-
Hadean/Pre-Archean Eon
~Began approx. 4.6 bya
~Hades,Roman god
~Earth and Moon -
Period: to
Timespan
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Archean Eon
~Began approx. 3.8 bya
~"The eon of life"
~Oldest discovered rocks and fossils
~First known plants -
Proterozioc Eon
~Began approx. 2.5 bya
~Eon of first multi -celled life
~First known animal (jellyfish) -
Phanerozioc Eon
~Began approx. 542 mya
~Eon of complex life
~Ended in the largest mass extinction the Earth has ever known -
Paleozoic Era
~Began approx. 570 mya
~"Ancient life"
~a time of dramatic geological, climatic, and evolutionary change
~ Fish, arthropods, amphibians and reptiles evolved -
Cambrian Period
~Began approx. 570 mya
~"the age of the trilobites"
~established by Adam Sedgwick, named it after Cambria (Lt. Wales),
~Cold -
Ordovician Period
~Began approx. 500 mya
~The Ordovician was shorter than the Cambrian period
~The trilobite became larger and smarter
~Shell fish was major life form -
Silurian Period
~Began approx. 400-430 mya
~life existed on land
~Ozone levels reached the required thickness to protect life on land from now on
~appearance of jawed and bony fish -
Devonian Period
~Began approx. 395 mya
~named after city, where rocks from this period were first studied.
~groups of plants had evolved leaves and true roots
~by the end the first seed-bearing plants appeared -
Missippian Period
~Began approx. 345 mya
~named after rocks exposed in the Mississippi River valley from this period -
Pennsylvanian Period
~Began appox. 320 mya
~The American state
~Amphibians were diverse and common
~amniote egg,a group of tetrapods -
Permian Period
~Began approx.280 mya
~first found in 1841 by geologist Sir Roderick Murchison,
~ sea levels generally low
~single supercontinent known as Pangaea -
Mesozoic Era
~ began 225 mya
~ era of reptiles or the age of dinosaurs
~means "middle life",in Greek
~began in the wake of the Permian-Triassic event, tone of the largest mass extinction
~ time of significant tectonic, climate and evolutionary activity -
Triassic Period
~ started around 225 mya
~ First appearance of dinosaurs in the fossils record.
~Triassic was named in 1834 by Friedrich von Alberti
~ Global climate mostly hot and dry -
Jurassic Period
~190- 195 mya
~ First bird
~ mammals
~dominance. of dinosaurs
moutain building -
Cretaceos Period
~ flowering plants
~increase in dinosaurs
~ sea level higher
~ ends with death of dinosaurs -
Cenozoic Era
~ started around 65 mya
~ last major division of geologic -
Tertiary Period
~ started around 65 mya
~ extinction with dinosaurs.
~ mountain bilding -
Eocence Period
~ occured around 59 mya
~ horses
~ whales
~ monkeys -
Oligocene Epoch
~ started approx. 38 mya
~ elephants and apes first appear in fossils from this Epoch -
Miocene Epoch
~ began around 26 mya
~ Hominids first found in fossil record -
Pliocene Epoch
~ began approx. 12 mya
~ first human like animals -
Quaternary Period
~ started around 3 mya
~ Glaciers advance and retreat again from the Poles, this molds the land
~Sea levels change with each freezing and thawing of the glaciers -
Pleistocene Epoch
~ occured approx. 3 mya
~ the first modern humans appeared
~ modern ice age -
Holocene Epoch
~recent 10,000 yrs ago
~ started with the end of the most recent glaciation
