1. Fishes

2. Common Characteristics
Bilateral Symmetry
Fins
Gills to breathe
Endoskeleton with backbone

3. 3 Classes Agnatha ~60+ species Chondrichthyes ~850 species
Osteichthyes ~20,000+ species

4. Agnatha - Jawless Fish

5. Agnatha - Jawless Fish No Jaw Long bodies No scales Cartilage skeleton
One fleshy fin
No swim bladder

6. Agnatha: Hagfish Scavenger Feed on dead/dying fish (or whales!)
Drill hole and suck blood and flesh
Tentacles for sensory, use tongue to scrape off pieces of flesh on dead fish, can tie themselves in knots
hagfish

7. Tie knot at tail, then slide it forward, can revove excess slime, escape from pred. gain leverage when tearing flesh from prey

8. Agnatha: Lamprey Many parasitic Attach with sucker-like mouth
Teeth scrape flesh or suck blood
Attach to fish, sometimes whales. Rasp hole in victim with tongue suck out blood and body tissues, rarely kill victims, leave weak and wounded

9. Chondrichthyes - Cartilaginous fish

10. Chondrichthyes - Cartilaginous fish
Sharks, skates, and rays
Well-developed fins(paired)
Cartilage skeleton
No swim bladder
Eat anything (almost)
Sharp teeth 6-20 rows typical shark has ~3,000 teeth), may go through as many as 24,000 teeth in a lifetime,
Don’t breed until years, give birth every other year
#’s dwindling snagged for sport, slaughtered for meat, fins,

11. Chondrichthyes - Cartilaginous fish
Skates and rays
Mouth on underside
Flap “wings”
May have sharp spines with poison glands on tail
Some generate electricity
Search for mollusks and crustaceans, spines for defense, electricity for killing prey or pred
“wings are pectoral fins,flap

12. Tiny, toothlike scales called denticles or
placoid scales on sharks

13. Osteichthyes - Bony Fish

14. Osteichthyes - Bony Fish
Endoskeleton of bone
Scales - Ctenoid
Swim bladder
Gill covers - Operculum

15. Osteichthyes - Bony Fish
3 groups
1. Lobe-finned (7 living sp.)
2. Lung fish - gills and lungs to gulp air
3. Ray-finned - diverse
Coelacanththought to be extinct found one in 1938 heavy jaws, limblike fins, extra lobe in tail
Lungfish, gulp air into modified lung when pools dry up
Ray finned thin bony spines called rays are connected by thin skin --->fins
,includes flat bottom dwellers halibut sea horses

16. Shape and Movement
Pelvic and Pectoral- stablizers for turning, stopping
Dorsal - stablize fish so doesn’t flip
Caudal - main thrust for swimming
Caudal fin shipped from side to side creates forward thrust, lampreys wriggle like eels,
Sharks have stiff fins, powerful swimmers, high speeds, but can’t go backwards or stop fast, no graceful movements, require forward motion to keep from sinking, no swim bladder, have oil in liver to help float. Like airplane

18. Bony fish have flexible fins! Speed and grace, can stop,
Ex. The butterfly fish has great dexterity and maneuverability

19. Swim Bladder in bony fish
Gas-filled sac for bouyancy move easeir and more effeciently, except deep-sea and active swimmers - just keep swimmiong mackeral

20. Coloration Chromatophores (pigments)
Mirror-like silver - light reflecting crystals
Countershading in open ocean euphotic
Counterillumination

21. Coloration
Disruptive
Vertical lines, eyespot make it hard to see head

22. Coloration Camouflage Colorful
Colorful for communication for mating or territory or warning toxic or spiny

23. Respiration
Blood flows in the opposite direction from water, can exchange gases the whole length of the blood vessel,

24. Respiration Gills extract oxygen and eliminate CO2
Lots of surface area- gill filaments
SA from gill filaments to exchange more gases

26. Water flows in the opposite direction from water, can exchange gases the whole length of the blood vessel

27. Respiration Water must flow continously past gills
Bony fish: operculum
Sharks : water enters through mouth or spiracle
Water must continuously move past gills to keep blood oxygenated
Pump water over them like goldfish gulping or swim fast with mouth open
Bony fish operculum , water expelled thru single opening on each side of ehad
Sharks, no perculum water enters mouth or spiracles on top of body. Passes thru slits on sides of body

28. Excretory system - osmoregulation

29. Some water, CO2 and salt excreted through gills
Kidneys remove wastes and salts

30. Bony fish:
Drink saltwater
Gills remove salt
Don’t pee much(very salty)
Sharks:
Blood salts similar to sea
Water
Retain a lot of nitrogenous
Waste (urea)
Gills and kidneys excrete
salt

31. Circulatory system: Closed, 2 chambered heart
No O2 blood from body ->atrium ->ventricle->gills to
Get O2 ->body O2 used->back to heart
Humans: Body to heart to lungs back to heart to body

33. Nervous System Brain, spinal cord, excellent sense organs Large eyes
Taste and smell: big olfactory sacs with receptors on head and entire body
Ears: don’t hear well, but have
Lateral line system

34. Nervous system

35. Pores connect to fluid-filled
canals under skin
Sensitive to vibrations and
pressure waves
Detect prey, danger, swim in
schools, dark murky water

37. Digestive System Complete digestive tract
Carnivores, herbivores, scavengers, parasites, filter feeders, go fishin’
Shark swallow food whole, have a spiral valve to digest and absorb nutrients instead of intestines

38. Digestive system

40. Reproduction