I hear that sharks have been around longer than a lot of plants, why didn't they die out like the dinosaurs?
user
That’s a good question! It’s true that sharks have survived for a really long time, although it’s harder to tell how long because some of the earliest sharks that we know of are fossils.  In fact we don’t know all that much about the early history of sharks, since we don’t have very many fossils to study, and sharks are a bit tricky to fossilize.
assistant
I hear that sharks have been around longer than a lot of plants, why didn't they die out like the dinosaurs?
user
That’s a good question! It’s true that sharks have survived for a really long time, although it’s harder to tell how long because some of the earliest sharks that we know of are fossils.  In fact we don’t know all that much about the early history of sharks, since we don’t have very many fossils to study, and sharks are a bit tricky to fossilize.
assistant
I hear that sharks have been around longer than a lot of plants, why didn't they die out like the dinosaurs?