This is Scientific Americans 60 Second Science.

I'm Steve Mursky.

Got a minute?

Forty years ago yesterday, November 24th, 1974,

paleoanthropologist Donald Johanson found in Ethiopia what's arguably

the most famous and important fossil of a human ancestor, Lucy.

Last month at the Science Writers 2014 meeting in Columbus, Ohio,

Johanson talked about the moment he laid eyes on Lucy.

On that eventful day in 1974, I was out with a graduate student, Tom Gray,

and we were walking back to our Land Rover

to go back to camp to enjoy a swim in the river with the crocodiles and enjoy a nice little lunch.

And I am always looking at the ground.

I find more quarters by parking meters than anybody I know I think.

And you know how it is you find what you're looking for, right?

Because a year before the discovery, a geologist had left his footprints four to five feet away from the

scullotone because he was looking for rocks. I was looking for bones and I found a

little piece of elbow that little hinge that allows us to flex and extend our arm.

And I knew from my studies of osteology, of comparative anatomy and so on that this had to be from a human ancestor and as I looked up the slope I saw other

fragments who roting out and we recovered over a two- long excavation operation roughly not counting hand

and foot bones 40% of a skeleton and this was important because first of all

broke the three million year time barrier.

All the fossils older than 3 million years at that point in the history of paleoanthropology

...