Life on alien planets probably wouldn't experience day and night – here's how that may change evolution 

 Organisms on Earth living deep underground or at the bottom of the sea may give us an idea what alien life without a circadian rhythm could be like. 

https://cdn.mos.cms.futurecdn.net/S4Z8qe2GutMbLkNuZAhWXe.jpg

https://www.space.com/life-alien-planets-wouldnt-experience-day-and-night-evolution