Mechanisms of Evolution

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Mechanisms of Evolution
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Genetic Equilibrium

• No change in allele frequencies thus evolution is
  not occuring!!

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• Microevolution
• changes in the allele frequencies within a
  population
• due to
• Genetic Drift (small populations bottleneck,
  founder effect)
• Gene flow (immigration emigration)
• Non-random mating
• Genetic mutations Variation
• Natural Selection

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Genetic Drift
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Better Beak Extensions
My Mutation Combo Total Seeds
Rd. 1
Rd. 2
1. Describe how natural selection played a role
in the evolution of the birds.2. Explain what
type of selection was displayed directional,
disruptive or stabilizing - at the conclusion
of the evolution of the birds in our
simulation.3. Explain how genetic drift
contributed to the evolution of the bird
types.Watch a real example.
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Speciation

• New species develop due to evolutionary changes
  that prevent them from interbreeding.
• Some mechanisms for speciation include 3 types of
  isolation that ultimately create
  Reproductive Isolation(the inability of species
  to successfully mate with each other)Typically
  result due to these types of isolation
• Behavioral interaction changes that result from
  isolation
• Geographic physical separation of the original
  population
• Temporal changes that result in different
  active times or mating times
• Examples

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Patterns of Evolution

• Extinctions
• The disappearance of species opens doors for
  others to fill those empty niches.

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Patterns of Evolution

• Adaptive Radiation
• The process of a single species developing into
  diverse forms that live in different ways
• Homologous Structures are a key to this!

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Patterns of Evolution

• Convergent Evolution
• Unrelated organisms develop similar solutions
  to evolutionary pressures
• Analogous Structures!

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Patterns of Evolution

• Co-evolution

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Tempo of Evolution

• Punctuated Vs. Gradualism