What is the evolutionary relationship between sharks and fish?

Sharks are a type of fish. They belong to the class Chondrichthyes, which also includes rays and skates. Chondrichthyes are cartilaginous fish, meaning their skeletons are made of cartilage instead of bone. They have been around for over 450 million years, making them one of the oldest groups of animals on Earth.

Sharks are closely related to the bony fish, which belong to the class Osteichthyes. Bony fish have skeletons made of bone, and they appeared around 200 million years after cartilaginous fish. Sharks and bony fish share a common ancestor, and they are both part of the phylum Chordata, which includes all animals that have a backbone.

Sharks are apex predators, meaning they are at the top of the food chain and have no natural predators. They are found in all oceans and at all depths. They play an important role in maintaining the balance of marine ecosystems.