- published: 11 Sep 2015
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A circadian rhythm is any biological process which displays an endogenous, entrainable oscillation of about 24 hours. These rhythms are driven by (or composed of) 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.
The earliest known account of a circadian process dates from the 4th century BC, when Androsthenes, a ship captain serving under Alexander the Great, described diurnal leaf movements of the tamarind tree.
The first recorded observation of an endogenous circadian oscillation was by the French scientist Jean-Jacques d'Ortous de Mairan in 1729. He noted that 24-hour patterns in the movement of the leaves of the plant Mimosa pudica continued even when the plants were kept in constant darkness, in the first experiment to attempt to distinguish an endogenous clock from responses to daily stimuli.
[Incomprehensible]
Pretty fingers on the phone
Non violent grace, this religion
No one wants to be alone
Reclaim the rust that northern birds take
It like a song that in their feet
[Incomprehensible] on the radio
Take a little time on Cherokees tree
Chaos and precision with a smile
Sipping summer in the shade
Thoughts for the plane with brown eyes waiting
Guitar, careless whirlwind, belief gets made
Carrying on so far under the cross
Manifestos to keep us sane
The time is so weary of conflict
Silent answers, silent name
I can't stand anymore decisions