Animals with Backbones Vertebrates Animals with Backbones

Vertebrates Animals in the sub-phylum Vertebrata have spinal cords and brains Marine vertebrates include: sharks, fish, turtles, birds, seals and whales

Class Agnatha: The jawless fishes Simple, more primitive fish that lack jaws. May represent the ancestors of bony fish and sharks. i.e hagfish and lamprey Characteristics include: No jaws Cartilaginous skeletons Lack scales, paired fins Long, eel-like Two class divisions: Myxini (hagfish) Petromyzontida (lampreys)

Class Osteichthyes: The bony fishes Osteichthyes contains the majority of the ocean’s fish Characteristics include: Jawed fish with skeletons made of bone Operculum: bony skin flap outside gills that helps fish breathe when not swimming Most use a swim bladder to keep them from sinking (adding or releasing gas) Swim bladders allow fish to hover motionless in the ocean. Most reproduce externally Bony fish have lateral lines that detect water motion and vibrations. This is how schools of fish can coordinate https://www.youtube.com/watch?v=15B8qN9dre4

Anatomy of a bony, ray-finned fish Fins are used for movement, support, and protection

Chondrichthyes: Cartilaginous fishes Class Chondrichthyes means ‘cartilaginous fish’ and consists of sharks, rays, skates and close relatives They share common features: Jaws Cartilage skeletons, not true bone Fatty liver used for buoyancy Lack swim bladder Most have placoid scales (modified teeth and are covered with a hard enamel)