1. Section 2 Jawless and Cartilaginous Fish
Chapter 39 Fish
Section 2
Jawless and Cartilaginous Fish

2. Fish Adaptations Stream-lined body & muscular tail
Paired-fins allow fish to manuver
Secrete mucus around body to help move in water and protect against infections
Store lipids (fat) to help aid in buoyancy
Use gills for gas exchange

3. Homeostasis
Freshwater fish = hypertonic (higher concentration of solutes than the surrounding water- gain water)
Saltwater fish = hypotonic (contain lower concentrations of solutes than their surroundings- lose water)

5. Sensory Functions Fish can sense light, chemicals, & sound
Some can sense electrical & magnetic fields
Many fish can see in color, but most cartilaginous fish can not see in color

6. Sensory Functions
Chemoreception- ability to detect chemicals in the environment
Sharks have great sense of smell & taste
Barbels- whisker-like organs near mouth

7. Barbels

8. Sensory Functions
Lateral line- allows fish to sense vibration in the water
Cartilagenous fish (sharks & rays)- ampullae of Lorenzini- detect weak electrical fields- help locate prey

9. Lateral Line

10. ampullae of Lorenzini

11. Jawless Fishes Hagfish & lamprey
Have an eel-like body, cartilaginous skeleton, and unpaired fins
Hagfish live in oceans
Lampreys live in freshwater

12. Hagfishes Bottom-dwellers in cold marine water, no jaws
Isotonic- same ion concentration as sea water
Feed on small invertebrates or dead & dying fish
Burrow in dead fish & consume internal organs

13. Hagfish

14. Lampreys ½ parasites, ½ free-living
Attaches to host with disk-shaped mouth
After feeding, lampreys drop off & host may recover, bleed to death, or die from infection
Fertilization occurs outside body (external fertilization)

15. Lamprey

16. Cartilaginous Fish Class Chondrichthyes
Sharks, skates, rays, & ratfish
Cartilage- flexible, lightweight material made of cells surrounded by tough fibers of protein
Skin is covered with placoid scales- feels like sandpaper

17. Sharks Whale shark- largest shark (60 feet)
Feed on plankton & floating plants & animals
Filter water using gill rakers
6 to 20 rows of teeth that point inward

18. Whale Shark

19. Sharks One shark uses 20,000 teeth in a lifetime
Each tooth is shaped based-on diet

20. Great White Shark

21. Hammer Head Shark

22. Black-tip Reef Shark

23. Bull Shark

24. Lemon Shark

25. Tiger Shark

26. Rays & Skates
Flatten-bodies with wing-like pectoral fins and whip-like tails
Rays have diamond or disk-shaped bodies
Skates have triangular bodies
Bottom-dwellers
Feed on crustaceans

27. Rays

28. Skates

29. Ratfishes Deep-water Have gill slits covered by a flap of skin
Some have a rat-like tail
Feed on crustaceans or mollusks

30. Ratfish

31. Adaptions Gas exchange in gills
Some sharks need to constantly move in order for gas exchange to occur
Rays usually take in water from ventral side, but when on bottom, they use spiracles located behind eye to draw in water

32. Adaptations
Sharks have an oil in their liver called squalene oil that contributes to their buoyancy
Convert ammonia to urea which is a less toxic waste

33. Reproduction
Internal fertilization- male transfers sperm to female’s body
No cartilaginous fish provides parental care once young are born

35. REVIEW!!!
Identify three characteristics of fish that makes them well suited to aquatic life.
Contrast the feeding behavior of hagfish to the feeding behavior of lampreys.
Identify the advantages of internal fertilization vs. external fertilization.