1. PHYLUM CHORDATA
Dorsal Notochord-long rod that supports the body-becomes the vertebrae in most.
Dorsal Nerve cord-becomes the central nervous system.
Pharyngeal gill slits-openings in the throat for feeding & breathing-becomes the Pharynx in humans.
Tail-forms in embryos and extends past the anus.

4. Evolution of Fishes Primitive fishes lacked jaws and paired fins
Ancestral jawless fish ruled the seas during Devonian Period: Age of Fishes

5. Evolution of Fishes

6. CLASS PISCES: FISHES

7. CLASS PISCES
SUBCLASS
SUBCLASS

8. Jawless Fishes = Agnathans
No true teeth/jaw
Skeleton made of fibers/cartilage
Cartilage-strong supporting tissue (softer/more flexible than bone)
Lack true vertebrae (keep notochord as adults)
ONLY VERTEBRATE PARASITES!
2 groups: Lampreys and Hagfishes

9. Lampreys
Parasites
Sucker-like oral disks with teeth to grasp and suck tissues/flesh

10. Hagfishes Detritivores No eyes Toothed tongue Secrete slime 6 hearts
Tie into knot

11. Hagfish

12. Cartilaginous Fishes = Chondrichthyes
Sharks, Rays, Skates
Cartilage skeleton (no bone)
Sharks have thousands of teeth in rows
Skates and Rays glide with wing-like pectoral fins (bottom-dwelling)

14. CARTILAGINOUS FISH 850 Species of Sharks, Rays, & Skates
Skeleton is made of cartilage. S-shaped swimming/rigid fins.
External Gill slits.
Store oils & constant motion to stay afloat.
Scales are small bony plates (at one time used as sandpaper).

15. RAYS & SKATES Flattened body for a bottom-dwelling niche
Spiracles & eyes on the dorsal side.
Mouth, nostrils & gill slits on ventral side.
Stingrays have a hollow barb.
Manta ray grows to 18’.

16. SHARKS Close to 300 species. Largest fish in the world-Whale Shark.
Can smell 1drop/blood
In 1 million parts/water.
Lateral line detect vibrations in the water
Ampullae of Lorenzini
Sense changes in electrical field.

17. WHALE SHARK

18. Bony Fishes = Osteichthyes
Bone skeleton (hard, calcified tissue)
Ray-Finned Fishes-fins formed from bony spines covered by thin layers of skin (largest group)
Lobe-Finned Fishes-fleshy fins with bones (some jointed like arms/legs)…ex. Lungfish & Coelacanth

19. Fish: Aquatic Vertebrates Scales Paired Fins Gills Scales Eye
Caudal fin
Dorsal fin
Lateral line
Mouth
Operculum (gill cover)
Anal fin
Pelvic fin
Pectoral fin

20. Feeding
Herbivores, carnivores, parasites, filter feeders, and detritivores
Digestive tract: mouthesophagusstomachpyloric cecaintestineanus (solid waste)
Enzymes added by liver and pancreas

21. Digestive System Esophagus Stomach Intestine Liver Pyloric cecum Mouth
Anus
Pancreas

22. Respiration Gills on sides of pharynx to exchange gases
Gill Filaments-feathery structures with capillaries for gas exchange
Gill Rakers-prevents prey from escaping through gills
Gill Arches-support and protect gills
Operculum-protective bony cover over gill openings

23. Gills

24. Lungfish Adaptation to oxygen-poor water
Tube brings oxygen from air into fish’s mouth to “LUNG”

25. Circulation Closed system 2 chambered heart
Single loop: heartgillsbody (back to heart)

26. Fish Heart
Sinus Venosus-sac that collects oxygen poor blood from veins; sends blood toAtrium-large muscular chamber; sends it toVentricle-large muscular chamber that pumps blood; sends it toBulbus Arteriosus-muscular tube that connects toAorta-large blood vessel that sends blood to gills

27. Fish Heart
Atrium
Sinus Venosus
Bulbus arteriosus
Ventricle

28. Circulation in a Fish Gills Brain and head circulation
Body muscle circulation
Digestive system circulation
Heart

29. Excretion Eliminate nitrogenous waste as ammonia (urine)
Kidneys filter waste from blood
Diffusion through gills
Kidney

30. Response/Nervous System
Well-developed nervous system with brain
Eyes with color vision
Taste/Smell
Lateral Line System- detect currents/vibrations in water (sense nearby fishes)
Brain

31. Olfactory Bulbs-smell (olfaction)
Cerebrum-smell (and voluntary activities)
Optic Lobe-process info from eyes
Cerebellum-coordinates body movements
Medulla Oblongata-controls internal organs
Olfactory bulb
Cerebrum
Optic lobe
Cerebellum
Medulla oblongata

32. Movement
Swim Bladder-internal gas filled organ to adjust buoyancy in bony fish only

33. Movement continued… Contract paired sets of muscles Fins propel
Dorsal/Ventral fins for stability (Dorsal/Anal)
Paired fins for fine movements/turning (Pectoral/Pelvic)
Caudal fin for speed

34. Reproduction External/Internal fertilization
Oviparous-eggs (embryo) develop and hatch outside mom’s body; obtain food from egg yolk
Ovoviviparous-eggs stay in mom’s body; obtain food from egg yolk; young are “born alive”
Viviparous-embryos stay in mom’s body; obtain food from mom; young are born alive

36. Anadromous-live in ocean but migrate to fresh water to breed; Ex
Anadromous-live in ocean but migrate to fresh water to breed; Ex. Salmon

37. Migrations Catadromous- Breed in the oceans but live in freshwater
Eels migrate to the Sargasso Sea, they spawn at depths of 300 meters and die when done