What is a stromatolite? Where is there evidence of this?
What is cyano-bacteria? What changes did they cause?
How much oxygen is in our atmosphere today?
What does oxygen do to protect life? Why is this important?
Homework: Use your textbook and/or the Internet, to create a brief Geological timeline with examples of life and major geological and extinction processes at each time point. The following web site is one of the best that I have seen! (http://www.pbs.org/wgbh/evolution/change/deeptime/index.html)