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23 Cards in this Set
- Front
- Back
What is natural selection?
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Natural selection is the impact of all abiotic and biotic factors in a specific environment on the allele frequency of a population.
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What does natural selection result in?
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Natural selection results in populations that are better adapted to reproduce in a specific environment.
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What is essential for natural selection to occur?
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genetic variation
differential reproduction heredity |
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What is the source of new alleles in a population?
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Mutation
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What factors can act as agents of natural selection?
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All abiotic (non-living) and and biotic (living) factors can act as agents of natural selection.
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What are some examples of abiotic factors?
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Abiotic factors are non-living.
temperature cloud cover water rain snow fog water currents waves |
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What are some examples of biotic factors?
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Biotic factors are living.
competition predation (carnivory, herbivory) symbiosis (disease, mutualism, parasitism) |
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What does natural selection increase?
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Natural selection increases the ability to reproduce in a specific environment.
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What are the results of natural selcton?
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Natural selection results in populations that are better adapted to reproduce in a specific environment.
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Alleles that increase reproduction always _________ in frequency in the future.
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increase
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Alleles that reduce reproduction always ________ in frequency in the future.
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decline
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What does natural selection impact?
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Natural selection impacts the frequency of alleles that affect reproduction in a specific environment.
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What does sexual reproduction increase in populations?
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genetic variation
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What is the source of new alleles in a population?
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mutation
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Besides mutation, what else can create new alleles into populations?
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migration
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Explain meiosis.
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Meiosis generates all possible combinations of our maternal and paternal chromosomes in the gametes we produce.
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Explain crossing-over in meiosis.
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Crossing-over during meiosis forms new combinations of maternal and paternal alleles on a single chromosome that can cause new phenotypes.
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Why do some populations that reproduce asexually consist of genetically-diverse individuals?
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Due to mutation, genetic variation does occur in populations that reproduce asexually.
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What is the benefit of natural selection?
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Natural selection maximizes the reproductive ability of individuals in an environment (increases "fitness").
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What is necessary to coordinate reproduction?
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A successful genome has the alleles necessary to coordinate reproduction so it is transmitted to the next generation.
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What is the benefit of negative health consequences?
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Alleles with negative health consequences exist in populations because they increase reproduction.
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What is the benefit of disease-promoting alleles?
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Disease-promoting alleles exist in populations because they increase reproduction in heterozygotes.
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What is the heterozygote advantage?
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One copy of the sickle-cell allele increases resistance to malaria.
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