Scientist

One has to take initiative in life to achieve what he or she wants.

But what really excited me was the idea that humans had a tremendous pre-history that went back millions of years. I wanted to go to Africa to find some of these creatures.

I realized immediately that this was a terribly important discovery, but I didn't realize how important it would be until we had spent a lot of time in the laboratory studying it.

You don't just magically flip some evolutionary switch somewhere and transmute a quadruped into an upright-walking bipedal human.

When the first fossils began to be found in eastern Africa, in the late 1950s, I thought, what a wonderful marriage this was, biology and anthropology. I was around 16 years old when I made this particular choice of academic pursuit.

Lucy brought with her an image of our human ancestors that you don't get when you find a jaw or an arm bone or a leg bone. Here was 40 percent of a single skeleton.

All mammals undergo a certain degree of diversification. Darwin knew that. When he drew a family tree, it had many branches on it.

But it really wasn't until three to four years later, when we had an opportunity in the lab to make very detailed observations, and comparisons with other fossil discoveries, that we realized she was a new species of human ancestor.

If you were to go to the National Museum in Addis Ababa, you would walk into a huge room filled with literally tens of tons of fossils, and most of them would be elephants and rhinos and hippopotamus and monkeys and giraffes and antelopes and so on. Hominids are very rare in the landscape, and it's very rare to find them.

What's changed is we now have good anatomical, geological, archaeological evidence that Neanderthals are not our ancestors. When I wrote 'Lucy,' I considered Neanderthals ancestors of modern humans. We have gone back twice the age of Lucy, six million years. And we see that upright bipedal walking goes back that far in time.

I think that many of my ideas are correct, but I'll bet you, before my death other discoveries will be made that will prompt me to alter various ideas I have about human evolution.

Normally, we are happy to find a fragment of jaw, a few isolated teeth, a bit of an arm, a bit of a skull. But to find associated body parts is extremely rare.

What makes us human depends on what place on our evolutionary path we're talking about. If you go back six million years ago, what makes us human is that we were walking upright. That's all. If you go to 2.6 million years ago, it's the fact that we're designing and making stone tools.

Journalists often ask me when I go to the field, 'What do you expect to find?' And my answer always is, 'The unexpected,' because we're just looking at the tip of the iceberg; we've just scratched the surface.

Regardless of what we look like on the outside, genetically, on the inside, everyone is an African.

I was being groomed as an undergraduate to specialize in Midwestern prehistory, but going back to my teenage days, my interest has always been in our early human ancestors. I wanted to work in Africa.

Scientists are very afraid of being proven wrong.

As an undergraduate, I had an opportunity to go on a number of archeological digs. So I had experience excavating, digging up remains of ancient Indian villages in the Midwest and in the Southwest.

One has to devote oneself to a particular pursuit. To be successful at anything, you have to make a total commitment to it.

And what I wanted to do was, I wanted to explore problems and areas where we didn't have answers. In fact, where we didn't even know the right questions to ask.