-
Precambrian Time 4,600 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
A. Dorrego Period 1
Geological Timescale -
Cambrian 542 MA
22 Trilobites appear 23 Shelled brachiopods appear -
Ordovician 488 MA
1 There is very little plant life 30 Colonies of tiny invertebrates call grapolites florished and vertebrates appeared, fish did not have jaws or teeth and their bodies were covered with bony plates. -
Silurian 444 MA
24 Eurypterids, sea stars, and coral become more common 33 Vascular land plants and animals, such as scorpions begin to evolve in the land -
Devonian
31 Huge plants begin to develop, early amphibians form 37 Age of fishes, fish that can breath out of the water and spend time on land form -
Mississippian Period 359 MA
2 Swamps and forests cover the land 21 Early reptiles resembling large lizards appear -
Pennsylvanian Period 318 MA
4 Giant cockroaches appear 15 Coal deposit forms -
Permian 299 MA
8 Appalachian mountains are created because of the collision of tectonic plates and Savannahs form 38 Environmental change causes mass extinction of sea invertebrates as the seas retreat -
Triassic 251 MA
16 World of the dinosaur enters the squirrel-sized dinosaur and the first forest dwelling mammals appear 34 Ichthyosaurs are living in the ocean, new invertebrates called ammonite develop -
Jurassic 200 MA
3 Flying reptiles called pterosaurs are in the air now. 1 Dinos are getting big and dominate the land - Lizard hipped and bird hipped appear - carnivores and herbivores have appeared -
Cretaceous 146 MA
5 First flowering plants appear - angiosperm 35 Impact hypothesis dinosaur mass extinction -
Paleocene 65.5 MA
12 The first primate evolves 29 Small rodents evolve -
Eocene 55.8 MA
17 Flying squirrels, whales and bats appear 25 World temperature drops about 4 degrees celsius -
Oligocene 33.9 MA
6 Himalaya develops due to uplifting caused by the Indian subcontinent and Eurasian continents colliding 27 Many early mammals become extinct, clams and snails flourish -
Miocene 23 MA
32 Antarctic ice caps begin to form 36 Mediterranean sea dries and refills 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 Homosapiens (modern humans) appeared and hunters 20 Species that did not evolve to survive extreme cold moved to warmer climate areas or became extinct. -
Holocene 0.0115 MA
19 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 humankind has caused mass extinctions of plant and animal species, polluted the oceans and altered the atmosphere 14 There is an argument as to when this epoch began, some scientists think it began in the 1800's others think it began with the atomic age in the 1950's
