Analyze Population Data for Evolution - Biology
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Calculate expected heterozygote frequency when $p=0.60$ and $q=0.40$.
Calculate expected heterozygote frequency when $p=0.60$ and $q=0.40$.
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$2pq=0.48$. $2pq = 2(0.60)(0.40) = 0.48$
$2pq=0.48$. $2pq = 2(0.60)(0.40) = 0.48$
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What is heterozygote advantage?
What is heterozygote advantage?
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Heterozygotes have highest fitness, maintaining both alleles. Balancing selection maintains genetic diversity.
Heterozygotes have highest fitness, maintaining both alleles. Balancing selection maintains genetic diversity.
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Identify the Hardy–Weinberg condition: what must be true about mutation?
Identify the Hardy–Weinberg condition: what must be true about mutation?
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No mutations occur. Mutations would change allele frequencies over time.
No mutations occur. Mutations would change allele frequencies over time.
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Identify the Hardy–Weinberg condition: what must be true about mating?
Identify the Hardy–Weinberg condition: what must be true about mating?
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Mating is random. Prevents preferential mating patterns that alter genotype frequencies.
Mating is random. Prevents preferential mating patterns that alter genotype frequencies.
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Identify the Hardy–Weinberg condition: what must be true about population size?
Identify the Hardy–Weinberg condition: what must be true about population size?
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Population is very large (minimizes genetic drift). Large populations reduce random sampling effects.
Population is very large (minimizes genetic drift). Large populations reduce random sampling effects.
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Which Hardy–Weinberg genotype frequency corresponds to homozygous recessive?
Which Hardy–Weinberg genotype frequency corresponds to homozygous recessive?
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$q^2$. Frequency of $aa$ genotype in Hardy-Weinberg equilibrium.
$q^2$. Frequency of $aa$ genotype in Hardy-Weinberg equilibrium.
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Which Hardy–Weinberg genotype frequency corresponds to heterozygotes?
Which Hardy–Weinberg genotype frequency corresponds to heterozygotes?
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$2pq$. Frequency of $Aa$ genotype; factor of 2 accounts for both combinations.
$2pq$. Frequency of $Aa$ genotype; factor of 2 accounts for both combinations.
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State the Hardy–Weinberg allele frequency equation for two alleles.
State the Hardy–Weinberg allele frequency equation for two alleles.
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$p+q=1$. The two allele frequencies must sum to 1.
$p+q=1$. The two allele frequencies must sum to 1.
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Identify the formula for allele frequency $p$ from genotype counts $AA$, $Aa$, $aa$ in $N$ individuals.
Identify the formula for allele frequency $p$ from genotype counts $AA$, $Aa$, $aa$ in $N$ individuals.
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$p=\frac{2AA+Aa}{2N}$. Counts each homozygote twice and heterozygote once for allele $A$.
$p=\frac{2AA+Aa}{2N}$. Counts each homozygote twice and heterozygote once for allele $A$.
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What is mutation as an evolutionary mechanism?
What is mutation as an evolutionary mechanism?
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Source of new alleles via DNA sequence changes. Introduces novel alleles but usually at low rates.
Source of new alleles via DNA sequence changes. Introduces novel alleles but usually at low rates.
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What does it mean if allele frequency changes across generations in a dataset?
What does it mean if allele frequency changes across generations in a dataset?
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Evolution is occurring in that population. Frequency changes indicate evolutionary forces are acting.
Evolution is occurring in that population. Frequency changes indicate evolutionary forces are acting.
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What is the gene pool of a population?
What is the gene pool of a population?
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All alleles present in the population. The collective genetic variation available for evolution.
All alleles present in the population. The collective genetic variation available for evolution.
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Identify the allele frequency change if $p$ shifts from $0.50$ to $0.62$ in one generation.
Identify the allele frequency change if $p$ shifts from $0.50$ to $0.62$ in one generation.
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$\Delta p=0.12$. $\Delta p = 0.62 - 0.50 = 0.12$
$\Delta p=0.12$. $\Delta p = 0.62 - 0.50 = 0.12$
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Calculate expected carrier (heterozygote) frequency when $q=0.10$ and $p=0.90$.
Calculate expected carrier (heterozygote) frequency when $q=0.10$ and $p=0.90$.
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$2pq=0.18$. $2pq = 2(0.90)(0.10) = 0.18$
$2pq=0.18$. $2pq = 2(0.90)(0.10) = 0.18$
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Calculate $p$ if $q=0.30$ for a two-allele locus under Hardy–Weinberg notation.
Calculate $p$ if $q=0.30$ for a two-allele locus under Hardy–Weinberg notation.
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$p=0.70$. Since $p + q = 1$, then $p = 1 - 0.30 = 0.70$
$p=0.70$. Since $p + q = 1$, then $p = 1 - 0.30 = 0.70$
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Which inference is supported if a phenotype is rare and has higher fitness specifically because it is rare?
Which inference is supported if a phenotype is rare and has higher fitness specifically because it is rare?
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Negative frequency-dependent selection. Rare phenotypes gain advantage specifically from their rarity.
Negative frequency-dependent selection. Rare phenotypes gain advantage specifically from their rarity.
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Which inference is supported if a harmful allele persists because heterozygotes have higher fitness?
Which inference is supported if a harmful allele persists because heterozygotes have higher fitness?
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Balancing selection via heterozygote advantage. Heterozygote advantage maintains harmful alleles in populations.
Balancing selection via heterozygote advantage. Heterozygote advantage maintains harmful alleles in populations.
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Which inference is supported if a beneficial allele rises quickly in frequency after an environmental change?
Which inference is supported if a beneficial allele rises quickly in frequency after an environmental change?
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Positive selection increased the allele’s frequency. Rapid increase after environmental change indicates adaptive advantage.
Positive selection increased the allele’s frequency. Rapid increase after environmental change indicates adaptive advantage.
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What is the key population-level evidence that a trait is heritable?
What is the key population-level evidence that a trait is heritable?
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Trait variation correlates between parents and offspring. Parent-offspring correlation indicates genetic basis for the trait.
Trait variation correlates between parents and offspring. Parent-offspring correlation indicates genetic basis for the trait.
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What is a selective pressure in the context of population data?
What is a selective pressure in the context of population data?
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Environmental factor that causes differential survival or reproduction. Environmental factors create fitness differences between phenotypes.
Environmental factor that causes differential survival or reproduction. Environmental factors create fitness differences between phenotypes.
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Identify the strongest evidence for natural selection in population data across generations.
Identify the strongest evidence for natural selection in population data across generations.
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Consistent allele frequency change correlated with a selective pressure. Correlation between selection pressure and frequency change indicates causation.
Consistent allele frequency change correlated with a selective pressure. Correlation between selection pressure and frequency change indicates causation.
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Choose the best selection pattern if extremes decline and intermediate phenotypes become most common.
Choose the best selection pattern if extremes decline and intermediate phenotypes become most common.
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Stabilizing selection. Intermediate optimization indicates selection against extremes.
Stabilizing selection. Intermediate optimization indicates selection against extremes.
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Choose the best selection pattern if both extremes increase while intermediates decrease in frequency.
Choose the best selection pattern if both extremes increase while intermediates decrease in frequency.
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Disruptive selection. Both extremes increasing indicates selection against intermediate forms.
Disruptive selection. Both extremes increasing indicates selection against intermediate forms.
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Choose the best selection pattern if the mean phenotype increases steadily across generations.
Choose the best selection pattern if the mean phenotype increases steadily across generations.
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Directional selection. Consistent shift toward one extreme indicates directional selection.
Directional selection. Consistent shift toward one extreme indicates directional selection.
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Choose the best evolutionary mechanism if allele frequencies become more similar between two populations over time.
Choose the best evolutionary mechanism if allele frequencies become more similar between two populations over time.
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Gene flow. Migration homogenizes allele frequencies between populations over time.
Gene flow. Migration homogenizes allele frequencies between populations over time.
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Choose the best evolutionary mechanism if a new island population has unusual allele frequencies from few founders.
Choose the best evolutionary mechanism if a new island population has unusual allele frequencies from few founders.
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Genetic drift (founder effect). Few founding individuals create non-representative gene pools.
Genetic drift (founder effect). Few founding individuals create non-representative gene pools.
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Choose the best evolutionary mechanism if allele frequencies change randomly after a population crash.
Choose the best evolutionary mechanism if allele frequencies change randomly after a population crash.
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Genetic drift (bottleneck effect). Population crashes cause random allele loss through sampling effects.
Genetic drift (bottleneck effect). Population crashes cause random allele loss through sampling effects.
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What is frequency-dependent selection?
What is frequency-dependent selection?
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Fitness depends on how common or rare a phenotype is. Selection strength varies with phenotype abundance in population.
Fitness depends on how common or rare a phenotype is. Selection strength varies with phenotype abundance in population.
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What is nonrandom mating and how does it affect genotype frequencies?
What is nonrandom mating and how does it affect genotype frequencies?
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Mate choice/inbreeding changes genotype frequencies, not allele frequencies directly. Affects Hardy-Weinberg genotype predictions without changing allele frequencies.
Mate choice/inbreeding changes genotype frequencies, not allele frequencies directly. Affects Hardy-Weinberg genotype predictions without changing allele frequencies.
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What is natural selection in terms of population data?
What is natural selection in terms of population data?
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Nonrandom allele frequency change due to differential survival/reproduction. Fitness differences cause predictable frequency changes.
Nonrandom allele frequency change due to differential survival/reproduction. Fitness differences cause predictable frequency changes.
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