BIOL 112 Lecture Notes - Lecture 4: Allopatric Speciation, Zygote, Meiosis
Document Summary
Speciation: new species come about through isolation and modification. Isolation: a population needs to become reproductively isolated; there needs to be no gene flow between a population and it"s neighbors; no gene flow. Speciation is very closely related to gene flow: origin of new species, focal point of evolutionary theory, barriers to reproduction can lead to isolation. Species concepts: biological species concepts: ability to produce offspring, morphospecies; physical structures, phylogenetic species; groups criteria to designate species. Isolating mechanisms preventing interbreeding: extrinsic: physical barriers; (mountains/rivers) Reproductive isolation, changes through microevolution, genetic divergence, barriers to interbreeding: speciation. Have to start speciation with reproductive isolation tion. Sister species of snapping shrimp separated by the isthmus of panama. Founder effects can fly; mice cannot; fish can swim. Sym: same, patric: fatherland; they live in the same place. Separation due to intrinsic, reproductive barriers in geographically overlapping population: gene flow is reduced in absence of a geographic barrier.
