1. Phylum Chordata
Fish

2. I. Phylum Chordata
Includes Fish, Reptiles, Birds and Mammals
A. Characteristics of Chordates
1. All have bilateral symmetry
2. All have internal skeleton
3. Notochord – Flexible internal, supporting structure; “backbone”

3. 4. all have paired gill slits; at some point in life (even mammals)
5. Have 2 layer body covering – scales, feathers, hairs, skin,
6. Closed circulatory system
7. Highly developed nervous system
8. Chambered heart – 2, 3, or 4
9. Dorsal nerve cord – spinal cord; protected by the notochord

5. II. Fishes
A. General Info
1. Well developed senses- excellent smell, sight (for most)
2. Most have scales covering body
3. All secrete mucous to protect from bacterial and fungal infections

7. 4. Have gills for entire life
5. Most have fins; used for moving
6. Vary in size; 12mm to 40ft.
7. exothermic – body To changes with surrounding To = “cold blooded”
8. 3 classes of fish

8. B. Class Agnatha
1. “Jawless” fish; has no jaw
2. Circular mouth
3. Eel shaped body; long and slender
4. Most primitive living fish
5. Very smooth skin; no scales
6. Skeleton made of cartilage

9. 7. Two types of Agnathas
a. lamprey
1) found both freshwater and saltwater
2) has become a big problem in the Great Lakes
3) lampreys are considered parasites

11. 4) has a sucker like mouth with sharp teeth
5) “drill” into their prey; sucks out blood and fluids; “vampire fish”
6) lives up to 9 years
7) averages 2ft feet in body length

12. 8) gray in color
9) very strong suction ability

13. b. Hagfish
1) only found in saltwater
2) very slimy -> “slime-eel”
3) secretes so much mucus;
noses get clog; has to sneeze to clear nose
4) feed only on dead fish

14. 5) no eyes;
instead uses barbels -> very sensitive extensions can smell up to 2ft away
6) grayish/purplish in color
7) lives on the ocean bottom
8) coils up when resting
9) basically no skeleton except for spine

15. 10) gnaws on food with rough tongue

16. C. Class Chondrichthyes
Includes sharks and rays
1. General information
a. no true bones -> skeleton made of cartilage
b. very strong jaws, moveable

17. b. mouth on underside; can’t really see what goes into mouth
c. skin is like sandpaper; placoids -> cover entire body; Tooth scales
d. males easy to identify by a set of claspers by anal fins; for copulation
e. has internal fertilization
f. has 5, 6 or 7 open gill slits

18. 2. Sharks
a. General information
1) over 350 species
2) only 50 are known to attack man
3) Most feared sea creature; thanks to movies like “Jaws”

19. 4) More humans are killed and attacked by dogs than sharks
5) sizes vary from 6 inches- > cigar shark to 40 ft -> whale shark
b. Body of shark
1) streamlined for fast speeds -> hydrodynamic

20. 2) Very muscular body, tail moves from side to side;
tail fin is called the caudal ;
has two parts: upper part much longer than bottom part
3) very pointy nose; increases hydrodynamics ability; nose is very sensitive

21. 4) has lateral lines -> enhances. smell ability, run from nose
4) has lateral lines -> enhances smell ability, run from nose down the sides
5) tiny holes found within the lateral lines
6) most sharks must keep moving or will suffocate
7) teeth are very sharp and in rows; like a conveyor belt, teeth replace every 2-3 wks

22. 8) Very large liver; weigh about. 1/4 the body weight;
8) Very large liver; weigh about 1/4 the body weight; contains oil that humans use for vitamin A
9) Intestine is spiraled on the inside for storing food

23. 10) fins do not bend;
used for braking and steering;
dorsal fin most noticeable -> keeps shark from spinning

24. 2) filter feeders -> eat plankton & small marine life;
c. Feeding of sharks
1) Carnivores -> will eat just about anything ->seals, fish bumpers, tin cans
2) filter feeders -> eat plankton & small marine life;
two largest sharks are plankton feeders: whale and basking shark

25. 1) Great White-> most feared, but rare; largest carnivore
d. Types of sharks
1) Great White-> most feared, but rare; largest carnivore
2) Bull -> fastest shark and very aggressive; 45 m/h
3) whale shark -> largest of all fish; very shy; 6ft wide mouth

26. 4) Megamouth-> deep sea shark; only 8 discovered;
first found in 1978, 2nd in off the coast of CA
5) Hammerhead -> unusual head = very broad and flat; aggressive
6) And many more very interesting ones

27. e. Importance of sharks
1) Top of the food chain; keeps nature balanced
2) Used in cancer research
3) Used as food; shark fin soup; shark stakes
4) Clothing -> boots, etc.
5) Skin for burn victims, meshes really good

28. 6) Source of vitamins and oils

29. 3. Rays and Skates
a. General information
1) body is flattened
2) have “wings” to swim
3) most have a whip -like tail

30. 4) Most live on the bottom in the sand
5) very peaceful and shy animals, attack only when provoked
6) Feed mostly on squid, fish
7) Has spiracles to breathe while resting on the bottom

31. b. Protection
1) barb -> located on tail; whip it right into leg, very painful
2) “battery-packed sting” -> can knock a man out, stun prey
3) can swim very fast to avoid danger

32. c. Types of rays
1) Manta ray -> largest of all rays; 24ft “wing span”;
plankton feeder;
very, very peaceful;
no barbed spine

33. 2) Blue - spotted ->very poisonous; be careful
3) Common sting ray -> shuffle feet when entering water to avoid being hit by tail;
4) live mostly in shallow waters

34. D. Class Osteichthyes
Includes all bony fish
1. General information
a) largest class of vertebrates
b) skeleton made of bone (calcium carbonate)

35. Heaviest bony fish 5000 lbs

36. c) have protective, overlapping scales
d) swim using pectoral fins and tail ( sharks only use tails)
e) Most have external fertilization
f) Most have a air bladder -> allows them to “hover” or suspend

37. 2. Body plan
a. tail fins are even ->
sharks ->
b. most have large eyes
c. Mouth in front of body; sharks underneath
d. have nostrils; used only for smelling NOT respiration

39. f. have retractable fins; sharks cannot retract fins
e. 4 pairs of gills; protected by an operculum
f. have retractable fins; sharks cannot retract fins
g. mostly made of muscle; makes for very fast fish
h. variety of shapes and sizes

40. Class Agnatha
No scales
Gill holes
MouthNo jaw
Single long fin
Skeleton made of cartilage

41. Dorsal fin
Placoid scales
Uneven caudal fin
2nd dorsal fin
Lateral lines
Gill slits
mouth
Anal fin
Pelvic fin
Pectoral fin
Class Chondrichthyes
Cartilage skeleton

42. Skeleton bone
Dorsal fin
Pectoral fin
Caudal fin
Lateral line
Overlapping scales
Class Osteichthyes
mouth
operculum
Pelvic fin
anal fin