Evidence for Inherited Variation - Middle School Life Science
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What is an allele in a heredity model?
What is an allele in a heredity model?
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A different version of the same gene. Alleles create variation in traits.
A different version of the same gene. Alleles create variation in traits.
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What is the expected phenotype ratio from a model cross of $Aa \times Aa$ with $A$ dominant?
What is the expected phenotype ratio from a model cross of $Aa \times Aa$ with $A$ dominant?
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$3$ dominant phenotype : $1$ recessive phenotype. $AA$ and $Aa$ both show dominant phenotype.
$3$ dominant phenotype : $1$ recessive phenotype. $AA$ and $Aa$ both show dominant phenotype.
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What is a gene in a heredity model?
What is a gene in a heredity model?
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A DNA segment that influences a trait. Genes are the basic units of heredity.
A DNA segment that influences a trait. Genes are the basic units of heredity.
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What does genotype mean in a model of inheritance?
What does genotype mean in a model of inheritance?
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The allele combination an organism has. Genotype determines genetic makeup.
The allele combination an organism has. Genotype determines genetic makeup.
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What does phenotype mean in a model of inheritance?
What does phenotype mean in a model of inheritance?
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The observable trait produced by genes and environment. Phenotype results from genes and environment interacting.
The observable trait produced by genes and environment. Phenotype results from genes and environment interacting.
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What does it mean if an allele is dominant in a simple model?
What does it mean if an allele is dominant in a simple model?
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It is expressed with one copy in a heterozygote. Dominant alleles mask recessive ones.
It is expressed with one copy in a heterozygote. Dominant alleles mask recessive ones.
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What does it mean if an allele is recessive in a simple model?
What does it mean if an allele is recessive in a simple model?
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It is expressed only with two copies. Recessive traits need homozygous genotype.
It is expressed only with two copies. Recessive traits need homozygous genotype.
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Which statement correctly links meiosis to inherited variation in offspring?
Which statement correctly links meiosis to inherited variation in offspring?
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Meiosis shuffles alleles, creating new combinations. Sexual reproduction generates genetic diversity.
Meiosis shuffles alleles, creating new combinations. Sexual reproduction generates genetic diversity.
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What is an example of evidence from a model that a trait is polygenic?
What is an example of evidence from a model that a trait is polygenic?
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Many phenotypes form a continuous distribution. Bell curve distribution indicates polygenic trait.
Many phenotypes form a continuous distribution. Bell curve distribution indicates polygenic trait.
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What is polygenic inheritance in a model of variation?
What is polygenic inheritance in a model of variation?
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A trait controlled by many genes, producing a range. Multiple genes create continuous variation.
A trait controlled by many genes, producing a range. Multiple genes create continuous variation.
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What inheritance pattern produces both traits at the same time in heterozygotes (for example, red and white hairs together)?
What inheritance pattern produces both traits at the same time in heterozygotes (for example, red and white hairs together)?
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Codominance. Both alleles fully expressed together.
Codominance. Both alleles fully expressed together.
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What inheritance pattern produces an intermediate phenotype in heterozygotes (for example, red x white gives pink)?
What inheritance pattern produces an intermediate phenotype in heterozygotes (for example, red x white gives pink)?
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Incomplete dominance. Heterozygote shows blended phenotype.
Incomplete dominance. Heterozygote shows blended phenotype.
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Which model result matches a test cross $Aa \times aa$ for genotype ratio?
Which model result matches a test cross $Aa \times aa$ for genotype ratio?
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$1$ $Aa$ : $1$ $aa$. Test cross reveals 1:1 ratio.
$1$ $Aa$ : $1$ $aa$. Test cross reveals 1:1 ratio.
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Which option is the probability of heterozygous offspring from $Aa \times Aa$?
Which option is the probability of heterozygous offspring from $Aa \times Aa$?
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$\frac{1}{2}$. Half inherit one of each allele type.
$\frac{1}{2}$. Half inherit one of each allele type.
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Which option is the probability of recessive phenotype from $Aa \times Aa$ (complete dominance)?
Which option is the probability of recessive phenotype from $Aa \times Aa$ (complete dominance)?
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$\frac{1}{4}$. One quarter get two recessive alleles.
$\frac{1}{4}$. One quarter get two recessive alleles.
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Which model result matches a cross of $Aa \times Aa$ for phenotype ratio (complete dominance)?
Which model result matches a cross of $Aa \times Aa$ for phenotype ratio (complete dominance)?
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$3$ dominant : $1$ recessive. Mendel's 3:1 ratio for dominant traits.
$3$ dominant : $1$ recessive. Mendel's 3:1 ratio for dominant traits.
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Which model result matches a cross of $Aa \times Aa$ for genotype ratio?
Which model result matches a cross of $Aa \times Aa$ for genotype ratio?
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$1$ $AA$ : $2$ $Aa$ : $1$ $aa$. Monohybrid cross yields 1:2:1 genotype ratio.
$1$ $AA$ : $2$ $Aa$ : $1$ $aa$. Monohybrid cross yields 1:2:1 genotype ratio.
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What is a Punnett square used for in inheritance models?
What is a Punnett square used for in inheritance models?
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Predicting possible offspring genotypes and phenotypes. Visual tool for predicting genetic crosses.
Predicting possible offspring genotypes and phenotypes. Visual tool for predicting genetic crosses.
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What is the difference between homozygous and heterozygous genotypes?
What is the difference between homozygous and heterozygous genotypes?
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Homozygous: same alleles; heterozygous: different alleles. Describes whether alleles match or differ.
Homozygous: same alleles; heterozygous: different alleles. Describes whether alleles match or differ.
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What is the definition of inherited variation in a population?
What is the definition of inherited variation in a population?
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Differences in traits passed from parents to offspring. Genetic variation creates diversity within species.
Differences in traits passed from parents to offspring. Genetic variation creates diversity within species.
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What is the most direct model-based explanation for new inherited variation appearing in a population?
What is the most direct model-based explanation for new inherited variation appearing in a population?
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Mutations create new alleles that can be inherited. DNA changes produce variation passed to offspring.
Mutations create new alleles that can be inherited. DNA changes produce variation passed to offspring.
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What does a pedigree model help you infer about a trait in a family?
What does a pedigree model help you infer about a trait in a family?
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Likely inheritance pattern (dominant or recessive). Tracks trait inheritance through family generations.
Likely inheritance pattern (dominant or recessive). Tracks trait inheritance through family generations.
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Which model-based evidence best supports that variation is inherited rather than caused only by environment?
Which model-based evidence best supports that variation is inherited rather than caused only by environment?
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Offspring traits correlate with parent traits across generations. Environmental factors alone wouldn't show family patterns.
Offspring traits correlate with parent traits across generations. Environmental factors alone wouldn't show family patterns.
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What is the definition of codominance in an inheritance model?
What is the definition of codominance in an inheritance model?
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Both alleles are fully expressed in the heterozygote. Both traits appear together, not blended.
Both alleles are fully expressed in the heterozygote. Both traits appear together, not blended.
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Identify the genotypes produced by crossing $Aa \times Aa$ (list all possible offspring genotypes).
Identify the genotypes produced by crossing $Aa \times Aa$ (list all possible offspring genotypes).
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$AA$, $Aa$, and $aa$. Each parent contributes either $A$ or $a$ randomly.
$AA$, $Aa$, and $aa$. Each parent contributes either $A$ or $a$ randomly.
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