KINE 2011 Chapter Notes - Chapter 6.8: Gene Flow, Sexual Selection, Gamete

• School: York University
• Department: Kinesiology & Health Science
• Course: KINE 2011
• Professor: Ali Abdul Sater

Document Summary

Lo f4: geographic modes of speciation: allopatric speciation: speciation that results from geographic separation. Geographic separatio(cid:374) does(cid:374)"t fully (cid:272)ause spe(cid:272)iatio(cid:374), (cid:271)ut it is the first step. Most pre(cid:448)ale(cid:374)t (cid:449)ay for divergent evolution to occur (a node splits into two). Most common form of speciation for larger organisms. Usually happens when a physical barrier (like a highway) subdivides the population or when a small part of the population gets separated from the rest of the population (founder effect). In allopatric speciation, not all barriers are equal- different barriers isolate different organisms. A barrier to one species, may not be a barrier for another species. Geographic isolation does not (cid:374)e(cid:272)essarily (cid:373)ea(cid:374) the t(cid:449)o parts are (cid:374)o(cid:449) reprodu(cid:272)ti(cid:448)ely isolated, (cid:271)ut it"s possi(cid:271)le. Can occur by- vicariance: a physical barrier develops and splits the population (highway/ glacier/ river), or by dispersal & colonization: a small part of the population splits off. This limits the genetic exchange between the populations- removes gene flow.