Transcript DISRUPTING GENETIC EQUILIBRIUM

Warm-up 2/21:
Describe what happened with the gene pool
with the mice from yesterdays video.
(Min. 3 sentences & use as much Vocab as
you can.)
What are the five assumptions that must
hold true to achieve genetic equilibrium?
DISRUPTING GENETIC
EQUILIBRIUM
Ch. 16-2 pp. 321-325
Definitions..
Evolution is the change in a population’s
genetic material (alleles) over
generations.
 A population is in genetic equilibrium if
it’s not evolving
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WHAT PUSHES A POPULATION OUT OF
EQUILIBRIUM?
Population is in
equilibrium
5 Factors
I. Mutation

Produces and introduces new alleles in a population
II. Migration/ Gene Flow

Movement of individuals in or out of a population
 Immigration
– In (Entering population)
 Emigration – Out (Leaving population)
III. Genetic Drift
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The amount of an allele changes due to random events
Affects small populations mostly
Lose alleles if not enough to mate or a catastrophe occurs
IV. Natural Selection (3 Types)
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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
Normal Distribution
Distribution after Selection
Stabilizing Selection
Having average form of trait has highest fitness
Normal Distribution
Distribution after Selection
Disruptive Selection
Individuals with any extreme trait has a higher fitness
and most likely results in two new species
Normal Distribution
Distribution after Selection
V. Non-random mating

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Can amplify certain traits and reduce others through
sexual selection
Sexual Selection - Choose mates based on specific
traits and those traits increase in the population
HW:
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Quiz on Friday.
Vocab (Tri-fold) for: Gene Flow, Genetic Drift,
Stabilizing Selection, Disruptive Selection,
Directional Selection.
Read p 321-325 Do problem p 325 #2-5