Essay title: LucyOn November 24th, 1974, a group of paleontologists led by Dr. Donald Johanson discovered a partial skeleton approximately 3.5 million years old in the Afar region of Ethiopia. Johanson, along with colleague Tom Gray had been focusing their interests on another part of the Afar area, when Johanson decided to move in a different direction and hoped to get lucky. Johanson discovered portions of an arm bone and quickly declared it as a hominid. As they searched more, Johanson and Gray found a jaw bone, thigh bones, ribs, and vertebrae. After about 3 weeks Gray and Johanson concluded that about 40 percent of the skeleton was recovered. This would prove to be a groundbreaking step for paleontology.
For the record the correct identification for this discovery was AL-288-1 (Afar Locality #288), but was later renamed “Lucy.” It was named Lucy after the Beatles song “Lucy in the sky with diamonds”, which Johanson was listening to when he discovered the first bone. When he first discovered her, Johanson was immediately able to identify Lucy as a hominid. A hominid refers to a member of the zoological family Hominidae. Hominidae cover all species originating after the human/African ape ancestral split. It was so clear that Lucy was a hominid because she stood and walked in an upright position. How do we even know this much? When collecting the bones, Johanson observed the vertebrae
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This was the first step towards understanding Lucy’s anatomy. However, the study of Lucy in the wild had many limitations. First, the genetic structure was not the same in Lucy as in her relatives. For example, the human lineage consisted of 1 or 2 superfamily members, one from each of the genera. Although many early humans have been documented living in Africa and South America, there has been few scientific records of them living there or to whom they have been related. For example, none of the Neanderthal hominid fossils in Germany were examined on a large scale. So the identification was far from perfect.
If she was a hominid, it wasn’t obvious that the researchers would be working in part in Africa, which is where the DNA is extracted. Although she was known to have a human body and facial features, there appears to be far too many of the three hominids present within a single body (the other two included have a human head, legs and face). Thus, the work was limited to individuals in Africa and South America. The researchers looked at the genomes in their respective living groups, looking for a single individual. On the face of it, they found that the individuals differed considerably from one another. But no one knew that these differences were genetic. And it was this lack of identification that the researchers needed to know.
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We have since verified that Lucy is a true hominid. The genome sequence is unique to the first person she was in living, and our research led to more than a half a billion hominids to be observed since then. The first hominid to be documented was probably a female known in South America only as Gweny. But the third is very likely to be female and would probably have been less common. Our results suggest that Lucy might have been a very different specimen than Gweny.
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It turns out that there is still work to do to understand Lucy. First to find what exactly caused Lucy to evolve—and how and why?
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In our first analysis the only explanation that can be used is that the hominids were introduced because of lack of sufficient genetic diversity. There weren’t many examples of hominids that shared certain features in common with the people who lived there. The fact is that genetic diversity is usually very large (a bit more than half of the human genome is just 5,000 base pairs across) and does