BIOA01H3 Lecture Notes - Lecture 10: Somatic Cell, Meiosis, Hybrid Zone

• School: UTSC
• Department: Biological Sciences
• Course: BIOA01H3
• Professor: Mark Fitzpatrick

Document Summary

Speciation is the creation of new species. If gene flow is limited then divergence occurs through genetic drift, natural selection, mutation. Prezygotic isolation occurs diff species are prevented from mating: occurs b/c: Sexual selection (females attracted to same species) Allopatric speciation: river or glacier (barriers) separates the populations on both sides. Sympatric speciation: no physical barriers but speciation occurs in some of the population: thought spe(cid:272)iatio(cid:374) (cid:272)ould(cid:374)"t o(cid:272)(cid:272)ur (cid:271)/(cid:272) ge(cid:374)e flow was possi(cid:271)le (cid:271)ut (cid:374)atural selection overpowers, occurs b/c diff pops prefer diff habitats. Polyploidy condition of having more than two sets of chromosomes: can cause speciation since mutations rarely can alone, example: tetraploid indivs. are separated from wild-type b/c they produce diploid instead of haploid gametes. If the 2 gametes combine, zygote would be triploid which produce gametes with dysfunctional chromosome set. Seedless fruit are triploid (watermelon, oranges, grapes: autopolyploidy from chromosome duplications within a species (usually plants)