Evidence of Evolution

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Evidence of Evolution

• Blue-footed booby

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Evidence of evolution

• Fossil Record
• Anatomy
• Embryology
• Biochemistry
• Evidence in microevolution

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Fossil evidence
Mold Fossil

• Fossils ? remains of ancient life
• Fossils arranged according to age show a
  progression of changes
• The Law of Superposition ? a layer of rock is
  older than the layer above
• Fossils can be arranged by relative age
• Radioactive Dating ? naturally occurring
  radioactive substances decay at a known rate
• Transitional forms of fossils are evidence for
  evolutionary change

Preservation (insect in amber)
Cast Fossil
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Anatomy evidence

• Evolution works primarily by modifying
  pre-existing structures
• Homologous structures parts came from the same
  origins, but now may have different function
• e.g., forelimbs of all mammals contain the same
  pattern of bones, although the bones now carry
  out a variety of functions
• horse leg, bat wing, human arm, whale flipper

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Anatomy evidence

• Analogous structures parts came from different
  origin, but now have same function

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Anatomy evidence

• Vestigial structures parts have no current
  function (had a function in ancestors)
• Examples in humans wisdom teeth, erector pili,
  coccyx, ear muscles, appendix

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Embryology evidence

• Closely related organisms develop similarly,
  especially in early fetal stages
• This suggests that these organisms are related to
  other forms.
• Mammal embryos (including humans) have fish-like
  gill slits, tail

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Biochemistry evidence

• All organisms share certain biochemistry
• Genetic code for building amino acids
• All organisms use ATP for energy
• Plasma membranes of all organisms consist of a
  phospholipid bi-layer

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of amino acid differences between human
hemoglobin and other organisms
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H Human Chromosome C Chimp Chromosome
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Evidence for Microevolution Evolution Observed
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Evidence for Evolution Evolution Observed
Evolution of drug-resistance in HIV
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Evolution in Action
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Macroevolution
Large scale changes that take place over a long
period of time that create and eliminate species.
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Microevolution
Short time scale events (generation-to-generation)
that change the genotypes and phenotypes of
populations.