Aquatic anatomy refers to the physical structures and systems found in organisms that live in water, such as fish, amphibians, and marine mammals. These organisms have specialized adaptations, like gills for breathing underwater, streamlined bodies for efficient swimming, and fins or flippers for movement. In addition to gills, many aquatic animals possess unique features like scales for protection and buoyancy bladders to maintain depth. Understanding aquatic anatomy helps scientists study the evolution and behavior of these species, as well as their roles in ecosystems, such as coral reefs and freshwater lakes.