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What is natural selection that acts against one type of extreme form of a polyygenic trait to reduce genetic variation and change the average value of a trait within a population called?
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∙ 13y ago
directional selection
Wiki User
∙ 14y ago
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What is the order of natural selection?
Simply put. Mutation, variation and selection against the immediate environment.
Is natural selection a source of variation within species?
No, mutation and sexual recombination are the sources of variation and natural selection selects from those variations presented to it against the immediate environment.
What is genetic variation in natural selection?
Natural selection ' selects ' from among variations. Some organisms are better suited to their immediate environment and survive and out reproduce other organisms. All these organisms are genetically variant. That is the simple connection between natural selection and genetic variation. ( that variation coming about by mutation and recombination )
How do mutations relate to natural selection?
Mutation, a copying error in the replication of DNA, can give rise to variation in an organisms phenotype and if this new phenotype is beneficial to survival and reproductive success ( as little as 1% ) it will be selected naturally against the immediate environment, then if this so selected organism leave many descendents with the same beneficial traits then the populations gene pool will change in allele frequency and you have evolution. ( a 19th century sentence Darwin would be proud of! )
What is one factor that affects natural selection?
Mutation is the important " starter " of the adaptive change engendered by natural selection. Variation is key to selection and without variation in organisms there would be nothing to select from for the survival and reproductive success of the organism against the immediate environment.
What is the order of natural selection?
Simply put. Mutation, variation and selection against the immediate environment.
Is natural selection a source of variation within species?
No, mutation and sexual recombination are the sources of variation and natural selection selects from those variations presented to it against the immediate environment.
Why does evolution evolution by natural selection can not occur if the variation in a characteristic does not contribute to differences in fitness?
Differential selection is just that, differential. Some variation is marginally superior to another variation us fitness difference, so the key is to have variation. Then natural selection will " see " this slight variation and select the better adapted trait against the background of the immediate environment.
Why must there be variation in a population in order for natural selection to occur?
What would there be to select from if all the organisms in a population were not different in morphology and behavior. Some of these differences are reproductively successful against the immediate environment, and that environment is the natural selector.
Is considered an important factor in natural selection?
Mutation is the important " starter " of the adaptive change engendered by natural selection. Variation is key to selection and without variation in organisms there would be nothing to select from for the survival and reproductive success of the organism against the immediate environment.
Why is variation important for natural selection and what are the main sources of this variation?
Without variation natural selection would have nothing to select from that would confer survivability and reproductive success. on the organisms being selected against the organisms conspecifics and the immediate environment. Mutation and sexual recombination provide the main sources of this variation that is needed to make selection work. Mutation is the variation presented that causes the real adaptive change that can lead to speciation.
What must exist in a population before natural selection can act?
Competition + Variation. Classic example: Giraffes not always had long necks. There were variation in the species. When food sauces grew low competition increases and those with longer necks survived (more fruit/food at the top of trees) as they were more suited to the conditions. These long necked giraffes then breed and the offspring have long necks, thus natural selection of a "fitter" species. Hense - survival of the fittest.
Which type of natural selection in which the mean characteristics of a population are preserved?
This type of natural selection is called stabilizing selection because the mean traits of the population are being selected for against the immediate environment.
Why must there be Variation in the population in order for natural selection?
Without the subtle differences on organisms phenotypes what would natural selection select from? All organisms in a population are variants and some survive and reproduce better than other against the background of the immediate environment and these are selected by that environmental pressure.
What terms describes natural selection that acts against intermediate forms of a polygenic trait to increase genetic variation while not changing the average value of a trait within?
Disruptive selection
What is genetic variation in natural selection?
Natural selection ' selects ' from among variations. Some organisms are better suited to their immediate environment and survive and out reproduce other organisms. All these organisms are genetically variant. That is the simple connection between natural selection and genetic variation. ( that variation coming about by mutation and recombination )
What are the 3 ways natural selection can affect a population?
Directional selection: favors the phenotype at one extreme of a trait's range, selecting against the opposite extreme.Stabilizing selection: favors the intermediate phenotype, selecting against the phenotypes at both extremes of the trait's range.Disruptive selection: favors phenotypes at both extremes, selecting against the intermediate phenotype of the trait's range.
