PSYCH 3F03 Lecture Notes - Lecture 5: Natural Selection 2, Genetic Variation, Earwax
Document Summary
Define evolution from a strictly biological perspective and list the 5 mechanisms of evolution. Understand the ultimate source of all genetic variation (it"s mutation) Understand how an allele"s expression influences phenotype. Correction: mutations arise randomly, but the process of adaptive evolution (ns) is not random a biological definition of evolution: Evolution = a change in the frequency of an allele or genotype in a population over time. Allele: a uique copy of a gene (or gene variant: we usually all have the same genes, but what varies are our alleles. Genotype = the genetic constitution of an organism based on the alleles it possesses. Phenotypic evolution: a change in the frequency of alleles, resulting in a change in the distribution of phenotypic traits in a population. Phenotype = the physical expression of a trait (i. e. eye colour, aggressiveness) 5 mechanisms of evolution: natural selection, sexual selection mutations: a novel genetic difference between parents and offspring arise randomly.
