The Sea-Change: The Worldwide Hunt for the Ancestors of Animals

The Sea-Change: The Worldwide Hunt for the Ancestors of Animals is about one of the most absorbing puzzles in the whole of science: how the earliest animals lived, and what they looked like.These questions have haunted biology for two centuries because the facts seem to challenge its central dogma, the theory of evolution by natural selection.One of the main objections to Darwin's theory of evolution was that the earliest fossils are already large and complex animals, with no sign of the simpler predecessors that the theory requires.They were the trilobites, marine arthropods about the size of a hand that crawled on the seabed half a billion years ago.Darwin was well aware of this flaw. He admitted its force, and postulated, without evidence, that before trilobites evolved the seas must have swarmed with life.We now know that he was right, and that the oldest fossils appeared 50 million years previously.Indeed, modern molecular biology concludes that animals first evolved at least 700