BIOA01H3 Lecture Notes - Lecture 5: Balancing Selection, Biogeography, Sexual Selection

• School: UTSC
• Department: Biological Sciences
• Course: BIOA01H3
• Professor: Shelley Brunt

Document Summary

Sexual selection always favours traits that increase an individuals access to reproductive opportunities. Negative frequency-dependent selection and balancing selection maintain polymorphisms overtime. Various forms of selection that lead to the active maintenance of genetic va in natural populations. Alleles are said to be balanced because a stable equilibrium state is reach. If allele frequencies are disturbed from this equilibrium, selection will return back to that state. The relative fitness of genotypes are not constant but vary with their frequen the population. Fitness of a genotype increases as it"s frequency decreases. Recall: fitness is the ability to survive to reproductive age, find a ma produce offspring (the more offspring an organism produces during it lifetime, the greater it"s biological fitness) Natural selection does not necessarily lead to an absolute optimum in a particular trait. Why is evolution so controversial? ccess to ntain tic variation s reached eturn them equencies in a mate and ing its in a.