• Bony fishes are characterized by three key features: scales on the body, lungs or a swim bladder, and bone in the skeleton.
• Lobe-finned fishes have fleshy fins with a central bony axis, while ray finned fishes have non-fleshy fins supported by long flexible bones called rays.
• The external anatomy of a bony fish has several distinct characteristics—an operculum, fins, and scales.
• A fish's heart has two chambers that work together to move blood through the body.
• Water flows over fishes gills in a direction opposite to blood flow. Oxygen diffuses from the water into the blood very efficiently as a result of this process, which is called countercurrent flow.
• Fish adjust their overall density by regulating the amount of gas in the swim bladder, enabling them to move up or down in the water.
• Unlike cartilaginous fishes, most bony fishes reproduce by external fertilization in a process called spawning.
Vocabulary swim bladder (p. 787) ray-finned fish (p. 787) lobe-finned fish (p. 787) operculum (p. 788)
countercurrent flow (p. 791) spawning (p. 792) optic tectum (p. 792)
Was this article helpful?
Discover How To Sleep In Peace And Harmony In A World Full Of Uncertainty And Dramatically Improve Your Quality Of Life Today! Finally You Can Fully Equip Yourself With These “Must Have” Tools For Achieving Peace And Calmness And Live A Life Of Comfort That You Deserve!