Chapter17 - few) or founder effect (migration of a few) 3...

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1 Chapter 17 Microevolution Sections 17.1-17.3 only Definitions Species: Group of organisms that successfully interbreed in nature Population: Members of a species living in one defined area Gene pool: all the alleles that exist in a population Two scales of evolution Microevolution: change in the frequency of alleles in the population Macroevolution: formation of new species or categories of living things 5 ways to change allele frequency Mutation Gene Flow Genetic Drift Sexual selection Natural Selection
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2 Mutation Any permanent alteration in an organism’s DNA Point mutations (one nucleotide) Parts of chromosomes Only way to create new alleles Gene Flow New individuals migrate into a population Animals: moving around Plants: seed dispersal Example of one-way gene flow: isolated islands such as Hawaii Genetic Drift Chance alteration of allele frequency Smaller populations are most susceptible Populations become small by bottleneck effect (survival of a
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Unformatted text preview: few) or founder effect (migration of a few) 3 Example of bottleneck effect Founder Effect Small subpopulation migrates to a new area Random chance affects gene pool in new place Example: blindness caused by cornea plana 113 people worldwide, but 78 of them live in Northern Finland Inbreeding Mating of close relatives High chance of two recessive alleles Example: dog breeds Cocker spaniels: low genetic diversity Breeders only mate cocker spaniels with each other Floppy ears, but also frequent ear infections and instances of unprovoked aggression Sexual selection Some individuals get more mating partners and produce more offspring In species where this is important, usually females choose the mates Example: sage grouse 4 Natural Selection Traits that give survival or reproductive advantage increase over generations Works to adapt individuals to their environment...
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Chapter17 - few) or founder effect (migration of a few) 3...

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