时间生物学 英文.doc

ChronobiologyFrom Wikipedia, the free encyclopediaJump to: navigation, search Overview of human "circadian biological clock" with some physiological parameters.TimeMajor ConceptsPast ♦ Present ♦ FutureEternityArguments for eternityBroad StudiesChronologyHistory(Paleontology)FuturologyPhilosophyPresentism ♦ Eternalism,FatalismPhilosophy of Space and TimeReligionCreationEnd TimesDay of JudgementImmortalityAfterlife ♦ ReincarnationKalachakraTime measurement and StandardsMetric Time ♦ Hexadecimal timeRelatedSpacetime,Motion ♦ SpaceEvent ♦ ContinuumTime Travel ♦ (Grandfather Paradox)· v· t· eChronobiology is a field of biology that examines periodic (cyclic) phenomena in living organisms and 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 within biological rhythms mechanics.[1] Other aspects include development, reproduction, ecology and evolution.Contents [hide] · 1 Description· 2 History· 3 Recent developments· 4 Other fields· 5 See also· 6 References· 7 Further reading· 8 External articles[edit] DescriptionThe variations of the timing and duration of biological activity in living organisms 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 most important 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 can further be broken down into routine cycles during the 24-hour day:[2]· 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: white-tailed deer, some bats)Many other important cycles are also studied, including:· Infradian rhythms, which are cycles longer than a day, such as the annual migration or reproduction cycles found in certain 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.· Tidal rhythms, commonly observed in marine life, which follow the roughly 12-hour transition from high to low tide and back.· Gene oscillations – some genes are expressed more during certain hours of the day than during other hours.Within each cycle, the time period during which the process is more active is called the acrophase.[3] 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. How high (or low) the process gets is measured by the amplitude.[edit] HistoryA circadian cycle was first observed in the 18th century in the movement of plant leaves by the French scientist Jean-Jacques d'Ortous de Mairan (for a description of circadian rhythms in plants by de Mairan, Linnaeus, and Darwin see this page). In 1751 Swedish botanist and naturalist Carolus Linnaeus (Carl von Linné) designed a floral clock using certain species of flowering plants. By arranging the selected species in a circular pattern, he designed a clock that indicated the time of day by the flowers that were open at each given hour. For example, among members of the daisy family, he used the hawk's beard plant which opened its flowers at 6:30 am and the hawkbit which did not open its flowers until 7 am.The 1960 symposium at Cold Spring Harbor Laboratory laid the groundwork for the field of chronobiology.[4]It was also in 1960 that Patricia DeCoursey invented the phase response curve, one of the major tools used in the field since.Franz Halberg of the University of Minnesota, who coined the word circadian, is widely considered the "father of American chronobiology." However, it was Colin Pi。