BIOL 1082 Lecture Notes - Lecture 5: Chromosome, Meiosis, Allopatric Speciation
Document Summary
Thus, the members of biological species are united by being reproductively compatible. Such barriers block gene flow between the species and limit the formation of hybrids, offspring that result from an interspecific mating. Such barriers typically act in one of three ways: by impeding members of different species from attempting to mate, by preventing an attempted mating from being completed successfully, or by hindering fertilization if mating is completed successfully. Postzygotic barriers may contribute to reproductive isolation after the hybrid zygote is formed. Developmental errors may reduce survival among hybrid embryos. Or problems after birth may cause hybrids to be infertile or decrease their chance of surviving long enough to reproduce. Strengths: it directs our attention to a way by which speciation can occur: by the evolution of reproductive isolation. Weaknesses: the number of species to which this concept can be applied is limited.
