This is scientific American 60 second science. I'm Christopher in Tagayata.

Charles Darwin is most famously the author of The Origin of Species, but the last book he ever wrote gets far less attention today. It's called

the formation of vegetable mold through the action of worms. And earthworms were a passion.

He wrote about their habits, their soil-tilling abilities. He even kept

pots of worm-filled soil in his study. But his fascination was met with

ridicule by some. There's a famous cartoon where you you know, child starving as an old man is in the middle and he

evolves from monkeys because of his evolutionary theories and the monkeys evolved from earthworms.

Olaf Schmidt is a soil ecologist at University College Dublin

and not among those who would criticize Darwin for his interests.

I love earthworms.

Yeah, earthworms are brilliant. They are our friends, they're really important.

One particularly interesting group of worms, he says, are the so-called anisec worms, the deep soil dwellers.

And they live all their life in a single vertical channel in the soil.

And at night, the surface...

Looking for food, manure, straw, stuff like that.

And they pull it into their channels.

They're big boys, which makes them especially vulnerable to the plow.

You know, they're so big, so they're chopped, they are exposed to birds and so, and also their channels are destroyed.

Schmidt and his colleague Maria Bryonis analyzed the relationship between

Tilling and the health of a dozen species of earthworms.

They looked at 65 years worth of farm field

studies spanning the globe and they found that in heavily plowed fields half the

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