Geologic Time

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Geologic Time
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Evolutionary Time

• Evolution is documented in layers deposited over
  4.6 billion years.

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Big Bang
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Big Bang Video
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In the Beginning

• At one time people believed that the Universe was
  infinite It had no beginning and no end.

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Beginning of Time

• Now we know that the Earth has a beginning and a
  history.

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15 Billion Years Ago

• Scientists believe that about 15 billion years
  ago a tremendous explosion started the expansion
  of the Universe.

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Big Bang

• This occurrence was not a conventional explosion
  but rather an event filling all of space with all
  of the particles of the new universe rushing away
  from each other.

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Geologic Time
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Precambrian Eon4.55 Billion to 543 Million Years

• Hadean Era
• Archaean Era
• Proterozoic Era

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Precambrian Video
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Hadean Era 4.5 to 3.8 Billion Years Ago

• The solar system forms out of gas and dust about
  4.5 billion years ago.
• About 4.4 billion years ago the Earths core
  forms.
• About 4.2 billion years ago the Earth begins to
  cool causing massive rainfall and great oceans
  form.

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Liquid to Solid Earth

• Sometime during the first 800 million or so years
  of its history, the surface of the Earth changed
  from liquid to solid. Once solid rock formed on
  the Earth, its geological history began.

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Rocks

• About 4 billion years ago rocks form.
• The oldest meteorites and lunar rocks are about
  4.5 billion years old, but the oldest Earth rocks
  currently known are 3.8 billion years old.

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Meteors

• Meteors and other galactic debris showered the
  Earth for its first half billion years, making it
  uninhabitable.

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Archaean Era3.5 to 2.8 Billion Years Ago

• Both life and geological processes begin.
• The atmosphere is methane CH4 and ammonia NH3.
• There is little or no free oxygen.
• The Earths crust forms mostly from silicon,
  aluminum, iron, calcium, sodium, magnesium and
  potassium.

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Archaean EraLife Begins

• Life begins with bacteria that can fix nitrogen
  and are photosynthetic called stromatolites that
  appear in the shallow waters of the early oceans.
• The oldest fossils are 3.5 billion year old
  bacteria fossils.
• The first small continents form.

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End of Archaean Era

• By the end of the Archaean
• Bacteria had begun to conquer land.
• The first multicellular, organisms with cells
  containing a nucleus, appear in the oceans.
• An ozone layer had developed.
• The ozone layer meant sufficient oxygen for life
  to evolve and providing protection from harmful
  ultraviolet radiation.

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Proterozoic Era2.5 Billion to 543 Million Years
Ago

• Oxygen produced by photosynthetic organisms
  collects in the oceans and the atmosphere.
• Oxygen loving organisms are now able to evolve.
• Soft bodied animals large enough to be seen by
  the naked eye evolve.

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Late Proterozoic

• The first supercontinent, Rodinia forms.
• A major glaciation period begins.
• The ozone layer fully forms.

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Phanerozoic Eon543 Million Years Ago to Now

• Paleozoic Era
• Mesozoic Era
• Cenozoic Era

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Phanerozoic
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Paleozoic Era Periods

• Cambrian Period
• Ordovician
• Silurian

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• Devonian Period
• Carboniferous Pennsylvanian
• Mississippian
• Permian Period

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Paleozoic Era

• The Paleozoic begins with the Cambrian which is
  marked by the appearance of hard-shelled fossils
  about 543 million years ago.
• Two of the most important events in the history
  of animal life happen during this period.
• Multicellular organisms undergo an explosion in
  diversity.
• The largest mass extinction in history wipes out
  90 of life.

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Cambrian543 to 490 Million Years Ago

• Land covers 1/3 of the planet but remains devoid
  of life.
• Rodinia drifts apart.
• Gondwana forms.
• Climate is warm and stable.
• Life explodes About three dozen new animal
  species first appear in the oceans.
• The first chordates appear.

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Ordovician490 to 443 Million Years Ago

• Life Diversifies in a huge way.
• Jawless and heavily armored fish appear.
• The first sharks evolve.
• Green algae adapt to land.
• Glaciation on Gondwana wipes out 70 of marine
  species.

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Silurian443 to 416 Million Years Ago

• Climate warms again.
• Global ocean levels rise creating new marine
  habitats.
• Shallow water marine animals venture into fresh
  water habitats and then land habitats.

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Silurian

• Land areas are divided into Gondwana in the
  southern hemisphere.
• Baltica and Siberia near the Equator which will
  merge to become Laurussia (Euramerica).
• Complex vascular plants evolve on land.
• Arthropods become the first animal on land!

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Gondwana
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Devonian

• The Devonian climate is warm and stable.
• Plant life explodes.
• First four-legged animals evolve on land.
• Gondwana and Laurussia (or Euramerica) are drawn
  together.

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Devonian

• The Devonian ends with a cataclysmic extinction
  event.
• 70 to 80 of marine invertebrates are wiped out.

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Carboniferous

• Hot humid conditions are found in Laurussia.
• Gondwana is glacier ridden because it resides
  near the North Pole.
• Seed and spore producing plants that grow 50 to
  100 feet tall dominate the land.

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Carboniferous

• Giant insects fly around.
• Amphibians are the dominant vertebrate land
  animal.
• Reptiles evolve as the first animal who lives its
  entire life on land.

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Permian

• The super-continent, Pangaea is formed.
• Its surrounded by a single world-ocean called
  Panthalassa.
• Reptiles continue to evolve.

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Permian

• Mammal-like reptiles appear.
• Gymnosperms become the dominant plant group.
• Massive extinction nearly ends all life.

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Mesozoic Era

• Triassic Period
• Jurassic Period
• Cretaceous Period

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Triassic

• Mountains form in the West Coast of North
  America, Alaska and Chile.
• Life comes back from the edge of extinction.
• Mammal-like Lystrosaurs, dinosaurs, frogs and
  early crocodiles are the dominant vertebrates.
• The first true mammals arrive at the end of the
  Triassic.

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Jurassic

• Pangaea, which formed towards the end of the
  Paleozoic, begins to split apart.
• Greenland and North America split from Europe and
  Africa.
• Rocky and Sierra Nevada Mountain ranges form.

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Jurassic

• Modern sharks and bony fishes dominate the seas.
• Insects and dinosaurs dominate the land.
• Theropod dinosaurs, the ancestors of birds
  display feathers and soon take to the skies.
• Mammals continue to evolve.

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Cretaceous

• Pangaea continues to break apart and the present
  day continents take shape.
• The first flowering plants and pollinating
  insects appear.
• Dinosaurs dominate the landscape.

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Cretaceous

• Placentals, marsupials and monotremes join the
  mammals.
• Mass extinction at the end of the Cretaceous
  wipes out half of all animal life including all
  of the dinosaurs.
• The age of mammals begins!

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Cenozoic Era65 Million Years Ago-Now

• Tertiary Period
• Paleocene Epoch
• Eocene Epoch
• Oligocene Epoch
• Miocene Epoch
• Pliocene Epoch
• Pleistocene Epoch
• Holocene Epoch

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Paleocene65 Million Years Ago to 55 Million
Years Ago

• Climate is warm, damp and temperate.
• Dense forests are everywhere.
• Giant pines and sequoias grow to dizzying
  heights.
• Sea level falls exposing North America, Africa
  and Australia.

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Paleocene

• Mammals are able to migrate across continents
  that are still joined Europe, Asia and North
  America in the Northern Hemisphere
• Australia, South America and Antarctica in the
  Southern Hemisphere.
• Lizards, snakes and crocodiles are some of the
  largest predators.

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Eocene55 Million Years Ago to 35 Million Years
Ago

• Eocene starts out warm.
• The continents move closer to their current
  positions.
• Ocean and air circulation are changed by the
  moving continents.
• By the end of the Eocene, temperatures cool
  considerably.

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Eocene

• Open woodlands replace forests in subtropical
  latitudes.
• Land mammals become much larger.
• Rhinoceros, early pigs, camels and hippopotamus
  first appear.
• As the Earth cools many species go extinct.

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Eocene

• Mammals survive.
• Whales evolve from wolf-like mammals and re-enter
  the oceans.
• Mammals are now able to occupy land, air and sea.
• Horses first evolve.

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Oligocene34 Million Years Ago to 24 Million
Years Ago

• A geologically and biologically uneventful period
  by historys standards.
• Antarctica splits from Australia and South
  America.
• Little migration occurs between continents.

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Oligocene

• Some members of the camel family evolve and
  become deer-like.
• Members of the bear family develop fox-like
  characteristics.
• At the end of the Oligocene, the evolutionary
  line that leads to apes and humans evolves!

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Miocene24 Million Years Ago to 5 Million Years
Ago

• Temperatures begin to rise.
• Extensive mountain ranges form in the Americas
  and Asia. Air circulation changes.
• Antarctica freezes and global temperatures lower
  again.
• Marine mammals flourish.

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Miocene

• Land bridges allow animal migrations across
  continents.
• Grasslands dominate the Americas and parts of
  Eurasia.
• Grazing animals like deer and antelope evolve.
• Horses evolve their single toe hoof.
• The orangutans separate from the African apes.

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Pliocene5 Million Years Ago to 2 Million Years
Ago

• A land bridge connects North and South America.
• The Earth continues to cool and dry.
• The ocean gets divided into two, the Atlantic and
  Pacific. Marine life takes different
  evolutionary paths.

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Pliocene

• Human-like primates evolve in East Africa.
• Saber-tooth cats, pack hunting dogs and bears are
  the main predators.
• At the end of the Pliocene a global ice age
  begins.

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Pleistocene2 Million Years ago to 10,000 Years
Ago

• Glaciers repeatedly advance and retreat over
  North America and Europe.
• The periods of glacial retreat are called
  interglacial periods.
• Mammoths, rhinos, reindeer etc. evolve to have
  wooly coats.

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Pleistocene

• About 100,000 years ago, anatomically modern
  humans evolve.
• By the end of the Pleistocene nearly all large
  mammals are extinct including the wombats.

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Holocene

• The Holocene begins after the last glacial epoch
  11,000 years ago.
• Many scientists think that we might currently be
  in an interglacial period and that another ice
  age is coming.
• Many plant and animal species are expected to be
  extinct by the year 2025.
• How much of this is due to human activity versus
  natural extinction rates is difficult to
  determine.

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• http//www.palaeos.com/Timescale/Phanerozoic.htm
• http//www.pbs.org/wgbh/evolution/change/deeptime/
  index.html
• http//www.ucmp.berkeley.edu
• http//www.umich.edu/gs265/bigbang.htm
• http//en.wikipedia.org