Geologic time: 1. know the names of all the eons and the eras (you do not need to know the periods or the dates.) picture on ! know the major occurrences for each of the eons and eras as we covered them in class. (examples of what you will need to know: there was a 90% mass extinction of all marine species at the end of the solid / stable continents first appeared at the start of the 2. know how the geologic time scale was divided up. 3. be able to fill out the eons and eras for the geologic time scale. list eons list eras 4. what is so different about the phanerozoic eon? what does phanerozoic mean?