Where would we be without you

Everything we know about our earliest origins comes from a hundred or so fossils of a single organism: Pikaia. Pikaia is the oldest representative of the evolutionary lineage of vertebrates, that is fishes, amphibians, reptiles, mammals, and birds. Despite the importance we now attribute to it, Pikaia did not abound in the Burgess Shale biota – it was just one among many, clinging to life.