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The Neurobiology Of Circadian Rhythms, Patricia J. Sollars, Gary E. Pickard

School of Veterinary and Biomedical Sciences: Faculty Publications

Daily rhythms in nature, such as the opening and closing of flowers or our patterns of sleep and wakefulness and their association with the perpetual alteration of night and day, were recognized in antiquity although their origins were not questioned until the eighteenth century. The French Astronomer Jean-Jacques d’Ortous de Mairan conducted an investigation into whether the leaves of the Mimosa plant opened in response to light.¹ While de Mairan’s experiments were the first to question the origin of such daily rhythms, Augustin Pyramus de Candolle is credited with the first suggestion that they arose through an internal timekeeping …