This is CBS Eye on the World.

Here's John Batchler.

It is a great joy to welcome the author, Thomas Halliday, a paleontologist and an evolutionary

biologist.

His new book, Other Lands, a journey through Earth's extinct worlds.

Thomas takes us backwards in time to what we know about the beginning of life as we understand

it is evolved over the 500 million plus years that we've watched multicellular life, congeal

and cooperate.

We begin, however, in something where homo sapiens is present, it's called the Pleistocene

and it's a matter of going to a place we know very well, which is Alaska.

But this is a time when the sea levels are much lower and there is a connection to Siberia

called Beringia.

Thomas, congratulations, you write beautifully.

And sometimes your metaphors are so convincing, I don't want to use the scientific name.

So what is the mammoth step and what was happening there 20,000 years ago?

Good evening, Thomas.

Good evening.

Yes, the mammoth step was during much of the place, the largest ecosystem on the planet.

It's a grassland which is managed by big herbivores, so mammoths as the name suggests, but also

things like woolly rhinos and muscoxins and bison and relatives of some of the creatures

that are still around today, like caribbean, so on.

And it's fetched from Western Europe all the way through what is now Russia across, as

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