Something unique does seem to have taken place during this time when so many animal groups first appeared, but it's not an open-and-shut case.| Live Science
Crabby bodies are so evolutionarily favorable, they've evolved at least five different times. So why does this process, known as carcinization, keep happening?| Live Science
Scientists have discovered something strange happened to starfish over the course of their evolution, and they ended up as heads scampering around the seafloor.| Live Science