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Cambrian 570-500 MYA
The first era in earth's life where organisms first appeared. Early life is dominantly marine life and single cell bacteria. Trilobites are the dominant species -
Period: to
Paleozoic Era 570-225 MYA
"Old Life" -
Ordivician 500-435 MYA
Echinoderms and invertebrates are dominant, mollusks become abundant, earliest fish life are jawless, but later become jawed and armored. -
Silurian 435-395 MYA
Earliest terrestrial plants and animals. Tiktaalik eurypterids develop. -
Devonian 395-345 MYA
Armored fish go extinct, but ther is still an abundance of several fish species. Earliest recorded amphibians and ammonites. -
Carboniferous (Mississippian, Pennsylvanian) 345-280 MYA
Abundance of shark species and amphibians. Large swamps and coal froming forests are created. Earliest recorded reptiles. Scale trees and seed ferns are the most common plant life. -
Permian 280-225 MYA
First mass extinction occurs, marine animals mainly affected including trilobites. -
Period: to
Mesozoic Era 225-65 MYA
"Middle Life" -
Triassic 225-195 MYA
Earliest dinosaurs, abundance of cycads and conifers -
Jurassic 195-136 MYA
Earliest evidence of birds and mammals. Dinosaurs are dominant species. Ammonites return. -
Cretaceous 136-65 MYA
Earliest flowering of plants. Second mass extinction. Climax then extinction of dinosaurs. Great decline of brachiopods. Abundance of bony fish. -
Period: to
Cenozoic Era 65 MYA-Present
"Modern Life" -
Tertiary 65-1.8 MYA
Earliest placental mammals, modern mammals, large running mammals. -
Quarternary 1.8 m-Present
Large carnivores, neanderthals, humans, mastodons.
