Evidence of Evolution Part II

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Evidence of EvolutionPart II

• The study of living organisms reveals secrets of
  ancestry

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Theory of Evolution

• All life on Earth descended from a common
  ancestor
• Life originated as a simple form, and became more
  diverse and complex over time

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Evidence in Organisms

• Evolution proceeds by modifications of organisms
  which already exist

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Evidence in Organisms

• Homologous Structures
• Definition
• Examples (Can you give detailed descriptions
  of homologous bones?)

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I. Homologous Structures

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Homologous Structures

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Evidence in Organisms

• Similarities in Embryonic Development
• All animals ? cleavage, morula, blastula,
  layering after blastula (gastrula)
• All Vertebrates What did you observe?

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Similarities in Embryonic Development
The limbs of all tetrapods develop from limb buds
in similar ways (see below).
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Similarities in Embryonic Development

• How evidence of Evolution?

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Evidence in Organisms

• III. Vestigial Structures
• definition
• Examples
• Eyes on blind cavefish
• Human coccyx (tailbone)
• Femurs on pythons, whales
• Wings on a Kiwi bird
• How evidence of evolution?

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Evidence in Organisms

• What evidence suggests that life forms today
  share a common ancestor?
• Animal life
• Bone homology
• Embryological comparisons
• All life
• Biochemical evidence
• DNA/Proteins
• Energy reactions

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Question

• Why do scientists believe that all life on Earth
  descended from a SINGLE common ancestor?
• Why dont we think that several trees of life
  exist? (One for vertebrates, one for
  invertebrates, one for plants, one for fungi,
  etc?)

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ANSWER

• D
• N
• A

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II. Evidence in Organisms

• Evidence that Life forms change over time
• Vestigial Structures
• Definition
• Examples
• Artificial Selection
• Peppered Moth