Donald Johanson

Evolution is a fact. It is the best explanation of what is known from observations. It's a theory as powerful as the theory of gravity.

When I realized, in 1978, that Lucy did represent a new species of human ancestor, and that I had an opportunity to name this new species, I realized this was a revolutionary step in understanding human origins.

Where we are going as a species is a big question. Human evolution certainly hasn't stopped. Every time individuals produce a new zygote, there's a reshuffling and recombination of genes. And we don't know where all of that is going to take us.

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.

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.