Who Is Lucy? A New Discovery About Your Distant Ancestor Says A Lot About Humankind

You have a distant ancestor that you might not have heard of. But don't expect to find too much family resemblance. You and she two have some things in common, but walking upright and eating vegetables might be a few of the most remarkable. In fact, she's not even technically a modern human.

I'm talking of course about Lucy. She's one of the best examples of the hominin species Australopithecus afarensis that has been found by researchers. She lived in Ethiopia about 3.2 million years ago but is making headlines today. So, who exactly is Lucy and why does she matter?

This week she made the papers because a study published in Nature magazine on Monday suggested that she may have died due to a fall from a tree. That would contradict 40-plus years of hypotheses. She has a broken arm and broken shoulders, according to a CT scan that was performed while she was on loan to the United States in 2007 and 2008. The researchers say that could have only happened from a fall of more than 40 feet. Other scientists, though, contend that the breaks come from the fossilization process. Scientists will surely argue about this for some time to come.

You might be not have been born when she was first discovered (neither was I), but Lucy's discovery was a really big deal in 1974. Named after "Lucy in the Sky with Diamonds" by the Beatles because it was playing on repeat when she was discovered, her body shed a lot of light on our evolution as a species. American paleontologist Donald Johanson was working in Ethiopia when he came across an elbow bone and kept uncovering. Little did he know that 40 percent of Lucy's skeleton was there.

But it became clear very soon just how big of a deal it was. Johanson explained exactly how important she truly was to TIME in 2009:

She showed us conclusively that upright walking and bipedalism preceded all of the other changes we'd normally consider being human, such as tool-making. She gave us a glimpse of what older ancestors would look like. Lucy is really at a nice point on the family tree: she sits at this pivotal point between things that are more ancient and things that are more modern.

Walking upright was a big deal. But what about falling from trees? Is this a significant part of our evolution? John Kappelman, an anthropologist at the University of Texas and the lead author of the study, thinks it does. He argued that if she fell from a tree, that she then spent a significant period of her time above the ground too. Living partly in trees is its own theory called "arborealism." Kappelman suggested that Lucy could prove it. He told USA Today:

By understanding her death is how she came alive to me. Lucy was no longer simply a box of bones but in death became a real individual: a small, broken body lying helpless at the bottom of a tree.

Her species' evolution towards humans may have even contributed to her death, the Nature study argues. Adaptations to walk better could have made Lucy and her kind less nimble in trees, making her time spent there less safe and ultimately contributing to her death.

Johanson, though, is not convinced. "Elephant bones and hippo ribs appear to have the same kind of breakage," Dr. Johanson told The New York Times. "It's unlikely they fell out of a tree." Lucy's death like many other aspects of her life — and what exact traits she shares with you or me — will likely remain a mystery for some time to come.