BIOL 1500 Lecture Notes - Lecture 14: Allopatric Speciation, Sympatric Speciation, Carl Linnaeus
6 Oct 2016
School
Department
Course
Professor
Document Summary
In the 1700s, carolus linnaeus defined species by appearance. He also created a naming scheme for species. Each species" name combines the broader classification genus with the term species. Most recently, the biological species concept defines species based on their potential to interbreed and produce fertile offspring. Speciation, the formation of new species, occurs when some individuals can no longer interbreed with the rest of the group. If the potential to interbreed defines species, reproductive isolation results in new species. Postzygotic reproductive barriers reduce the fitness of offspring produced by members of 2 different species: hybrid in-viability hybrid offspring fail to reach maturity, hybrid infertility hybrid offspring unable to reproduce, ex. mules-infertile (female horse and male donkey). Meiosis does not occur in the mule"s germ cells because the two parents contribute different numbers of chromosomes, mules cannot produce gametes and thus are sterile.
