User:Gorton k/sandbox
From Wikipedia, the free encyclopedia
"Circadian" redirects here. For the album by the rock band 5th Projekt, see Circadian (album).
For the 2005 film, see Circadian Rhythm (film).
A circadian rhythm is a biological processes which displays an endogenous, entrainable oscillation of about 24 hours. These rhythms are driven by (or composed of) circadian oscillators, and rhythms have been widely observed in plants, animals, fungi and cyanobacteria. The term circadian comes from the Latin circa, meaning "around" (or "approximately"), and diem or dies, meaning "day". The formal study of biological temporal rhythms, such as daily, tidal, weekly, seasonal, and annual rhythms, is called chronobiology. Although circadian rhythms are endogenous ("built-in", self-sustained), they are adjusted (entrained) to the local environment by external cues called zeitgebers, commonly the most important of which is daylight.