variation

var·i·a·tion

V0028900 (vâr′ē-ā′shən, văr′-)n.1. a. The act, fact, or process of varying.b. The extent or degree to which something varies: a variation of ten pounds in weight.2. Something different from another of the same type: told a variation of an old joke. See Synonyms at difference.3. Magnetic declination.4. Biology The existence within a species or other group of organisms of differences in form, function, or behavior, especially when hereditary.5. Mathematics A function that relates the values of one variable to those of other variables.6. Music a. A form that is an altered version of a given theme, diverging from it by melodic ornamentation and by changes in harmony, rhythm, or key.b. One of a series of forms based on a single theme.7. A solo dance, especially one forming part of a larger work.

var′i·a′tion·al adj.

variation

(ˌvɛərɪˈeɪʃən) n1. the act, process, condition, or result of changing or varying; diversity2. an instance of varying or the amount, rate, or degree of such change3. something that differs from a standard or convention4. (Music, other) music a. a repetition of a musical theme in which the rhythm, harmony, or melody is altered or embellishedb. (as modifier): variation form. 5. (Biology) biology a. a marked deviation from the typical form or functionb. a characteristic or an organism showing this deviation6. (Astronomy) astronomy any change in or deviation from the mean motion or orbit of a planet, satellite, etc, esp a perturbation of the moon7. (Navigation) another word for magnetic declination8. (Ballet) ballet a solo dance9. (Linguistics) linguistics any form of morphophonemic change, such as one involved in inflection, conjugation, or vowel mutation ˌvariˈational adj ˌvariˈationally adv

var•i•a•tion

(ˌvɛər iˈeɪ ʃən)

n. 1. the act or process of varying: prices subject to variation. 2. an instance of this: a variation in quality. 3. amount of change: a temperature variation of 20°. 4. a different form of something. 5. the transformation of a musical theme with changes or elaborations in harmony, rhythm, and melody. 6. a solo dance, esp. one forming a section of a pas de deux. 7. any deviation from the mean orbit of a heavenly body. 8. the angle between the geographic and the magnetic meridian at a given point. 9. a deviation in character from others of the same species. [1350–1400; Middle English < Anglo-French < Latin variātiō=variāre to vary + -tiō -tion] var`i•a′tion•al, adj.

variation

The angular difference between true and magnetic north. See also deviation.

variation

A solo dance, especially a solo section of a pas de deux.

Thesaurus

Noun	1.	variation - an instance of change; the rate or magnitude of changefluctuationalteration, change, modification - an event that occurs when something passes from one state or phase to another; "the change was intended to increase sales"; "this storm is certainly a change for the worse"; "the neighborhood had undergone few modifications since his last visit years ago"vicissitude - a variation in circumstances or fortune at different times in your life or in the development of something; "the project was subject to the usual vicissitudes of exploratory research"allomerism - (chemistry) variability in chemical composition without variation in crystalline formdeviation, difference, divergence, departure - a variation that deviates from the standard or norm; "the deviation from the mean"permutation, substitution, switch, transposition, replacement - an event in which one thing is substituted for another; "the replacement of lost blood by a transfusion of donor blood"business cycle, trade cycle - recurring fluctuations in economic activity consisting of recession and recovery and growth and declinedaily variation - fluctuations that occur between one day and the nextdiurnal variation - fluctuations that occur during each daytide - something that may increase or decrease (like the tides of the sea); "a rising tide of popular interest"
	2.	variation - an activity that varies from a norm or standard; "any variation in his routine was immediately reported"varianceactivity - any specific behavior; "they avoided all recreational activity"
	3.	variation - a repetition of a musical theme in which it is modified or embellishedmelodic theme, musical theme, theme, idea - (music) melodic subject of a musical composition; "the theme is announced in the first measures"; "the accompanist picked up the idea and elaborated it"inversion - (counterpoint) a variation of a melody or part in which ascending intervals are replaced by descending intervals and vice versapartita - one of the variations contained in a partita
	4.	variation - something a little different from others of the same type; "an experimental version of the night fighter"; "a variant of the same word"; "an emery wheel is the modern variation of a grindstone"; "the boy is a younger edition of his father"version, edition, varianttype - a subdivision of a particular kind of thing; "what type of sculpture do you prefer?"
	5.	variation - an artifact that deviates from a norm or standard; "he patented a variation on the sandal"mongrel, bastard - derogatory term for a variation that is not genuine; something irregular or inferior or of dubious origin; "the architecture was a kind of bastard suggesting Gothic but not true Gothic"thing - an artifact; "how does this thing work?"
	6.	variation - the angle (at a particular location) between magnetic north and true northmagnetic declination, magnetic variationangle - the space between two lines or planes that intersect; the inclination of one line to another; measured in degrees or radians
	7.	variation - the process of varying or being variedphysical process, process - a sustained phenomenon or one marked by gradual changes through a series of states; "events now in process"; "the process of calcification begins later for boys than for girls"covariation - (statistics) correlated variation
	8.	variation - (astronomy) any perturbation of the mean motion or orbit of a planet or satellite (especially a perturbation of the earth's moon)astronomy, uranology - the branch of physics that studies celestial bodies and the universe as a wholeperturbation - (physics) a secondary influence on a system that causes it to deviate slightlylibration - (astronomy) a real or apparent slow oscillation of a moon or satellite; "the libration of the moon"
	9.	variation - (biology) an organism that has characteristics resulting from chromosomal alterationmutant, mutation, sportorganism, being - a living thing that has (or can develop) the ability to act or function independentlybiological science, biology - the science that studies living organismsfreak, lusus naturae, monstrosity, monster - a person or animal that is markedly unusual or deformed
	10.	variation - (ballet) a solo dance or dance figurepas seuldancing, terpsichore, dance, saltation - taking a series of rhythmical steps (and movements) in time to musicballet, concert dance - a theatrical representation of a story that is performed to music by trained dancers
	11.	variation - the act of changing or altering something slightly but noticeably from the norm or standard; "who is responsible for these variations in taxation?"change - the action of changing something; "the change of government had no impact on the economy"; "his change on abortion cost him the election"

variation

noun1. alternative, variety, modification, departure, innovation, variant This delicious variation on an omelette is easy to prepare.2. variety, change, deviation, difference, diversity, diversion, novelty, alteration, discrepancy, diversification, departure from the norm, break in routine Every day without variation my grandfather ate a plate of ham.
variety uniformity, tedium, monotony, dullness, sameness3. (often plural) difference, contrast, distinction, discrepancy, disparity, dissimilarity, dissimilitude local variations in price and availability

variation

noun1. The condition or fact of varying:difference, variance.2. The process or result of making or becoming different:alteration, change, modification, mutation, permutation.3. One that is slightly different from others of the same kind or designation:variant, variety, version.

Translations

变化变奏变奏曲

vary

(ˈveəri) verb to make, be or become different. These apples vary in size from small to medium.变化ˈvariable adjective1. that may be varied. The machine works at a variable speed.可变的2. (of eg winds, weather etc) liable or likely to change. British weather is very variable.易变的 noun something that varies, eg in quantity, value, effect etc. Have you taken all the variables into account in your calculations?变化ˈvariably adverb可变地ˌvariaˈbility – plural variaˈbilities – noun 可变性，易变性，变异性 ˌvariˈation noun1. the extent to which a thing changes. In the desert there are great variations in temperature.变化2. one of a series of musical elaborations made on a basic theme or melody. Brahms' variations on Haydn's `St Anthony's Chorale'. 变奏（曲） ˈvaried adjectiveHe has had a very varied career.各种各样的

variation

variation,

in music, a compositional device in which certain features of a musical unit, e.g., phase, are altered while others are retained in a subsequent statement of the unit. Modifications include melodic, harmonic, and rhythmic. Variation is fundamental in Western music, serving to identify the unique features of a composition by partitioning those features. Gregorian chant exhibits much melodic variation, and all music from the Middle Ages through the 20th cent. employs the technique in some form. Specifically the term refers to a musical form, also called "theme and variations," in which the varied item is an entire brief movement. The form originated in baroque dance suites, in which all movements have the same theme, and was popular during the 18th and 19th cent. Bach's Goldberg Variations and Beethoven's Diabelli Variations are famous examples of the genre.

variation,

in biology: see DarwinismDarwinism,
concept of evolution developed in the mid-19th cent. by Charles Robert Darwin. Darwin's meticulously documented observations led him to question the then current belief in special creation of each species.
..... Click the link for more information. .

variation

The periodic inequality in the Moon's motion that results from the combined gravitational attraction of the Earth and Sun. Its period is half the synodic month, i.e. 14.77 days, and the maximum longitude displacement is 39′29″.9. See also annual equation; evection; parallactic inequality; secular acceleration.

variation

Repetition of a theme with embellishments in rhythm, details, and materials while keeping the essential characteristics of the original. See also: Theme

Variation

(biology), the diversity of characters in individuals and groups of individuals of any degree of kinship. Variation is characteristic of all living organisms; hence, there are no individuals in nature that are identical in all characters. The term “variation” is also used to designate the ability of living organisms to respond to environmental influences with morphophysio-logical changes and to characterize the transformation of the forms of living organisms in the process of their evolution.

Variation may be classified according to the causes, nature, and character of the variability and also according to the purposes and methods of research. The following types of variation are distinguished: genetic variation (genotypic) and nongenetic variation (paratypic), individual and group variation, discontinuous (discrete) and continuous variation, qualitative and quantitative variation, independent variation of various characters and correlative variation, directed (determined, according to C. Darwin) and undirected (undetermined, according to C. Darwin) variation, and adaptive and nonadaptive variation. The most significant types of variation for solving the general problems of biology, and especially of evolution, are genetic and nongenetic variation on the one hand and individual and group variation on the other. All types of variation may be found under genetic and nongenetic variation and group and individual variation.

Genetic variation arises as a result of various types of mutations and their combinations in subsequent interbreeding. In every group of individuals existing over a sufficiently long period of time (sequences of generations) various mutations arise spontaneously and undirected, which subsequently combine, more or less randomly, with characters already present in the genetic pool. Variation resulting from the appearance of mutations is called variation through mutation while that conditioned by subsequent recombination of genes as a result of interbreeding is called variation through recombination.

The multiplicity of individual differences is based on genetic variation, including (1) distinct qualitative differences that are not connected to one another by transitional forms, as well as purely quantitative differences that form continuous sequences in which close members of the sequence may differ very little from one another; (2) changes in certain isolated characters (independent variation), as well as interrelated changes in a series of characters (correlative variation); and (3) changes that have adaptive significance (adaptive variation), as well as “indifferent” changes or even ones that decrease the vitality of their bearers (nonadaptive lethal variation). All these types of genetic changes constitute the substance of the evolutionary process. In the individual development of an organism, the manifestation of hereditary characters is always determined not only by the basic genes responsible for the given characters but also by their interaction with many other genes that make up the genotype of the individual and by the conditions of the external environment in which the organism develops.

The concept of nongenetic variation includes those changes in characters that are produced in individuals or in certain groups of individuals by the action of external factors (nutrition, temperature, light, humidity). Such nongenetic characters (modifications) are not transmitted by heredity in their concrete manifestations in each individual. They develop in individuals of succeeding generations only under the same conditions in which they arose. Such variation is also called epigenetic variation. For example, the coloration of many insects darkens at low temperatures and lightens at high ones; however, their offspring will have the coloration in accordance with the temperature at which it has developed, regardless of the coloration of the parents. There exists still another form of nongenetic variation—so-called protracted modifications—often found in unicellular organisms and occasionally in multicellular ones. They arise under the influence of external factors (for example, temperature or chemical factors) and are expressed in qualitative or quantitative deviations from the original form, which usually gradually disappear in subsequent reproduction. Protracted modifications are apparently based on changes of the stable cytoplasmic structures.

There is a close connection between nongenetic and genetic variation. There are no nongenetic (in the literal sense) characters, since nongenetic changes are a reflection of the genetically conditioned capacity of organisms to respond with definite changes in their characters to various factors in the external environment. At the same time, the limits of nongenetic changes are determined by the reaction norm of the genotype to environmental conditions.

Genetic and nongenetic variation are studied by investigating the differences in characters among certain individuals of a population (individual variation) and the differences among populations (group variation); individual variation also underlies any intergroup difference. Even within a closely related group there are no absolutely identical individuals that would not vary in the degree of expression of any genetic or nongenetic character. In view of the complexity of the organization of living systems, even in genotypically identical (for example, monozygotic twins) individuals that develop under practically identical conditions one can always discover insignificant morphophysiological differences associated with inevitable fluctuations in environmental conditions and in the processes of individual development.

Group variation includes the differences among aggregates of any rank—from differences among small groups of individuals within a population to differences among the kingdoms of living nature (animals and plants). In essence, the entire taxonomy of organisms is constructed on the comparative study of group variation. Of special significance in studying the triggering mechanisms of the evolutionary process are various forms of intraspecific group variation. Most of the species are divided into subspecies or geographic races. In the event of the complete isolation of geographic forms, they may differ markedly in one or several characters. Populations that inhabit extensive territories and are not separated by sharply isolating barriers may (owing to mixing and interbreeding) gradually merge, forming a quantitative gradient in certain characters (clinal variation). Geographic variation, including clinal variation, under natural conditions is the result of the effect of isolation, natural selection, and other factors of evolution that lead to the division of an original group of individuals in the course of historical formation into two or several groups differing in the numerical proportions of their genotypes.

In some instances, the differences among groups of individuals within a species are unrelated to the differences in their genotypic composition but are conditioned by modificatory variation (various reactions of similar genotypes to different external conditions). So-called seasonal variation occurs as a result of the influence of various weather conditions on the development of certain generations (for example, in some insects and herbaceous plants that produce two generations per year, the spring and autumn populations differ from one another in a number of characters). Sometimes, seasonal forms may be the result of the selection of different genotypes (for example, early- and late-flowering forms of grasses on haymaking meadows: over many generations, individuals that flowered in the summer, the time of hay mowing, were eliminated). Of great interest is ecological variation—differences between groups of individuals of one species that grow or live in different places (highlands and lowlands, marshy and dry areas). Often such forms are called ecotypes. The emergence of ecotypes may also be the result of modificatory changes, as well as of the selection of genotypes that are better adapted to local conditions. Various forms of polymorphism (variability within a population) are conditioned by genetic variation. In some populations, one observes the existence of two or more clearly distinguishable forms (for example, in almost all populations of bipunctate ladybugs, one finds the black form with red dots and the red form with black dots). Various evolutionary mechanisms may underlie this phenomenon: different adaptation of coexisting forms to conditions of various seasons of the year; increased viability of heterozygotes, in whose offspring both homozygotic forms are constantly split; or other, as yet insufficiently studied, mechanisms. Thus, both group and individual variation include changes that are genetic as well as nongenetic in nature.

Contrasted to the independent variation of characters is correlative variation—interrelated change of various characters: the relationship between growth and weight of the individual (positive correlation) or between the rate of cell division and the size of the cells (negative correlation). Correlations may be conditioned by purely genetic causes (pleiotropy), or by the interde-pendencies of processes of establishing certain characters in the development of the individual (ontogenetic correlation), or by similar reactions of various characters to the same external influences (physiological correlation). Finally, correlations may reflect the history of the origins of populations from a mixture of two or more forms, each of which contribute complexes of interrelated characters rather than separate characters (historical correlation). The study of correlative variation has great significance in paleontology (for example, in reconstructing extinct forms from certain fossil remains), anthropology (in reconstructing facial features from a study of the skull), selection and medicine.

The principal methods of studying variation are the comparative-descriptive and the biometric methods. These two methods permit investigation of the paratypic as well as genotypic components of the integral phenotypic variation. Thus, the former may be studied by comparing genotypically identical clones and pure lines developing under different conditions. It is more difficult to distinguish purely genotypic variation from the phenotypic variation. It is possible to do this on the basis of biometric analysis. The determination of the percent of convergence of certain characters in monozygotic and dizygotic twins is used in medical genetics for the same purposes.

Heredity and variation of living organisms are sometimes juxtaposed as “conservative” and “evolutionary” principles. In reality, however, they are very closely connected. Relative instability of the genotype favors mutations that lead to variation through recombination—that is, genotypic variation as a whole. Paratypic (nongenetic) variation is merely the result of the relative stability of the genotype in determining the reaction norms in ontogenesis during the development of the characters of individuals. The possibility of the experimental influence on genetic as well as nongenetic variation follows from this. The former may be strengthened by the influence of mutagenic factors (radiation, temperature, chemical substances). The scope and direction of variation through recombination may be controlled by means of artificial selection. Nongenetic variation may be influenced by changing the environmental conditions (nutrition, light, humidity) under which the development of the organism occurs.

A precise conception of the categories and forms of variation is necessary in the construction of evolutionary schemes and theories (since the phenomena of heredity and variation lie at the root of the evolutionary process) and in the practical selection of plants and animals and in the study of various problems in medical geography and population anthropology.

REFERENCES

Filipchenko, Iu. A. Izmenchivost’ i melody ee izucheniia, 2nd ed. Leningrad, 1926.
Chetverikov, S. S. “O nekotorykh momentakh evoliutsionnogo protsessa s tochki zreniia sovremennoi genetiki. ”Zhurnal eksperimenta’noi biologii, 1926, vol. 2, no. 1.
Johannsen, W. Elementy tochnogo ucheniia ob izmenchivosti i nasledst-vennosti s osnovami variatsionnoi statistiki. Moscow-Leningrad, 1933.
Johannsen, W. O nasledovanii v populiatsiiakh i chistykh liniiakh. Moscow-Leningrad, 1935.
Haldane, J. Faktory evoliutsii. Moscow-Leningrad, 1935. (Translated from English.)
Darwin, C. “Proiskhozhdenia vidov….” Soch., vol. 3. Moscow, 1939.
Shmal’gauzen, I. I. Organizm, kak tseloe v individuaTnom i istoricheskom razvitii. [2nd ed.]. Moscow-Leningrad, 1942.
Astaurov, B. L. “Izmenchivost’.” In Bol’shaia meditsinskaia entsik-lopediia, vol. 11. Moscow, 1959.
Vavilov, N. I. “Zakon gomologicheskikh riadov v nasledstvennoi izmenchivosti.” Izbrannye proizvenediia, vol. 1. Leningrad, 1967. Pages 7–61.
Vavilov, N. I. “Linneevskii vid kak sistema.” Izbrannye proizvedeniia, vol. 1. Pages 62–87.
Lobashev, M. E. Genetika, 2nd ed. Leningrad, 1967.
Mayr, E. Zoologicheskii vid i evoliutsiia. Moscow, 1968. (Translated from English.)
Timofeev-Resovskii, N. V., N. N. Vorontsov, and A. V. Iablokov. Kratkii ocherk teorii evoliutsii. Moscow, 1969.
Fisher, R. The Genetical Theory of Natural Selection. Oxford, 1930.
Falconer, D. Introduction to Quantitative Genetics. Edinburgh-London, 1960.

N. V. TIMOFEEV-RESOVSKII, E. K. GINTER,
N. V. GLOTOV, and V. I. IVANOV

Variation in microorganisms. In microorganisms, as in other organisms, a distinction is made between nongenetic and genetic variation. Any morphological or physiological character may undergo change: the size and shape of microorganisms and the form and pigmentation of their colonies, their ability to assimilate or synthesize various organic substances, their pathogenicity, and so forth.

Genetic variation in microorganisms is the result of mutations that arise spontaneously or are produced by physical or chemical mutagens (ultraviolet rays, ionizing radiation, ethylenimine). In mutants such quantitative characters as the ability to biosynthe-size amino acids, antibiotics, enzymes, vitamins, and the like may be sharply intensified or decreased. There also arise deficient mutants, which are capable of growing only with the addition of certain amino acids, purines, pyrimidines, and the like to the medium.

Microorganisms multiply very rapidly. It is therefore much easier to study all forms of variation in them and to effect artificial selection of beneficial mutants. Thus, in continuous cultur-ing in a medium containing, for example, an antibiotic, phenol, or mercuric chloride, one may readily obtain forms that are resistant to the given substance (adaptive variation). Also observed in microorganisms are interrelated changes (correlative variation). Thus, the emergence in pathogenic microbes of rough colonies is accompanied by a decrease in their immunogenicity. In microorganisms that have a true sexual process (certain molds and sporogenic yeasts), crossbreeding is possible, accompanied by a recombination of genes and the production of hybrids. Such hybrids cannot be produced in Fungi Imperfecti and in bacteria, which lack a true sexual process.

A. A. IMSHENETSKII

variation

[‚ver·ē′ā·shən] (astronomy) declination

variation

The angular difference between the direction of true north and magnetic north at any given point. It is measured in degrees east or west according to whether magnetic north lies east or west of this north. Variation is determined by the geographical location of the aircraft and is not affected by the aircraft heading. The variation indicated on a map or a chart is not a fixed quantity but is subject to change. Variation is indicated by dashed lines on maps and charts. All maps and charts also indicate the rate of the annual change of variation.

variation

1. Musica. a repetition of a musical theme in which the rhythm, harmony, or melody is altered or embellished b. (as modifier): variation form 2. Biologya. a marked deviation from the typical form or function b. a characteristic or an organism showing this deviation 3. Astronomy any change in or deviation from the mean motion or orbit of a planet, satellite, etc., esp a perturbation of the moon 4. another word for magnetic declination5. Ballet a solo dance

variation

var·i·a·tion

variation

var•i•a•tion

variation

variation

variation

variation

vary

variation

a variation on the theme of (something)

variations on the theme of something

variation

variation,

variation,

variation

variation

Variation

REFERENCES

variation

variation

variation

variation

var·i·a·tion

variation

var·i·a·tion

variation

variation

Synonyms for variation

noun alternative

Synonyms

noun variety

Synonyms

Antonyms

noun difference

Synonyms

Synonyms for variation

noun the condition or fact of varying

Synonyms

noun the process or result of making or becoming different

Synonyms

noun one that is slightly different from others of the same kind or designation

Synonyms

Synonyms for variation

noun an instance of change

Synonyms

Related Words

noun an activity that varies from a norm or standard

Synonyms

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noun a repetition of a musical theme in which it is modified or embellished

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noun something a little different from others of the same type

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noun an artifact that deviates from a norm or standard

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noun the angle (at a particular location) between magnetic north and true north

Synonyms

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noun the process of varying or being varied

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noun (astronomy) any perturbation of the mean motion or orbit of a planet or satellite (especially a perturbation of the earth's moon)

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noun (biology) an organism that has characteristics resulting from chromosomal alteration

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noun (ballet) a solo dance or dance figure

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noun the act of changing or altering something slightly but noticeably from the norm or standard

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