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14 Cards in this Set
- Front
- Back
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Allowpatric speciation
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Occurs by geographical isolation (separates the populations)
Leads to divergence by genetic drift or natural selection |
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Sympathetic speciation
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Occurs by ecological isolation (same geographical area has more than one distinct habitat) and subsequent divergence or by rapid chromosomal change.
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Polyploidy
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Happens in plants when a fertilized egg copies it's DNA but doesn't divide.
If resulting cell divisions are normal, organism is tetraploid |
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Isolating mechanisms
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Structural and/or behavioral modifications that prevent interbreeding
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Pre-mating isolating mechanisms
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Incompatibilities that prevent mating between species
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Post-mating isolating mechanisms
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Incompatibilities that prevent the formation of vigorous, fertile hybrids between species
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Geographic isolation
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Prevents members of different species from ever meeting
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Geographic isolation
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Prevents members of different species from ever meeting
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Ecological isolation
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Confines members of different species to different habitats; rarely interact
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Temporal isolation
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Different species that inhabit the same habitat cannot mate if they have different mating seasons
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Behavioral isolation
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Elaborate courtship rituals
Includes bright colors and specific mating calls Attract members of the opposite sex but members of different species are indifferent to them |
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Mechanical incompatibility
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Reproductive parts don't fit together
Some species use internal fertilization and some use external Individuals using different types would have trouble combining DNA |
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Gametic incompatibility
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When male inseminates female but the sperm may not fertilize the eggs
Fluids in the female reproductive tract may weaken or kill sperm from other species How plants prevent pollination from a different species |
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Hybrid Inviability
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If fertilization does occur, offspring may not be able to survive
Can be highly coordinated due to attempting to use behaviors of the two different parent species |
