Geological Time Scale

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Geological Time Scale

• Name the four ERAS from oldest to newest

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• Precambrian (oldest)
• Paleozoic
• Mesozoic
• Cenozoic (newest)
• RememberPPMC

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• What are the four PERIODS of the Paleozoic Era
  from oldest to youngest?

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• Cambrian (fish - first vertebrates)
• Ordovician (amphibians and reptiles)
• Silurian (amphibians and reptiles)
• Devonian (amphibians and reptiles)
• Carboniferous (primitive plants like ferns)
• Permian (primitive plants like ferns)

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• Name the three Periods of the Mesozoic Era from
  oldest to youngest

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• Triassic (gymnosperms - pine trees appear and
  flying animals evolve)
• Jurassic (age of the dinosaurs)
• Cretaceous (angiosperms - flowering plants and
  winged )insects

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• Name the two Periods of the Cenozoic Era from
  oldest to youngest.

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• Tertiary ( age of mammals - apes,sabertooths,Mammo
  ths)
• Quaternary (humans evolve)

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The Precambrian Era started around 4.6
b.y.a.Living things first appeared during this
era. When and what was the first living thing?
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• 3.5 b.y.a. the first living thing, a prokaryotic
  cell (bacteria) appeared!

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• What effect did these prokaryotic cells have on
  the earths atmosphere?

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• Certain cells called autotrophs (cyanobacteria)
  appeared that photosynthesized releasing oxygen
  into the atmosphere.
• What two advantages did this result in
  encouraging life on land?

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• It released oxygen into the atmosphere for
  breathing.
• It released oxygen into the atmosphere that
  created OZONE - a layer of O3 in the upper
  atmosphere that absorbs the suns harmful
  ultraviolet rays.

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• Throughout the long 4 billion years or so of the
  precambrian era, we see the prokaryotic cell
  without a nucleus evolve into WHAT kind of cell
  that DOES have a nucleus

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• A Eukaryotic cell

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• Eventually, this eukaryotic cell evolves and
  evolves into simple water creatures.
• Finally, the next era begins when we see the
  first vertebrate, the fish appear.
• What era came after the precambrian and how many
  m.y.a. did it start?

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• The Paleozoic Era - beginning 540 m.y.a.
• In this era, we see simple plant life rise on
  land, greening the earth and releasing even more
  oxygen into the atmosphere.
• This allows to fish evolve to survive on land,
  giving rise to amphibians and reptiles.
• This Era ends when a 90 percent of all marine
  species die out. What is an event like this
  called?

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• A mass extinction.
• The mass extinction at the end of the paleozoic
  era was the largest to ever occur.

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• What era came after the Paleozoic era and how
  many m.y.a did it begin?

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• The Mesozoic Era - beginning about 248 m.y.a.
• Mesozoic means middle life in Greek

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• The mesozoic era was dominated by dinosaurs BUT
  what other three important things show up on
  earth during this time?

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• Cone bearing seed plants (gymnosperms)
• Flowering seed plants (angiosperms)
• Flying animals

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• The Mesozoic Era ended in a mass extinction.
• What are the two main theories that scientists
  think caused this mass extinction?

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• A asteroid or meteor hit the earth spitting dust
  into the atmosphere blocking out the suns rays.
• There were wide-spread volcanic eruptions spewing
  ash and dust into the sky blocking out the suns
  rays.

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