". . . We and many other animals sleep and wake in cycles that repeat every twenty-four hours. Some ocean protists, dinomastigotes, luminesce when dusk comes, ceasing two hours later. So hooked are they into the cosmic rhythm of Earth that even back in the laboratory, away from the sea, they know the sun has set. Many similar examples abound because living matter is not an island but part of the cosmic matter around it, dancing to the beat of the universe.
Life is a material phenomenon so finely tuned and nuanced to its cosmic domicile that the relatively minor shift of angle and temperature change as the tilted Earth moves in its course around the sun is enough to alter life’s mood, to bring on or silence the song of bird, bullfrog, cricket and circada. But the steady background beat of Earth turning and orbiting in its cosmic environment provides more than a metronome for daily and seasonal lives. Larger rhythms, more difficult to discern, can also be heard. . . "
from What is Life?