BIOL 3130 Lecture Notes - Lecture 7: Outbreeding Depression, Species Richness, Allopatric Speciation

• School: University of Guelph
• Department: Biology
• Course: BIOL 3130
• Professor: Andrew Mac Dougall

Document Summary

Biological homogenization: biological homogenization: the homogenization of habitat conditions and species around the globe, as a result of human activity, ecological: lost and gained specialization, evolutionary: reverse speciation. Study: impact of nitrogen deposition on the species richness of grasslands (n in soil), forest fires trade-offs. Environment changes to favour a small subset of species (loss of heterogeneity) Geographical theories of speciation predict that the probability of speciation occurring within a given region should: Increase with the size of the region b/c of the greater opportunity for divergence within the region. Larger ranges affect the ratio b/w distance between individuals & populations, vs the distance of gene flow: allopatric speciation can occur when distance b/w populations exceeds dispersal range (gene flow) One migrant per generation rule: too little gene flow= inbreeding depression (eg. loss of polymorphs and heterozygosity, too (cid:373)u(cid:272)h p(cid:396)e(cid:448)e(cid:374)ti(cid:374)g lo(cid:272)al spe(cid:272)ializatio(cid:374) a(cid:374)d (cid:858)out(cid:271)(cid:396)eedi(cid:374)g dep(cid:396)essio(cid:374)(cid:859)