Listener supported, WNYC Studios.

It's the 50th anniversary of the discovery of our very, very, very old ancestor, Lucy.

And she doesn't look a day over 3.2 million years old.

I certainly thought that she would be terribly important to the field of paleo anthropology.

I had no idea that she would be the most famous skeleton found in the 20th century.

It's Monday, November 25th, and you're listening to Science Friday.

I'm SciFRI producer Rasha Iridi.

On November 24th, 1974, 50 years ago, a pair of paleoanthropologists made the discovery of a lifetime,

a set of 47 bones hidden in the dusty, rocky hills of a fossil site in Hadar, Ethiopia.

The skeleton belonged to a 3.2 million-year-old hominin nicknamed Lucy.

She marked the very first specimen of Australopithecus aferens, a species of early hominins that were very likely our own ancestors.

Here's Cyphrise Kathleen Davis with more.

Lucy might be the most famous fossil in the world, and she's transformed our understanding

of human evolution. So today, we're looking back at 50 years of Lucy with the people who know her best.

The paleo legend who discovered her, Dr. Don Johansson, founding director of the Institute of Human Origins at Arizona State University, and Dr. Zariya-Lemzeged paleo anthropologist at the University of Chicago.

Welcome to Science Friday and welcome back.

Happy to be here. Wonderful. Thank you. Thanks for having us. So, Don, I want to start with you.

Can you believe it's been 50 years? How are you feeling this week? Well, you know, I went back to

Ethiopia a couple of times this year and saw Lucy after 50 years, and she didn't

look a day older.

But I look in the mirror in the morning when I shave and I realize that 50 years is quite

a long time.

...