Definitions

• General lineage species concept


  species are metapopulations that exchange alleles frequently enough to comprise the same gene pool
• Phylogenetic species concept


  smallest possible group descending from a common ancestor and recognizable by unique, derived traits
• Biological species concept


  species are groups of interbreeding populations that are reproductively isolated from other such groups
• Geographic isolating barriers


  extrinsic properties of landscape that prevent gene flow
• Reproductive isolating barriers

  Intrinsic features of organisms that prevent interbreeding
• Postmating-prezygotic barriers


  gametic incompatibility- sperm or pollen from one species fails to penetrate and fertilize the egg of another species
• Postzygotic barries 


  prevents zygotes from successfully developing and reproducing themselves
• Bateson-Dobzhansky-Muller incompatibilities 


  arise from epistatic interactions at 2 or more loci
• Allopatric


  speciation that arises from geographic separations
• Sympatric


  Reproductive isolation evolves without geographic isolation
• Parapatric 


  geographic barrier only partially separates populations
• Reinforcement 


  natural selection favors prezygotic reproductive isolation mechanisms that prevent the formation of hybrids with reduced fitness
• Reciprocal selection


  a pair of species evolves in response to one another
• key innovations


  a new trait enables exploitation of many niches
• coevolution

  reciprocal evolutionary change between interacting species, driven by natural selection
• reciprocal selection

  a pair of species evolves in response to one another
• Batesian mimicry

  non-toxic species mimics a toxic species
• microevolution

  evolution occurring within populations
• macroevolution

  evolution above the species level
• dispersal

  movement of populations from one region to another within limited return exchange
• vicariance

  formation of geographic barriers to dispersal that divide a formerly continuous population
• Turnover

  total extinction and originations in a time period
• Cambrian

  high turnover
• Paleozoic

  mid turnover
• Modern

  low turnover