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It has been argued that for plants that display foliar nyctinasty, it is a crucial mechanism for survival; however, most plants do not exhibit any nyctinastic movements. [1] Nyctinasty is found in a range of plant species and across xeric , mesic , and aquatic environments, suggesting that this singular behavior may serve a variety of ...
Examples include circannual or annual cycles that govern migration or reproduction cycles in many plants and animals, or the human menstrual cycle. Ultradian rhythms , which are cycles shorter than 24 hours, such as the 90-minute REM cycle , the 4-hour nasal cycle , or the 3-hour cycle of growth hormone production.
Overview, including some physiological parameters, of the human circadian rhythm ("biological clock").. Chronobiology is a field of biology that examines timing processes, including periodic (cyclic) phenomena in living organisms, such as their adaptation to solar- and lunar-related rhythms. [1]
A zeitgeber (/ ˈ (t) s aɪ t ɡ eɪ b ər, ˈ z aɪ t-/ (T)SYTE-gay-bər, ZYTE-, German: [ˈtsaɪtˌɡeːbɐ]) is any external or environmental cue that entrains or synchronizes an organism's biological rhythms, usually naturally occurring and serving to entrain to the Earth's 24-hour light/dark and 12-month cycles.
Bacterial circadian rhythms, like other circadian rhythms, are endogenous "biological clocks" that have the following three characteristics: (a) in constant conditions (i.e. constant temperature and either constant light {LL} or constant darkness {DD}) they oscillate with a period that is close to, but not exactly, 24 hours in duration, (b) this "free-running" rhythm is temperature compensated ...
Post-translational feedback loops (PTFLs) involved in clock gene regulation have also been uncovered, often working in tandem with the TTFL model. In both mammals and plants, post-translational modifications such as phosphorylation and acetylation regulate the abundance and/or activity of clock genes and proteins.
The latter occurs not only in plants but also in animals when the carbon and energy from plants is passed through a food chain. The fixation or reduction of carbon dioxide is a process in which carbon dioxide combines with a five-carbon sugar , ribulose 1,5-bisphosphate , to yield two molecules of a three-carbon compound, glycerate 3-phosphate ...
These anticipatory food mechanisms point to an interconnectedness of peripheral oscillators such as the liver and gut microbiota. It has been shown that animals and humans that experience “shift work” outside of their normal fasting/feeding cycles demonstrate disruption in feeding cycles as noted by alterations of circadian genes. [ 15 ]