* * *Periodic biological fluctuation in an organism corresponding to and in response to periodic environmental change, such as day and night or high and low tide.The internal mechanism that maintains this rhythm even without the apparent environmental stimulus is a "biological clock." When the rhythm is interrupted, the clock's adjustment is delayed, accounting for such phenomena as jet lag when traveling across time zones. Rhythms may have 24-hour (circadian rhythm), monthly, or annual cycles. See also photoperiodism.
* * *periodic biological fluctuation in an organism that corresponds to, and is in response to, periodic environmental change. Examples of such change include cyclical variations in the relative position of the Earth to the Sun and to the Moon and in the immediate effects of such variations, e.g., day alternating with night, high tide alternating with low tide.Behaviour, Animal.The internal mechanism by which such a rhythmic phenomenon occurs and is maintained even in the absence of the apparent environmental stimulus is termed a biological clock. When an animal that functions according to such a clock is rapidly translocated to a geographic point where the environmental cycle is no longer synchronous with the animal's cycle, the clock continues for a time to function synchronously with the original environmental cycle. Humans similarly transported over great distances often experience fatigue and lowered efficiency for several days, a phenomenon known as “jet lag,” or jet syndrome (jet lag).A rhythm with a 24-hour cycle is called a circadian (circadian rhythm) (from Latin circa, “about”; di, “day”—i.e., “about a day”), solar day, diel, daily, diurnal, or nychthemeral rhythm. A lunar tidal rhythm—the regular ebb and flow of oceans (ocean) and very large inland bodies of water—subjects seashore plants and animals to a rhythmic change; typically two high and two low tides occur each day (about 24.8 hours). Many species of shorebirds exhibit this rhythm by seeking food only when beaches are exposed at low tide. Monthly rhythms, averaging approximately 29.5 days, are reflected in reproductive cycles of many marine plants and in those of many animals. Annual rhythms are reflected in the reproduction and growth of most terrestrial plants and animals in the temperate zones.
* * *
Look at other dictionaries:
biological rhythm — biologinis ritmas statusas T sritis Kūno kultūra ir sportas apibrėžtis Periodiškas organizmo biologinių vyksmų ir fiziologinių funkcijų intensyvumas, kuris priklauso nuo veiksnių, susijusių su metų laikais, nuo Žemės sukimosi apie savo ašį arba… … Sporto terminų žodynas
biological rhythm — biolog′ical rhythm′ n. phl biorhythm … From formal English to slang
biological rhythm — Physiol. biorhythm … Useful english dictionary
rhythm — rhythmless, adj. /ridh euhm/, n. 1. movement or procedure with uniform or patterned recurrence of a beat, accent, or the like. 2. Music. a. the pattern of regular or irregular pulses caused in music by the occurrence of strong and weak melodic… … Universalium
biological — biologically, adv. /buy euh loj i keuhl/, adj. 1. pertaining to biology. 2. of or pertaining to the products and operations of applied biology: a biological test. n. 3. Pharm. any substance, as a serum or vaccine, derived from animal products or… … Universalium
rhythm — noun ADJECTIVE ▪ fast, slow ▪ constant, good, perfect, regular, steady ▪ the steady rhythm of his heartbeat … Collocations dictionary
rhythm — noun Etymology: Middle French & Latin; Middle French rhythme, from Latin rhythmus, from Greek rhythmos, probably from rhein to flow more at stream Date: 1560 1. a. an ordered recurrent alternation of strong and weak elements in the flow of sound… … New Collegiate Dictionary
rhythm — 1. Measured time or motion; the regular alternation of two or more different or opposite states. 2. SYN: r. method. 3. Regular or irregular occurrence of an electrical event in the electrocardiogram or electroencephalogram. SEE ALSO: wave. 4.… … Medical dictionary
biological — adj. Biological is used with these nouns: ↑attack, ↑characteristic, ↑clock, ↑complexity, ↑diversity, ↑entity, ↑evolution, ↑father, ↑heritage, ↑laboratory, ↑make up, ↑ … Collocations dictionary
biological time — noun the time of various biological processes • Hypernyms: ↑time • Hyponyms: ↑circadian rhythm, ↑menopause, ↑climacteric, ↑change of life, ↑gestation, ↑gestation period, ↑ … Useful english dictionary