Abstract:
Due to Earth’s rotation about its own axis, environmental variables such as light, temperature
and humidity undergo daily cycling. It is widely believed that such daily cycling in
environmental variables has driven the evolution of biological time-keeping systems that help
time various behavioral and physiological activities of organisms at appropriate times of the day.
In order to be, of functional value, such daily timing systems or circadian clocks (Latin: circa,
‘about’, and dies, ‘day’) facilitate the establishment of stable and reproducible phaserelationships
(ψent) with environmental cycles/zeitgeber.
