Biology 1001A Chapter Notes - Chapter 18: Genotype Frequency, Allele Frequency, Stabilizing Selection
25 Nov 2016
School
Department
Course
Professor
Document Summary
Quantitative variation: individuals differ in small, incremental ways. The width of the curve is proportional to the variability the amount of variation among individuals, and the mean describes the average value of the character. Qualitative variation: they exist in two or more discrete states, and intermediate forms are often absent. Polymorphism: the existence of discrete variants of a character. Phenotypic variation: differences in appearance or function among individuals of a population. May be caused by genetic differences, environmental differences, or an interaction between genetics and the environment. Only genetically based variation is subject to evolutionary change. It is the phenotype of an organism, rather than its genotype that makes it successful or not. Organisms with different genotypes often exhibit the same phenotype. Organisms with the same genotype sometimes exhibit different phenotypes. We can test for an environmental cause experimentally by changing one environmental variable and measuring the effects on genetically similar subjects.
