1. April 10th & April 14th
Honors Biology

2. History of the Earth (4/10)
4.5 BYA – Formation of the earth
3.5 BYA – Evolution of 1st life forms (simple, anaerobic bacteria)
2.2 BYA – Photosynthetic bacteria begins pumping oxygen (O2) into the atmosphere
542 MYA – Cambrian Explosion (huge increase in diversity of multicellular life forms)
252 MYA – Permian Extinction (largest mass extinction event in history)
65 MYA – Extinction of Dinosaurs

3. Warmup (4/14) What are some possible causes of mass extinctions?
Where did the oxygen that you are breathing come from?

4. Mass Extinctions 5 mass extinctions in the history of life on earth
We are currently in the 6th mass extinction
Worldwide amphibian populations are plummeting (bell weather species)
Increase in CO2 in ocean on levels not seen since Permian Extinction
Ocean acidification could wipe out life in the ocean on a massive scale
99% of all species that have ever existed have gone extinct