Sharks are fish which have cartilages rather than bones. These fish evolved earlier than dinosaurs, which were reptiles. The fossil records show that sharks existed about 400 million years ago. Dinosaurs were found during the Triassic period, i.e. about 225 million years ago.
The archaeopteryx is considered to be the earliest bird and it is the link between birds and reptiles. The archaeopteryx had a set of teeth, which are not found in birds. However it had wings, feathers and reduced fingers, all found in modern birds.
Crocodiles have 24 sharp teeth on each jaw, which are meant to grasp and crush, not to chew. The teeth are continuously replaced during a crocodile’s lifetime. Each tooth is hollow, and a new tooth grows inside the old one in order to be ready once the old tooth is lost. Young crocodiles can replace…
