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THE LUCY MAN

Prometheus Books

Chapter One

As the young scientist walked through the Ethiopian desert, he carefully watched where he put his feet so he would not step on something other than the sand and the stones. He was hot and tired with the noontime sun bearing down on him, and he was about ready to stop looking and return to camp. "Just one more gully to explore," he thought as he pushed himself to continue.

In that gully, the young scientist found what he had spent years dreaming of—a fossilized arm bone of a long-extinct hominin. Hominins are our ancestors, near-human animals who walked upright on two feet. It was November 1974 and discovering this arm bone marked the beginning of Dr. Donald C. Johanson's distinguished career as a paleoanthropologist, a scientist who studies human origins and evolution.

After finding the arm bone, Don looked around expectantly for more bone pieces. He began to wonder if the leg bone, and the pieces of a pelvis, jaw, and skull he was collecting could belong to one individual. If so, who was this creature? Whoever this used to be, Don realized that finding so many pieces of one hominin skeleton was a major discovery. Up until that time, no fossil skeleton of a human ancestor had ever been found.

Don called to one of his colleagues to come see what he had discovered. His colleague Tom Gray rushed over to share Don's excitement. Both were hot, sweaty, and dirty, but they hugged each other and jumped up and down in jubilation.

Everyone back at camp was equally excited and spent the evening celebrating by listening to a tape of the Beatles that included the song "Lucy in the Sky with Diamonds." After observing that the bones were in proportion to one another and that there were no duplicates, Don determined that all the bones did indeed belong to one individual. By the small size of the bones and teeth and the shape of the pelvis (hip bones), he knew that it was female. The next morning, the fossil from the desert originally designated A.L. 288-1 had a name—Lucy.

WHY LUCY IS SPECIAL

What is it about one set of bones that makes it more important than another? Lucy's bones have been examined, measured, scanned, and studied by a variety of scientists for many years now. Her skeleton is special because it is so complete that it tells scientists a great deal about her as our ancestor. Lucy was different from any hominin discovered before her and therefore represented a new species. Her bones have been dated at 3.2 million years old (by potassium-argon analysis, described in chapter 4), which made her the oldest and best preserved skeleton of an upright-walking human ancestor ever found until the 1990s.

Lucy was a small creature who was about three and a half feet tall. From her wisdom teeth—the larger teeth in the back of the jaw that only erupt in mature hominins—Don knew she was fully grown when she died. Her bones were in remarkably good condition; they had not been chewed on by a predator, such as a hyena. Don is not sure how Lucy died. There is one small puncture wound in one of her pelvic bones. She may have been walking along the edge of an ancient lake or stream, getting a drink of water, or collecting turtle or crocodile eggs to eat when she was suddenly attacked by a crocodile and drawn into the water. Lucy's body settled into the mud, preventing a scavenger from pulling it apart and scattering her bones. Gradually the minerals in the water turned her bones into stones. Being buried in the mud helped to fossilize her skeleton for it to come to Don's attention millions of years later.

Since he discovered Lucy, Don and other scientists have found other fossils of her species. In fact, in Ethiopia near where Lucy was found, Don and his team uncovered an entire group of individuals of all ages and sizes, adults and children, males and females, that they fondly called the "First Family." A scientist on Don's team found two fossil hominin teeth at the bottom of a hillside. Leg bones were seen higher up the hill. Because they were two right legs, Don realized that more than one individual was waiting to be uncovered. Site 333, as the hillside was called, revealed over two hundred fossil pieces representing thirteen individuals. These hominins were all lying close together, and there was no evidence of damage by hyenas. Don thinks this group died together in a catastrophe like a flash flood.

We now know certain things about Lucy's species. Males were much bigger than females; walking upright on two feet began well before brain size grew much bigger than that of apes; and stone tool use came even later than that. We also know that even though they were not yet human because of their small brain size, Lucy and her kind were the beginning of the social group we identify as the human family.

It took many years for scientists to clean, sort, and describe all the bones they found. But, like Lucy, the First Family members were on the way to being human because they walked upright on two feet. Paleoanthropologists have decided that walking upright is the first marker for becoming human. Early hominins may not have looked like us, but they are considered our ancestors because the changes of human evolution were beginning to take place.

Lucy defined both Don's past and his future at the same time. She represented his ancient human ancestor and the foundation for the development of his career. Don admits that his professional life has been a combination of luck and risk. He was lucky to glimpse Lucy when he was in the right place at precisely the right time. Any earlier than that exact moment, and she may still have been buried in the dirt; any later, and the torrential seasonal rains of Ethiopia might have washed her away. Don thinks he was also lucky that Lucy was given a name and not just a number. Most fossils are only numbered or identified according to where they were found. Having a cute woman's name bestowed a personality upon the fossil with which regular people could identify as a long-lost relative.

Don has no doubt that taking risks is an important part of being human. He took a huge risk traveling to Ethiopia as a young scientist with a brand-new doctoral degree. But he believed in his own intelligence and he trusted his ability. Africa was already known as the place where humanity originated. That led him to look in the right place for hominin fossils. Later, he took an even bigger risk in declaring that Lucy was a new species and in naming her species Australopithecus afarensis (pronounced aw-stray-lo-PITH-a-kus af-a-REN-sis). This new species changed the structure of the human family tree. Many scientists resisted the change at first. If Don had been wrong about this new species, he would have lost the respect of his colleagues. But again, he believed he was right and after finding more of Lucy's species as confirmation, Don's addition to our family tree is now generally accepted in the science world today.

Let's see how discovering Lucy changed Don's life and how our lives have been changed because of what we now know about human evolution, thanks to both Lucy and Don.

(Continues...)

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Excerpted from THE LUCY MAN by C.A.P. Saucier Copyright © 2011 by C. A. P. Saucier. Excerpted by permission of Prometheus Books. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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