Twenty Years Ago Today: Australopithecus Afarensis

Your great-great grandmother would like a drink, please Three and a bit million years ago today, life was good for our ancestors in East Africa. The climate was warm, but did not spoil the fruit hanging from the branch. The rains came in their season and made the land lush and green. And while there might have been some pesky beasts with big teeth and better eyes than our forebears, there were plenty of trees to climb. In fact, it's altogether possible that they spent very little time outside the trees, given how well suited their arms were for climbing.

Life was so easy that the men and women of what would one day become Ethiopia evolved very little over the course of a million years. And why would they? There was nothing to really trouble their lives, which meant no major evolutionary pressure to force any change. Doubtless some small alterations were made in their bodies and minds, but nothing that made any significant physical difference.

So for thousands of years, they lived in a kind of paradise, though of course there were still accidents. One of them drowned in a river. Whether it was just a foolish swim beyond his depth or a terrible storm that burst the banks and swept him away to his death, we'll never know. All we can say is that fragments of his skeleton were found in the late twentieth century, smashed beyond recognition - but still susceptible to patient, careful reconstruction.

His skull was in over 200 pieces, but once it had been pieced back together, paleontologists realised that this man was a relative of a woman whose skeleton had been found in 1974, who had been dubbed 'Lucy' by her finders and 'Dinknesh' - 'Wondrous One' - by Ethiopians. And yet they were separated in time by 200,000 years, with 10,000 generations lying between them. Those who nicknamed him 'son of Lucy' were just a teensy bit inaccurate; he was her great-great-great-grandfather to the power of lots.

And so, twenty years ago today, a paper was published in the scientific journal Nature which described the finding of Lucy's ancestor. The paper argued that with this piece of evidence, they could now link this with Lucy and a few other specimens ranging in age between 3.9 and 2.9 million years ago, and say that they were a single species - Australopithecus Afarensis, named for the Afar region in which their remains were first found.

The cause of their extinction is not fully known, but climate change and competition from other species like Homo Erectus are possibilities. Their simple, easy world disappeared along with them, and what was left became just that little bit busier and more demanding. A process which eventually leads to us. Where it leads after that is another question entirely...