Types of Natural Selection 2024-25

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What is Directional Selection?

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A type of natural selection where an extreme phenotype is favored, causing the allele frequency to shift toward that phenotype.

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What is Stabilizing Selection?

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A type of natural selection that favors intermediate phenotypes, reducing genetic diversity and increasing the frequency of the average phenotype.

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What is Disruptive Selection?

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A type of natural selection that favors extreme phenotypes at both ends of the spectrum, leading to two or more contrasting phenotypes in the population.

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Example of Directional Selection?

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When a population of deer migrates to a colder environment, thick-furred deer survive better than thin-furred or average-furred deer.

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Example of Stabilizing Selection?

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Human babies that are born at an average size have higher survival rates compared to those that are too small or too large.

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What is the effect of Stabilizing Selection on genetic diversity?

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It decreases genetic diversity by favoring the average phenotype and reducing the extremes.

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What is the effect of Directional Selection on a population?

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It shifts the population's traits toward one extreme phenotype over time.

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What is an example of Disruptive Selection in nature?

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A population of birds with either very large or very small beaks may thrive, while those with average-sized beaks may struggle to find food.

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How does Natural Selection relate to Evolution?

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Natural selection is a mechanism of evolution, where individuals with favorable traits are more likely to survive and reproduce.

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What is the role of genetic variation in Natural Selection?

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Genetic variation provides the raw material for natural selection to act upon, allowing populations to adapt to changing environments.