Geologic%20Time%20Scale

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Geologic Time Scale
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Earths History Continued

• Now that we have all of these pieces of evidence,
  we are able to reconstruct a timeline of Earths
  Historywe call this timeline the Geologic Time
  Scale.

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Geologic Time Scale

• Geologic Time Scale a timeline of Earths
  History divided by major events or changes on
  Earth
• What do we call these major events or changes?

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Catastrophic Events

• Catastrophic Events events that cause major
  destruction or change life completely
• Examples
• Mass extinctions
• Ice Ages
• Meteor strikes
• Major volcanic eruptions

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EONS largest division of time4 Eons of Time

• 1. Hadean
• 2. Archean
• 3. Proterozoic
• 4. Phanerozoic
• The first 3 eons make up Precambrian Time which
  is 90 of Earths History! It lasted nearly 4
  billion years of Earths 4.6 billion year
  history!

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PRECAMBRIAN TIME

• MAIN EVENTS
• After Earth its moon were formed, there was
• Major volcanic activity leading to the formation
  of Earths Crust!
• Oxygen levels in the atmosphere rise!
• Single-celled micro-organisms simple
  multi-celled organisms, like sponges jellyfish,
  in the ocean towards the end.
• NO animals or plants on land!

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Phanerozoic Eon 544 million years ago present
day

• Explosion of Life!
• Contains 3 Eras
• Paleozoic Era Age of Amphibians
• Mesozoic Era Age of Dinosaurs
• Cenozoic Era Age of Mammals

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Paleozoic Era Ancient

• 544 mya 248 mya
• More diverse marine life such as fish and
  amphibians developed
• Life begins moving onto land towards the end of
  this era
• Reptiles, insects, and simple land plants like
  ferns developed
• Pangaea exists about 280 million years ago
• Ends with a Mass Extinction possibly from a
  meteor strike (???) kills 90 of all ocean
  species and 70 of land dwellers!

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Mesozoic Era Middle

• 248 mya 65 mya
• Pangaea begins to break apart about 200 million
  years ago!
• Dinosaurs rule the land!
• Small early mammals, birds, and more complex
  flowering plants and flying insects are seen
• Ends with another Mass Extinction due to meteor
  strike off the coast of Mexico
• Dust cloud blocked sunlight, killed plant life
  and affected the food chain

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Cenozoic Era Recent

• 65 mya Present
• First primates appear
• Primitive whales enter the ocean
• Larger land mammals like horses, pigs (have
  hooves) cats, dogs, bears
• Animals developed migration techniques and
  coevolution patterns
• Quaternary Period the past 2 million yrs
• Last Ice Age ends
• 1st modern humans leading to Homo Sapiens
  and modern civilizations

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Geologic Time Scale Summary

• The Geologic Time Scale is divided by
  catastrophic events not equal time segments!
• In general, life goes from simple to more
  complex!
• Most life occurs towards the end of the Geologic
  Time Scale!

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The Clock of Eras

• The last comparison put Earths Geologic Time
  Scale into 1 year but what if we put it into 1
  day?
• http//www.youtube.com/watch?vH2_6cqa2cP4