Sharks are evolutionary advanced animals and are incredibly well adapted for their place in ocean ecosystems. In this video, differences between sharks and other fish are highlighted and celebrated. One such difference is in each group’s ability to control their vertical position in the water. Bony fish have a swim bladder that they can inflate and deflate to control their buoyancy. Sharks, on the other hand, must swim and control their depth with their fins. The included lesson looks at the basic biology of sharks and how sharks and bony fish control buoyancy.