Vertebrates Animals with Backbones Vertebrates o Animals in

Vertebrates Animals with Backbones

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

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

Class Osteichthyes: The bony fishes o Osteichthyes contains the majority of the ocean’s fish o Characteristics include: o Jawed fish with skeletons made of bone o Operculum: bony skin flap outside gills that helps fish breathe when not swimming o Most use a swim bladder to keep them from sinking (adding or releasing gas) o Swim bladders allow fish to hover motionless in the ocean. o Most reproduce externally o Bony fish have lateral lines that detect water motion and vibrations. This is how schools of fish can coordinate o https: //www. youtube. com/watch? v=15 B 8 q. N 9 dre 4

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

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