Chronobiology
Description
From the Wikipedia:
"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] These cycles are known as biological rhythms. Chronobiology comes from the ancient Greek χρόνος (chrónos, meaning "time"), and biology, which pertains to the study, or science, of life. The related terms chronomics and chronome have been used in some cases to describe either the molecular mechanisms involved in chronobiological phenomena or the more quantitative aspects of chronobiology, particularly where comparison of cycles between organisms is required.
Chronobiological studies include but are not limited to comparative anatomy, physiology, genetics, molecular biology and behavior of organisms related to their biological rhythms.[1] Other aspects include epigenetics, development, reproduction, ecology and evolution."
(https://en.wikipedia.org/wiki/Chronobiology)
Typology
From the Wikipedia:
"Chronobiology studies variations of the timing and duration of biological activity in living organisms which occur for many essential biological processes.
These occur
(a) in animals (eating, sleeping, mating, hibernating, migration, cellular regeneration, etc.),
(b) in plants (leaf movements, photosynthetic reactions, etc.), and in microbial organisms such as fungi and protozoa.
They have even been found in bacteria, especially among the cyanobacteria (aka blue-green algae, see bacterial circadian rhythms). The best studied rhythm in chronobiology is the circadian rhythm, a roughly 24-hour cycle shown by physiological processes in all these organisms. The term circadian comes from the Latin circa, meaning "around" and dies, "day", meaning "approximately a day." It is regulated by circadian clocks.
The circadian rhythm regulates behaviour including timing of the activity phase. Depending on their innate active phase, organisms can be classified into one of three categories:
- Diurnal, which describes organisms active during daytime
- Nocturnal, which describes organisms active in the night
- Crepuscular, which describes animals primarily active during the dawn and dusk hours (ex: domestic cats,white-tailed deer, some bats)
While circadian rhythms are generated by endogenous processes, they can be regulated by both endogenous and exogenous signals. Other biological cycles may be regulated by exogenous signals.
Many other important cycles are also studied, including:
- Infradian rhythms, which are cycles longer than a day. 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.[citation needed]
- Tidal rhythms, commonly observed in marine life, which follow the roughly 12.4-hour transition from high to low tide and back.
- Lunar rhythms, which follow the lunar month (29.5 days). They are relevant e.g. for marine life, as the level of the tides is modulated across the lunar cycle.
Within each cycle, the time period during which the process is more active is called the acrophase.[4] When the process is less active, the cycle is in its bathyphase or trough phase. The particular moment of highest activity is the peak or maximum; the lowest point is the nadir."