BIOL 1004 Lecture Notes - Lecture 3: Species Problem, Genetic Drift, Secondary Sex Characteristic
2 Dec 2017
School
Department
Course
Professor
Document Summary
Microevolution is the change in allele frequencies in a population over generations. There are three main mechanisms that can cause allele frequency change: natural selection, genetic drift (chance events that alter allele frequencies), and gene flow (the transfer of alleles between populations). Of all these, only natural selection consistently improves the match between organisms and their environment (adaptation). Quantitative variation: continuous variable, i. e. how height is. We"re all different heights, no one is like super freak tall or midget or whatever like we"re all on a certain level of the scale. Most heritable variations involve quantitative characteristics which vary along a continuum within a population. Often resulting from the influence of two or more genes on a single phenotypic character. Gene variability can be measured at the whole gene level or at the molecular level of dna. Gene variability can be quantified as the average heterozygosity (the average percentage of loci that are heterozygous).
