1. Take a deep breath: What is the source of the oxygen that you just inhaled?
2. How do you know there is oxygen in seawater?
1. In what context could 10 million years be considered a “blink of an eye?”
2. What happened during the Cambrian Explosion?
3. Define “phylum,” and provide two examples.
4. Why are fossils found in the Burgess Shale so valuable to scientists?
5. Explain how hallucigenia got its name.
6. When did oxygen levels first begin to rise on Earth?
7. How does halite form?
8. How much oxygen did the oceans contain at the start of the Cambrian Period?
9. What would burrowing worms do to oxygen levels in marine muds?
10. Explain what a “feedback loop” is.
1. How are increased ocean levels of calcium linked to the Cambrian Explosion?
2. If you dug down deeper into the Burgess Shale formation, would you expect to find a greater or lesser diversity of fossilized creatures? Explain your answer.
1. Create a map that highlights the mountain chain that includes the Burgess Shale formation.