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Cambrian Period-570-500 MYA
The Cambrian period had an abundant amount of marine organisms and the Earth was covered in oceans, All life was in oceans. -
Ordovician-500-435
Area north of tropics was almost entirely ocean with supercontinent Gondwana dominating south. known for diverse marine invertebrates with some signs of early vertebrates. -
Silurian-443-395
Earth underwent considerable chamges from the melting of large glaciers causing rising sea levels. Coral reefs first appeared and fish went through remarkable evolution. -
Devonian-395-345
Primarily small plants but first land living verebrates introduced as well as wingless insects and arachnids. There was two supercontinents, Gondwana and Euramerica -
Carboniferous-345-280
Earliest reptiles and abundant sharks and amphibians. Scale tree and coal forming forest. Amnoite eggs gave ancestors of birds ability to lay their eggs and not fear desiccation. -
Permian-280-225
Largest mass extinction in recorded history of earth. Extinction of many kinds of marine life. Massive areas of land and water. Single ocean known as Panthalassa. -
Triassic-225-195
After mass extinctio form Permian period new groups flourished. Earliest dinosaurs found. There was abundant cycades and conifers. -
Jurassic-195-136
Abundant plant eating dinosaurs roaming the earth and ammonites. Earliest birds like pterosuars. -
Cretaceous-136-65
Last portion of "age of dinosaurs". The break up of the world-continent Pangea continued. Great decline of brachiopods. Abundance of boney fish and earliest flowering plants. -
Tertiary-65-1.8
Earliest placental mammals, many modedern mammals and large running mammals. -
Quaternary-1.8-Present
There was large carnivores, neanderthals, humans and mastodons. Climate was much drier and colder early on than in present time.
