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Precambrian
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 material deposits in the world occur in the rocks during this period. -
Period: to
E. Nealy p.4
Geological Timescale -
Cambrian
EVENT 22- trilobites appear. EVENT 23- shelled brachiopods appear. -
Ordovician
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
EVENT 24- eurypterids, sea stars, and coral become more common. EVENT 34- vascular land plants and animals, such as scorpions begin to evolve on land. -
Devonian
EVENT 31- huge plants begin to develop, early amphibians. EVENT 37- age of fishes, fish that can breath out of the water and spend time on land form. -
Mississippian
EVENT 2- swamps and forests cover the land. EVENT 21- early reptiles resembling large lizards appear. -
Pennsylvanian
EVENT 2- giant cockroaches appear. EVENT 15- coal deposits form. -
Permian
EVENT 21- early reptiles resembling large lizards appear. 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 Dinosaurs! Enter the squirrel sized dinosaur and the first forest dwelling mammals appear. EVENT 29- small rodents evolve. -
Jurassic
EVENT 3- flying reptiles called pterosaurs are in the air now. EVENT 13- whoa those dinos are getting big and dominate the land - Lizard-hipped and bird-hipped - carnivores and herbivores have arrived. -
Cretaceous
EVENT 5- first flowering plants appear. EVENT 35- Impact hypothesis - dinosaur mass extinction. -
Paleocene
EVENT 12- first primates evolve. EVENT 6- himalayas develop due to uplifting caused by the Indian subcontinents colliding. -
Eocene
Event 1 new animals such as Horses and bats started to appear. Event 2 more new animals like flying squirrels and whales started to appear. -
oligocene
EVENT 32- antarctic icecaps begin to form. EVENT 27- many early mammals become extinct, clams and snails flourish. -
Miocene
EVENT 8- appalachian Mountains are created because of the collision of tectonic plates and savannahs form. EVENT 18- various species migrated between continents across land bridges. -
Pliocene
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). EVENT 36- Mediterranean Sea dries up and refills several times due to tectonic forces and dropping sea levels. -
Pleistocene
EVENT 9- homosapien (modern humans) appeared and are hunters. EVENT 25- world wide temperatures drop about 4 degrees Celsius (39.2 degrees Fahrenheit). -
Holocene
EVENT 19- the last glacial period ended and sea levels rose, Great Lakes formed.EVENT 28- modern human developed agriculture and used tools made of bronze and iron. -
Anthropocene
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 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 think it began with the atomic age in the 1950's.
