Lucy: The first human

      Lucy: the Truth Behind the Mystery

One warm, sunny day in November of 1974, anthropologist Donald Johanson was walking through the desert of Hadar, Ethiopia when he came across the elbow bone of a skeleton, slightly protruding to the surface. Johanson took the bone back to his camp and began to analyze it with colleagues. He soon realized that he had more than just a single elbow bone, but a number of bones, all from the same skeleton. Johanson returned to the site of discovery and dug up more and more bones, all of which he believed belonged to a single hominid. He called in experts on bone structure and locomotion and then began to determine conclusions based on the findings that these experts were making. Johanson believed that Lucy, as he has come to call his skeleton, was the oldest human ancestor, at 3.2 million years old. She was the most complete hominid skeleton ever found with 40 % of her skeleton having been recovered. Lucy was also the best preserved skeleton of a hominid, with her bones in excellent condition. But most important was Johanson’s claim and reason for putting her in the lineage of humans, which was that she was bipedal (walked upright, on two feet). This claim was based on evidence supplied by Johanson, locomotion expert Owen Lovejoy, and many other experts in various fields, and they were well-supported and have changed the way we interpret human evolution.

The most remarkable discovery about Lucy, that went along with her being bipedal, was that her brain size was very small. It was about a third of the size of humans, and much closer in size to that of apes. This was a crucial discovery, because before finding Lucy, it was commonly believed that brain growth occurred in apes first and then, only after that, did apes start to walk upright and develop more human characteristics. These beliefs held that once hominids started to walk upright, their hands were suddenly free to start making tools, weapons, and carrying food back for others. These were some of the major characteristics that led to the development of the human species. But now, with the discovery of Lucy, the chronology of when these changes might have taken place was being disputed.

Donald Johanson believes that Lucy is “the missing link,” a species that represents the moment when humans split from apes. He believes she is the creature he has always been looking for and imagined was out there. Other scientists think that Lucy is not so much a transition in between apes and humans, as she is a starting off point. They believe that it was only after Lucy that a split took place and evolution diverged from her into two different paths; one that would eventually lead to us, and the other into the path of apes. While questions like these are still being raised as to the order of evolution, Lucy has certainly shaken up the world with her small brain and bone features that indicate she was bipedal. Johanson has found enough evidence to prove that she did indeed walk on two feet and is therefore a significant ancestor in the lineage of human beings.

When Johanson set out in Hadar in November of 1974, accompanied by scientist Tom Gray, he was looking for a creature that would “bridge the gap,” between humans and apes. He had good reason to be looking in Africa, because Charles Darwin had claimed that common ancestors existed  between early humans and modern African apes. Johanson chose to look in a Hadar desert because it was well-known that Hadar was a good place to find fossils. It had “tons of fossils eroding out and bones of every imaginable creature perfectly preserved in stone” (Johanson,76).

According to Johanson’s account of the discovery, it was mid-afternoon, when he looked back behind him and saw “a glint in the sunlight of a piece of elbow.” After the elbow, he found a piece of a shinbone, and then the lower piece of a thighbone. Johanson believed the bones might all belong to the same creature because “they were all scattered on the surface of one small place and there were no duplicate bones,” (Johanson,156). At first, Johanson and Gray thought the bones belonged to a monkey, but then they brought them back to their camp and looked at them more closely.

Through the use of rock hammers, dental tools, whisk brooms, and screens “to sift through piles of sediment,” a number of new observations were made (Thimmesh,17).  From these observations, ideas about the fossils were then able to be theorized.  One observation was that the bones were all the same size and color, which indicated that they did indeed belong to a single creature. Another claim was that Lucy was a female. This came from the notion of sexual dimorphism, that there is a difference in the body size between males and females of certain ape species. It was a pattern seen in gorillas such as Silverbacks, and males were possibly twice the size of females.

A team now returned to the site looking for a skull. They wanted to get an idea about possible brain size. What they found were a number of bone fragments, some of which were part of the skull they were searching for. Within the next year, potassium argon dating was used to establish that Lucy was roughly 3.2 million years old, and another expedition was sent out, this one recovering much more of the skeleton. They now found a thighbone, ribs, vertebrae, and many other fossil bones. Johanson named the species Australopithecines. “Australo” meaning southern, and “pithecines” meaning ape.

Owen Lovejoy, the expert on animal locomotion, who Johanson had brought in to look at the bones, confirmed Johanson’s belief that it was not the skeleton of a monkey, but that of a hominid. He made these determinations based on the knee joint which could be locked straight. A leg of a monkey cannot lock. Other conclusions developed as more pieces of the skeleton were discovered.

When they recovered pieces of the skull, Johanson and his colleagues were able to confirm their beliefs that Lucy was a female. “We determined it was a ‘she’ from the small stature, lightly built bones, and small canine (teeth), in her lower jaw.” (Johanson,17). Lucy’s small root size helped the scientists to infer the size of the teeth. The skull also helped them to determine that Lucy was an adult. Her body was the size of that of a modern six year old, with Lucy only 3 ½ feet tall and 65 pounds. But the skull showed that molars had formed in her jaw, indicating that she had reached the age of adulthood.

After making these initial determinations about Lucy’s size, age, and sex, the scientists then began to reconstruct both Lucy and her environment. They had 40% of her skeletal structure in-tact, but were able to use information to reconstruct even more. They determined what other parts of her skeleton would have looked like, “because the left and right sides of a skeleton are near replicas of each other,” and suddenly the amount of her skeleton they could be certain about increased to 75% (Edey,42). The scientists were able to use the way her arms were proportionately longer than her legs to determine that even though she was bipedal, she also spent time moving around in trees.

Johanson and his scientists were able to reconstruct Lucy’s environment by studying the animal remains that were found to be from the same time as Lucy. In order to establish dates for the animal fossils, a process called “determining the stratigraphic column” was employed. The fossils themselves could not be dated, but the rocks that were found around them could be. This was done by heating the rocks up and calculating how much argon was given off, with “the more argon a sample has, showing the older it is,” explained geochronologist James Aronson (Johanson,30). Using this process, scientists were able to determine that Lucy’s environment was mostly forest. The animal fossils were able to tell scientists not only about the environment in which they lived, but also about the challenges they faced. Based on the basalt levels found in the rocks, it was determined that not far from where Lucy existed, volcanoes were erupting.

While Lucy was a remarkable finding herself, just based on her age, the amount of skeleton that was recovered, and her wonderful condition, were equally impressive discoveries that came from looking closely at her bone structure. It was Owen Lovejoy who noticed the most significant characteristic of Lucy’s bones, which was that her knee joint was able to lock her leg straight and thus enable her to walk upright. “I realized that a man-like knee joint meant man-like walking,” said Donald Johanson. “This would be the first evidence from anywhere that anything had walked upright three million years ago,” (Johanson,39).  Johanson knew the possible importance of what he had found and did not want to make any revolutionary claims without first being certain. He knew that he needed a human knee joint to compare with Lucy’s, and so he traveled to an Afar burial ground nearby, uncovered some human remains, and compared the knee joints. His beliefs were confirmed. Lucy’s knee joint had more in common with that of a human than it did with that of an ape.

Lucy’s pelvic bone was also a very unusual part of her discovery. It was smaller than that of a monkey, yet “it rose above her hip joint and allowed her hip muscles to steady her body during each step,” (Themmish,42). Because the pelvic bone was so short, the entire center of the body and its mass would be lower, making it easier for Lucy to stand upright. Both the knee joint and the pelvic bone proved individually that Lucy was bipedal.

Johanson had made a remarkable discovery, but after that, I believe he started to get greedy. He wasn’t satisfied with what he had discovered and wanted to link Lucy to other discoveries, perhaps to have other well-respected names in the field who would validate his findings. He went to see Mary and Richard Leakey who had discovered a series of footprints in Laetoli, Tanzania, that they believed were made by hominids. The footprints were dated between 3.8 and 3.6 million years old, putting them close to the same time as when Lucy walked the earth. But there were substantial problems.

The footprints looked to be made by modern humans. They did show that whatever creature made them was bipedal, but they did not match up to the reconstruction scientists had made of Lucy’s foot, or to any other australopithecus foot. While I agree with Donald Johanson and Owen Lovejoy about Lucy’s age and ability to walk upright, the footprints do not seem to fit at all. According to Russell Tuttle, the primate morphologist who was enlisted by Mary Leakey to analyze the footprints, “australopithecines had feet that were distinctly ape-like and were incompatible with the Laetoli footprints, leaving us with somewhat of a mystery,” (Thimmesh,24). Instead of connecting Lucy to the footprints, like Johanson had hoped, the findings in Laetoli only clouded the issue. They did prove that there were creatures during Lucy’s time who were bipedal, but they also raised the question of whether there might have been another species, whose fossils are still unfound, with a foot more similar to that of humans than Lucy’s was.

While the argon dating and ways of determining that Lucy was an adult female who walked on two legs all seem accurate, there are still other findings about her that need to be questioned. Her hip bones, for example, were not the way Owen Lovejoy would have liked them to be. They looked more like that of a chimpanzee than like that of a human, but instead of accepting this, Lovejoy decided to come up with reasons for how this might have happened. He claimed that the bones were crushed after Lucy died, causing them to flatten and look more like that of a chimp. Lovejoy then made his own version of the hipbones in plaster, the way he wanted them to be. This seems like he was following the procrustean bed of history technique where a historian will change the facts to fit his theory. In the case of Lucy’s hipbones, Own Lovejoy was literally changing the way her bones looked and fit together in order to fit what he believed.

Most of what Donald Johanson found and claimed about Lucy is valid. He and Lovejoy have determined, based on both the knee joint and the pelvis bone separately, that Lucy was bipedal. While I agree with these findings and methods by which they were attained, I strongly disagree with the altercations made to the hipbones, and I certainly think the footprints found at Laetoli were not made by Lucy. Despite these problems and questionable issues, the fact remains, Lucy was alive 3.2 million years ago and she had a small brain and walked on two feet. Therefore, she is our oldest found ancestor and has changed the order in which we thought our evolution occurred. Hominids were thought to have increased their brain size before they started walking around on two feet, but Lucy proves that this chronology should be reversed. Her discovery and the findings made by Donald Johanson have cleared up and brought to light new evidence about human development and is a very significant building block in the history of our evolution.



Bibliography

Books

  1. 1.       Johanson, Donald C., Lucy’s Legacy: the Quest for Human   

           Origins.  Harmony books, New York, 2009


2. Edey, Maitland, Lucy: the Beginnings of Human Kind,

        Simon and Schuster, New York, 198


  1. 3.       Thimmesh, Catherine, Lucy Long Ago: Uncovering the  

           Mystery of Where We Came From

        Houghton Mifflin Books, New York, 2009,


Articles / Websites

  1. 1.      National Geographic Magazine, Face to Face With Lucy’s

          Family.  Johanson, Donald C, Volume 189, Number 3,

       National Geographic Society, Washington D.C.,

       March 1996


  1. 2.     National Geographic, New Fossil Ape May Shake Human 

         Family Tree. Wadhams, Nick, Nairobi, Kenya,

         August 22, 2007

         www.news.nationalgeograpphic.com/news/2007/08-

         fossil-ape.html


3.Los Angeles Times, Nova Goes in Search of Human Origins

Maugh, Thomas L,  Los Angeles, California, February 28th, 1994


4.The Washington Post, Skull of Oldest Human Ancestor is Found,

Rensberger, Boyce, Washington D.C., March 31, 1994


5.Cosmic Log, Lessons From Lucy,

Boyle, Alan, February 10, 2009,

Cosmiclog@msnbc.com





Video

1.Nova: In Search of Human Origins – the Story of Lucy

March 28, 2000, 60 minutes, Boston, Massachusetts,

Featuring Donald Johanson