Classes of Fish #1 Agnatha : Jawless Fish 1) Oldest of all fish 500 mya 2) No Jaw 3) Eel-like Body 4) Light skeleton made out of cartilage. 5) Gill slits on the side of the body. 6) Unpaired fins 7) Examples: Lamprey and Hagfish Objectives: 1. List the three classes of fish. Draw a simple picture for each class and provide a one sentence description. 2. Describe the purposes associated with the lateral line http://www.flickr.com/photos/boarderjon/294353224/ system and the swim bladder. #2 Chondrichthyes : Cartilagenous fish 1) Stream-lined Body 2) Jaws Formed from a bony gill arch 3) Skeleton made of cartilage strengthened be calcium carbonate. A thin layer of bone covers the cartilage. 4)Teeth: modified scales 5) Some possess a lateral line system 6) Examples: Sharks, Rays, and Skates 1 #3 Osteichthyes : Bony Fish 1) Skeleton made of bone . 2) Lateral Line System : Specialized sensory system that runs along the length of the fish. It accurately indicates the position and rate of movement of the 2 Groups of Bony Fish fish. In addition, it can also detect motion of other 1) Ray-finned fish : Fins supported by living things in the water. It is similar in function to bony rays. hearing. Example: Perch 3) Gill Cover : A hard plate called an operculum covers 2) Lobe-finned fish : Fin is a fleshy lobe and protects the gills. Muscles attached to the supported by bone. operculum allow it to move in order to push water Example: Lungfish through the gills. Fish that do not have operculum must swim in order to breath. 4) Swim Bladder : Gas sac that regulates buoyancy (the depth which the fish swims). 2.