Chapter 39 Fish

1. Chapter 39Fish 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.