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R. Gruber. P-6. Geological Timescale.

By RG0614113587

  • Precambrian

    Precambrian
    The presence of stromatolites indicates that shallow seas covered much of earth during intervals in this period. / Nearly half of the valuable mineral deposits in the world occur in the rocks of this period.
  • Period: to

    R.Gruber. P-6

    Geological timescale

  • Cambrian

    Cambrian
    trilobites appear. / shelled brachiopods appear.

  • Ordovician

    Ordovician
    the last glacial period ended and sea levels rose, Great Lakes formed. / species that did not evolve to survive extreme cold moved to warmer climate areas or became extinct (dire wold & giant ground sloth.

  • Silurian

    Silurian
    vascular land plants and animals, such as scorpions begin to evolve on land. / there is very little plant life during this period.

  • Devonian

    Devonian
    eurypterids (sea scorpions), sea stars and coral become more common. / huge plants begin to develop, early amphibians form.

  • Carboniferous

    Carboniferous
    coal deposits form. /

  • Pennsylvanian period

    Pennsylvanian period
    giant cockroaches appear. / swamps and forest cover the land.

  • mississipplan period

    mississipplan period
    early reptiles resembling large lizards appear. /

  • permian

    permian
    Appalachian mountains are created because of the collision of tectonics & savannahs. /

  • triassic

    triassic
    flying reptiles called pterosaurs are in the air now. / ichthyosaurs are living in the ocean, new invertebrates call ammonite develop.

  • Jurassic

    Jurassic
    whoa those dinos are getting big & dominate the land - lizard hipped and bird-hipped apear - carnivores and herbivores have arrived.

  • Cretaceus

    Cretaceus
    first flowering plants appear - angiosperm. / impact hypothesis - dinosaurs mass extinction.

  • paleocene

    paleocene
    homosapien (modern humans) appeared & are hunters. / first primate evolve.

  • eocene

    eocene
    world wide temperatures drop about 4 degrees celsius (39.2 degrees Fahrenheit). / antarctic icecaps begin to form.

  • oligocene

    oligocene

  • miocene

    miocene

  • pliocene

    pliocene
    various species migrated between continents across land bridges. / Mediterranean Sea dries up and refills several times due to tectonic forces a dn dropping sea levels.

  • pleistocene

    pleistocene
    many early mammal become extinct, clams and snails flourish. /

  • holocene

    holocene
    Some scientist believe that human kind has caused mass extinctions of plants and animal species, polluted the oceans and altered the atmosphere. / there is argument as to when this epoch began, some scientist think it began with the Industrial Age in the early 1800's other think it began with the atomic age in the 1950's.