Despite their differences, vertebrates, worms and insects are all believed to be descended from a common ancestor - a worm-like organism, named Urbilateria, which lived some 600 million years ago. Urbilateria displayed bilateral symmetry - its body was symmetrical along its longitudinal axis - and this body plan was inherited by the diverse array of organisms descended from it. But, according to new research, just published in the journal Cell, it wasn't just bilateral symmetry that Urbilateria's descendants inherited: at the earliest stages of their evolution, vertebrates - including humans - may have inherited the organization of their nervous systems from Urbilateria as well.