50 Years Of Science With Lucy, Our Famous Early Ancestor

On the anniversary of Lucy’s discovery, paleoanthropologists reflect on what she means to science, and what she taught us about ourselves.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

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• 1:20Speaker 03

  It's the 50th anniversary of the discovery of our very, very, very old ancestor, Lucy. And she doesn't look a day over 3.2 million years old.

• 1:31Speaker 04

  I certainly thought that she would be terribly important to the field of paleoanthropology. I had no idea that she would be the most famous skeleton found in the 20th century.

• 1:43Speaker 03

  It's Monday, November 25th, and you're listening to Science Friday.

• 1:49Speaker 03

  I'm Sci-Fry producer Rasha Ureidi. On November 24th, 1974, 50 years ago, a pair of paleoanthropologists made the discovery of a lifetime, a set of 47 bones hidden in the dusty, rocky hills of a fossil site in Hadar, Ethiopia. The skeleton belonged to a 3.2 million-year-old hominid nicknamed Lucy. She marked the very first specimen of Australopithecus afferensis, a species of early hominins that were very likely our own ancestors. Here's Sci-Fry's Kathleen Davis with more.

• 2:25Speaker 05

  Lucy might be the most famous fossil in the world, and she's transformed our understanding of human evolution. So today, we're looking back at 50 years of Lucy with the people who know her best. The paleo legend who discovered her, Dr. Don Johansson, founding director of the Institute of Human Origins at Arizona State University, and Dr. Zarai Alamsaged, paleoanthropologist at the University of Chicago. Welcome to Science Friday, and welcome back.

• 2:54Speaker 04

  Happy to be here. Wonderful. Thank you.

• 2:56Speaker 06

  Thanks for having us.

• 2:58Speaker 05

  So, Don, I want to start with you. Can you believe it's been 50 years? How are you feeling this week?

• 3:04Speaker 04

  Well, you know, I went back to Ethiopia a couple of times this year and saw Lucy after 50 years, and she didn't look a day older. But I look in the mirror in the morning when I shave, and I realize that 50 years is quite a long time. It is amazing to think about how quickly that time has gone and how well-known Lucy has become, and what an impact she's had, not only on the average person's thinking about human origins, but on the science itself.

• 3:35Speaker 05

  Take me back to that day where you discovered Lucy. What were you doing? How did you find her?

• 3:41Speaker 04

  Well, it was a Sunday morning, and my student, Tom Gray, and I were out recording the location of a discovery of a beautiful pig. We think pigs are beautiful, that's 3.2 million years. And on the way back to our Land Rover, it was getting, you know, well over 100 degrees, and we were thinking about going for a swim in the river and having some lunch. But I am always looking at the ground. So I happened to look over my right shoulder, and I spotted a little fragment of bone, just about two inches long, that had looked like a wrench with a little notch in it. And it's part of the forearm bone that allows us to flex and extend at the elbow.

• 4:25Speaker 04

  And it looked peculiar to me because I thought at first it was probably a baboon. It was so small. But as I bent down, picked it up and looked at it, I could see that it was not a baboon. It was not from an antelope or a gazelle. It was from a human ancestor. And as we kneeled down and looked closer at the ground, we saw bits of a skull, bits of a lower jaw, bits of ribs. And I realized that right there at my feet was a partial skeleton, which I knew was older than three million years. I didn't know who it was. But I had no idea that she would be the most famous skeleton found in the 20th century.

• 5:07Speaker 05

  So Zari, tell me, how did you meet Lucy and how did she inspire you?

• 5:12Speaker 06

  Well, when Lucy was discovered, I was a little kid. So I was not aware of her impact. It was not until I was assigned to work at the National Museum of Ethiopia, where Don and his colleagues had stored Lucy, that I start to spend time with Lucy and many other fossils that were discovered from across Ethiopia. So for me, the inspiration and the first contact with Lucy was actually hanging out with her physically on a daily basis.

• 5:44Speaker 05

  So growing up in Ethiopia, was Lucy like a local celebrity?

• 5:49Speaker 06

  In Ethiopia, growing up, she was not as popular as she is today. But clearly, you could find her name in textbooks and in lectures in some places. But if you go to Ethiopia today, you will see Lucy restaurant, Lucy cafe, Lucy, you name it, you know. So, yeah, she has now led to even the naming of the country's motto or logo, which is the land of origins, which I coined. And in order to do that, I obviously leaned on Lucy and many discoveries, including mine, the discovery of Salam, to show that Ethiopia is indeed one of the cradles of mankind, even though Africa broadly is a cradle of mankind.

• 6:32Speaker 04

  And Ethiopia is really one of the great centers of human origins research. But we also have to be reminded that she has her own Ethiopian name, which is Dikaneesh, which means that you are wonderful.

• 6:44Speaker 05

  Oh.

• 6:45Speaker 04

  But everybody seems to know her as Lucy, both here and in Ethiopia.

• 6:50Speaker 05

  I've got to get myself to a Lucy Cafe. That sounds wonderful.

• 6:53Speaker 06

  And the coffee is good because not only is the country the origin of Lucy, but it's also the origin of coffee. So

• 7:00Speaker 05

  Sure is.

• 7:01Speaker 06

  Lucy Cafe, you will have great coffee accompanied by Lucy.

• 7:05Speaker 05

  Wow, that's on my bucket list now. Let's talk a little bit about why Lucy was such an important discovery. Don, can you pick, let's say, two of the most profound things that we've learned from Lucy in the past 50 years?

• 7:20Speaker 04

  Well, I think one of the most profound things we learned was that she was a new species. She was a new kind of human ancestor. She was a Australopithecus, that tongue twister, but she was very different from all other species. And with that recognition came the realization that we had to look again at the geometry of the human family tree. Where did she sit on the human family tree? When she was found, the predominant view was that the common ancestor to our own genus Homo, we are Homo sapiens, and other kinds, other species of Australopithecus, was Australopithecus africanus in South Africa.

• 8:03Speaker 04

  Now she was placed at the pivotal place on the tree where she roughly around three million years ago gave rise to at least two, probably three different lineages. And one of those lineages ultimately led to us, Homo sapiens, through a very complicated pathway. But she became the last common ancestor for all those later humans.

• 8:29Speaker 05

  Mm hmm. Zari, what is on Lucy's highlight reel for you?

• 8:34Speaker 06

  Well, you know, what Lucy did was the discovery of the small brain in Lucy and also upright walking. It sealed the deal. That is, yes, upright walking came before small brain, and we did not need the large brain that we have today to become part of a member of the human lineage. I think that was the, one of the main contributions of Lucy.

• 9:00Speaker 05

  Don, have we learned everything that we can from Lucy in that time? I mean, has her time come and gone, or is there still more to learn?

• 9:10Speaker 04

  Well, you know, when we talk about Lucy, we really talk about her species, Australopithecus avarensis. I would say that there will always be something new. There was a recent wonderful article that Zarai participated in, where they began to reconstruct brain capacities in virtual space, which was not really possible before that. We know that now they were about 30% larger brains than the average for a chimpanzee. So there is something going on in terms of selection for larger brains. So I would say that as new techniques become available, we will find a lot more information. And as we look at her through a different theoretical telescope,

• 9:56Speaker 04

  we may change her place on the tree. I'm sure much more will be learned.

• 10:01Speaker 05

  Zarai, I want to ask you about this fossil that has been nicknamed Lucy's baby. Tell us about her and how did you find her?

• 10:09Speaker 06

  Yes, so I was working at a site called Tekeka, which is not far from Hadar where Lucy was found. And obviously, I expected to make discoveries, but I never would have thought of discovering such an amazingly complete skeleton. It is over 60% complete. It is a child that died at the age of two and a half, dated to 3.2 million years ago, which is 150,000 years older than Lucy. But what was important about the discovery is most of the bones that we find, including Lucy, come from adult individuals. And that is because the juvenile, the infants,

• 10:53Speaker 06

  their skeletons are fragile, so they disintegrate or get chewed by scavengers. So in many ways, when you work just on adults, the sample size you have is biased. Just think of someone from Mars coming to the planet Earth, and you would hide all the children, and they'll study only the grownups. And they will go report, they say, well, humans are this high, this tall, this big, but they're ignoring the children. So in many ways, what Salam or Lucy's child did is...

• 11:27Speaker 06

  Brought new information that completes the picture that has already been drawn by Don and his colleagues. So it's a unique and amazing addition to our knowledge of the Lucy species, but broadly speaking, early humans.

• 11:44Speaker 03

  After the break, what it means on a personal level to study our origins. Stick around.

• 11:55Speaker 01

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• 14:14Speaker 05

  Don, you have had quite the career, and that's putting it mildly. What has motivated you to spend so many years searching for our origins?

• 14:24Speaker 04

  Well, it really came from reading about human origins when I was a teenager. And the book that startled me was Man's Place in Nature, which stated that we in the African age shared a common ancestor, therefore, our oldest ancestor should be found in Africa. And I think that the title continues to be exceedingly important to me and relevant today, Man's Place in Nature. Because for a long time, people in anthropology have thought that culture makes us above the natural world. And I think that we are still part of the natural world. And I think every time we find one of these fossils, of course, it was a missing, so it was a missing link.

• 15:08Speaker 04

  But I think, more importantly, it's a link to the natural world in which we live. And I think everybody has this question sometime in their lives, usually when they're very young. Where did I come from? How did I get here? And we are fortunate on this planet as Homo sapiens to have the curiosity and the ability to go back and to actually find that evidence. And it deeply sets us in the framework of the natural world.

• 15:35Speaker 05

  In the grand scheme of evolution, is our species all that unique, in your opinion?

• 15:41Speaker 04

  Well, we are, we have a, a, a, a certain level of uniqueness, each species does. Uh, we are unique because we are a combination of both biological evolution, which is glacially very slow, genetic change is slow, but also cultural evolution. And, uh, we are a creature that is actually not because we wanted it, but we're in control of the future of the planet and we're not doing a very good job. Uh, so I think every species is unique, uh, and we have to recognize that and understand that we were, we are not the end point in evolutionary change. We were not destined to be.

• 16:22Speaker 04

  We're here because we have survived the whims and caprices of climate change, of challenges that we don't even know about. And we, we should, we should cherish that and, uh, really appreciate the fact that we're alive. Because a few genes different and you wouldn't be you, Zari would be Zari, I wouldn't be me. We have been given the gift of the universe.

• 16:48Speaker 05

  Zari, in studying human evolution, has it changed how you think about humanity?

• 16:55Speaker 06

  Oh yeah, definitely. Uh, it's a privilege to study human origins. Uh, you know, as Don says, uh, we are unique, yes, but the fish is unique also and the frog is, as is the antelope. So our uniqueness should not dictate that we feel detached from nature because we are integral part of nature. You know, I jokingly ask my students at the University of Chicago, are you more or less evolved than the fish? And all of them would answer, we are more evolved. Well, I will put you in the ocean and we will see who is more evolved. So unless we contextualize our understanding of being human.

• 17:34Speaker 06

  It is going to be difficult for us to interact, at least to continue interact with nature, as we destroy it in terms of global warming and climate change and acidification. As we destroy and kill any species, it's gonna come back and haunt us. And that's why, understanding our place in nature and really determining how we wanna interact with nature is going to determine our own survival or not. You know, the species that Lucy and Salam belong to, we call it primitive ancient species, but they managed to survive for close to a million years. Homo sapiens have been on the planet only for 200, 300,000 years ago, so we need to

• 18:19Speaker 06

  be a little humble and have respect for the past and ensure that we can actually have the future. So it's a combination of understanding the past and then so we can work on present and then try to forecast the future is what excites me and what inspires me to do what I do.

• 18:36Speaker 05

  How has Lucy's discovery changed the field of paleoanthropology in Ethiopia over the past 50 years?

• 18:43Speaker 04

  When I began in 1970, a long time ago, my first trip to Ethiopia, there were no Ethiopian scholars. There were only foreign scientists who came and did their research and left. And it's very, very gratifying that over the years, quite a number of Ethiopian-born scholars are now at the forefront of the research. And in addition to that, in the 1970s, there was really no place for us to work. There was a very old museum, but there was no place that was dedicated to storing and working on these fossils. Today, there's a major building that was constructed by the government of Ethiopia

• 19:28Speaker 04

  that invites scholars from all over the world to come and study those fossils in contemporary modern laboratories. And as Ariz said, it is now called Country of Origins, and our origins, in fact, of many origins. Lucy and these fossils have dramatically changed the worldview of Ethiopia.

• 19:52Speaker 06

  Well, you know, just yesterday at the University of Chicago, my PhD student graduated, he earned his PhD effectively working on the Lucy species. So basically, this would be Don's grandchild in some way. And if not for the inspiration that came from Lucy and many other discoveries, including mine, I don't think you would be interviewing me today. I don't think you would be interviewing Don today. So, yes, you can make many discoveries, and Lucy is not the only fossil. We have so many hundreds and thousands of fossils, both human and non-human. But you always need that iconic specimen that is going to capture imagination.

• 20:35Speaker 06

  So you can then think broadly and then ask the question, where do we come from? And in regards to what happens locally in Ethiopia, I think what Lucy did is inspired young people like myself to not only train themselves, but train others. Inspired the government to invest in paleoanthropology and build this lovely building for us to do research, but also inspire the public. So now, in grade four textbook, you will see my name on page five or six, where kids will say Ethiopian anthropologist, there are I who discovered Salam. So just this gestalt, everything put together, the Lucy impact is simply huge, and it never stops.

• 21:19Speaker 06

  Lucy continues to be the benchmark for any discovery. You cannot run away from Lucy.

• 21:24Speaker 05

  Well, what a wonderful place to end. I would like to thank you both so much for being here.

• 21:30Speaker 06

  Thank you for having us.

• 21:31Speaker 04

  Yeah, thank you so much.

• 21:33Speaker 05

  Dr. Don Johansson, founding director of the Institute of Human Origins at Arizona State University, and Dr. Zarai Alemsaged, paleoanthropologist at the University of Chicago.

• 21:48Speaker 03

  That's it for this week's show. Lots of people helped make it happen, including

• 21:51Flora Lichtman?

  Santiago Flores. Emma Gomez. Diana Plasker.

• 21:55Speaker 03

  Phyllis Samers. On our next episode, why it took more than seven weeks for Asheville to get potable water after Hurricane Helene, and using oyster shell reefs to counter sea level rise in Louisiana. Join us. I'm SciFrag producer, Rasha Uridy.