ANTH 1102 Lecture Notes - Lecture 13: Stabilizing Selection, Natural Selection, Sexual Selection
13 Sep 2016
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Document Summary
Darwin"s missing keys: how inheritance worked. Why siblings varied: where variation came from. How new traits appeared: how population change. Discovered genes: traits determined by discrete inherited particles, occur in pairs and show dominance and recessives, gregor mendel. Variability: laws of independent assortment and recombination. Creates the genetic variability between siblings: meiosis cell division (separation, fertilization (recombination) Punnett square: trait = eye color, b for brown (dominant, b for blue (recessive, b for green (recessive, bb = father, gg = mother, phenotypes. Half have green/blue eyes: simple/discrete traits vs. complex/polygenic traits. Crossing over: chromosomes intertwine and exchange dna during meiosis. Mutations: primary source of all new variation: spontaneous alteration of genetic material (dna) Natural selection: forms most reproductively successful are selected: environmental adaptation, directional selection, sexual selection, stabilizing selection. Random genetic drift: gene frequency changes due to chance: increases chance for speciation. Gene flow: exchange genetic material through interbreeding: decreases chance for speciation.
