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