01:119:115 Lecture Notes - Lecture 36: Disruptive Selection, Stabilizing Selection, Zygosity
5 Apr 2016
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V natural selection ( a closer look: natural selection acts on phenotype. B: phenotypic variation results from different alleles. Three types of selection can change normal distribution. Stabilizing selection favors intermediate variants and acts against extreme phenotypes. Directional selection favors individuals at one end of the phenotypic range. Disruptive selection favors individuals at both extremes of the phenotypic range. Species is a latin word meaning kind or appearance . Speciation- processes where one species splits into two new species. Microevolution- changes over time in the alleles in a population. Macroevolution- a broad pattern where species are formed. The biological species concept states that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring; they do not breed successfully with other populations. Gene flow between populations holds the phenotype of a population together.
