Biology 1001A Lecture Notes - Lecture 21: Reproductive Isolation, Sympatric Speciation, Disruptive Selection

• School: Western University
• Department: Biology
• Course: Biology 1001A
• Professor: Beth Mac Dougall- Shackleton

Document Summary

(cid:1005)5(cid:1004)+ years after the origi(cid:374) of pe(cid:272)ies, there(cid:859)s still (cid:374)o perfe(cid:272)t defi(cid:374)itio(cid:374) of spe(cid:272)ies. Over 50 species concepts have been proposed. Criteria used by morphological, biological and phylogenetic species concepts to define species. Species: (cid:862)disti(cid:374)(cid:272)t (cid:272)luster i(cid:374) phe(cid:374)otypi(cid:272) spa(cid:272)e, (cid:374)o(cid:374)- o(cid:448)erlappi(cid:374)g (cid:449)ith other (cid:272)lusters(cid:863) Uses visible anatomical characteristics to classify species; individuals of one species share measurable traits that distinguish them from other species. Things that look the same probably belong to the same species. Biological species concept: reproductive isolation & shared gene pool. Species: (cid:862)i(cid:374)ter(cid:271)reedi(cid:374)g or pote(cid:374)tially i(cid:374)ter(cid:271)reedi(cid:374)g group of i(cid:374)di(cid:448)iduals, reprodu(cid:272)ti(cid:448)ely isolated fro(cid:373) other su(cid:272)h groups(cid:863) Things that freely interbreed + produce fertile offspring belong to the same species. Emphasizes genetic cohesiveness (same species experiences gene flow) and also genetic distinctness (populations of diff species cannot exchange information) If two populations interbreed naturally and produce fertile offspring under natural conditions, they are part of the same species. Donkeys and horses interbreed but mules are sterile.