Fish Notes Class:Agnatha Jawless Fish

General Fish Information Fish make up half of all vertebrates on Earth. Fish make up half of all vertebrates on Earth. 15, 300 marine species 15, 300 marine species 9,000 freshwater species 9,000 freshwater species They first appeared more than 500 million years ago. They first appeared more than 500 million years ago. 3 groups of fish 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. 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. Fishes – the term “fishes” refers to more than one species of fish.

3 Main Body Parts 1. Fins – movement 1. Fins – movement

3 Main Body Parts 2. Scales protection. protection. Many species secrete a protein-like “slime” that contains natural antibiotics to protect them from disease. 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. On many bony fish species you can count the rings on the scales to determine age.

3 Main Body Parts 3. Gills Oxygen exchange. Oxygen exchange. in through the mouth in through the mouth out through the gills out through the gills Oxygen passes out of water into bloodstream by diffusion. Oxygen passes out of water into bloodstream by diffusion.

1. Lamprey: Parasites Parasites Primarily freshwater fish – breed in rivers and lakes and some move to saltwater as adults. Primarily freshwater fish – breed in rivers and lakes and some move to saltwater as adults. Sucker-like mouth with horn- like teeth Sucker-like mouth with horn- like teeth Attach to fish and suck up tissues and body fluids of host. 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. Lampreys have an anticoagulant in the saliva that keeps the blood of the victim fluid. Jawless Fish – Class Agnatha Lamprey Lamprey Mouth

Jawless Fish – Class Agnatha Hagfish Hagfish * no eyes, jaws, scales or paired fins * no eyes, jaws, scales or paired fins * worm-like body * worm-like body * 4-6 short tentacles around the mouth * 4-6 short tentacles around the mouth * toothed tongue * toothed tongue * scavengers or parasites of slow moving fish * scavengers or parasites of slow moving fish * produce enormous amounts of slime – 5 gal/min * produce enormous amounts of slime – 5 gal/min * The slime is a defense mechanism. – slime cocoon * The slime is a defense mechanism. – slime cocoon * Uses a knot to get rid of slime - also sneezes * Uses a knot to get rid of slime - also sneezes Hagfish slime Hagfish