1. The Geologic Time Scale

2. Sections of time
ERA Two or more geological periods comprise an era, which is hundreds of millions of years in duration.

3. PERIOD The period is the basic unit of geological time in which a single type of rock system is formed, lasting tens of millions of years. EPOCH An epoch is a division of a geologic period; it is the smallest division of geologic time, lasting several million years.

4. Eon- Era- Period- Epoch- Age.
Humans as we know ourselves appeared in the Pleistocene Epoch of the Quaternary Period in the Cenozoic era of the Phanerozoic Eon…..

5. Pre Cambrian time 4.6 Billion years ago- 542 MA Earth Forms
Stromatolites are dominant life form

6. Paleozoic Era
542 to 251 mya
Multicellular life!!

7. Paleozoic, Cambrian, 488-542 MA Trilobites dominate
many phyla develop.
“Cambrian Explosion”

8. Paleozoic, Ordovician, 488 to 444 mya
North America is under shallow sea.
Modern Oxygen rich atmosphere develops
Vertebrates Develop

9. Paleozoic, Silurian
444 MA 416 MA
First Land Plants and Animals

10. Paleozoic, Devonian,
416 MA -359 MA
First amphibians
Age of fishes

11. Paleozoic, Carboniferius, Missippian
359 MA – 318 MA
Amphibians Flourish
Forests and swamps cover land

12. Paleozoic, Carboniferius, Pennsylvanian
318 MA – 299 MA
Giant flying insects
First Reptiles, ROAR!!

13. Paleozoic, Permian
299 MA – 251 MA
Pangea comes together

14. Mesozoic Era
"The Age of Reptiles" 251 MA to 65.5 MA

15. Mesozoic, Triassic
251 MA – 200 MA
Dinosaurs appear
Mammals appear

16. Cycads and conifers dominate

17. Mesozoic, Jurassic 200 MA- 146 MA Dinosaurs are the dominant animal.
Primitive vertebrate flight, first birds

18. Mesozoic, Cretaceous, 146-65.5MA Flowering plants appear (angiosperms)
Modern Birds
All good until……

19. K-T Extinction 65MA Kills off Dinosaurs Asteroid or volcano
Iridium rich dust….

20. Cenozoic Era "The Age of Mammals" 65.5 mya through today
Continents at present locations

22. Cenozoic, Tertiary, Paleocene
mya
Paleocene- age on mammals begins
First Primates

23. Cenozoic, Tertiary, Eocene
mya
Rodents appear. Primitive whales appear.

24. Cenozoic, Tertiary,Oligocene
mya
Dogs and cats appear!
But they did not look like that -

25. Cenozoic, Tertiary, MioceneMA
Due to high abundance of grasses, herds of large mammals abound.

26. Cenozoic, Tertiary, Pliocene
First hominids (australopithecines). Modern forms of whales. Megalodon swam the seas
Hominid- where humans and apes split

28. Lions Tigers and Bears….
Appear in the Pliocene

29. Cenozoic, Quauernary, Pleistocene
Quaternary Period "The Age of Man" 1.8 mya to today
Pleistocene- The Last Ice Age ma
Humans (Homo sapien) appear. You better remember this!

30. Mammoths, saber-toothed cats,

31. Quaternary, Holocene 11,500 ya to today
Marked by complex human civilization
Ice melted, and sea level rose 140 m!