If jellyfish need sleep to keep their nerve nets intact, the need to sleep probably predates the evolution of brains, eyes, and even bodies that are the same on both left and right sides. In ...

One of the biggest mysteries of evolution is how species first developed complex vision. Jellyfish are helping scientists solve this puzzle, as the group has independently evolved eyes at least nine ...

LAWRENCE — Some jellyfish have simple eyes; some have complex ones. Other jellyfish have no eyes at all. Indeed, recent research has shown jellyfish eyes in different species have evolved separately ...

They don’t have a brain or spinal cord. They float around in a way that often appears aimless. Though jellyfish lack a central nervous system, these gelatinous creatures again show that they might ...

An artistic reconstruction of Auroralumina attenboroughii, based on a fossil dated to the Ediacaran Period and recently discovered in the U.K.'s Charnwood Forest. ((Dunn/Kenchington, et al., Nature ...