[eutropia]

TFA also acknowledges this:

  > There could well be many other functions that have since joined in with the sleep cycle (such as memory consolidation), but the authors hypothesize that mitochondrial function is the process that underlies all of them. If you need oxygen, then you need sleep!

[hearsathought]

> If you need oxygen, then you need sleep!

Do plants sleep? Don't some insects, like flies, live without any sleep?

[burkaman]

Insects do sleep, the paper we're discussing is a study of flies.

[jhrmnn]

I think it should have been “If you need oxygen and have a CNS, then you need sleep.” Other tissues can take oxidative break during wakefulness, but since CNS is _generating_ wakefulness, if it takes a break, by construction there is sleep.

[mock-possum]

Plants breathe out oxygen, like we breathe out the other one.

[cubefox]

No, plants don't sleep, and neither do fungi or single celled organisms. Sleep seems to be a property specifically of animals.