Geological Time Scale Worksheet 1. Name the four Era’s. 2. How many periods are in each era? 3. Name the 7 EPOCH’s in the Era Cenozoic? 4. Ma stands for millions of years. a. How long was the Mesozoic Era?___________ b. How long was the Cenozoic Era?____________ c. How old is the earth, in billions of years? ______________ d. How long was the age of Mammals? ________________ e. How long has there been land plants on the earth? _____________ 5. How long ago did the following take place? a. Rocky Mountain form - __________________ b. Grand Canyon form - __________________ c. Flowering plant start to grow - ________________ d. Cambrian explosion - __________________ 6. How long were dinosaurs on the earth? ________________ 7. How long has oxygen been fully present in the atmosphere? ______________ 8. How many years ago did Pangea form? __________________ 9. Estimate how long was the Age of Amphibians? ______________________ 10. What Era and period occurred during: a. 418 to 355 million years ago _________________________ i. describe what was present during this time frame. b. 251 to 65 million years ago _________________________ i. describe what was present during this time frame. ii. What occurred in the Lithosphere during this time period? 11. What was present when primates first appeared? How long have primates been present on the earth? 12. Name the era, periods and times frame in regards to the Age of Fish. 13. How many major extinctions have there been? At what time did they all occur?