1. Geologic Time Scale Summary Precambrian - Cenezoic 4.6 Billion Years - Today

2. Learning Targets • Become familiar with the Geologic Time periods • Learn the major events that happened in each period

4. Precambrian • 4.6 billion years ago - about 550 million years ago (formation of Earth) • No life on land • Fossil bacteria and algae • Crust becomes solid • Oxygen in atmosphere

5. Paleozoic Era • About 550 mya - 250 mya • Age of invertebrates • “Paleo” = ancient, “zoic” = life • Warmer temperatures in North America, Appalachian Mts. form

6. Cambrian Period • 550 mya - 490 mya • Cambrian explosion • First great expansion of sea life • Burgess Shale

8. Ordovician period • 490 mya - 440 mya • Jawless fish • First land plants • Ends in mass extinction Hagfish

9. Silurian Period • 440 mya - 408 mya • First jawed fish • Insects like millipedes and centipedes • First vascular plants on land • All plants we know today besides algae and fungi

10. Devonian Period Dunkleosteus • 408 mya - 360 mya • Age of Fish --> Fish and land plants become very diverse • First sharks appear • Non-winged insects move to land • Tetrapods move to land near end • Late Mass extinction

11. Carboniferous Period • 360 mya - 280 mya • Can be split into Mississippian and Pennsylvanian periods • First insects with wings • First reptiles • Cockroaches first appear • Wide spread Coal Swamps

13. Permian Period • 280 mya - 248 mya • Age of Amphibians • Continents merge into Pangea • Largest ever extinction ends the Permian • MASS EXTINCTION GRAPH

14. DINOSAURS!!! Dimetrodon

15. Therapsid

16. Mesozoic Era • 250 mya - 65 mya • “Age of Reptiles” aka “Age of Dinosaurs” • “Meso” = middle “Zoic” = life • 3 Time periods --> Triassic, Jurassic, Cretaceous

17. Triassic Period • 250 mya - 208 mya • First dinosaurs, mammals, and crocodyloforms • Ends with a mass extinction • Extinction allows dinosaurs to fill niches and diversify

19. Jurassic Period • 208 mya - 146 mya • Lots of dinosaurs including sauropods • First flowering plants • Pangea breaks apart

22. Cretaceous Period • 146 mya - 65 mya • Dinosaurs rule the earth • First crocodiles, ants, bees, snakes • Feathered dinosaurs appear • K/T mass extinction --> no more dinosaurs or pterosaurs

24. Sea Monsters of the Mesozoic

25. Cenozoic Era • 65 mya - ?????? • “Age of Mammals” • Could be age of birds, flowering plants or insects • Ceno = new zoic = life • 2 time periods --> Tertiary and Quaternary

26. Tertiary Period • 65 mya - 1.8 mya • Mammals abound • Primitive primates • Horses, whales, pigs, deer • Grasses common • Megalodon

28. Quaternary Period • 1.8 mya - ???? • Ice Ages • Large mammals like mammoths, mastadons, sabertooths, giant sloths • First Homo sapiens • Mr. Wirth was born

31. Macrauchenia stood at five feet tall, at a length of ten feet