Abstract:
Questions regarding certain behavioural programmes happen to be very intriguing. How do
animals know when to sleep and when to forage? How do plants know when to change the
orientation of their leaves towards the Sun? How do humans know the seasonal ups and
downs of crop? How do flowers open and close their petals at specific times of the day?
Mysteries of such nature had been floating around until when attempts were first made to
study the basis for such rhythmic activity in organisms. Early philosophers asked if such
rhythmic behaviours are just passive responses to cycling environmental variables as a
consequence of the Earth’s rotation, if they were endogenously generated and if they were
innate.
