How is swimming accompolished in bony fish as compared to shark?

Answer 1

Sharks are set apart from other fish mainly by their body composition. Usually fish have skeletons made of bone, just like mammals, reptiles, amphibians and birds. Sharks are unique in that their skeletons are made entirely of cartilage. Cartilage differs from bone since its flexible, but it is similar in sturdiness. Also cartilage had less density than bone, which keeps the shark lightweight so they don't sink in the ocean and prevents sharks from needing an air bladder like other fish. Another unique feature of the shark is its skin texture, which consists of a type of scales called denticles. This differs from bony fish which have large noticeable scales. Denticles are aligned in such a way that water is channeled over the body minimizing drag. Sharks are similar to bony fish in that they both breathe by extracting oxygen from the water. As the shark moves, water enters the mouth and passes over the gills and escapes via gill slits behind its head. The oxygen gets diffused into the sharks bloodstream as the water passes through. These slits are covered in bony fish, but are exposed in sharks. The majority of bony fish depend on a swim bladder which navigate them through the water. The bony fish takes in oxygen and releases a portion of the gas into the bladder, which increases its buoyancy causing the fish to rise. When the fish sinks, it does this by squeezing some of the gas out of its bladder, which decreases its buoyancy. So in essence, a bony fish is kind of like the good year blimp. The shark on the other hand is more like a plane, without a swim bladder it uses its own forward movement to control position. Much like a plane uses its propeller, a shark uses its tail to move forward by swinging it back and forth. This forward movement pushes water around the fins, creating lift.

Answer 2

Boney fish are fish with actual bones whereas sharks have only cartilage (a flexible bone-like material that is also in your nose).