This is CBS I In The World. I'm John Batsy with Thomas Halliday, paleontologist, and

writing wonderfully of other lands, his new book, A Journey Through Earth's Extinct Worlds.

We now go to a part of the success of Agrarian Life, the root system. But did I know to pay

attention to it until Thomas's book? No. We go to the Devonian 470 million years ago, and it's called

the Michael Reisel. What is that Thomas? Well, Michael Reisel is composed of two parts. Michael refers

to fungus and the writer refers to roots. And it's essentially a way in which fungi and plants

interact with one another to extract the maximum benefit, really, from the soil around them,

and really, this collaboration is crucial to the move of life on to land. I mean, we tend to think,

what we think about life appearing on land, that there's some sort of holiday pioneer that suddenly

emerges out of the sea and wanders up on its fins. But really, that's not how life works. Life

thrives in collaboration and the movement of communities rather than individuals. And

in the middle of the Caledonides Mountains in the Devonian, it's one of these places where we find

evidence of these tight interactions between fungi plants and animals that really characterize the

early move on to land. Without the assistance of fungi plants would not have been able to develop

roots and to exploit the mineral resources of the rocks around them. And the plants themselves

being able to extract energy from light, that's really handy for the fungus as well. So you get

this collaboration, but you also get parasitism. We have evidence from Riny of a fungi that are

invading individual plant cells, which are then trying to isolate those cells by hardening the

surface or expanding them. And we get really a very detailed and intimate look into the way

that organisms have interacted on land for the last 400 million years. The atmosphere was oxygen

poured to that contribute to the success of these roots and funguses working together.

It's well oxygen is not really something that plants need to be in the atmosphere. Oxygen is

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