1. 10. 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.

2. CLASSES OF CHORDATES

3. CLASS PISCES
SUBCLASS
SUBCLASS

4. Classes of Pisces

5. SUBCLASS AGNATHA Jawless fish, that are the only vertebrate parasites.
Hagfish live in salt,
Lampreys live in fresh
Water.
Have a sucker-like oral disk, with teeth that rasp the flesh & suck out juices from tissue.

6. Hagfish

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

8. 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’.

9. SHARKS Close to 300 species. Largest fish in the world-Whale Shark.
Can smell1drop/blood
In 1 million parts/water.
Lateral line detect vibrations in the water
Ampullae of Lorenzini
Sense changes in electrical field.

10. WHALE SHARK

12. CLASS OSTEICHTHYES (BONY FISH)
96% of all fish belong to this group.
Bony skeletons, gill operculum's.
Rigid bodies, flexible fins.
Swim bladders for buoyancy.
Chromatophores for color.

13. SKIN & SCALES
The skin of bony fish has chromatophores-mating, camouflage.
Light, flexible scales for protection.
Produce mucus to reduce friction in water & protect against predators.

14. FINS & LOCOMOTION
Due to the rigid nature of their body, bony fish “flex” their fins for propulsion.
Paired fins are for fine movements.
Dorsal & Ventral are used to stabilize.
Caudal is for speed!

15. SWIM BLADDER & GILLS
Swim/air bladder-gas filled sac that can be used for buoyancy, sound & protection.
Gills extract Oxygen efficiently from water.
Covered by an operculum, there are 3 parts-gill raker, gill arch & gill filaments.
Blood flow in the filaments is opposite the flow of water resulting in the greatest amount of gas exchange!

16. BONY FISH ANATOMY

17. GILL EFFICIENCY
Counter-flow efficiency

18. Concurrent exchange Blood Water 100% 20% 30% 35% 40% 45% 50% 55% 60%
90%
85%
80%
75%
70%
65%
Fluids flow in the same direction
equilibrium between the two fluids occurs

19. Counter Current Exchange
Blood
Water
100%
20%
30%
40%
50%
60%
70%
80%
90%
Fluids flow in the opposite directions
Equilibrium between the two fluids never occurs

21. LATERAL LINE
Lateral line is a series of pits on the side of a fish that lead directly to spinal cord.
It can sense the slightest movements in the water. (vibrations)
Schooling: fish use this sense to school..(about 80 % of all species school at one time)
Schooling helps with: mating,
Protection in #’s, disruptive.

22. REPRODUCTION
Oviparous-both sexes spawn & eggs are fertilized externally.
Ovoviparous-some incubate the eggs
Viviparous-some species actually bear their young live!

23. 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

24. Anadromous- Breed in freshwater but live in salt
Atlantic Salmon makes multiple trips in its lifetime
Pacific Salmon only once

25. SYMBIOSIS