Science / Why biological clocks do not have exactly 24 hours
Almost every living creature is equipped with a biological clock - a tool that makes it easier for it to survive on a planet that completes a rotation every 24 hours. But the clocks of most creatures are not exactly synchronized with the Earth: those of animals range from 23 to 26 hours, plants have cycles ranging from 22 to 28 hours, while the human clock stretches to just over 24 hours. Research by Dr. Hiroaki Daido of Osaka Prefectural University in Japan, recently published in the journal "Physical Review Letters" may explain the roots of this diversity.
Deido suspected that the reason for the lack of synchronization with the Earth lies in ecology: just as certain species minimize competition with other species - by different preferences in types of food and habitats - so will they prefer different hours of activity. He created a computer model of a group of biological species, each of which has a clock of a different length, and found that when he lengthened or shortened the hours of light and heat relative to those of the natural day, all the species that rigidly adhered to 24 hours became extinct. This probably happened because they had to negotiate the biological "rush hour", which other species avoided.
One result, at least, suggests that this may not be just a theory. Biologists from the Claude Bernard University in Lyon, France, reported last year that three species of wasps that laid eggs inside fruit fly larvae divided the day between them in exactly the way that Dido's model predicts. One species preferred to lay eggs in the morning, two in the afternoon and the third in the afternoon. Their watches were set to different lengths - 22.5, 21.5 and 24.5 hours.
By adopting a "shift schedule", each wasp species could go about its business in peace. Therefore, a "tailor-made" schedule can increase efficiency and productivity more than blind obedience to the ticking of the clock. Mention this to your boss the next time you're late for work.
