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Why We Sleep: A Hypothesis for an Ultimate Evolutionary Origin for Sleep (2020)

• mytailorisrich 2y ago
  > Circadian rhythms are ubiquitous across nature as nearly every organism studied, including bacteria, algae, fungi, plants and animals, all exhibit physiological cycles that are near to 24 hours in length, even when uncoupled from the daily light/dark cycle This seems to somewhat invalidate the hypothesis that sleep is an adaptation to survival in alternating niches: day at night. At face value for a non-expert it's also very clear why a bacterium should need to behave differently during the day/night cycle. Perhaps this was originally the case when life originally started on Earth and it is somehow so fundamentally "baked in" and required for cells to function that it cannot be evolved "out"? As also per: > The day/night problem therefore created a powerful, pervasive and inescapable selection pressure. Adaptation to these two niches must therefore lie deep within our DNA, as in fact, we find a circadian clock functioning in all cells of all organisms.