattern, that they had lived in a harem” (Lucy in Search of Human Origins). Bipedalism allows for the use of ones hands to bring food back to one’s mate.

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Bipedalism, pair bonding and human reproduction are all related, each having an effect on the other. Although quadruped animals obviously are more well suited for running than biped animals, “quadrupedalism… can be given – indeed, will be given up – if other, more useful adaptations are available” and “when the total survival strategy of the creature is studied” one cannot only look at one specific advantage, but rather look at the entire picture (Johanson 324). I believe that Johanson’s classification of Lucy as an Australopithecus Afarensis, is correct. She encompasses many traits which are common only to apes, while simultaneously encompassing traits which are common only to humans. Questions have been risen by others regarding the use of the 1973 knee joint Johanson found to prove that Lucy was a bipedal walker. I believe, that Johanson’s use of the knee is well justified, because it is of a similar date. If the evidence of Lucy’s pelvis did not exist, I would have questioned Johanson’s decision, but the pelvis really confirms Lucy’s bipedal walking ability. Several creationist individuals, such as the lecturer in the Owen Lovejoy Doctors “Lucy” video, have found Lovejoy’s theory that a part of Lucy’s pelvis was deformed absurd, because they find it unlikely for an animal or whatever other creature walking by to accidently crush it (Owen Lovejoy Doctors “Lucy”).. I, however, disagree with these few individuals. I see it as very possible because of the amount of years which have elapsed since Lucy has been dead. During a period of around 3.6 million, many things can happen, and for someone or something to walk past the pelvis and crush a piece of it seems extremely probable. I believe that Lucy definitely falls in between ape and human, but more human than ape solely because of her bipedal ability. I completely agree with the approach Johanson took in making his conclusions, specifically those pertaining to Lucy. Johanson constantly sought out the opinion of others who were better versed, more adept, and more knowledgeable in whatever subject his question was

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pertaining to. He went to James Aronson for a second opinion on the geological placement of the different layers and for an accurate reading on how old each of his findings were. Although “there is no such thing as no bias” Johanson eliminated many possible sources of bias by working with Tim White to draw his conclusions of Lucy (Johanson 257). He took a very professional approach, not letting his arrogance get in the way of any his work. Johanson’s field tests during The Golden Decade, have had significant revamping effects on the field of paleoanthropology; effects which have changed many of the core beliefs of paleoanthropologists. These core beliefs include answers to the question: “what came first, the stone tools or the bipedal walking?” Johanson’s findings have pushed back the previous estimate of when humans first began walking erect. Johanson created a spur of interest in the field of paleoanthropology with his finding of Lucy. His conclusion of Lucy as a bipedal, and Lucy’s inclusion into the Australopithecus Afarensis family will always be a topic of controversy.

Farooq, 10 Works Cited Johanson, Donald C., and Maitland A. Edey. Lucy, the Beginnings of Humankind. New York: Simon and Schuster, 1981. Print. IN Search Of Human Origins Episode One THe Story Of Lucy. Prod. Michael Gunton. NOVA, 1994. Videocassette. "Owen Lovejoy Doctors "Lucy"" YouTube. YouTube, 6 Nov. 2009. Web. 25 Oct. 2015. "About the Reconstruction of the Lucy Pelvis - Final Point." YouTube. YouTube, 26 Sept. 2008. Web. 25 Oct. 2015. Leakey, Mary D. "Discoveries at Laetoli in Northern Tanzania."Proceedings of the Geologists' Association 92.2 (1981): 81-86. Web. 25 Oct. 2015. "Lucy’s Story." ASU Institute of Human Origins, n.d. Web. 25 Oct. 2015. ....