Transcript Fish Notes
Fish Notes Class:Agnatha Jawless Fish • • • • • General Fish Information Fish make up half of all vertebrates on Earth. 15, 300 marine species 9,000 freshwater species They first appeared more than 500 million years ago. 3 groups of fish 1. Jawless – Class Agnatha 2. Cartilaginous – Class Chondrichthyes 3. Bony – Class Osteichthyes • Fish – The term “fish” refers to a single individual or more than one of the same species. • Fishes – the term “fishes” refers to more than one species of fish. 3 Main Body Parts • 1. Fins – movement 3 Main Body Parts 2. Scales • protection. • Many species secrete a protein-like “slime” that contains natural antibiotics to protect them from disease. • On many bony fish species you can count the rings on the scales to determine age. 3 Main Body Parts 3. Gills • Oxygen exchange. • in through the mouth • out through the gills • Oxygen passes out of water into bloodstream by diffusion. Jawless Fish – Class Agnatha 1. Lamprey: • Parasites • Primarily freshwater fish – breed in rivers and lakes and some move to saltwater as adults. • Sucker-like mouth with hornlike teeth • Attach to fish and suck up tissues and body fluids of host. • Lampreys have an anticoagulant in the saliva that keeps the blood of the victim fluid. Lamprey Lamprey Mouth Jawless Fish – Class Agnatha • Hagfish • * no eyes, jaws, scales or paired fins • * worm-like body • * 4-6 short tentacles around the mouth • * toothed tongue • * scavengers or parasites of slow moving fish • * produce enormous amounts of slime – 5 gal/min • * The slime is a defense mechanism. – slime cocoon • * Uses a knot to get rid of slime - also sneezes Hagfish Hagfish slime