BIO152H5 Lecture Notes - Lecture 20: Hermit Warbler, Allopatric Speciation, Hybrid Zone
Document Summary
Hawthorn flies native to north america. Apple trees introduced to north america. Maggot flies" original habitat was hawthorn trees. Apples mature faster than hawthorn fruit and natural selection favored apple-feeding flies. Isolation due to preference of habitation: apple-feeding flies show temporal isolation from hawthorn feeding flies: prezygotic restriction to gene flow. Occurs when populations become isolated by habitat preference is an important cause of speciation in sympatric populations. Breeding coloration (mate choice) is the main reproductive barrier that keeps the 2 species separate. Under monochromatic light, females mate with other species because the colouration of the two is the same. Genetic changes accumulate as a result of natural selection, genetic drift, sexual selection. Sympatric speciation: no geographic isolation - rarer than allopatric speciation, polyploidy, habitat/food preference, sexual selection. A geographic area where interbreeding between two species is common and fertile hybrid offspring are produced.
