This article was contributed by Amanda Nottke
3.2 million years ago she lived and died, in what is now the country of Ethiopia. In 1974 she was excavated by an international team of paleoanthropologists. She was given the nickname “Lucy” after the Beatles song “Lucy in the Sky with Diamonds”, which had been a camp favorite. And from now until October 25th you can visit her at the Discovery Times Square Exhibition in Manhattan (http://www.discoverytsx.com/nyc).
The scientific name of her species is Australopithecus afarensis, and they are thought by some to be ancestral to both later Australopithecus species and the genus Homo, which exclusively includes modern day humans. Another school of thought puts her as ancestral to a side branch of the Australopithecines which later went extinct. So she represents at least a great-aunt species of modern humans, if not a grandmother. The discovery of Lucy’s remains in the 1970s rocked the paleoanthropology field, as well as captivating the public imagination. Why was her discovery so revolutionary?
Lucy: A Bipedal Ape?
One of the most striking aspects of Lucy’s discovery was the completeness of her remains. Several hundred bone fragments were uncovered, accounting for 40% of her skeleton. No other hominid fossil of her age, before or since, has been quite so comprehensive. This has allowed scientists to develop a detailed picture of her size and appearance, including her height (3 feet, 6-8 inches) and her weight (approximately 65 pounds). Although the bones of her face are mostly missing, her skeleton and jaw bones (along with the discoveries of other A. afarensis skulls) suggested she appeared similar to a chimpanzee, with one important difference: Lucy was fully bipedal.
Lucy was a fascinating mix of chimp-like and human-like traits, with some features startling similar to us, given our 3 million year difference in age. From the neck up, including her face and cranial capacity, she was much like a chimpanzee. But from the neck down, particularly the anatomy of her pelvis and knees, she was similar to a modern human. It was this combination of traits which proved so shocking to paleoanthropologists at the time.
New Theories of Human Evolution
Before the discovery of Lucy and other A. afarensis in the 1970s, the predominant theory of human evolution was that the first major development in pre-humans was an expansion of cranial capacity (brain size). These brainy pre-humans were then believed to have developed bipedalism and other modern human traits. The discovery of what was essentially a bipedal ape turned this theory on its head, indicating that bipedalism was one of the first, if not the first, adaptation distinguishing our ancestors from the ancestors of our closest modern relatives, the chimpanzees. So it was not initially our brains that separated us from chimps and gorillas, it was our ability to walk on two feet.
Since Lucy’s discovery, the field of paleoanthropology has incorporated her and other fossil hominid remains into a newer understanding of human evolution. To summarize very briefly, bipedalism occurred earlier than the first expansion of brain size above that of the apes (and the first use of stone tools), and much earlier than the first ancestors with modern human brain size. Why did bipedalism occur earlier than the increase in brain size, and was it in any way responsible? Some scientists think so.
These fossil findings have given rise to exciting new hypotheses connecting anatomy with behavior and perhaps to the evolution of society as well. For example, bipedal anatomy allows for walking or running long distances and frees the hands to make and carry tools. These adaptations may have allowed human ancestors to become much more efficient hunter-foragers. However, the narrow hips required for bipedalism also may have necessitated earlier births (smaller babies) requiring extended care, creating the need for human society. Paleoanthropologists and evolutionary biologists are currently working on these and other theories, with the goal of answering a major question of human evolution: What made us human?
Lucy’s U.S. Tour: Controversies and Opportunities
35 years after her discovery, Lucy and the theories she inspired are still influencing the field of human evolution. She is no doubt one of the most valuable paleoanthropological discoveries ever, and because of this there has been some controversy surrounding her U.S. tour. Over the next few years she will visit six American cities, including Seattle and New York City. However, some feel she should have remained in Ethiopia where she was found, and others are simply concerned that the tour may damage her. On the plus side, her visit here will allow for further scientific examination with the latest scanning and imaging technologies, as well as unprecedented exposure to the general public. She is here now, only 4 hours away for those of us in Boston, and this is a remarkable opportunity for us to look face to face with one of our earliest ancestors.