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Precambrian
Event 1-There is very little plant life during this period. Event 10-The presence of stromatolites indicates the 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 Therrien
Geological Timescale -
Cambrian
Event 22- Trilobites appear Event 23- Shelled brachiopods appear -
Ordovician
Event 27-Many early mammal become extinct, clams and snail flourish 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
Event 24-Eurypterids, sea stars and coral become more common. Event 33-Vascular land plants and animals, such as scorpions begin to evolve on land. -
Devonian
Event 31-Huge plants begin to develop, early amphibians form. Event 37-Age of fishes, fish that can breath out of water and spend time on land form. -
Carboniferous
Event 2- Swamps and forests cover the land Event 4- Giant cockroaches appear Event 15- Coal deposits form Event 21- Early reptiles resembling large lizards appear -
Permian
Event 8-Appalachian Mountains are created because of the collision of tectonic plates and savannas form. Event 38- Environmental change causes mass extinction of sea invertebrates (trilobites and eurypterids) as the seas retreat. -
Triassic
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. -
Jurassic
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 has arrived. -
Cretaceous
Event 5-First flowering plants appear-angiosperm. Event 35-Impact hypothesis-Dinosaur mass extinction. -
Paleocene
Event 12-First primates evolved. -
Eocene
Event 17-Flying squirrels, bats and whales appear. Event 25-World wide temperatures drop at least 4 degrees celsius. Event 26-First modern horses appear. Event 29-Small rodents evolve. -
Oligocene
Event 6-Himalayas develop due to uplifting caused by the Indian subcontinent and Eurasian continents colliding. -
Miocene
Event 32-Antarctic ice caps begin to form. Event 36- Mediterranian Sea dries up and refills several times due to tectonic forces and dropping sea levels. -
Pliocene
Event 18- Various species migrated between continents across land bridges -
Pleistocene
Event 9-Homosapien (modern humans) appeared and are hunters. Event 20-Species that did not evolve to survive extreme cold moved to warmer climate areas or became extinct (dire wolf and giant ground sloth) -
Holocene
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 19-The last glacial period ended sea levels rose, Great lakes formed. -
Anthropocene
Event 14-There is argument as to when this epoch began, some scientists think it began with the industrial age in the early 1800s others think it began with the atomic age in the 1950s
