Download DISRUPTING GENETIC EQUILIBRIUM

GENETIC EQUILIBRIUM I
pp. 321-325
WHAT IS EQUILIBRIUM?
 No net change in the population
 Evolution is likely not occurring
Hardy-Weinberg Principles
To stay in equilibrium:
 No natural selection
 No mutations
 No gene flow
 Infinitely large population
 Mating is random
WHAT PUSHES A POPULATION
OUT OF EQUILIBRIUM?
I. Natural selection
Organisms best suited to their environment
live to reproduce and pass on their genes
Acts on a phenotype
Varying types of selection
directional selection: individuals with a
more extreme form of trait have higher
fitness
stabilizing selection: having average form of
trait has highest fitness
disruptive selection: individuals with any
extreme trait has a higher fitness
sexual selection: choose mates based on
specific traits and those traits increase in
the population