Famous Bad Decisions 1886 -Sors Hariezon 1933-Joe Shuster & Jerry Siegel 1955-Sam Phillips 1862 - Ambrose Burnside 1876 - George Custer 1929 – Trofim Lysenko • Head of Soviet Ministry of Agriculture • Strong advocate of Lamarckian Evolution (acquired characteristics) • Attempted to vernalize wheat by freezing prior to germination Differential Reproduction • The driving force behind evolution • Populations shift because not all members of the population have the same fitness • Nature provides selective pressures that determine who reproduces most Selective Pressure • Nature “selects” for various phenotypes based upon whether or not the features of the organism increase its differential reproduction Modes of Natural Selection • Stabilizing: Favors average phenotypes • Directional: one phenotypic extreme favored • Disruptive: Both extreme phenotypes are favored Directional Selection & Industrial Melanism (Kettlewell Moth Experiment) Transitioning Phenotypes Stabilizing Selection Stabilizing Selection Disruptive Selection Disruptive Selection Endler’s Trinidadian Guppy Analysis Trinidadian Guppy Analysis • Purpose: To see how the selective pressures of coloration and predation affect the phenotypic distribution in a population • Hypotheses to Be Tested: – Bright coloration leads to preferential mating, causing the population to shift towards bright. – Bright coloration leads to increased predation, leading to a phenotypic shift towards drab Procedure • To access simulation, google “Sex and the Single Guppy” • There are nine (9) combinations of predator and prey to test. • Each simulation should be run for 100 weeks. Stop manually at this point • BEFORE looking at analysis of results, record the phenotypic results, pop. size and # of Generations