AP BIOLOGY

Detailed explanation-1: -Osteichthyes (bony fish) use swim bladders that are filled with oxygen taken in by their gills. The more air in the swim bladder the more buoyant the fish and the less air in the swim bladder the less buoyant the fish. The swim bladder is similar to human lungs in the way that it expands and deflates.

Detailed explanation-2: -Swimbladders are only found in boney fish. Sharks and rays can maintain buoyancy in water by using oil within their body. Not all boney fish have a swimbladder though; many bottom dwelling species lost theirs as buoyancy is not necessary for them.

Detailed explanation-3: -Tropical reef clown fish, freshwater eels, pelagic swordfish, deep water anglerfish, and river dwelling catfish are all examples of fish in the class Osteichthyes.

Detailed explanation-4: -Chondrichthyes. Chondrichthyes are a taxonomic class of cartilaginous fishes that encompass sharks and rays (elasmobranchs) and chimaera. Though there are exceptions, in general, Chondrichthyes have exposed gills, no swim bladder, internal fertilization, and placoid denticles.