EVOLUTION

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EVOLUTION

• Process that results in genetic change (gene
  frequencies) over time and space
• gene frequencies are examined in populations
• explains differences among
• existing population (space)
• lineages of populations (time)

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What are the mechanisms (processes) of evolution?

• mutation
• migration
• chance
• natural selection

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But what about SEXUAL REPRODUCTION?
no change in time or space
SIGNIFICANCE?
Time 1
within population variation
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Evolutionary Mechanisms

• Mutation

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Mutations affecting tree form
Lombardy poplar Populus nigra var. italica
weeping willow Salix babylonica
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SIGNIFICANCE?
MUTATION
Time 1
ultimate source of variation
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Evolutionary Mechanisms

• Mutation
• Migration

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SEEDS CARRY GENES
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POLLEN GRAINS CARRY GENES
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MIGRATION
SIGNIFICANCE?
Time 1
adds new genes (or source of stabilization)
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Evolutionary Mechanisms

• Mutation
• Migration
• Chance

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CHANCE EVENTS
SIGNIFICANCE?
Time 1
genetic drift
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CHANCE EVENTS
SIGNIFICANCE?
Time 1
founder effect
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Evolutionary Mechanisms

• Mutation
• Migration
• Chance
• Natural Selection
• (environment)

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SNOW
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(No Transcript)
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GROUND FIRE
Thick bark
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Open Fire Scar
Burried Fire scar
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CROWN FIRE
Serotinous cones
Root sprouts
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predators
crossbill
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NATURAL SELECTION
Time 1
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SIGNIFICANCE?
ADAPTATION genetically determined traits that
convey advantage for survival and reproduction in
a particular environment
SPECIATION (later)