Brilliantly summarised!
I know light plays a crucial role in regulating the clockwork. However, the other day I was curious about knowing if unicellular organisms has any homolog of sleep? I landed on this article which talked by circadian rhythm in cyanobacteria. There they talk about metabolism affecting the clockwork. And here we talk about clockwork affecting metabolism. Now I know that perhaps in many animals the clockwork regulation has been centralized. That is to say that apart from different in nocturnal and diurnal species the clockwork is regulated majorly by light input. But I am just curious to know of the clockwork also takes feedback from metabolism itself? How does food we eat affect the clockwork, if at all? Does the microbiome matter too then? Like what if we were locked in dark for weeks, will the clockwork still function and be set by our eating habits?