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Precambrian - 4,600 MA
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
LJin/P.8
Geologic Timescale -
Cambrian- 542 MA
EVENT 22 Trilobites appear. EVENT 23 Shelled brachiopods appear. -
Ordovician- 488 MA
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-444 MA
EVENT 24 Eurypterids (sea scorpions), sea stars and coral become more common. EVENT 33 Vascular land plants and animals, such as scorpions begin to evolve on land. -
The Devonian Period-416MA
EVENT 31 Huge plants begin to develop, early amphibians form. EVENT 37 Age of Fishes, fish that can breathe out of the water and spend time on land form. -
The Mississippian Period-359 MA
EVENT 2 Swamps and forests cover the land. EVENT 8 Appalachian Mountains are created because of the collision of tectonic plates & Savannah's form. -
The Pennsylvanian Period-318 MA
EVENT 4 Giant cockroaches appear. EVENT 15 Coal deposits form. -
The Permian Period-299 MA
EVENT 32 Antarctic icecaps begin to form. EVENT 38 Environmental change causes mass extinction of sea invertebrates (trilobites & eurypterids) as the seas retreat -
The Triassic Period-251 MA
EVENT 16 Welcome to the world of the dinosaur! Enter the squirrel sized dinosaur & the first forest dwelling mammals appear. EVENT 34 Ichthyosaurs are living in the ocean, new invertebrates call ammonite develop. -
The Jurassic Period-200 MA
EVENT 3 Flying reptiles called pterosaurs are in the air now. EVENT 13 Whoa those dinos are getting big & dominate the land-lizard- hipped and bird-hipped appear-carnivores and herbivores have arrived. -
The Cretaceous Period-146 MA
EVENT 1: Flowering plants and modern birds.
EVENT 2: Mass extinctions mark the end of the Mesozoic Era. -
Eocene-55.8 MA
EVENT 17 Flying squirrels, whales and bas appear. EVENT 26 Fisrt modern horses appear. -
Oligocene-33.9 MA
EVENT 27 Many early mammals become extinct,clams and snails. EVENT 21 Early reptiles resembling large lizards appear. -
Miocene-23.0 MA
EVENT 18 Various species migrated between continents across land bridges. EVENT 20 Species that didn't evolve to survive extreme cold moved to warmer climate areas or became extinct (dire wolf & giant ground sloth) -
Pliocene-5.3 MA
EVENT 6 Himalayas developed due to uplifting cost by the Indian subcontinent and Eurasian continents colliding. EVENT 36 Mediterranean Sea dries up and refills several times due to tectonic forces and dropping sea levels. -
Pleistocene-1.8 MA
EVENT 9 Homosapien (modern humans) appeared & are hunters. EVENT 25 World wide temperatures drop about 4 degrees Celsius (39.2 degrees Fahrenheit) -
Holocene-0.0115 MA
EVENT 19 The last glacial period ended and sea levels rose, great lakes formed. EVENT 28 Modern humans developed agriculture and used tools made of bronze and iron. -
Paleocene- 65.5 MA
EVENT 12 First primates evolve EVENT 29 Small rodents evolve. -
Anthropocene - Present
EVENT 7 Some scientist believe that human kind has caused mass extinctions of plants and animal species, polluted the oceans and altered the atmosphere. EVENT 14 There is arguments as to when this began, some scientist think it began with the industrial age in the early 1800's others think it began with the atomic age in the 1950's.
