1. Single-celled bacterial life first appears. Earth is covered in shallow oceans.
2. “Age of Dinosaurs”
3. Pangaea is assembled.
4. “Age of Mammals”
5. Series of ice ages and glaciations occur.
6. Explosion of life forms in the sea. Diversity of marine life increases – especially invertebrates (lacking back bone)
7. Plants invade the land; insects, amphibians, and reptiles appear and flourish.
8. This era ends with a mass extinction caused by an impact of an asteroid or comet.
9. This is a very humid, tropical era due to so much volcanic green house gases; flowering plants, the 1 st birds, and 1 st mammals appear.
10. Shallow seas cover most of Earth. Life includes sponges, jellyfish, trilobites, “squid” etc.
11. This era is divided into lots, and lots of periods – each ended by a mass extinction (Ex: Cambrian, Silurian, Devonian, etc)
12. This era is divided into 3 periods: Triassic, Jurassic, and Cretaceous.
13. This era is divided into 3 periods: Paleogene, Neogene, Quarternary.
14. Humans evolve!
Order of Eras.
15. Place the Eras in order, starting with the formation of Earth.
________________________ era  ______________________  era  ____________________  _________________ era
(Earth forms)
Precambrian Time
17. What was the first life like? Describe it.
16. Which era lasted the longest amount of time?
(today)
18. How did photosynthesizing bacteria change the atmosphere? Change temperatures?
Big Ideas
19. Give an example of the type of event that causes a mass extinction in Earth’s history. Be specific. (Sentences)
20. Give an example of how a change in geology or climate resulted in a change in biology (new life form).