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Evolution 2
Dr. James . Whitfield, Ph.D
Hardy-Weinberg Equilibrium

Five Factors are known to effect HWE,
these include
Hardy-Weinberg Equilibrium
Five Factors are known to effect HWE,
these include
 Gene migration or gene flow

Hardy-Weinberg Equilibrium
Five Factors are known to effect HWE,
these include
 Gene migration or gene flow
 Genetic drift

Hardy-Weinberg Equilibrium
Five Factors are known to effect HWE,
these include
 Gene migration or gene flow
 Genetic drift
 Mutation

Hardy-Weinberg Equilibrium
Five Factors are known to effect HWE,
these include
 Gene migration or gene flow
 Genetic drift
 Mutation
 Genetic recombination

Hardy-Weinberg Equilibrium
Five Factors are known to effect HWE,
these include
 Gene migration or gene flow
 Genetic drift
 Mutation
 Genetic recombination
 Natural selection

Founder Effect

The founder effect can result if genes/alleles
migrate from one population to another.
Genes are lost in the original and added to
the new population. If this migration happens
multiple times it is called gene flow. If the
same changes occur by chance it is called
genetic drift. In any of these cases if the
change is substantial enough speciation may
occur and these individuals will become the
founders of future generations
Founder Effect

The founder effect can also occur as a
result of a genetic bottleneck. A
bottleneck can occur after a natural
disaster or a severe disease that wipes
out a significant percentage of the
population. The surviving population may
not represent the same genetic make-up
as the original population hence the
survivors become the founders of the
new population
Founder Effect

The founder effect can also result as a
consequence of natural selection. Given
enough time natural selection coupled
with gene flow, variation due to
recombination of genes, gene flow and
genetic drift can all lead to speciation.
Three different types of populations may
occur, they are referred to as
Stabilizing

Stabilizing – in stabilizing selection the
average is favored and the extremes are
tightened (less favorable) genetic diversity
is decreased
Robin eggs and human
baby weight, spider size
Directional

Directional – in directional selection both
extremes are favored but at different
times
Bird beaks,
peppered moth
Disruptive

Disruptive – In disruptive selection both
extremes are favored at the same time. It
is not good to be average. Two distinct
populations form
Sea sponges
Rabbits