1. Phlyum Chordata Subphylum Vertebrata
FISH:
Agnatha
Chondrichthyes
Osteichthyes

2. Subphylum Vertebrata Kingdom Animalia Phylum Chordata
Have Backbone = vertebrae (plural) vertebra (singular)
Dorsal row of hollow skeletal elements which enclose and protect the nerve cord.
Spinal cord ends in a brain attached to spine
Fish
Amphibians
Reptiles
Birds
Mammals

3. Fish 24,000-30,000 species, ~15,000 are marine
Most abundant vertebrates
Eukaryotic, multicellular
Organ level of organization
Bilateral symmetry
Endoskeleton, made of bone or cartilage

4. General Fish Characteristics
Gills
Backbone (vertebrae)
Paired Fins
Single Loop Circulation
Two chambered heart

5. Fish have a two chambered heart and single loop circulation:
blood is passed over the gills where it picks up oxygen, goes to the body and returns to the heart

6. Fish Respiration Water flows over gills as fish opens mouth and swims.
Water flows opposite direction of blood flow.

7. Fish Respiration O2 diffuses from the water into the blood.
Gills are made of thousands of gill filaments.
Gills are covered by the 0perculum.

8. FISH 3 classes Agnatha Chondrichthyes Osteichthyes Jawless fish
Cartilaginous fishes
Osteichthyes
Bony fishes

9. The jawless fishes: Agnatha
Most primitive
Lack jaws and paired fins
Feed by suction: teeth and muscular mouths
Elongated cylindrical body
Cartilaginous skeletons

10. Hagfish
“Slime eels”
Secrete large amounts of mucus from skin when agitated
Feed on dead or decaying fishes
Bore into prey, eat them from inside out.
Knot and slide technique
Hagfish Slime and sharks
Hagfish Info

11. Lamprey fresh and salt water
Breed and hatch in freshwater rivers and lakes
Live/feed at sea as adults
Parasitic, suck blood from other fish
Predators of bottom invertebrates

12. Chondrichthyes Include: Paired fins (often stiff)
RAY
Include:
Sharks
Rays
Skates
Ratfish
Paired fins (often stiff)
Skeleton made of cartilage
Lighter, more flexible than bone
SKATE
RATFISH
SHARK

13. Chondrichthyes Moveable jaws with well developed teeth
“Conveyor belt” teeth replacement
Placoid scales- rough, sandpaper skin
Teeth and skin composed of same material.

14. Spiracles: 1st pair of gill slits modified, used to take in water even when ventrally located mouth in sediment
Heterocercal caudal fin: upper lobe extends further than lower lobe

15. Sharks Paired pectoral fins
Great predators (teeth and speed) great whites
5 to 7 gill slits
Two dorsal fins
Nictitating membrane = extra eye lid, protects eye during feeding
Nares for smell
Great whites can detect one drop of blood per every 1 million drop of water from 2 miles away!

16. Special senses Gel-filled sensory pores Detect weak electrical fields
Ampullae of Lorenzini
Lateral line
Gel-filled sensory pores
Detect weak electrical fields
Such as: muscular contractions, heart beats, nerve impulses
Sense irregular swimmers
Pores along body that detect water vibrations and pressure
Allows to avoid obstacles, orient to currents, detect prey

17. Ampullae of Lorenzini

18. huge diversity
Size
Eating habits
Shape

19. Shark Diversity Whale shark Rhincodon typus Megachasma pelagios
Squaliolus laticaudus
Pygmy shark
Shark Diversity
megamouth shark
Whale shark
Goblin shark
Mitsukurina owstoni
Rhincodon typus

20. Shark Diversity Hammerhead Thresher Flattened head
Eyes and nares separated for improved sensory intake
Thresher
Very long upper lobe of caudal fin
Herd and stun fish

21. Diversity: filter feeders
Whale Shark: largest fish
Eat plankton!
Basking Shark-2nd largest

22. Diversity: Body shape video
Angel Sharks
Saw shark
Flattened body
Bury in sediment
Alternating tooth size
Blade like snout

23. Rays and Skates Examples Often flattened
Sting rays, electric rays, guitarfish, sawfish, skates, manta rays
Often flattened
Mostly live on bottom = demersal
Pectoral fins are flat, expanded, fused with head
Eyes on top of body typically.

24. Skates and Rays Feeding
Teeth modified into grinding plates
Eat clams, crabs, anything in sediment
Uncover prey by sifting sediment with
pectoral fins

25. Ray gills 5 gill slits always on the underside of body
Spiracles on top to pump water over gills when lying on sediment

26. Rays vs. Skates Whip like tail, often containing poison
Stinging spines
Give birth to live young
Lack whip like tail and poison
Lay egg cases

27. Ratfish-chimieras Mostly deep water One pair of gill slits
Cartilaginous
Bottom dwellers often
Feed on bottom dwellers
Sometimes, a snout-like nose

28. Videos Chondrichthyes diversity Which way to angel shark teeth curve?
How do wobbegong sharks attract fish?
What are the sensory organs used for on saw sharks?

29. Rays Diversity
How many species of rays are there?
How do rays differ from sharks?

30. Shark Fin Soup

31. Osteichthyes

32. Reproduction
Most fish lay eggs that are fertilized externally - called spawning
Some fish bear live young

33. 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.

36. Class Osteichthyes
Bony Fish: Salmon, Carp, Tuna

37. Types of Osteichthyes Most fish are this type
Ray Finned
Most fish are this type
Fins are supported by bony structures called Rays.

38. Types of Osteichthyes
Lobe Finned
Fins are long, fleshy, muscular, supported by central core of bones.
Thought to be ancestors of amphibians.
Examples are: Coelacanth, Lungfish