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Natural selection is the adaptation and modification of populations of living organisms.
Some people pass on more genes to the next generation than others. Allele frequencies alter as a result of this.

Stabilizing Selection:
When there are selective forces acting against two extremes of a characteristic, the intermediate or "middle" trait is selected for.
Directional Selection:
When selective forces act in favor of one extreme of a trait, this form of natural selection develops.
Disruptive Selection:
When selective pressures are operating in favor of the two extremes and against the intermediate characteristic, this form of natural selection arises. This is a less prevalent sort of selection.

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1.Natural selection is the process through which populations of living organisms adapt and change.

2.Natural selection can cause microevolution (change in allele frequencies), with fitness-increasing alleles becoming more common in the population. Fitness is a measure of reproductive success (how many offspring an organism leaves in the next generation, relative to others in the group).

Directional selection:directional selection, is a mode of negative natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype.

Stabilizing:Stabilizing selection is any selective force or forces which push a population toward the average, or median trait. Stabilizing selection is a descriptive term for what happens to an individual trait when the extremes of the trait are selected against.

Disruptive:Disruptive selection is a type of natural selection that selects against the average individual in a population.

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Natural selection occurs when there are differences in fitness among members of a population. As a result, some individuals pass more genes to the next generation. This causes allele frequencies to change

natural selection on polygenic traits can affect the distributions of phenotypes in three ways: directional selection, stabilizing selection, or disruptive selection.

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-Natural selection occurs when there are differences in fitness among members of a population. As a result, some individuals pass more genes to the next generation. This causes allele frequencies to change.

https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook-2.0/section/5.21/primary/lesson/natural-selection-bio/

-Natural selection on polygenic traits can affect the distributions of phenotypes in three ways: directional selection, stabilizing selection, or disruptive selection.

https://www.etsu.edu/uschool/faculty/tadlockd/documents/bio_chp18sec2_show2019.pdf

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Natural selection is the process where individuals of a population are deemed unfit to survive or that more than one variation of individuals are deemed fit to survive. Depending on the situation, It can cause microevolution (change in allele frequencies) and the allele frequency may be reduced or increased.

Stabilizing selection: occurs when there are selective pressures working against two extremes of a trait and therefore the intermediate or “middle” trait is selected for.

Directional selection: occurs when selective pressures are working in favour of one extreme of a trait.

Disruptive selection: occurs when selective pressures are working in favour of the two extremes and against the intermediate trait.

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1-When there exist fitness inequalities among individuals of a population, natural selection takes place. As a result, some people pass on more genes to their offspring than others. Allele frequencies shift as a result of this.

2- When traits at both ends of the phenotypic distribution are chosen against, stabilizing selection occurs. This reduces the range of possible variations. Human birth weight is one example. Babies that are born too big or too little have a lower chance of surviving. As a result, the birth weight is kept within a rather restricted range.

Directional selection occurs when one of two extreme phenotypes is selected for. This shifts the distribution toward that extreme. This is the type of natural selection that the Grants observed in the beak size of Galápagos finches.

Disruptive selection occurs when phenotypes in the middle of the range are selected against. This results in two overlapping phenotypes, one at each end of the distribution.

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The process by which populations of living organisms adapt and change is known as natural selection. Observable evolutionary changes in a species can occur over many generations.
Stabilizing direction
occurs when phenotypes at both extremes of the phenotypic distribution are selected against. This narrows the range of variation. An example is human birth weight. Babies that are very large or very small at birth are less likely to survive. This keeps birth weight within a relatively narrow range
Directional selection
occurs when one of two extreme phenotypes is selected for. This shifts the distribution toward that extreme. This is the type of natural selection that the Grants observed in the beak size of Galápagos finches
Disruptive selection
occurs when phenotypes in the middle of the range are selected against. This results in two overlapping phenotypes, one at each end of the distribution.

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- Natural Selection: Process by which organisms in nature with variations most suited to their environment survive and reproduce (Terminology and concepts ppt).
- Natural selection can either increase or decrease allele frequencies, depending on the trait favored.
- Three types of natural selection:
Directional favors one extreme phenotype.
Stabilizing favors the mean.
Disruptive favors two extreme phenotypes.

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1) Natural selection is the process where individuals of a population are deemed unfit to survive or that more than one variation of individuals are deemed fit to survive and prosper. Depending on the situation, the allele frequency may be reduced or increased. Though, as mutations occur constantly, the allele frequencies of any population is ever changing.

2) Directional selection:Directional selection occurs when individuals at one end of the curve have higher fitness than individuals in the middle or at the other end.
Stabilizing selection:Stabilizing selection occurs when individuals near the center of the curve have higher fitness than individuals at either end.
Disruptive selection: Disruptive selection occurs when individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle.

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What is natural selection and what are its effects on allele frequencies? Describe three types of natural selection for a polygenic trait.

Natural selection is the adaptation and change in populations of living organisms. Natural selection can cause microevolution (change in allele frequencies). Directional selection: Directional selection occurs when individuals at one end of the curve have higher fitness than individuals in the middle or at the other end. Stabilizing selection: Stabilizing selection occurs when individuals near the center of the curve have higher fitness than individuals at either end. Disruptive selection: Disruptive selection occurs when individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle.

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1. Natural selection: a process in which individuals that have certain traits tend to survive and reproduce at higher rates than other individuals. If certain phenotypes make an organisms more fit than others, then allelic frequency of those genes will increase

2. the three types are -

directional selection: one of two extreme phenotypes is selected for

stabilizing selection: phenotypes at both extremes of the phenotypic distribution are selected against.

disruptive selection: both extremes against

websites used:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjQx-nCz8z2AhX2QfEDHSDAAMQQFnoECAEQAw&url=https%3A%2F%2Fquizlet.com%2F513493279%2Fchapter-23-population-genetics-flash-cards%2F&usg=AOvVaw3EJ3jc7JZh4LVAUiGUl9nN

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1.When there are changes in fitness among individuals of a population, natural selection occurs. As an outcome, some people pass on more genes to the next generation than others. Allele frequencies change as a result of this.

2.
- directional selection: Negative natural selection in which an extreme phenotype is favored over others, causing allele frequency to shift in the direction of that phenotype over time.

- stabilizing selection: any or all selecting processes that drive a population toward the average or median trait

- disruptive selection: a sort of natural selection that favors the extremes in a population above the average member.

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What is natural selection and what are its effects on allele frequencies?
Natural selection occurs when there are differences in fitness among members of a population. As a result, some people pass more genes on to the next generation. This causes changes in allele frequencies.

Describe three types of natural selection for a polygenic trait.
Natural selection for polygenetic traits can affect the distribution of phenotypes in three ways: directional selection, stabilizing selection or disruptive selection.

References:
Foundation, CK-12. “12 Foundation.” CK, https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook-2.0/section/5.21/primary/lesson/natural-selection-bio/.

https://www.etsu.edu/uschool/faculty/tadlockd/documents/bio_chp18sec2_show2019.pdf

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1. Natural selection occurs when there are differences in fitness among members of a population. As a result, some individuals pass more genes to the next generation. This causes allele frequencies to change.

2.

1. Stabilizing selection occurs when phenotypes at both extremes of the phenotypic distribution are selected against. This narrows the range of variation. An example is human birth weight. Babies that are very large or very small at birth are less likely to survive. This keeps birth weight within a relatively narrow range.

2. Directional selection occurs when one of two extreme phenotypes is selected for. This shifts the distribution toward that extreme. This is the type of natural selection that the Grants observed in the beak size of Galápagos finches.

3. Disruptive selection occurs when phenotypes in the middle of the range are selected against. This results in two overlapping phenotypes, one at each end of the distribution.

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Natural selection occurs when there are differences in fitness among members of a population. As a result, some individuals pass more genes to the next generation. This causes allele frequencies to change.(flexbooks.ck.12.org)

Natural selection on polygenic traits can affect the distributions of phenotypes in three ways: directional selection, stabilizing selection, or disruptive selection.(www.etsu.edu)

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- Natural selection is the adaptation and modification of populations of living organisms. It occurs when members of a population have different levels of fitness. As an outcome, some people pass on more genes to the next generation than others. Allele frequencies alter as a result of this.
Microevolution (changes in allele frequencies) can occur as a result of natural selection, with fitness-increasing alleles becoming more frequent in the population. Fitness is a method to estimate reproductive success (how many offspring an organism leaves in the next generation, relative to others in the group).
- Directional Selection: In a directional selection, one of the phenotype is favored in an ecosystem.

Stabilizing selection: It is a type of natural selection in which the intermediate trait is favored.

Disruptive Selection: Disruptive trait is a type of natural selection in which the traits on the extreme sides are favored.

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Natural selection is a process by which a species changes over time in response to changes in the environment. Natural selection changes allele frequencies in a way that leads to adaptation to the environment fitness is the ability of an organism to compete successfully in passing its alleles on to the next generation .
Natural selection on polygenic traits can affect the distributions of phenotypes in three ways: directional selection, stabilizing selection, or disruptive selection.
How natural selection affects single-gene and polygenic traits within population (adobe.com)

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1. Natural selection on single-gene traits can lead to changes in allele frequencies and, thus, to changes in phenotype frequencies.

2. Natural selection on polygenic traits can affect the distributions of phenotypes in three ways: directional selection, stabilizing selection, or disruptive selection.

3. directional selection is a mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype.

4. Stabilizing selection (not the same thing as negative or purifying selection) is a type of natural selection in which the population mean stabilizes on a particular non-extreme trait value.

5. Disruptive selection, also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups.

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How natural selection affects single-gene and polygenic traits within population

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1. Natural selection on single-gene traits can lead to changes in allele frequencies and, thus, to changes in phenotype frequencies. 2. Natural selection on polygenic traits can affect the distributions of phenotypes in three ways: directional selection, stabilizing selection, or disruptive selection. 3.

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1-Natural selection occurs when there are differences in fitness among members of a population. As a result, some individuals pass more genes to the next generation. This causes allele frequencies to change
2- stabilizing selection - average form of a trait is favored
Directional selection - on extreme form of a trait is favored
Disruptive selection- either/both extremse of a trait are favored over an average form of a trait