selection

selection
The combined effect of the causes and consequences of genetic factors that determine the average number of progeny of a species that attain sexual maturity; phenotypes that are lethal early in life ( e.g., Tay-Sachs disease), that cause sterility ( e.g., Turner syndrome), or that produce sterile progeny are selected against. When s. is used of individual pedigrees, other factors, notably variance of the number of progeny and number that survive to maturity, are important considerations; in large populations, these factors even out and the mean only is of importance. [L. se-ligo, to separate, select, fr. se, apart, + lego, to pick out]
- artificial s. interference by humans with natural s. by purposeful breeding of animals or plants of specific genotype or phenotype to produce a strain with desired characteristics; e.g., breeding of dairy cattle for high milk production.
- medical s. preservation, by medical care and treatment, of individuals of pathologic genotypes who would not otherwise reproduce, thus tending to increase the frequency of pathologic genes in the population; conversely, reduction of the frequency of pathologic genes by preventing reproduction of individuals of specified genotype by surgical sterilization or other means.
- natural s. “survival of the fittest,” the principle that in nature those individuals best able to adapt to their environment will survive and reproduce, while those less able will die without progeny, and the genes carried by the survivors will increase in frequency. This principle is heuristic rather than rigorous since it cannot be tested, the outcome being tautologous with the empirical definition of fitness.
- sexual s. a form of natural s. in which, according to Darwin theory, the male or female is attracted by certain characteristics, form, color, behavior, etc., in the opposite sex; thus modifications of a special nature are brought about in the species.

* * *

se·lec·tion sə-'lek-shən n a natural or artificial process that results or tends to result in the survival and propagation of some individuals or organisms but not of others with the result that the inherited traits of the survivors are perpetuated compare DARWINISM, NATURAL SELECTION

* * *

se·lec·tion (sə-lekґshən) [L. selectio choice] the play of forces that determines the relative reproductive performance of the various genotypes in a population.

Medical dictionary. 2011.

Игры ⚽ Поможем сделать НИР
Synonyms:

Look at other dictionaries:

  • sélection — [ selɛksjɔ̃ ] n. f. • 1609 « choix » (didact.); lat. selectio I ♦ 1 ♦ (rare av. XIXe) Action de choisir les objets, les individus qui conviennent le mieux. Faire une première sélection parmi, entre des candidats. ⇒ présélection. Critères de… …   Encyclopédie Universelle

  • selection — se‧lec‧tion [sˈlekʆn] noun 1. [uncountable] the careful choice of a particular person or thing from a group: • The Health Authority is not involved in staff selection and recruitment. • Our deputy manager can supply details of the job,… …   Financial and business terms

  • Selection — Sélection Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom …   Wikipédia en Français

  • Selection 37 — Sélection 37 Sélection 37 Longueur hors tout : 11,35 m hors tout, 8,95 m flottaison Maître bau : 3,25 m Tirant d’eau : 1,90 m …   Wikipédia en Français

  • Sélection 37 — Équipage 8 maximum Longueur hors tout 11,35 m hors tout, 8,95 m flottaison Maître bau 3,25 m Tirant d eau 1,90 m Voilure 70,25 m² Déplacement 3,4 t (lest 1,1 t) Architecte …   Wikipédia en Français

  • Selection No 1 — Selection No. 1 EP von Drum Connection Veröffentlichung 1. Januar 2011 Label Drum Connection Music …   Deutsch Wikipedia

  • Selection — Se*lec tion, n. [L. selectio: cf. F. s[ e]lection.] . The act of selecting, or the state of being selected; choice, by preference. [1913 Webster] 2. That which is selected; a collection of things chosen; as, a choice selection of books. [1913… …   The Collaborative International Dictionary of English

  • Selection — Álbum de Marlango Publicación 2007 Género(s) jazz blues pop Discográfica Subterfuge Records …   Wikipedia Español

  • selection — [sə lek′shən] n. [L selectio] 1. a selecting or being selected 2. a) a person or thing chosen b) a group or collection of these c) a variety from which to choose [a selection of colors] 3 …   English World dictionary

  • selection — I (choice) noun adoption, appointment, appropriation, assignment, compilation, cooptation, decision, delectus, denomination, designation, determination, electio, election, extraction, indication, naming, nomination, ordainment, ordination,… …   Law dictionary

  • selection — ► NOUN 1) the action or fact of selecting. 2) a number of selected things. 3) a range of things from which a choice may be made. 4) a horse or horses tipped as worth bets in a race or meeting. 5) Biology the evolutionary process which determines… …   English terms dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”