I know evolution is governed by chance and it is random but does it make sense to “ruin” sleep if there’s light? I mean normally, outside, you never have pure darkness, there are the moon and stars even at night. In certain zones of the Earth we also have long periods of no sunshine and long periods of only sunshine.
I don’t know if my question is clear enough but I hope so.
Bonus question: are animals subject to the same contribution of light or lack of it to the quality of sleep?
Yeah, sure! This happens to be my field of research.
So I was referring to this particular paper, which unfortunately (to my knowledge) didn’t get much follow-up.
Tangentially, there is much other evidence that circadian rhythms have evolved in part to deal with differences in microbial pathogens at the day vs. at night. However, whether it’s because the composition of bacteria in the atmosphere is different, or because animals are more likely to get themselves exposed to pathogens when they’re foraging, or a mix of both, is unclear. My favorite paper that demonstrates this effect is this one, where the circadian clock affects how strongly the immune system responds to bacteria in the lungs. I’ll also include the seminal paper here that first kickstarted the idea that immunology is fundamentally circadian, although frankly I didn’t like how the paper was written. It looked at how mice responded to Salmonella infection at the day vs. at night and found a difference in immune response that then led to a difference in how severe the infection got.
Plenty to read, thanks.
I see that first paper is for tropical environments, is this also found in other parts of the world?
To my knowledge, a similar study has never been repeated with other biomes. Which is a shame, since I can almost guarantee that a similar diel cycle exists in virtually every biome.