A publication of the Archaeological Institute of America
Donald C. Johanson reflects on the legacy of our most famous early ancestor.
November 30 marks the 30th anniversary of the discovery of "Lucy," a 3.2-million-year-old female of the species Australopithecus afarensis at Hadar, Ethiopia. At the time she was found, Lucy was our oldest-known human ancestor by more than a million years. ARCHAEOLOGY. Johanson of the Institute of Human Origins at Arizona State, to chat about the find and what has happened since in the field of paleoanthropology.
Tell us about the day Lucy came to light.
I joined the International Afar Research Expedition in 1972, and it was two years later that I discovered Lucy. I was 31 years old then, had just finished my Ph.D., and was absolutely bullheaded about finding something. One day, as we were returning to camp, I happened to glance over my shoulder and eyed a gray piece of bone on the ground. I turned to one of my graduate students and said, "That's a hominid." Then looking up a slope I saw other portions and knew I had found parts of a very ancient skeleton. I have to admit that I was overwhelmed, gratified, and excited to have made the find.
Since Lucy's discovery, several other important specimens have come to light that have pushed the human family tree back another 1.2 million years. Why is Lucy still so important?
When you read about a new find from Africa, Lucy is nearly always used as a benchmark. Often a new find is characterized as "older than," "younger than," or "even more primitive than" Lucy. She remains the oldest most-complete skeleton thus far known. With well-preserved upper and lower limbs, a nearly complete lower jaw, fragments of ribs and backbone, and, very importantly, a pelvis, she offers us extraordinary insight into hominid locomotion, body size, and proportions not obtainable from isolated finds.
Where do you see the field going in the next few years?
We are beginning to look for discoveries that will shed some light on the beginnings of the lineage of Homo, which ultimately gave rise to us, Homo sapiens. There is widespread controversy about the number of species of early Homo, their adaptations, diets, geological age, migrations, geographic range, and so on, but it is becoming clear that the roots of our lineage stretch back to some time between 2.5 and 3 million years ago.
Why does early Homo generate so much controversy?
In part this is because the early evidence, from about 2.5 million years ago, is very fragmentary and not firmly dated. Second, even though stone tools and associated butchered bone are known from 2.6 million years ago, that does not necessarily mean that they were made by Homo. There is almost an implicit opinion in paleoanthropology that only Homo made stone tools.
What is the earliest evidence for Homo?
In 1994 at Hadar we discovered an upper jaw, with a nearly complete set of teeth. This specimen, dated to 2.33 million years ago, can be definitely assigned to Homo, although we cannot currently delegate it to a specific species. But most important, numerous stone tools were found in the same stratum from which the jaw came, so it is highly likely that the tools were made by this Homo. During excavations we found several flakes that fit back together onto the core from which they were struck, meaning that some early hominid 2.33 million years ago actually sat on that very spot and fashioned a tool--remarkable, truly remarkable!
How are paleoanthropologists incorporating genetic technology into their research?
Some of the highest levels of genetic variation are in African populations, indicating that they became Homo sapiens first and then migrated out of Africa. There are also certain telltale genes that are uniquely African in many of the world's populations, which add further credence to an African origin for all humankind. Excavations at several sites around Africa, especially in the south, where some have suggested the first Homo sapiens arose, may uncover early skeletal material from which we may be able to extract DNA and draw connections between these early humans and specific modern populations.
Why the name Lucy?
Technically, she is known as AL-288. But surely such a noble little fossil lady deserved a name. Shortly after her discovery, the Afar team was sitting around one evening in camp listening to the Beatles and someone said, "Why don't we call her Lucy? You know, after 'Lucy in the Sky with Diamonds'?" So she became Lucy.