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
system and the swim bladder.
http://www.flickr.com/photos/boarderjon/294353224/
#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
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#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
fish. In addition, it can also detect motion of other
living things in the water. It is similar in function to
hearing.
3) Gill Cover: A hard plate called an operculum covers
and protects the gills. Muscles attached to the
operculum allow it to move in order to push water
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 Groups of Bony Fish
1) Ray-finned fish: Fins supported by
bony rays.
Example: Perch
2) Lobe-finned fish: Fin is a fleshy lobe
supported by bone.
Example: Lungfish
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