Henry Gee

Now, before then, there was almost no oxygen.

Now, this caused a revolution in the biosphere, and that precipitated the evolution of what we call the eukaryotic cell.

That is the kind of cell from which you and I are made up of, as opposed to bacteria.

Now, bacteria had got together to create that.

And then...

nothing much seemed to happen for a billion years.

It's what geologists who don't get up in the morning for anything less than apocalyptic disaster call the boring billion.

But things were going on in the background.

Now, um,

Most eukaryotes that live today are single-celled.

Amoebas, paramecia, flagellates, dinoflagellates that cause these blooms, many horrible diseases, malaria, they're single-celled.

But there were signs of multicellular eukaryotes.

About 1.8 billion years ago, seaweeds.

About a billion years ago, there were early seaweeds, early fungi, but nothing animal-like until the breakup of a huge supercontinent.

Now, we know about the supercontinent of Pangaea, and I remember we chatted about that.

Well, there is a supercontinent cycle where the Earth breathes on a period of about 500 million years.

So the continents tend to glom together into a big supercontinent, and then they break up, and then they glom together again.

And a friend of mine, a geologist called Ted Neal, has written about this in a book called Supercontinent.

And I owe it to him to tell everybody that it's not about the importance of pelvic floor exercises.

It's about the supercontinent cycle.