Circannual rhythms anticipate the Earth’s annual periodicity

Helm, B. and Lincoln, G. A. (2017) Circannual rhythms anticipate the Earth’s annual periodicity. In: Kumar, V. (ed.) Biological Timekeeping: Clocks, Rhythms and Behaviour. Springer India, pp. 545-569. ISBN 9788132236863 (doi:10.1007/978-81-322-3688-7_26)

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Life on Earth has evolved in a periodic world, which in most environments cycles predictably between conditions that are favourable or unfavourable for an organism. Organisms use favourable seasons to reproduce and grow, and withdraw during unfavourable seasons. To deal with the predictable changes in their environments, all taxonomic groups have evolved genetically programmed timing mechanisms. These govern seasonal cycles in physiology and behaviour that optimise survival and reproductive success, and have been formally described as circannual rhythms. Experimentally, under conditions of constant day length and temperature, circannual rhythms of many species continue to be expressed, even throughout the life cycle, illustrating the fundamental endogenous control. Under natural conditions, they are usually entrained by seasonal time cues, notably photoperiod, to synchronise the biology to environmental periodicity. Here we review long-term timekeeping strategies from classical vertebrate models to invertebrate and unicell life histories. These circannual rhythms enable organisms to anticipate Earth’s periodicity.

Item Type:Book Sections
Glasgow Author(s) Enlighten ID:Helm, Dr Barbara
Authors: Helm, B., and Lincoln, G. A.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Publisher:Springer India

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