Natural Selection (Continued) - AP Biology
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What is the definition of natural selection?
What is the definition of natural selection?
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The process by which organisms better adapted to their environment tend to survive and reproduce. Darwin's mechanism for evolution through environmental pressures.
The process by which organisms better adapted to their environment tend to survive and reproduce. Darwin's mechanism for evolution through environmental pressures.
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What is directional selection?
What is directional selection?
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Selection that favors one extreme phenotype. Shifts population toward one end of the trait distribution.
Selection that favors one extreme phenotype. Shifts population toward one end of the trait distribution.
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Which term describes selection that acts against both extreme phenotypes?
Which term describes selection that acts against both extreme phenotypes?
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Stabilizing selection. Maintains population around the average phenotype value.
Stabilizing selection. Maintains population around the average phenotype value.
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What is the founder effect?
What is the founder effect?
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Genetic drift occurring when a new population is established. Small founding population carries limited genetic diversity.
Genetic drift occurring when a new population is established. Small founding population carries limited genetic diversity.
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Which term describes the loss of genetic variation due to random events?
Which term describes the loss of genetic variation due to random events?
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Genetic drift. Random sampling effects strongest in small populations.
Genetic drift. Random sampling effects strongest in small populations.
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Which term describes changes in allele frequencies due to random sampling?
Which term describes changes in allele frequencies due to random sampling?
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Genetic drift. Random changes occur independently of natural selection pressures.
Genetic drift. Random changes occur independently of natural selection pressures.
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Identify a source of genetic variation in a population.
Identify a source of genetic variation in a population.
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Recombination. Crossing over during meiosis creates new allele combinations.
Recombination. Crossing over during meiosis creates new allele combinations.
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Identify a mechanism that can lead to genetic drift.
Identify a mechanism that can lead to genetic drift.
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Bottleneck effect. Random reduction in population size that reduces genetic diversity.
Bottleneck effect. Random reduction in population size that reduces genetic diversity.
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Which type of selection favors extreme phenotypes?
Which type of selection favors extreme phenotypes?
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Disruptive selection. Selects against intermediate values, increasing variation.
Disruptive selection. Selects against intermediate values, increasing variation.
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Identify a factor that can lead to adaptive radiation.
Identify a factor that can lead to adaptive radiation.
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Ecological opportunities. New environments allow rapid diversification into multiple niches.
Ecological opportunities. New environments allow rapid diversification into multiple niches.
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Which factor can increase genetic variation within a population?
Which factor can increase genetic variation within a population?
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Mutation. Creates new alleles that increase genetic diversity.
Mutation. Creates new alleles that increase genetic diversity.
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What is a selective pressure?
What is a selective pressure?
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An environmental factor that influences survival and reproduction. Determines which traits are advantageous or disadvantageous.
An environmental factor that influences survival and reproduction. Determines which traits are advantageous or disadvantageous.
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What is genetic hitchhiking?
What is genetic hitchhiking?
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An allele's increase in frequency due to linkage with a favorable allele. Neutral allele increases due to proximity to beneficial allele.
An allele's increase in frequency due to linkage with a favorable allele. Neutral allele increases due to proximity to beneficial allele.
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Identify the result of a population's adaptation to its environment over time.
Identify the result of a population's adaptation to its environment over time.
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Increased fitness. Better-adapted populations have higher survival and reproductive rates.
Increased fitness. Better-adapted populations have higher survival and reproductive rates.
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Which type of selection can lead to speciation?
Which type of selection can lead to speciation?
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Disruptive selection. Can split populations into distinct groups with different traits.
Disruptive selection. Can split populations into distinct groups with different traits.
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What is the significance of a selection coefficient?
What is the significance of a selection coefficient?
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It measures the strength of selection against a genotype. Quantifies how much a genotype reduces reproductive success.
It measures the strength of selection against a genotype. Quantifies how much a genotype reduces reproductive success.
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How does sexual selection differ from natural selection?
How does sexual selection differ from natural selection?
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Sexual selection focuses on traits that improve mating success. Sexual selection specifically targets reproductive success over survival.
Sexual selection focuses on traits that improve mating success. Sexual selection specifically targets reproductive success over survival.
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What is coevolution?
What is coevolution?
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Reciprocal evolutionary changes in interacting species. Species evolve in response to each other's evolutionary changes.
Reciprocal evolutionary changes in interacting species. Species evolve in response to each other's evolutionary changes.
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Which term refers to a trait that arises due to common ancestry?
Which term refers to a trait that arises due to common ancestry?
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Homologous trait. Shared evolutionary origin produces similar structures across species.
Homologous trait. Shared evolutionary origin produces similar structures across species.
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Which type of selection favors intermediate phenotypes?
Which type of selection favors intermediate phenotypes?
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Stabilizing selection. Reduces variation by selecting against extreme values.
Stabilizing selection. Reduces variation by selecting against extreme values.
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What is an adaptation?
What is an adaptation?
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A heritable trait that increases fitness. Must be both inherited and beneficial for survival or reproduction.
A heritable trait that increases fitness. Must be both inherited and beneficial for survival or reproduction.
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Identify a result of stabilizing selection.
Identify a result of stabilizing selection.
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Reduction in phenotypic variation. Average phenotypes have highest fitness, reducing population variation.
Reduction in phenotypic variation. Average phenotypes have highest fitness, reducing population variation.
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What is sexual dimorphism?
What is sexual dimorphism?
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Distinct differences in size or appearance between sexes. Results from different selective pressures on males and females.
Distinct differences in size or appearance between sexes. Results from different selective pressures on males and females.
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What is the role of recombination in evolution?
What is the role of recombination in evolution?
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Shuffles alleles, creating new combinations. Independent assortment and crossing over increase genetic diversity.
Shuffles alleles, creating new combinations. Independent assortment and crossing over increase genetic diversity.
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Which term describes the differential survival and reproduction of individuals?
Which term describes the differential survival and reproduction of individuals?
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Differential fitness. Measures relative reproductive success among individuals in a population.
Differential fitness. Measures relative reproductive success among individuals in a population.
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Which phenomenon can result from random mating in large populations?
Which phenomenon can result from random mating in large populations?
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Hardy-Weinberg equilibrium. Describes stable allele frequencies when evolution is not occurring.
Hardy-Weinberg equilibrium. Describes stable allele frequencies when evolution is not occurring.
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What role does genetic variation play in natural selection?
What role does genetic variation play in natural selection?
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It provides the raw material for selection. Without variation, natural selection cannot act on populations.
It provides the raw material for selection. Without variation, natural selection cannot act on populations.
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Which type of selection favors one phenotype over others?
Which type of selection favors one phenotype over others?
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Directional selection. Creates consistent change in one direction over time.
Directional selection. Creates consistent change in one direction over time.
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Which term refers to the movement of alleles between populations?
Which term refers to the movement of alleles between populations?
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Gene flow. Migration transfers genetic material between populations.
Gene flow. Migration transfers genetic material between populations.
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Identify a factor that can lead to reproductive isolation.
Identify a factor that can lead to reproductive isolation.
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Geographic barriers. Physical separation prevents gene flow between populations.
Geographic barriers. Physical separation prevents gene flow between populations.
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