BLG 567 Lecture Notes - Lecture 5: Polymerase Chain Reaction, Single-Nucleotide Polymorphism, Ecological Speciation
Document Summary
Biospecies: when organisms can potentially breed together to produce fertile offspring. 2 components of ecological speciation: ecological source of divergent selection, means of reproductive isolation. Process of ecological speciation: two subpopulations become geographically isolated, reproductive isolation builds up, subpopulations re-meet, natural selection favours all features that reinforces reproductive isolation. Allopatric phase: when subpopulations are in different places. Restores genetic diversity by introducing new alleles. Mostly results in deleterious alleles (lower fitness), these are usually eliminated by selection. Without mutation, evolution would eventually stop (no new alleles) Climatic change, the evolution, and distribution of species: Present distribution of species is a result from past climatic changes. Present day flora and fauna developed in warm climates. As ice retreated from last ice age, different forest species advance in different ways at different speeds. Organisms that have evolved in isolation from each other and then converged on similar forms of behaviour or function.
