A circadian rhythm ( /sɜrˈkeɪdiən/) is any biological process that displays an endogenous, entrainable oscillation of about 24 hours. These rhythms are driven by a circadian clock, 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.
Read more about Circadian Rhythm: History, Criteria, Origin, Importance in Animals, In Plants, Biological Clock in Mammals, Light and The Biological Clock, Enforced Longer Cycles, Human Health
Famous quotes containing the word rhythm:
“There is a rhythm to the ending of a marriage just like the rhythm of a courtship—only backward. You try to start again but get into blaming over and over. Finally you are both worn out, exhausted, hopeless. Then lawyers are called in to pick clean the corpses. The death has occurred much earlier.”
—Erica Jong (b. 1942)