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29 Cards in this Set
- Front
- Back
Evolution
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Change over time; process by which modern organisms have descended from ancient organisms
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Theory
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a well-supported testable explanation of phenomena that have occurred in the natural world
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Fossil
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the preserved remains of ancient organisms
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Artificial Selection
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a process by which nature provided genetic variation in organisms, and humans select those variations that they find useful.
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Struggle for existence
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the competition within a species for resources, such as food, living space, and other necessities of life.
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Fittness
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How suitable an organism is to survive
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Adaptation
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a inherited trait that helps an organism survive and reproduce
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Survival of the fittest
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A theory developed by Darwin, that states organisms more fit for their specific environment (adaptations) survive and reproduce more successfully than those without
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Natural Selection
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process by which individuals that are better suited to their environment survive and reproduce more successfully
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Descent with modification
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the theory that all species have descended, with changes, from other species over time
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Common descent
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The principle that states that all species- living and nonliving- were derived from a common ancestor.
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Homologous structures
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Structures that have different mature forms but develop from the same embryonic tissue; provides strong evidence that all 4 limbed vertebrates have descended.
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Vestigial organs
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traces of organs in other species; organs that do not serve a function
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Gene pool
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common group of genes (all alleles) that are present in a specific population
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Relative frequency
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the number of times an allele appears in a gene pool
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Single gene trait
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a trait that is controlled by one one gene, such as a widows peak
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Polygenic trait
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traits that are controlled by two or more genes, which usually has two or more alleles
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Speciation
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Formation of new species
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genetic drift
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random change in allele frequency
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founder effect
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a situation in which allele frequencies change as a result of the migration of a small subgroup of a population
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genetic equilibrium
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when allele frequencies remain the same
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Hardy-Weinberg principle
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states that allele frequency in a population will remain constant unless one or more factors cause these frequencies to change
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Reproductive Isolation
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when 2 populations cannot interbreed and produce fertile offspring
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Directional selection
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when individuals at one end of the curve have higher fitness than individuals in the middle or at the other end
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stabilizing selection
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when individuals near the center of the curve have higher fitness than individuals at either end of the curve
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disruptive selection
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when individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle
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behavioral isolation
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when 2 pop. are capable of interbreeding but have different mating behavior
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geographic isolation
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when 2. pop are seperated by a geographical barrier
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temporal isolation
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when 2 or more species reproduce at different times
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