The only vertebrate group represented in this lab is the fish group.
Vertebrates are organisms with a backbone. Fish have a higher likelihood
of becoming a fossil, because they can be preserved in fine grained
sediments after they die. Many land vertebrates do not have conditions
right for preservation. The carbonized impression of the fish shows
details of the entire fish.
The shark teeth only represent a small part of the shark, yet you can
estimate the size of the shark. Big teeth come from big sharks. The
abundance of shark teeth is caused by a shark discarding its teeth once
it bites into something.