Hardy-Weinberg Genetic Equilibrium

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Hardy-Weinberg Genetic Equilibrium

• Hardy-Weinberg equilibrium describes populations
  that are not evolving
• Genotype frequencies stay the same over time as
  long as certain conditions are met
• Very large populations
• No emigration or immigration
• No mutations
• Random mating
• No natural selection

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DISRUPTING GENETIC EQUILIBRIUM

• CH. 16-2 PP. 321-325

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Definitions..

• Evolution is the change in a populations genetic
  material (alleles) over generations.

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Definitions..

• Evolution is the change in a populations genetic
  material (alleles) over generations.
• A population is in genetic equilibrium if its
  not evolving

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WHAT PUSHES A POPULATION OUT OF EQUILIBRIUM?
5 Factors
Population is in equilibrium
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I. Mutation

• Produces and introduces new alleles in a
  population
• New allele can create beneficial trait

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II. Migration/ Gene Flow

• Movement of individuals in or out of a population
• Immigration In (Entering population)
• Emigration Out (Leaving population)

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III. Genetic Drift

• The amount of an allele changes due to random
  events (EX extreme weather, disease, habitat
  destruction, etc)

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III. Genetic Drift

• The amount of an allele changes due to random
  events (EX extreme weather, disease, habitat
  destruction, etc)
• Affects small populations mostly

Population of the nearly extinct northern
Elephant Seal have lost genetic
variabilityindividuals are homozygous for all
their genes tested. This result of genetic drift
makes the species vulnerable to extinction.
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III. Genetic Drift

• The amount of an allele changes due to random
  events (EX extreme weather, disease, habitat
  destruction, etc)
• Affects small populations mostly
• Lose alleles if not enough to mate or a
  catastrophe occurs

Population of the nearly extinct northern
Elephant Seal have lost genetic
variabilityindividuals are homozygous for all
their genes tested. This result of genetic drift
makes the species vulnerable to extinction.
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IV. Natural Selection (3 Types)

• Organisms best suited to their environment live
  to reproduce and pass on their genes
• Acts on a phenotype

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V. NON-RANDOM MATING

• Can amplify certain traits and reduce others
  through sexual selection

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V. NON-RANDOM MATING

• Sexual Selection - Choose mates based on specific
  traits and those traits increase in the
  population
• EX Peacock tails
• Tails are bright and heavy. Only the males who
  are able to get away from predators and have
  enough energy to grow a tail must have the best
  traits.

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Class work

• Hardy Weinberg Scenarios and Chart