What is fish with out an eye. FSH

History Earliest fish had no jaws and no paired fins-filtered feed 1st fish bodies covered with bony plates For 100 million years-fish were the only vertebrates

Superclass Agnatha Jawless vertebrates Most primitive, living vertebrates Ostracoderms (extinct); lamprey and hagfish Lack paired appendages; cartilaginous skeleton; notochord throughout life; rasping mouth

Superclass Gnathostomata, I Placoderms (extinct): first with hinged jaws and paired appendages Class: Chondrichthyes~ Sharks, skates, rays Cartilaginous fishes; well developed jaws and paired fins; continual water flow over gills (gas exchange); lateral line system (water pressure changes)

Rise of Sharks & Bony Fish About 400 mya all the other fish disappeared and were replaced by sharks and bony fish. The jaws improved-developed the hyomandibular arch from gills More fins developed.

Continue Sharks became the top predators-skeletons of cartilage Sharks first fish with bony teeth Sharks use internal fertilization and pups born alive Skates and ray develop around 200 mya

Life cycles: Oviparous- eggs hatch outside mother’s body Ovoviviparous- retain fertilized eggs; nourished by egg yolk; young born live Viviparous- young develop within uterus; nourished by placenta

Bony Fish Evolved 400 mya Developed heavy bony skeleton for protection and anchoring of muscles Evolved in fresh water Developed two types Ray finned most fish perch- has swim bladder-95% of all fish are teleosts (advanced ray finned fish) Lobe finned evolved 390 mya-fin is more like limb than fin-EX :Coelacanth

Some lobed-finned fish walk on land

Key Adaptations 1. Gills for breathing 2. Backbone 3. Single looped circulation system- blood is pump from heart to gills to body back to heart Nutritional requirements fish are unable to make all the amino acids needed so they must get these amino acids by eating them- (true for all vertebrates)

Superclass Gnathostomata, II Class: Osteichthyes Ossified (bony) endoskeleton; scales operculum(gill covering); swim bladder (buoyancy) Most numerous vertebrate Ray-fined (fins supported by long, flexible rays): bass, trout, perch, tuna, herring Lobe-finned (fins supported by body skeleton extensions): coelocanth Lungfishes (gills and lungs): Australian lungfish (aestivation)

Bony Fish adaptations Swim bladder secrets and absorbs gases in order to make fish rise or sink in water-gas is CO2 Lateral line system sensory organ located along the side of a fish (hearing) Gill cover (operculum) hard plate covering the gills that pumps to push water over gills (so fish doesn’t have to swim to breath.)

Homework Draw a picture of a fish and label each fin-determine what each fin does.