Fish fingers do the walking

It took another 100 million years before the descendants of fish took their first steps on land. These were the amphibians. But I suppose the fish can be excused. You can't develop legs overnight.

First came some fish which had evolved arm bones, exactly like yours and mine. But fish fingers didn't exist hundreds of millions of years ago, either in the frying pan or on a fish. Instead of fingers, they still had fins. Not much use for picking their noses, that's for sure. Then some other animal called Acanthostega, living in what is now Greenland, grew fingers from its hands instead of fins. Unlike your five digits (four fingers and a thumb), they had eight fingers on each limb. I wonder whether the decimal system that we use for counting (10 millimetres in a centimetre and so on) developed because on our two hands we have ten digits.

Maybe if these early amphibians had developed the ability to count it might have been based on sixteen rather than ten. It seems unlikely that these animals could have spent much, if any, time on land. The fossils show they still had gills like fish, so they must have continued to live in the water most of the time.

Eventually species evolved that had limbs strong enough to support their weight on land. The problem then was breathing. Fish breathe in water using gills. Humans breathe in air using lungs, like all other animals with backbones. Fossils don't show us how this evolution from gills to lungs took place. But it's obvious that it did happen.

He-ll lot back. b^fcacW)


These strange fish with limbs were able to spend more and more time out of water. Eventually some began to live in one of the newly growing forests that were beginning to clothe the land. The first

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