Geologic Time- grace

Cambrian period- 500-570 mya

500 BCE

Earliest record of marine life. Trilobites are dominant. There was a cold climate but it grew warmer and there was rising sea levels flooding low lying land masses. There were one celled algae but not a lot of plants.

Ordovician period 500-435 mya

500 BCE

Echinoderms(starfish, sand dollars) invertebrates are dominate, mollusks are abundant. Jawed and armored fish.

Silurian period 435-395 mya

435 BCE

earliest terrestrial plants and animals. Tiktaalik Euryperterids develop

Devonian period 395-345 mya

395 BCE

armored fish go extinct but abundance of several species of fish.Earliest amphibians and ammonites.

Carboniferous period 345-280mya

345 BCE

abundant sharks and amphibians. Large swamps and coal forming in forest. Earliest reptiles. Scale trees and seed ferns.

Permian period 280-225 mya

280 BCE

extinction of many type of marine animals including trilobites due to large volcanic eruptions. 95% of species went extinct.

Triassic period 225-195 mya

225 BCE

earliest dinosaurs, abundant cycads and conifers

Jurassic period 195-136 mya

195 BCE

earliest birds and mammals. abundant dinosaurs and ammonites

cretasious period 136-65mya

136 BCE

earliest flowering plants. climax of dinosaurs followed by their extinction. Great decline of brachiopads. abundance of bony fish. Extinction of 65% of species including dinosaurs.

Teritary period 65-1.8 mya

65 BCE

earliest placental mammals, modern mammals, large running mammals

Quaternary 1.8m-present

1 BCE

large carnivores, neanderthals, humans, mastodons