1. Fishes
Section 30.1

2. Animal Classification
Sponges
Cnidarians
Worms
Mollusks
Arthropods
Echinoderms
Invertebrates
Animals
Amphibians
Reptiles
Fishes
Ectotherms
(cold-blooded)
Vertebrates
Phylum Chordata
Birds
Mammals
Endotherms
(warm-blooded)

3. Classes of Fishes Superclass Agnatha – jawless fishes
Hagfish feed on dead or dying fishes
Lampreys use suckerlike mouths to suck out the prey’s blood
Skeleton made of cartilage

4. Classes of Fishes

5. Classes of Fishes Class Chondrichthyes (kahn DRIHK the ez)
Cartilaginous fishes
Sharks, skates and rays

6. Classes of Fishes
Class Osteichthyes (ahs tee IHK the ez)
Bony fishes

7. Fishes Breathe Using Gills
Fishes have gills made up of feathery gill filaments that contain tiny blood vessels
Oxygen and carbon dioxide are exchanged through the capillaries in the gill filaments

8. Two-Chambered Hearts
One chamber receives deoxygenated blood from the body tissues, and the second chamber pumps blood directly to the capillaries of the gills

9. Two-Chambered Hearts Atrium – receiving chamber of the heart
Ventricle – pumping chamber of the heart

10. Sexual Reproduction External fertilization is common in most fishes
Spawning – External fertilization in fishes
Cod can produce as many as 9 million eggs, of which only a small percentage survive
No parental involvement after spawning
Cartilaginous fishes undergo internal fertilization

11. Paired Fins
Fishes in classes Chondrichthyes and Ostheichthyes have paired fins
Fins – fan-shaped membranes that are used for balance, swimming, and steering

12. Paired Fins Dorsal – towards the backbone Pectoral – chest area
Pelvic – hip area
Anal
Caudal - tail

13. Developed Sensory Systems
Lateral line system – a line of fluid-filled canals running along the sides of a fish that enables it to detect movement and vibrations in the water
Found in cartilaginous and bony fishes

14. Developed Sensory Systems
Fishes have eyes
Some fishes that live in areas absent of light may have reduced, almost non-functional eyes
Blind cave fish (small, non-functioning eyes)

15. Developed Sensory Systems
Some fishes have an extremely sensitive sense of smell
Sharks can follow a trail of blood through the water for 300 feet

16. Scales Scales – thin bony plates formed from the skin
Scales can be toothlike, diamond-shaped, cone-shaped, or round

17. Scales
Shark scales are similar to teeth found in other vertebrates

18. Jaws
The advantage of jaws is that they enable an animal to grasp and crush its prey with great force

19. Jaws
Sharks have up to 20 rows of teeth that are continually replaced (e.g. vending machine)
Their teeth point backwards to prevent prey from escaping once caught

20. Vertebrae Provides Flexibility
Separate vertebrae are important for fish locomotion which involves continuous flexing of the backbone

21. Swim Bladder
Swim bladder – a thin-walled, internal sac found just below the backbone in most bony fishes
A swim bladder controls a fish’s depth by regulating the amount of gas in the bladder

22. Swim Bladder
Some fishes remove gases through a special duct that attaches the swim bladder to the esophagus
Sharks don’t have swim bladders
Sharks maintain their buoyancy via fatty livers