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Precambrian Period
EVENT 10 The presence of stromatolites indicates that shallow seas covered much of Earth during intervals in this period. EVENT 11 Nearly half of the valuable mineral deposits in the world occur in the rocks of this period. -
Period: to
D. Palacios 6
Geological Timescale -
Cambrian Period
EVENT 22 Triobites appear. EVENT 23 Shelled brachiopods appear. -
Ordovician Period
EVENT 1 There is very little plant life during this period. EVENT 30 Colonies of tiny invertebrates call graptolites flourished and vertebrates appear, Fish did not have jaws or teeth and their bodies were covered with bony plates. -
Silurian Period
EVENT 24 Eurypyerids (sea scorpions), sea stars and coral become more common. -
Devonian Period
EVENT 31 Huge plants begin to develop, early amphibians form. EVENT 37 Age of Fishes, fish that can breath out of the water and spend time on land form. -
Mississippian Period
EVENT 2 Swamps and forests cover the land. EVENT 21 Early reptiles resembling large lizards appear. -
Pennsylvanian Period
EVENT 4 Giant cockroaches appear. EVENT 15 Coal deposits form. -
Permian Period
EVENT 8 Appalachian Mountains are created because of the collision of tectonic plates & savannahs form. EVENT 38 Environmental change causes mass extinction of sea invertebrates (trilobites & eurypterids) as the seas retreat. -
Triassic Period
EVENT 16 Welcome to the world of the Dinosaur! Enter the squirrel sized dinosaur & the first forest dwelling mammals appear. -
Jurassic Period
EVENT 3 Flying reptiles called pterosaurs are in the air now. EVENT 13 Whoa those dins are getting big and dominate the land- Lizard hipped and bird-hipped appear- carnivores and herbivores have arrived. -
Cretaceous Period
EVENT 5 First flowering plants appear- angiosperm. EVENT 35 Impact hypothesis- dinosaur mass extinction. -
Paleocene Period
EVENT 12 First primates evolve. EVENT 29 Small rodents evolve. -
Eocene Period
EVENT 17 Flying squirrels, whales, and bats appear. EVENT 25 World wide temperatures drop about 4 degrees celsius (39.2 degrees fahrenheit). -
Oligocene Period
EVENT 6 Himalayans develop due to uplifting caused by the Indian subcontinent and Eurasian continents colliding. EVENT 27 Many early mammal become extinct, clams and snails flourish. -
Miocene Period
EVENT 32 Antarctic icecaps begin to form. EVENT 36 Mediterranean Sea dries up and refills several times due to tectonic forces and dropping sea levels. -
Pliocene Period
EVENT 18 Various species migrated between continents across land bridges. EVENT 26 First modern horses appear. -
Pleistocene Period
EVENT 9 Homosapien (modern humans) appeared & are hunters. EVENT 20 Species that did not evolve to survive extreme cold moved to warmer climate areas or become extinct (dire wolf & giant ground sloth). -
Holocene Period
EVENT 19 The last glacial period ended and sea levels rose, Great Lakes formed. EVENT 28 Modern human developed agriculture and used tools made of bronze and iron. -
Anthropocene Period
EVENT 7 Some scientists believe that human kind has caused mass extinctions of plant and animal species, polluted the oceans and altered the atmosphere. EVENT 14 There is argument as to when this epoch began, some scientists think it began with the industrial age in the early 1800's, others think it began with the atomic age in the 1950's.
