| 释义 |
life cycle
life cyclen.1. The course of developmental changes through which an organism passes from its inception through the stage at which it reproduces.2. A progression through a series of differing stages of development: the life cycle of a star.3. The span of a product's existence from its initial development through the period of marketing and active use to eventual obsolescence.life cycle n (Biology) the series of changes occurring in an animal or plant between one development stage and the identical stage in the next generation life′ cy`cle
n. 1. the sequence of developmental changes undergone by an organism from one primary form, as a gamete, to the recurrence of the same form in the next generation. 2. a series of stages, as childhood and middle age, that characterize the course of existence of an individual, group, or culture. [1870–75] life cycle The series of changes in the growth and development of an organism from its beginning as an independent life form to its mature state in which offspring are produced. In simple organisms, such as bacteria, the life cycle begins when an organism is produced by fission and ends when that organism in turn divides into two new ones. In more complex organisms, the life cycle starts with the fusion of reproductive cells and ends when that organism produces its own reproductive cells, which then may go on to reproduce.life cycleThe total phases through which an item passes from the time it is initially developed until the time it is either consumed in use or disposed of as being excess to all known materiel requirements.life cycleThe sequence of events between the start of one generation and the start of the next.Thesaurus| Noun | 1. |  life cycle - a series of stages through which an organism passes between recurrences of a primary stageorganic phenomenon - (biology) a natural phenomenon involving living plants and animals | | 2. | life cycle - the course of developmental changes in an organism from fertilized zygote to maturity when another zygote can be producedgrowing, growth, ontogenesis, ontogeny, maturation, development - (biology) the process of an individual organism growing organically; a purely biological unfolding of events involved in an organism changing gradually from a simple to a more complex level; "he proposed an indicator of osseous development in children" |
Translationsciclo di vitaciclo vitalelife cycle
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 cycleThe 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.life cycle
life cy·clethe entire life history of a living organism.life cyclen.1. The course of developmental changes through which an organism passes from its inception through the stage at which it reproduces.2. A progression through a series of differing stages of development: the life cycle of a star.3. The span of a product's existence from its initial development through the period of marketing and active use to eventual obsolescence.life cycle the serial progression of stages through which an organism passes from FERTILIZATION to the stage producing the GAMETES. In higher animals and plants the life cycle lasts from fertilization until the resulting individual itself produces gametes, but in many organisms there are asexual stages. see ALTERNATION OF GENERATIONS.life cycle
Life cycleThe lifetime of a product or business, from its creation to its demise or transformation.Industry Life CycleThe period of time from the introduction of an industry to its decline and stagnation. Different analyses posit different stages of an industry life cycle (usually four to five), but all emphasize that an industry has a beginning, with technological innovation; a period of rapid growth; maturity and consolidation; and finally decline and possibly death. For example, in the video cassette recording (VCR) industry, the mid-1970s were a period of decentralized technological innovation, with VHS and Betamax formats vying for dominance. Later, video cassettes very quickly became a common household item. In the maturity phase, different companies selling VCRs attempted to corner a greater market share for their own (identical) versions of the product. Finally, the industry declined and was eventually supplanted by DVD players. An industry life cycle can be prolonged by several factors, including opening new markets to the product, finding new uses for the same product, or even attaining government subsidies. The concept of an industry life cycles applies most readily to the sale of goods and it is difficult to gauge how it works in a service economy.life cycle - the stage people have reached in their life, from single at home through young parents to solitary retired. See SOCIOECONOMIC GROUP, BUYER BEHAVIOUR.
- see PRODUCT LIFE CYCLE.
life cycleThe various phases of a project—predevelopment, development, leasing, operating, and rehabilitation. life cycle
Related to life cycle: Product life cycle, Life cycle assessment, Project life cycleWords related to life cyclenoun a series of stages through which an organism passes between recurrences of a primary stageRelated Wordsnoun the course of developmental changes in an organism from fertilized zygote to maturity when another zygote can be producedRelated Words- growing
- growth
- ontogenesis
- ontogeny
- maturation
- development
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