selection


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Related to selection: Selection sort

se·lec·tion

(sĕ-lek'shŭn),
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 (for example, Tay-Sachs disease), that cause sterility (for example, Turner syndrome), or that produce sterile progeny are selected against. When selection 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]

selection

/se·lec·tion/ (sĕ-lek´shun) the play of forces that determines the relative reproductive performance of the various genotypes in a population.
directional selection  selection favoring individuals at one extreme of the distribution.
disruptive selection , diversifying selection selection favoring the two extremes rather than the intermediate.
natural selection  the survival in nature of those individuals and their progeny best equipped to adapt to environmental conditions.
sexual selection  natural selection in which certain characteristics attract male or female members of a species, thus ensuring survival of those characteristics.
stabilizing selection  selection favoring intermediate phenotypes rather than those at one or both extremes.

selection

(sĭ-lĕk′shən)
n.
Biology A natural or artificial process that involves the survival and reproduction of some kinds of organisms instead of others (because they have traits that are better adapted to the environment or that are preferred by a breeder, for example) and results in changes in the traits of a population or species.

se·lec′tion·al (-shə-nəl) adj.

selection

[silek′shən]
Etymology: L, seligere, to choose
1 the act or product of choosing.
2 the process by which various factors or mechanisms determine and modify the reproductive ability of individuals with specific genotypes within a population, thus influencing evolutionary change. Kinds of selection are artificial selection, natural selection, and sexual selection.

selection

Vox populi The chosing among a number of different options. See Adverse selection, Artificial selection, Group selection, Kin selection, Negative selection, Patient selection, Sex selection.

se·lec·tion

(sĕ-lek'shŭn)
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.
[L. se-ligo, to separate, select, fr. se, apart, + lego, to pick out]

selection

the differential rate of reproduction of one phenotype in a population as compared to other phenotypes. Hence an organism that produces more offspring which survive to reproduce than another type is at a ‘selective advantage’. The environmental pressures causing selection can be either natural (e.g. competition for food) or artificial (e.g. insecticides, see DDT). See DIRECTIONAL SELECTION, NATURAL SELECTION, STABILIZING SELECTION.

se·lec·tion

(sĕ-lek'shŭn)
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.
[L. se-ligo, to separate, select, fr. se, apart, + lego, to pick out]

selection,

n 1. the act of choosing between or among a variety of options or alternatives.
2. the process by which various factors or mechanisms determine and modify the reproductive ability of a genotype within a specific population. Also referred to as
natural selection.
selection, shade (tooth color selection),
n the determination of the color (hue, brilliance, saturation, translucency) of the artificial tooth or set of teeth for a given patient.
selection, tooth,
n the selection of a tooth or teeth (shape, size, color) to harmonize with the individual characteristics of a patient.
selection, tooth color,
n See selection, shade.

selection

1. choosing the individual units to be included in a sample. See also random selection.
2. choosing the animals to be retained for breeding purposes; genetic selection.

artificial selection
selection based on human decisions.
selection coefficient
proportionate reduction in the average genetic contribution made by a specific genotype, relative to the contribution made by another genotype. Denoted by s.
selection criteria
the animal characteristic which is used in a selection program.
selection differential
a measure of the gain achieved by selection; the phenotypic superiority of selected individuals, compared to the population from which they were selected.
selection index
a single overall estimate of the patient's true breeding value obtained from as many sources of information as are available.
individual selection
selection on the results of performance testing of the subject.
selection intensity
the superiority of the individuals selected for breeding, relative to the population from which they were selected.
selection limit
the situation in which the entire population is homozygous for the same set of favorable genes; called also selection plateau.
selection/mutation balance
when the rate of removal of a gene from the population by selection equals the rate at which mutations occur.
selection plateau
see selection limit.
selection program
the method used to select individuals from a population to be used for breeding. Usually includes nomination of the characters to be selected, the optimum size of the population in which the program is to operate, the intensity of selection available, the accuracy of the selection procedures, lengths of the generations in the species, the target rate of response.

Patient discussion about selection

Q. clonex symptoms in Selective Mutism Syndrome children My son is 6.5 years old, with selective mutism syndrome - in a months time he shall be entering first grade. We have, the past 2 years been with therapists specializing in this field. He has improved outside a closed system i.e. within the kindergarten (primarily) we even see some regression. We have been at major dilemmas with giving him medication but due to the critical time - we were recommended to take 0.125 mg of Clonex medication. we are a little worried and would like to understand the possible symptoms

A. As a benzodiazepin, it can cause drowsiness, weakness and other changes in behavior. There may be some other side-effects, that you can read about here (http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a682279.html)

More discussions about selection
References in classic literature ?
Dyott, left alone, moved with an air of selection to the window, and it was as so stationed, gazing out at the wild weather, that the visitor, whose delay to appear spoke of the wiping of boots and the disposal of drenched mackintosh and cap, finally found her.
But you observe that the principle on which my selection is made, is to give adequate, and not disproportionate illustration to each of the theses enumerated in my introduction, as at present sketched.
Austin Dobson's Selections from Steele (Clarendon Press) prefaced by his careful "Life.
Yet there remained so many good names that Chandos and Felton, to whom the selection had been referred, had many an earnest consultation, in which every feat of arms and failure or success of each candidate was weighed and balanced against the rival claims of his companions.
Smiling, blushing, limpid eyed, Anne tripped back and gave a quaint, funny little selection that captivated her audience still further.
The climax of the whole selection came in the line,
This fundamental subject of Natural Selection will be treated at some length in the fourth chapter; and we shall then see how Natural Selection almost inevitably causes much Extinction of the less improved forms of life and induces what I have called Divergence of Character.
I have written the present volume because I have found no other that, to my mind, combines satisfactory accomplishment of these ends with a selection of authors sufficiently limited for clearness and with adequate accuracy and fulness of details, biographical and other.
And that's not all--twenty years ago he would have found in that literature traces of conflict with authorities, with the creeds of the ages; he would have perceived from this conflict that there was something else; but now he comes at once upon a literature in which the old creeds do not even furnish matter for discussion, but it is stated baldly that there is nothing else--evolution, natural selection, struggle for existence--and that's all.
At this point the conversation was interrupted by the arrival of a gentleman in orange-coloured plush, accompanied by another selection in purple cloth, with a great extent of stocking.
My Cabinet Selections were all made before our former interview, but you have supplied a noble instance of patriotism in subordinating your personal preferences to the general good.
And in learning to read poetry it is at first well to use selections chosen for us by those wiser than ourselves.