Henry Gee

Well, it is, Tristan.

I mean, here we are actually together simultaneously, both at once and at the same time.

Who'd have thought it?

Two of them left.

Bluebell and Poppet.

And they're still squawking and laying eggs.

Yes, today we're going to explode the Cambrian, and it's always been a big mystery.

If you cast your mind back to the Victorian times, to the days of Darwin and pioneering geologists like Hutton and Lyell, who got an idea of which rock came before what, but of course they had no idea how long, the lengths of time that these rocks had taken to sediment.

And the lowest rocks in the sequence with fossils in was called the Silurian.

I mean, it's all since been divided up into flats with a kind of retail outlet underneath.

Now it's called the Cambrian.

But before the Cambrian, there was nothing.

After the beginning of the Cambrian, there were lots of fossils, clams, lots of trilobites, which are these animals that look a bit like woodlice or pillbugs.

full of feelers and antennae and legs and eyes and armour and lots of other animals like that.

So people wondered, how is it that at the beginning of this period there's lots of life, lots and lots, but immediately before, absolutely nothing?

And Darwin was worried about this.

He wrote in The Origin of Species that this particular gap was the chief difficulty of his theory of evolution.

That's right.

It was the first time we actually saw animals big enough to see with the naked eye with hard parts.

Right.