Microevolution

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Microevolution
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Microevolution Definition

• Microevolution
• small changes in a species over time.
• Example
• bacterial resistance to antibiotics.

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Main Concept of Microevolution

• 1. You must have genetic variation.
• 2. You have environmental change.
• 3. A combination of forces will cause change.

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Other Key Concepts

• 4. These forces include
• isolation, migration, natural selection and
  mutation.
• 5. These factors will form a slow change of gene
  frequencies over time.

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What give us Genetic Variation

• Mutation
• Change in an organisms DNA.
• Gene Shuffling
• Mixing of genes during the process of
  reproduction.

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Mutation
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DNA
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New OrganismNew Traits

• Traits of Mom Traits of Dad
• B blood A blood
• No widows peak Widows Peak
• Tongue Roller Tongue Roller
• Brown Eyes Blue Eyes
• Black Hair Blonde Hair

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Junior

• AB blood
• No Widows Peak
• Non Tongue Roller
• Hazel Eyes
• Brown Hair

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Genetic Frequency

• How often a particular trait shows up in a
  particular population.
• Usually done by percentage.

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Peppered Moth
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Peppered Moth
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Peppered Moth Genetic Frequency

• Year of Light Moths of Dark Moths
• 1 90
  10
• 2 83
  17
• 3 71
  29
• 4 64
  36
• 5 48
  52
• 6 39
  61
• 7 33
  67
• 8 22
  78
• 9 12
  88
• 10 8
  92

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Natural Selection

• Survival of the Fittest
• Organisms with genes that are suited for their
  environment survive and pass them on.
• Organisms with genes that are not suited for
  their environment die out and do not pass them on.

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Genetic Drift

• Only take place in small populations.
• Some traits will be randomly passed more then
  others therefore showing up more often within a
  population.

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Migration

• Movement of individuals in or out of a
  population.
• Brings in new traits and genes.
• Makes organisms adapt to new environments.

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Isolation

• A barrier forms between members of a population
  not allowing them to mate.
• Could be physical, temporal (reproduce at
  different times) or behavioral.

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Meadowlarks

• Eastern Western

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Islands

• Island Canyon

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Orchids
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Mutations

• Add new traits into a population.
• If those new traits are helpful then they will be
  kept in that population and passed on.