“Lucy” was the name given to an important fossil that was found in the early 1970s. This fossil was important because it was the most complete fossil found to that date of a very early human ancestor. In other words, this was a fossil of a being that was very far back in the human family tree, giving us a great deal more insight into the evolutionary process that led from tree-dwelling apes to human beings.
Before Lucy, the fossils of human ancestors that had been found were very fragmentary. Anthropologists generally only found parts of skulls and perhaps small fragments of other bones. By contrast, a relatively large portion of Lucy’s skeleton was found. The pieces found added up to about 40% of her entire skeleton. Because so much of her was found, anthropologists were able to determine a great deal about this very early (living roughly 3.2 million years ago) human ancestor. Lucy’s scientific importance, combined with the degree to which she caught the public’s attention and made people care more about the study of human evolution, makes her fossil an important find.
Lucy is A. afarensis. Skeleton was found eroding out of a hillside by Don Johanson in the Hadar region of Ethiopia. Remains were about 40% complete and was one of only three mostly complete remains (at the time) over 100,000 years old. The next year, 1975, Johanson found dozens of hominid bones at another Hadar location. This was about 13 individuals.
Lucy was still small brained but the bones indicated a form of bipedalism, a short slow stride. This gave the idea that bipedalism began prior to larger brain development. They were so primitive they may have spent as much time in trees as on the ground.
Now A ardi has been found that predates Lucy.