Help! 1. From what sources did water arrive in Earth’s atmosphere?
2. What are the two main reasons that an oxygen-rich atmosphere is important for life on Earth?
3. List three ways Earth is different today from when it was first formed.
4. What is the difference between a craton, shield, and platform?
5. What does a greenstone indicate about the plate tectonic environment in which it formed?
6. What happened to all of the heat Earth had when it formed?
7. What was Laurentia and what lands was it composed of? What happened to it?
8. How was Rodinia like Pangaea?
9. What is the RNA world hypothesis and why is it called that?
10. What is the difference between prokaryotes and eukaryotes?
11. How do the rocks of the Grand Canyon indicate marine transgressions or regressions?
12. What was the configuration of oceans during the time of the supercontinent Pangaea?
13. What geologic evidence is left after a continent breaks apart?
14. What happens immediately after a mass extinction to the diversity of organisms? What happens thousands or millions of years later?
15. Describe the big advance reptiles had over amphibians.
16. Why are there so many different species on Earth today?