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Precambrian 4600 MA
10 The presence of stromatolites indicates that shallow seas covered much of earth during intervals in this period. 11 Nearly half of the valuable mineral deposits in the world occur in the rocks of this period. -
Period: to
K Leighton P1
Geological Timescale -
Cambrian 542 MA
22 Trilobites appear. 23 Shelled brachiopods appear. -
Ordovician 488 MA
1 There is very little plant life during this period. 30 Colonies of tiny invertebrates called grapotolites flourished and vertebrates appear, fish did not have jaws or teeth and their bodies were covered with bony plates. -
Silurian 444 MA
24 Eurypterids ( sea scorpions), sea stars and coral become more common. 33 Vascular land plants and animals, such as scorpions begin to evolve on land. -
Devonian 416 MA
31 Hue plants begin to develop, early amphibians form. 37 Age of fishes, fish that can breath out of water and spend time on land form. -
Mississippian Period 359 MA
2 swamps and forests cover the land. 21 Early reptiles resembling large lizards appeared. -
Pennsylvanian Period 318 MA
4 giant cockroaches appear. 15 coal deposits form. -
Permian 299 MA
8 Appalachian Mountains are created because of the collision of tectonic plates & savannas form. 38 Environmental changes causes mass extinction of sea invertebrates (trilobites & eurypterids) as the seas retreat. -
Triassic 251 MA
16 Welcome to the world of the dinosaur! Enter the squirrel sized dinosaur & the first forest dwelling mammals appear. 34 Ichthyosaurs are living in the ocean, new invertebrates call ammonite develop. -
Jurassic 200 MA
3 Flying reptiles called pterosaurs are in the air now. 13 Whoa those dinos are getting big & dominate the land- lizard-hipped and bird-hipped appear - carnivores and herbivores have arrived. -
Cretaceous 146 MA
5 First flowering plants appear - angiosperm. 35 Impact hypothesis - dinosaur mass extinction. -
Paleocene 65.5 MA
12 First primates evolve. 29 Small rodents evolve. -
Eocene 55.8 MA
17 Flying squirrels, bats and whales appear. 25 World wide temperatures drop about 4 degrees Celsius (39.2 degrees Fahrenheit). -
Oligocene 33.9 MA
6 Himalayas develop due to uplifting caused by the Indian subcontinent and Eurasian continents colliding. 27 Many early mammal become extinct, clams and snails flourish. -
Miocene 23.0 MA
32 Antarctic ice caps begin to form. 36 Mediterranean Sea dries up and refiles several times due to tectonic forces and dropping sea levels. -
Pliocene 5.3 MA
18 Various species migrated between continents across land bridges. 26 First modern horses appear. -
Pleistocene 1.8 MA
9 Homo sapiens (modern humans) appeared and are hunters. 20 Species that did not evolve to survive extreme cold moved to warmer climate areas or became extinct (dire wolf & giant sloth) -
Holocene 0.0115 MA
19 The last glacial period ended and sea levels rose, Great Lakes formed. 28 Modern human developed agriculture and used tools made of bronze and iron. -
Anthropocene, Current date
7 Some scientists believe that human kind has caused mass extinctions of plant and animal species, polluted the oceans and altered the atmosphere. 14 there is an argument 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.
