Fish

1. Fish

2. Kingdom- Animalia Phylum - Chordata Subphylum-Vertebrata Classes- Agnatha,Chondrichthyes, Osteichthyes

3. Taxonomy of Vertebrates: Agnatha • Agnatha include hagfish & lamprey. • Have long, eel-like bodies without jaws or paired fins. • Cartilage skeletons.

4. Chondrichthyes • Chondrichthyes include sharks, rays, & skates. • Contain cartilage skeletons. • Paired fins, & jaws.

5. Osteichthyes • Osteichthyes are bony fish with jaws. • Paired fins. • Bone and cartilage in their skeletons.

6. Evolution: • Fossil record shows jawless fish without paired fins appeared first about 550 million years ago. • Ostracoderm was a jawless, bottom-feeding ancestor to the agnathans (modern jawless fish).

7. Development of jaws & paired fins allowed better movement & increased ability to capture prey. • Extinct acanthodians or spiny fish were first jawed fish with paired fins. • Jaws probably developed from gill arches (bone that supports the pharynx).

8. Characteristics of  Fish:   • Streamlined body & muscular tail for swimming. • Most with paired fins for maneuvering. • Body covered with protective scales & mucus layer to reduce friction when swimming.

9. Have less dense body tissues & store less dense lipids to help them float. • Respire through gills. • Most have a lateral line system or a row of sensory structures running down each side of the organism to detect changes in water temperature, pressure, current.

10. Most with well-developed sense of sight & smell. • Some can detect electrical currents. • Ectotherms (adjust body temperature to environment). • Two chambered heart (upper atrium receives blood & lower ventricle pumps blood).

11. Agnatha (Jawless Fish): • Hagfish (live in oceans) & lampreys (found in marine & freshwater). • Circular mouths. • Sharp teeth & strong rasp-like tongue to tear hole in prey & suck out blood & body fluids.

12. Known as cyclostomes. • Eel-shaped body. • Mucus covers body. • Skeleton made of cartilage. • No paired fins. • Gills without bony cover (called operculum).

13. Retain their notochord throughout their life. • Hagfish are bottom dwellers in cold marine waters that burrow in mud, scavenge on dead & dying fish, & have tentacles around their mouth. • Lampreys are usually parasites with a keen sense of smell to locate prey, lay their eggs in freshwater streams, & are covered with a poisonous slime.

14. Chondrichthyes • Includes sharks, rays, & skates. • Endoskeleton of cartilage. • Hinged jaws & paired fins. • Placoid scales & tooth-like dermal spines on scales.

15. Marine. • Carnivorous. • Sharks are torpedo shaped. • Rays & skates have broad, flat bodies with wing-like fins and a tail.

16. Shark Characteristics: • Fast swimmers. • Large, oily liver (20% of body weight) makes them buoyant. • Tough, leathery skin. • Whale shark is largest & filter feeds on plankton.

17. Sharks are adapted for a predatory lifestyle. • No operculum, must keep moving to breathe. • Have live births. • Special scales feel like sandpaper.

18. Ventral mouth with 6-20 rows of sharp, replaceable teeth. • Short, straight intestine with spiral valve to slow food movement. • 5-7 pairs of gills for gas exchange. • Kidneys remove wastes & maintain water balance. • Electroreceptors on head help find prey & navigate. • Lateral line along side of body contains sensory cells to detect vibrations & pressure. • Separate sexes with external fertilization.

19. Ray & Skate Characteristics: • Usually harmless to humans. • Broad, wing-like pectoral fins used to glide through water. • Flattened bodies with ventral mouth. • Both eyes on top of head.

20. Have protective coloration (darker on top & lighter on bottom). • Feed on fish & invertebrates. • Stingray with poison spine by tip of tail. • Electric ray gives off strong, electric shock. • Manta ray is largest.

21. Bony Fish (Osteichthyes) Characteristics • Skeleton made of bone. • Hinged jaws. • Paired fins. • Gills for gas exchange. • Lateral line. • Body covered with scales & mucus coating. • Includes lobe-finned, ray-finned, and lung fish.

22. Types of Osteichthyes Ray Finned: • Most fish are this type. • Fins are supported by bony structures called Rays. • Teleosts are the most advanced form of ray finned fish (symmetrical tails and mobile fins). Lobe Finned: • Fins are long, fleshy, muscular, supported by central core of bones. • Thought to be ancestors of amphibians. • Examples are: Coelacanth, Lungfish

23. Lobe-finned Fish: • Muscular, paddle-like fins supported by bone. • Gills. • Known as coelacanths. • Thought to be extinct until 1938 when species found in Africa. • Live in deep oceans.

24. Lungfish: • Use lungs & gills. • Eel-shaped body. • Live in shallow, tropical rivers of Africa, Australia, & South America. • Come to surface & gulp air when oxygen level is low. • Form mud cocoon & become dormant if stream dries up.

25. Ray-finned Fish: • Fan-like fins supported by rays. • Includes salmon, perch, catfish, tuna. • Body covered with round, overlapping cycloid or ctenoid scales & mucus. • Four sets ofgills covered by bony operculum.

26. Have movable fins. • Dorsal fin(s) located on top keep fish upright & used for defense. • Caudal fin or tail moves side to side to help steer. • Pectoral fins (paired) on each side behind the operculum. • Pelvic fins (paired) on ventral surface near the head. • Anal fin (single) behind anus.

27. Fins

28. Fish Anatomy

29. Different Dorsal Fins

30. Fish Respiration • Water flows over Gills as fish opens mouth and swims. • Water flows opposite direction of blood flow. • O2 diffuses from the water into the blood. • Gills are made of thousands of gill filaments. • Gills are covered by the Operculum.

31. Closer Look

32. Fish Circulation • Fish heart has 2 chambers • Single loop circulation • Blood flows into gills, picks up O2, goes to the body, returns to the heart.

33. Fish Reproduction • Most Fish reproduce sexually, and fertilize their eggs externally (Sharks-internally). • Spawning is the process of fertilizing eggs. • Baby fish are called FRY.

34. Fish Adaptations • Lateral Line System- used to detect vibrations, orient the fish in water, it is a line of cells running down the side of the fish. • Operculum- gill cover, movement of operculum allows more water to be drawn in. • Swim Bladder- a gas filled sac that helps the fish maintain buoyancy. Sharks don’t have a swim bladder! • Fins- Dorsal, Caudal, Pectoral, Pelvic, Anal.

35. Swim bladder is thin-walled sac in abdomen that creates buoyancy from diffusion of dissolved gas from blood. • Kidneys filter the blood & help maintain water balance. • Ectothermic - body temperature regulated by the environment.

36. Adaptations Air Bladder Operculum Lateral Gills Line Fins

37. Keen sense of smell (nostrils) & have chemical receptors over the body. • Can detect the earth's magnetic field as a guide to navigate oceans.

38. Salmon Life Cycle: • Migrate up to 3200 kilometers following magnetic cues in the ocean. • Follow mucus trails when navigating rivers. • Return to birthplace to spawn. • Males change color & jaw lengthens & develops a hook.

39. Female uses her tail to build gravel nest & lays up to 10,000 eggs.  • Male deposits sperm over eggs. • Adults usually die after spawning. • Pacific salmon return to sea when 15 cm long; while Atlantic salmon may stay in river up to 7 years. • Secrete mucus coating in river as return to sea. • May stay in ocean 6 months to 5 years.

40. THE END!!!