Evidence%20for%20evolution

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Evidence for evolution
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Darwins key ideas

• A. REPRODUCTION Organisms produce more offspring
  than can survive
• B. VARIATIONVariety in traits exist
• C. SURVIVAL OF THE FIT Some traits allow
  survival are passed on
• D. Over time certain variations make up most of a
  population they may be different from their
  ancestors

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Evidence for Evolution

• 1. Fossil record
• 2. Comparative anatomy
• 3. Comparative embryology
• 4. Comparative biochemistry
• 5. Plate tectonics

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Fossil Evidence

• Remains of once living organisms provide evidence
  of change over time.
• Limited
• Type of material preserved (bone, shell,
  impressions, amber)
• Incomplete record
• Easily disrupted

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Plant Fossil Evidence
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Law of superposition
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Comparative Anatomy Structural similarities
link related species
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Homologous Structures

• Same underlying structures, different
  functions, different environments common
  ancestor

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Homologous structures in plants
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Vestigial Structures

• Structures that are present in an organism but
  are reduced in size and either have no use or
  have a less important function than they do in
  other related organisms.

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Snake Human
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Comparative embryology

• Similar embryo development in closely related
  species

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5.Comparative Biochemistry

• Similar DNA sequences code for similar traits in
  closely related species.

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Plate Tectonics(Geographical distribution)

• Continental masses were one land mass

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• Closely related species have common ancestors on
  now separated continents

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