life cycle


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life cycle

the series of changes occurring in an animal or plant between one development stage and the identical stage in the next generation

Life cycle

The consecutive, interlinked stages of a product or structure and its fixtures, beginning with raw materials acquisition and manufacture and continuing with its fabrication, manufacture, construction, and use, and concluding with any of a variety of recovery, recycling, or waste management options.

life cycle

see LIFE COURSE.

Life Cycle

 

or cycle of development, the group of developmental phases through which an organism passes in attaining maturity and becoming capable of giving rise to the next generation (thus completing the life cycle).

The length of a life cycle is determined by the number of generations that develop during the course of a year or the number of years required to complete the cycle; it also depends on the length of the period of dormancy or diapause. In animals one may distinguish a simple life cycle, in which there is direct development of individuals, and a complex life cycle, with metamorphosis or alternation of generations. In development with metamorphosis the life cycle can be observed in the development of a single individual. For example, in the swine tapeworm, ovum → oncosphere → cysticercus → adult tapeworm; in the cockchafer, ovum → larva → pupa →imago.

In development with alternation of generations or of the modes of reproduction the life cycle can be observed in two or more individuals belonging to different generations, until the initial form reappears. For example, in the Scyphozoa, ovum → planula → scyphistoma → ephyra → medusa; in the liver fluke, ovum → miracidium → rediae → cercaria → adolescaria → adult worms; in aphids, ovum → stem-mother → migrants sexupara → bisexual insects. Thus, the unit in studying the life cycle may be either the individual ontogeny or a series of alternating ontogenies. In higher plants one may distinguish annual, biennial, and perennial life cycles. The alternation of the gametophye and sporophyte generations is characteristic of the life cycles of many lower plants and ferns. In parasitic fungi the life cycle is similar in its complexity to the cycles of certain parasitic worms. In rust molds the life cycle is complex; there are forms that yield aeciospores, urediospores, and teleutospores, as well as a basidial stage. In the protozoans the most complex life cycles are found in the Sporozoa (for example, in Gregarinida and Haemosporidia).

M. S. GILIAROV

life cycle

[′līf ‚sī·kəl]
(biology)
The functional and morphological stages through which an organism passes between two successive primary stages.

life cycle

lierne ribs
That period of time over which a building or piece of equipment can be reasonably expected to carry out its intended function.
References in periodicals archive ?
Merely understanding the importance of life cycle systems management is not sufficient, so let's first be clear on what exactly the term means.
Shortly thereafter, the Deputy Under Secretary of Defense for Logistics and Materiel Readiness (L&MR) issued a March 10, 2007, policy memo entitled "Life Cycle Sustainment Outcome Metrics" providing detailed guidance to the logistics and sustainment community, including a series of 14 life cycle sustainment enablers to assist program managers, life cycle logisticians, and systems engineers in meeting the new KPP and KSA requirements.
Everyone can state the problem of data life cycle management.
Furthermore, among species at latitudes above 50[degrees]N--those of Winnipeg, Manitoba; Brussels, Belgium; and Kiev, Russia--Root and her colleagues found that spring life cycle milestones moved forward an average of 5.
The facilities director can use the building-by-building, life cycle planning results to back up the data shown in the renewal curve.
Rather, it focuses on selected logistics processes that impact operation and support costs which are estimated to comprise above 75 percent of a weapon system life cycle cost (LCC) if the weapon system is purchased off-the-shelf.
Life cycle thinking, from a design and purchasing standpoint, holds the promise of decreasing environmental risks and costs.
It introduces the historiography and the relevant theoretical perspectives ('Durkheim and beyond'); discusses the working of the law on suicide; develops the key organizing context of the life cycle in Victorian towns, which is the overarching theme around which most of Bailey's questions are pivoted; sets the local context for the study by presenting the urban ecology of Hull; charts the changing incidence of suicide statistically, with appropriate caveats; and moves on to the main body of the evidence, discussing the incidence and context of suicide at four life-cycle stages (and thereby breathing new life into discussions of living standards from a completely novel angle).
Victor Guyan, a partner with Andersen, said Reliance used a technology known as "claim components," which improved the consistency of the professionals' performance, freed more time for them to do the impact-related parts of their jobs, provided needed information on outcomes at certain points in a claim's life cycle and fostered better working relationships with employees.
The product life cycle represents a core element of marketing theory and has done for four decades.
The son or daughter's transition to work and adult life can be analyzed as a non-normative family stressor co-occurring with stressors associated with normative aspects of the family life cycle.
The product life cycle consists of an initial period of emergence or introduction followed by stages of accelerating growth, maturity, and decline.