The Geological Time Scale

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The Geological Time Scale
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Geological Time Scale

• The Earth is about 4.6 billion years old
• Since then Earth has experienced continuous
  change
• Some changes occur quickly, like volcanoes,
  earthquakes and floods, while others occur so
  slowly we can barely notice them, like erosion,
  and moving continents.

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Geological Time Scale

• To make the age of the Earth more understandable
  geologists have designed the Geological Time
  Scale, which breaks the 4.6 billion years into
  smaller portions.

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Geological Time Scale

• As the Earth changes so do the organisms that
  live on it.
• Species have developed through time and changed
  as their environment changed.
• Others have dominated the planet for millions of
  years only to be replaced by other species better
  adapted to changing conditions.

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For example...
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But what really killed them?
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Earths Timeline
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Earths Timeline
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Earths Timeline
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Earths Timeline
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• This might help

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Geological Time Scale

• Mass extinctions have occurred several times in
  Earths history
• Dinosaurs died about 65 mya
• 250 mya 96 of marine animals and 75 of land
  animals were wiped out
• After every major extinction there is an
  opportunity for different species to become
  dominant

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The Principle of Faunal Succession

• This principle states that species change in form
  through time.
• Each form is different from those that come
  before and after
• From the fossils they find geologists use this
  principle to tell the order of layers in a rock
  sequence

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The Evolution of the Horse
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Index Fossils

• These are fossils that can help tell the age of
  the rock layer it is found in.

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Index Fossils

• These are fossils that can help tell the age of
  the rock layer it is found in.
• The Three Characteristics of an Index Fossil

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Index Fossils

• These are fossils that can help tell the age of
  the rock layer it is found in.
• The Three Characteristics of an Index Fossil
• Its easy to recognize
• It was only in existence for a short period of
  time
• It is found in many locations around the world

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Trilobite

• The layer you find this fossil in is 540 myo

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Earliest multicellular life?