Activity Cycle

Activity Cycle


a term in biology denoting periodic variations in animal mobility and behavior in connection with alteration (seasonal, daily) of living conditions and oscillations of metabolic intensity which result from such oscillations. The activity cycle is one manifestation of biological rhythms, which are inherent in all organisms. The seasonal activity cycle, associated with variation in day length, temperature curve, humidity, food supply, and the like, determines the periodicity of reproduction, animal and bird migrations, food storing, and fat accumulation. Certain land mammals and nearly all cold-blooded animals go into hibernation during the cold months of the year. Daily activity cycles result from changes in temperature, illumination, and other factors; with these are associated daily migrations of animals (this is characteristic mainly of plankton, soil organisms, and a few others). On the basis of type of daily activity, animals can be classed as diurnal, nocturnal, crepuscular, and around the clock. Variations in the activity cycle are not uncommon; many animals lead a diurnal existence during winter and a nocturnal existence during summer.


Kalabukhov, N. I. “Sutochnyi tsikl aktivnosti zhivotnykh.” Uspekhi sovremennoi biologii, 1940, vol. 12, no. 1.
Biologicheskie chasy. Moscow, 1964. (Collection of articles translated from English.)


References in periodicals archive ?
From January to May of this year, three homeowners association were chosen as pilot areas to undergo Urban Container Gardening (UCG) activity cycle 1.
In one such study involving patients with metastatic colorectal cancer, circadian rhythm /rest activity cycle (more activity during the day, more rest at night) was associated with better quality of life and predicted survival.
This band should contain the 6 ka solar activity cycle mentioned in (Xapsos and Burke, 2009; Shopov et al.
The SCN is a small region inside the hypothalamus which regulates a 24hours rest and activity cycle and helps animals know when they should eat or rest.
The activity cycle for Surf Snowdonia's motor will oscillate between stasis and full power every minute during routine operation.
The 11-yr signal in the sunshine data is strongly suggestive of a relationship with the well-known 11-yr solar magnetic activity cycle (Gnevyshev 2007).
As component of the Community Empowerment Activity Cycle of Kalahi-CIDSS, the communities have to conceptualize an operation and maintenance plan which include putting up barangay ordinances or forming an association to maintain their own community projects.
In fact, we think it happens every 22 years as part of the Sun's major activity cycle, with the North and South Poles of the Sun's "bar magnet" swapping ends and the magnetic fields associated with them causing an increase in solar activity.
Based on these data, Wolfgang Gleissberg suggested in 1939 that there could be a roughly 100-year cycle superimposed on the 11-year activity cycle.
The frequency with which these phenomena occur varies in a somewhat irregular activity cycle of about 11 years, during which the global magnetic field of the Sun reverses.
In other words, if there is a total of four activities, the activity cycle will have four unit modules, such as "B" or "C" in Fig.
Experts say that a rise in solar activity is common right now because the Sun is in a phase of its 11-year activity cycle that is nearing the solar maximum, expected in 2013.