Hello, my name's David Rundsenman and this is past, present, future, the History of Ideas podcast.

Today we are doing really big picture history. It's a conversation about the story of the species.

I'm talking to the paleontologist and science writer Henry G about the rise and fall of homo sapiens.

When did we as a species reach our peak and when did the rot set in?

I'm aware this conversation is a little bit different from our usual conversations on

PPF, but I also hope that it is really interesting.

There are lots of interesting and surprising things coming up, including the fact that the peak probably happened far longer ago than you might expect.

And also, I'm afraid that we are a lot further along the road to ruin than you might hope.

So, Henry, we're having a conversation very broadly about the rise and fall of homo sapiens. And one of the questions is how to frame that story, when did the rise end,

when did the fall begin? And you're going to give us an answer as to when the

fall began that might surprise people. But in order to get there, we need to talk about the rise.

And I'm sure I'm not alone in being quite hazy about the pre-homomopians part of the human story.

So if we could start at the beginning, when and how did the

human story begin, the genus Homo, how far back do we have to go? And what are we talking about

when we are talking about the very first humans? The beginnings of the genus Homo are shrouded in mystery, but it's about two and a half million years ago, around about.

You couldn't exactly say it was two and a half million years ago last Tuesday.

About that time, there was a pronounced change in the climate.

The world got very much cooler than in the tropics much drier.

And appearing from a mass of upright chimpanzees, more or less, which were our immediate

ancestors, were creatures that were much more dedicated to living life on the ground.

They had longer legs, shorter arms.

They were obligately walking on two legs.

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