Fish

Fish➔ Kingdom: Animalia➔ Phylym: Chordata➔ Three Classes:

1. Jawless fish (agnatha)2. Cartilaginous fish (chondricthyes)3. Bony Fish (osteichthyes)

Fish Characteristics➔ Gills for breating➔ Backbone (vertebrae)➔ Paired fins➔ Closed circulatory System➔ Two-chambered heart

Wat t e s ar t he !

Fish AnatomyInternal Features

Fish AnatomyExternal Features

Fins

Fish Respiration➔ Water flows over gills as fish opens mouth and

swims➔ Water flows opposite direction of blood flow➔ O2 diffuses from the water into the blood➔ Gills are made of thousands of gill filaments➔ Gills are covered by the operculum (gill cover)

Fish Respiration

Reproduction➔ Most reproduce sexually, and fertilize their eggs

externally ➔ Sharks/rays fertilize internally

◆ Some keep their eggs in their uterus (viviparous)◆ Others will lay the eggs oviparous)

➔ Spawning is the process of fertilizing eggs➔ Baby fish are called FRY

Jawless Fish➔Class: Agnatha➔No Jaws➔Skeleton made of cartilage➔Soft skin (no scales)➔7 gills➔Lack a swim bladder ➔Examples: Lampreys, Hagfish

Cartilaginous Fish ●Class: Chondrichthyes●Swim constantly to force oxygen into their

gills●Caudal fin (tail) is large/strong●Skeleton made of cartilage (not bone).●5-7 gill slits located on each side of the body●Examples: Sharks and Rays

● 350 different species of sharks

● 300 species of rays and skates

Bony Fish➔Class: osteichthyes➔Skeleton made of bone ➔Teeth are fixed onto the upper jaw ➔Swim bladder: air filled sac that helps

them with buoyancy➔Do not have to swim to breathe (can move

gill covers to force water over gills.)

➔Examples: Trout, Perch, Pike, Goldfish