Cambrian Explosion

For years, we knew very little about the microcosmos. Bacteria and protoctists abundant for over two thousand million years remain soft-bodied. The great discoveries of Cambrian fossils were taken to imply an explosion of life from virtually nowhere.

A tremendous burst of animal evolution springs form protoctists and animal biomineralization. Life rapidly radiates. All of today's animal phyla (great groups) originate in the Cambrian period. Magnificent fossils traces (burrows) record our own distinguished, flexible ancestors — the worms.