1. Divisions of Geologic Time

2. Geologic time (p. 591 / Back of the Text)
The time of the physical formation and development of Earth
Ranges from billion years ago until the present day

4. Eons > Eras > Periods > Epochs
Largest division of geologic time
Precambrian Eon
Subdivided into the Hadean, Archean, Proterozoic
The fossil record suggests life started to develop in the Archean
Phanerozoic
The current eon
Lots of fossil evidence

5. Eons > Eras > Periods > Epochs
years in duration
Divisions of time are based on the appearance of different forms of life represented in the fossil record
Ceno - recent
Meso - middle
Paleo - old
Zoic - life

6. Eons > Eras > Periods > Epochs
year duration
Sometimes named after the region in which characterisitic fossils from the time period were discovered
Example: Edicaran Period named after Ediacara Hills in Austrailian

7. Eons > Eras > Periods > Epochs
years in duration
Why are there Epochs represented in the Cenozoic Era, but any others?

8. Mass Extinction Events: Turn to page. 594