variation (redirected from phenotypic variation)

variation, in music

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.

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variation, in biology

variation, in biology: see Darwinism.

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variation

In music, basic technique consisting of changing the music melodically, harmonically, or contrapuntally. The simplest variation type is the variation set, in which two or more sections are based on the same musical material, which is treated with different variational techniques in each section. The practice, originally involving use of a repeated bass line (basso ostinato, or ground bass), began in early 16th-century dance music in Italy and Spain. Ground-bass forms include the chaconne and passacaglia, both of which usually employ a brief bass line repeated many times. In the 17th century, organ and harpsichord variations became a standard form in Germany. Keyboard variations in the 19th century often employed popular tunes or opera melodies; variation form was also commonly used in symphonies, quartets, and sonatas. It declined in importance after the classical era but has never ceased to be employed by composers. The music of certain non-Western cultures also uses variational techniques. The art music of southern India is built on the concept of a string of pieces, each a variation on a given “theme.” A somewhat different concept of multilevel variation is found in the gamelan (orchestra) music of Indonesia. The variations are not consecutive but are simultaneous, a technique called heterophony.

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variation

In biology, any difference between cells, individual organisms, or groups of organisms within a species caused either by genetic differences (variation in genotype) or by the effect of environmental factors on the expression of genetic potentials (variation in phenotype). Variation may be shown in physical appearance, metabolism, fertility, mode of reproduction, behaviour, learning and mental ability, and other obvious or measurable characters. Genotypic variations are caused by differences in number or structure of chromosomes or by differences in the genes carried by the chromosomes. Eye colour, body form, and disease resistance are genotypic variations. Phenotypic variations may result from factors such as climate, food supply, and actions of other organisms. Phenotypic variations also include stages in an organism's life cycle and seasonal variations in an individual. Because they do not involve hereditary alteration and in general are not transmitted to future generations, phenotypic variations are not important in evolution. See also polymorphism.

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variation

1. Music

a. a repetition of a musical theme in which the rhythm, harmony, or melody is altered or embellished

b. (as modifier): variation form

2. Biology

a. 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 declination

5. Ballet a solo dance

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variation [‚ver·ē′ā·shən]

(astronomy)

declination