For the first time, researchers have identified sleep patterns in the brains of tiny zebrafish—and they look remarkably similar to the brain activity in sleeping humans
Replying to @NatGeo
That wake and sleep mirrors the Earth's daily light and dark cycle seems to be anecdotal evidence that life originated on #Earth and that, as such, life is essentially part of the Earth. Which implies that cellular life will not be found anywhere else in the #universe.
There are creatures on Earth that have evolved never seeing the light of day/rarely having to. Moles, cave-dwellers and deep-sea creatures jump to mind. Even if life is reliant on solar-cycles, we've already discovered hundreds of other planets with similar conditions to Earth.
There are also several ideas as to how life originated, but even one of those implies very low/no light: Hydro-thermal Vents. With the extensive distribution of CHON in the universe, and the universe's vastness, assuming that life only originates here seems incredibly arrogant.