2. Ch. 39 - Fish  How many of you have a fish aquarium?  What are some types of fish?  What makes a fish different from other animals that we have talked about? –Vertebrates  What phylum do vertebrates belong to? –Chordata  Video Video

3. Classification of Vertebrates  Kingdom: Animalia –Phylum: Chordata Subphylum: vertebrata  All chordates at some stage develop 3 things.  1. Notochord – dorsal rod of specialized cells.  2. Dorsal nerve cord- hollow tube just above the notochord.  3. Pharyngeal pouches – small outpockets of the anterior gut.  Most have a post anal tail

4. 3 Classes of fish  1. Agnatha – means “jawless” –Lampreys & hagfish –Both have a notochord their whole life. –Lamprey are mainly freshwater –Hagfish are marine –Hagfish have a toothed tongue that saws a hole in its prey –Pg. 803  Video Video

5. Chondrichthyes (class) #2  Sharks, rays, & skates  Movable jaws; unlike agnatha  Placoid scales – tooth-like spines on their skin.  Pg. 817  Video Video

6. Shark Characteristics  Very fast side-to-side swimming motion  Have 6-20 rows of teeth pointing backwards. Why?  Can use more than 20,000 teeth in its lifetime.  They have 2 pectoral fins just behind their head that act like wings. They compensate for the thrust of the tail fin.  Video Video

7. Rays & Skates  Rays have more of a disk-shaped body  Skates have a triangular-shaped body  Both have flattened bodies  Both have great camouflage and hide well in the sand.  Sting rays have a very powerful sting.  Video Video

8. Osteichthyes (class) #3 33 types of bony fish 11. Lobe-finned fish –F–For over 70 million years scientists thought this fish was extinct until 1938 a South American fisherman caught one. 22. Lungfish –C–Can live out of water for long periods of time. 33. Ray-finned fish –H–Have fins supported by bones(rays). Most fish are this type. Examples?

9. External Anatomy of a Fish  Yellow Perch  Perca flavescens  Operculum – hard covering that protects the gills on each side.  Caudal fin – tail fin (thrust)  2 Dorsal fins  1 Anal fin  2 Pectoral & Pelvic fins –Helps steer, brake, & move up and down.

10.  Integument – skin –Scales that overlap like shingles –Contain chromatophores, which are cells that allow the fish to change colors.  Lateral line – senses vibrations (no ear)

11. Internal Anatomy of a Fish  Food Passage:  Pharynx  Esophagus  Stomach  Pyloric ceca (intestine)  The pyloric ceca are outpockets of the stomach, that have lots of villi that line it.

12. Circulatory System  2-chambered heart  Atrium – collecting chamber  Ventricle – pumping chamber  The blood is pumped through arteries to small capillaries in the gills for has exchange. The blood then returns to the heart through veins.

13. Respiratory System  Gills with a large surface area  Swim bladder allows the fish to adjust its density so it can float without using much energy.

14. Nervous System 55 lobes of the brain 11. Optic lobes – the largest lobes, for sight. 22.Olfactory lobes – smell 33. Cerebrum – intelligence 44. Cerebellum – balance 55. Medulla oblongata – regulates interior organs.

15. Reproductive System  Separate sexes  1. External Fertilization – occurs when the eggs are fertilized outside the female’s body. –Ex. Salmon, trout, perch, (most species)  2. Internal Fertilization – occurs when the eggs are fertilized inside the body. –Ex. Guppies, swordtails, mollies

16.  Spawning is the release of the eggs.  Milting is the release of sperm.  What is one way fishes protect each other? –Schools of fish  What is the age limit on a fishing license? –16 -65