Victors of the Dry Land

시즌 1, 에피소드 7: The development of the backbone was a crucial advance in evolution. In this remarkable natural history documentary, David Attenborough explores how this evolutionary leap probably came from a most unlikely source, a little jelly-like creature called a sea squirt. He investigates when fish crawled from the water onto the land and became amphibians, plus the growth of reptiles and birds.