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  11-Nearly half of the value mineral deposits in the world occur in the rocks of this period.
 23-Shelled branchiopods appear.
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  Geological timescale
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  7- Some scientists believe that human kind has caused mass extinctions of plant and animals species, polluted the oceans and altered the atmosphere.
 38- Environmental change causes mass extinctions of sea invertibrates (trilobites & eurypterids) as the seas retreat.
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  14-There is argument as to when this epoch began, some scientists think it began with the industrial age in the early 1800's other with the atomic age in 1950's.
 28- Small rodents evolve.
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  31-Huge plants begin to develop , early amphibians form.
 24- Eurypterids (sea scorpions), sea stars and coral became more common.
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  1- There is very little plant life during the period.
 37- Age of fishes, fish that can breath out of the water and spend time on land form.
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  2- Swamps and forests cover the land.
 10- The presence of stromatolites indicates that shallow seas covered much of the earth during intervals in this period.
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  4- Giant cockroaches appear.
 15- Coal deposits form.
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  30- Colonies of tiny invertebrates call graptolites florished and vertibrates appear, fish did not have jaws or teeth and their bodies were covered with bony plates.
 19-The last glacial period ended and sea levels rose, great lakes formed.
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  16- Welcome to the world of the dinosaur! Enter the squirrel sized dinosaur & the first forest dwelling mammals appear.
 8- Appalachian Mountains are created because of the collins of tectonic plates & savannahs form.
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  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.
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  33-Vascular land plants and animals, such as scorpion begin to evolve on land
 37- Age of fishes, fish that can breath out of the water and spent time an land time.
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  12- First primates evolve.
 18- Various species migrated between continents across land bridges.
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  17- Flying squirrels, whales and bats appear.
 26- First modern horse appear.
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  22- Trilobites appear.
 19- The last glacial period ended and sea levels rose, Great Lakes formed.
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  21- Early reptiles resembling large lizards appear.
 25- World wide temperature drop about 4 degrees celsius (39.2 degrees fahrenheit)
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  20- Species that did not evolve to survive extreme cold moved to warner climate areas of became extinct (dire wolf & giant ground sloth)
 28- Morden human developed agriculture and used tools made of bronze and iron.
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  32- Antarctic icecaps begin to form.
 34- Ichthyosaurs are living in the ocean, new invertebrates call ammonite develop.
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  6- Himalayas develop due to uplifting caused by the indian subcontinent and eurasian continents colliding.
 9- Homosapien (modern humans) appeared & are hunters.
