LIFESCI 3C03 Chapter Notes - Chapter 23: Reproductive Isolation, Zygote, Evolutionary Radiation
Document Summary
We can recognize and identify many species by their appearance. Linnaeus described hundreds of species on the basis of their appearance morphological species concept. Species form over time: each species starts at a speciation event and ends at either extinction or another speciation event, at which it produces two daughter species. If individuals of a population mate with one another, but not with individuals of other populations, they constitute a distinct group within which genes recombine. Allopatric speciation requires almost complete genetic isolation: speciation that results when a populations is divided by a physical barrier. If individuals of two different populations lack complete prezygotic reproductive barriers, postzygotic reproductive barriers may still prevent gene exchange. Individuals that mate with individuals of the related species should evolve prezygotic reproductive barriers more rapidly that allopatric pairs of species. Hybrid zones may form if reproductive isolation is incomplete.