Lost the beat

Mice suffer from a decrease in biological fitness if their internal clock is mixed up. Mice with deviant internal rhythms due to a genetic mutation have fewer offspring and shorter life spans than normal conspecifics whose rhythms follow the 24-hr cycle of a day more accurately. This discovery was made by a team of scientists led by researchers from the Max Planck Institute for Ornithology and Princeton University. Internal clocks that generate daily rhythms in living beings are among the most important achievements on earth. They are essential for coordinating processes of life with the environment. The study on mice shows that a deviation of internal rhythms from the 24-hr rotation of the earth has a direct influence on biological fitness. Almost all living things possess internal clocks that govern periods of sleep and waking, and ensure that these processes are in synchrony with night and day.