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17 Cards in this Set
- Front
- Back
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speciation
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the process by which one species splits into two or more species
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species
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group of populations whose members have the potential to interbreed in nature and produce biable, fertile offspring-but do not produce viable fertile offsprings with members of other such groups
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reproductive isolation
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the existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring
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hybrids
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offspring that resul from an inspecific mating
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prezygotic barriers
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(before the zygote) block fertilization from occuring
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postzygotic barriers
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(after the zygote) may contribute to reproductive isolation after the hybrid zygote is formed
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morphological species concept
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characterizes a species by body shape and other structural feaures
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ecological species concept
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views a species in terms of its ecologicalniche, the sum of how members of the species interact with the nonliving and living parts of their environment
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phylogenetic species concept
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defines a species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life.
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allopatric speciation
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gene flow is interrupted when a population is divided into geographically isolated subpopulations
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sympatric speciation
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speciation occurs in populations that live in the same geographic area
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polyploidy
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when a species may originate from an accident during cell division and results in extra sets of chromosomes
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autopolyploidy
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an individual that has more than 2 chromosomes sets that are all derived from a single species.
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allopolyploid
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when various mechanisms can change a sterile hybrid into a fertile polyploid
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hybrid zone
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a region in which members of different species meet and mate, producing at least some offspring of mixed ancestry
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reinforcement
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when barriers to reproductive between species should be stronger for sympatric species than for allopatric species
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punctuated equilibria
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in the fossil record, long periods of apparent stasis, in which a species undergoes little or no morphological change, interrupted by relatively brief periods of sudden change
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