1. Compare and contrast mass extinctions and background extinctions. How do their size and geographic and taxonomic extent differ? 2. Suppose that a species first appears in the fossil record 350...

1. Compare and contrast mass extinctions and background extinctions. How do their size and geographic and taxonomic extent differ?

2. Suppose that a species first appears in the fossil record 350 mya. Why is it logical to argue that this species actually existed before this date?