Fins as early legs

“Walking” fish may help scientists understand how ancient animals learned to move on land

By Stephen Ornes, 13:31 PM January 4, 2012





You may not be familiar with the word tetrapod, but you know one when you see it. All tetrapods are vertebrates — animals with backbones — and most move on land. They also have four limbs — or their ancestors did, as in the case of snakes and whales, for example. Reptiles, birds and amphibians all count as tetrapods, as do mammals. You’re a tetrapod.


By studying fossils, scientists know that tetrapods haven’t always roamed Earth. They evolved from animals called lobe-finned fishes, which a...

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