Studying Fossil Evidence

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Studying Fossil Evidence

• Chapter 17

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The Fossil Record

• The fossil record provides evidence about the
  history of life on Earth. It also shows how
  different groups of organisms, including species,
  have changed over time (or evolved).

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Dating Fossils

• Relative Dating
• Method of determining the age of a fossil by
  comparing its placement with that of fossils in
  other layers of rock.
• Radioactive Dating
• Method of calculating the age of a fossil based
  on the amount of remining radioactive isotopes it
  contains

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Biological Diversity

• Biological Diversity (Biodiversity)
• The variety of living organisms found in a
  particular place
• The fossil record tells us what kind of
  biological diversity existed in a particular
  place at a particular time in history.

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Mass Extinction

• Event in which many types of living things become
  extinct at the same time.
• We know of Mass Extinctions because of the fossil
  record.

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Mass Extinction

• Mass Extinction means that MOST, but NOT ALL
  species went extinct during a short time period.
• Because of GREAT BIOLOGICAL DIVERSITY before a
  catastrophic event, some individuals of some
  species survive the event.

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Mass Extinction

• Adaptive Radiation When many species disappear,
  habitats and ecological opportunities are left
  open for survivors take over
• The result seems to be a burst of evolution that
  produces many new species
• For example, when the dinosaurs went extinct,
  that cleared the way for evolution of modern
  mammals and birds

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The fossil record shows speciation

• By studying the fossil record, we can see how
  species change over time.

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Tempo of Speciation

• Gradual Speciation
• Slow, steady change over time
• Punctuated Equilibrium
• Long stable periods interrupted by brief periods
  of rapid change.

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Numbers of Species
Which groups demonstrated the greatest
biodiversity during the Cenozoic Period?
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In Review

• The Fossil Record shows us Biodiversity, Mass
  Extinctions, Speciation and Evolution
• Fossil Dating
• Relative Dating
• Radioactive Dating

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In Review

• Biological Diversity (Biodiversity)
• The number of species that exist
• Mass Extinctions
• Most species die off
• Those species left living, evolve into new
  species by taking over the habitats and
  ecological opportunities left by those that went
  extinct EVOLUTION
• Tempo of Speciation
• Gradual Speciation
• Punctuated Equilibrium