Genetic Variation - Middle School Life Science
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Which process creates new alleles in a population?
Which process creates new alleles in a population?
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Mutation. Only mutations can create brand new genetic variants.
Mutation. Only mutations can create brand new genetic variants.
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Which option best indicates genetic variation: different fur colors or different ages?
Which option best indicates genetic variation: different fur colors or different ages?
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Different fur colors. Fur color is genetic; age is environmental.
Different fur colors. Fur color is genetic; age is environmental.
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Which data type most directly measures genetic variation: allele frequencies or population size?
Which data type most directly measures genetic variation: allele frequencies or population size?
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Allele frequencies. Shows the proportion of each allele variant in the population.
Allele frequencies. Shows the proportion of each allele variant in the population.
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Identify the population with greater genetic variation: all AA vs AA, Aa, and aa present.
Identify the population with greater genetic variation: all AA vs AA, Aa, and aa present.
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AA, Aa, and aa present. Three genotypes means more genetic diversity than just one.
AA, Aa, and aa present. Three genotypes means more genetic diversity than just one.
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What is genetic drift?
What is genetic drift?
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Random changes in allele frequencies, strongest in small populations. Like flipping coins - chance affects which alleles survive.
Random changes in allele frequencies, strongest in small populations. Like flipping coins - chance affects which alleles survive.
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What is independent assortment?
What is independent assortment?
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Random separation of chromosome pairs into gametes. Each gamete gets a random mix of maternal and paternal chromosomes.
Random separation of chromosome pairs into gametes. Each gamete gets a random mix of maternal and paternal chromosomes.
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What is crossing over?
What is crossing over?
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Exchange of DNA between homologous chromosomes during meiosis. Creates new allele combinations on chromosomes.
Exchange of DNA between homologous chromosomes during meiosis. Creates new allele combinations on chromosomes.
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Which process increases variation by shuffling alleles during meiosis?
Which process increases variation by shuffling alleles during meiosis?
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Genetic recombination. Creates new combinations of existing alleles.
Genetic recombination. Creates new combinations of existing alleles.
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Which type of selection favors one extreme phenotype and reduces variation?
Which type of selection favors one extreme phenotype and reduces variation?
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Directional selection. Pushes population toward one trait value.
Directional selection. Pushes population toward one trait value.
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Which process moves alleles between populations when individuals migrate and reproduce?
Which process moves alleles between populations when individuals migrate and reproduce?
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Gene flow. Migration spreads genetic diversity between groups.
Gene flow. Migration spreads genetic diversity between groups.
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Which process shuffles alleles during meiosis to increase variation?
Which process shuffles alleles during meiosis to increase variation?
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Crossing over (recombination). Chromosomes exchange segments, creating new combinations.
Crossing over (recombination). Chromosomes exchange segments, creating new combinations.
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What is a genotype?
What is a genotype?
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An organism’s allele combination for a gene. Written as letters (e.g., AA, Aa, aa).
An organism’s allele combination for a gene. Written as letters (e.g., AA, Aa, aa).
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What is a phenotype?
What is a phenotype?
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Observable trait produced by genes and environment. What you see results from genes plus environmental factors.
Observable trait produced by genes and environment. What you see results from genes plus environmental factors.
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Which term means two identical alleles for a gene?
Which term means two identical alleles for a gene?
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Homozygous. Same alleles inherited from both parents (AA or aa).
Homozygous. Same alleles inherited from both parents (AA or aa).
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Which term means two different alleles for a gene?
Which term means two different alleles for a gene?
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Heterozygous. Different alleles from each parent (Aa).
Heterozygous. Different alleles from each parent (Aa).
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What is a mutation in DNA?
What is a mutation in DNA?
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A change in the DNA sequence. Can be harmful, beneficial, or neutral.
A change in the DNA sequence. Can be harmful, beneficial, or neutral.
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Which process creates new alleles and is the ultimate source of variation?
Which process creates new alleles and is the ultimate source of variation?
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Mutation. Only mutations can create brand new genetic variants.
Mutation. Only mutations can create brand new genetic variants.
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Which process randomly separates chromosomes into gametes, increasing variation?
Which process randomly separates chromosomes into gametes, increasing variation?
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Independent assortment. Chromosomes sort randomly into sex cells.
Independent assortment. Chromosomes sort randomly into sex cells.
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Which event combines alleles from two parents and increases variation?
Which event combines alleles from two parents and increases variation?
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Random fertilization. Any sperm can fertilize any egg, mixing parental genes.
Random fertilization. Any sperm can fertilize any egg, mixing parental genes.
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What is gene flow?
What is gene flow?
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Movement of alleles into or out of a population via migration. Introduces new alleles when organisms move between groups.
Movement of alleles into or out of a population via migration. Introduces new alleles when organisms move between groups.
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Which type of variation is caused by different alleles (not environment)?
Which type of variation is caused by different alleles (not environment)?
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Genetic variation. Inherited differences, not changes from lifestyle or environment.
Genetic variation. Inherited differences, not changes from lifestyle or environment.
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Identify the best evidence of genetic variation: different eye colors or different suntans?
Identify the best evidence of genetic variation: different eye colors or different suntans?
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Different eye colors. Eye color is inherited; suntans are environmental.
Different eye colors. Eye color is inherited; suntans are environmental.
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What is a gene locus?
What is a gene locus?
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The specific location of a gene on a chromosome. Like an address for finding a gene on its chromosome.
The specific location of a gene on a chromosome. Like an address for finding a gene on its chromosome.
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What is genetic variation within a population?
What is genetic variation within a population?
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Differences in DNA (alleles) among individuals of the same species. These differences create the variety we see within a species.
Differences in DNA (alleles) among individuals of the same species. These differences create the variety we see within a species.
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Which situation is an example of gene flow: mutation in one bird or birds migrating and breeding?
Which situation is an example of gene flow: mutation in one bird or birds migrating and breeding?
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Birds migrating and breeding. Movement and reproduction transfers alleles between populations.
Birds migrating and breeding. Movement and reproduction transfers alleles between populations.
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