BIOB51H3 Lecture 19: Lecture 19
Document Summary
A lot of different ways to define species. Slide 7: species are evolutionary independent of their trajectories, mechanisms of evolution operating independently leads to differences in allele frequencies. Slide 8: talking about sexual species, species not in same geographical space, gene flow is critical: allele frequencies remain similar; species can have unique characteristics. I(cid:373)po(cid:396)ta(cid:374)t that ge(cid:374)e flo(cid:449) is a(cid:373)o(cid:374)g those populatio(cid:374)s if they"(cid:396)e to (cid:396)e(cid:373)ai(cid:374) (cid:272)ohesi(cid:448)e spe(cid:272)ies than other species but common across that one species. Slide 11: allopatric speciation: populations become geographically isolated, sympatric speciation: much harder for this to happen, prefer particular habitats and become adapted to them. Slide 12: diagram shows steps: start out with (a) group of populations that are isolated, divergence occurs, reproductive isolation? (a/b) Slide 16: results show that hypothesis is correct, stepping stone model corresponds to phylogenetic tree, many different types of flies, group of flies have many different types of food sources, corresponds to branching pattern.
