The clocks around & within us

Explore the history and discoveries in chronobiology. A panorama of nearly 2’000 images and videos illustrates circadian, lunar and seasonal rhythms in living organisms. The history of the field began in 1729 when a French astronomer discovered that the daily leaf movements of the mimosa plant persisted in the absence of external time cues. This was the first demonstration of the endogenous nature of circadian rhythms (“horloges vivantes”). Nearly three hundred years later the 2017 Nobel Prize for Physiology or Medicine was awarded for dissecting out how circadian “clock genes” tick.

We now know that biological clocks are ubiquitous in nature, their role is to make sure the right behaviour occurs at the right time, to provide temporal organisation for optimal function, whether it be finding food, meeting a mate, or avoiding predators. We can study rhythms in cyanobacteria, fruit flies, zebra fish, tidal crabs, migrating birds, hibernating hamsters, seasonal breeding sheep. The key synchroniser for these internal clocks is light and duration of daylength. In humans, the built environment and lifestyle may limit the necessary access to daylight. Body clocks are thus often out of sync with social schedules, leading to mood and sleep disorders, and long-term effects on health.

Rediscover the importance of light!