1. Phylum Chordata Subphylum Vertebrata
FISH PART TWO:
Agnatha
Chondrichthyes
Osteichthyes

2. Fish: General 24,000-30,000 species of fish 15,000 marine
95% Osteichthyes
1,000 Chondrichthyes
~350 known shark sharks

3. Osteichthyes and Chondrichthyes
General Characteristics seen in these groups:
Highly efficient gills
Scales cover the body
Streamlined
Paired fins
A wide variety of jaw and feeding types
Lateral line and other sensory organs

4. show the position of fins in cartilaginous and bony fish

5. Osteichthyes 95% of all fish species Skeleton composed of bone
Paired fins
Hinged jaws
Homocercal tail
lobes equal size
Flat bony scales
Ctenoid-tiny spines on borders (b)
Cycloid-smooth (a)

7. Fins Caudal Fin Dorsal and anal fins Pectoral and pelvic fins
Forward movement
Dorsal and anal fins
provide steering and stability – keep it from rolling
Pectoral and pelvic fins
help it turn, balance, and brake

8. Osteichthyes Nares Bony operculum covers gills Lateral line
protection
Lateral line
Sensory and communication
Swim bladder
Air-filled bladder
Buoyancy control
Lacking in sharks

9. Varied Body shape Dependent on their environment Soles and Flounder
Flat shape
Bottom dwellers
Bury themselves in sand as camouflauge

10. Varied Body shape Tuna and Billfish
Fusiform =streamlined, strong, fast swimmers
Long
Fins as rudders-not flexible
Caudal fin flexible
Predators
caudal peduncle (area just before the tail) is very thin – this allows all the muscles to concentrate in this area allowing for greater thrust of the caudal fin = FAST

11. Varied Body shape Reef fish Compressed body shape
Thin, quick, short bursts of speed.
Ex: Angelfish
Do not inhabit open oceans
Coral, oyster reefs
Feather like fins
Flexibility
Allows for greater control around features

12. Varied Body shape Eels Elongated body Live in crevices
Live among rocks

14. Body shape for Camouflage
camouflage fish
Shape allows for camouflage,
Ex: Kelp fish, Pipe fish, trumpetfish, stone fish,

15. Coloration Warning coloration Cryptic coloration Disruptive coloration
Using colors to advertise danger, poison, bad tasting
Cryptic coloration
Blending with environment to deceive prey and predators
Some can change color
Disruptive coloration
Presence of stripes, bars, spots to break up outline of fish body
In groups, hard to distinguish just one fish
Countershading
Light bellies (blend with sun when looking up)
Dark backs-blend with depths/bottom when looking down

16. Swimming Patterns “s-shaped” swimming pattern
Bands of muscle along the body, myomeres, drive this swimming motion
Depending on the type of fish, different fins may be used primarily for the forward movement

17. Sharks: Swimming, Oily liver
In sharks, swim bladder absent
a large lipid-rich liver to help in buoyancy
Sharks tend to sink when not in motion and there is no lift from the swim bladder while swimming either
While swimming, sharks aided by the “lift” provided by the position and stiffness of pectoral fins

19. Bony fish: Swimming
Pectoral fins are not needed for lift therefore normally not stiff in construction
Exception: fast swimming species like tuna, billfish
Pectoral fins are often flexible and used for maneuverability
In some slower-swimming species, forward movement provided by pectoral fins

20. Respiration
Gills
Covered by operculum for protection
Exchange of oxygen and carbon dioxide takes place on gill filaments

21. Feeding Mouth size and location reveals dietary preferences
“Beak” (fused teeth) in parrotfish
scrape algae and other organisms off of hard surfaces
Butterfly fish
long tube-like mouth to feed on corals
Barracuda
uses rows of sharp teeth and a wide mouth to capture its prey – other fish
Forward mouth-chase prey
Herring
Larger mouth-filter feeder

22. Regulating Internal Environment: Bony Fish
Salt water solute-rich, blood less saltier than water
Salt water fish lose water through osmosis
Osmoregulation = the process of managing internal water/solute balance
A variety of ways to osmoregulate include:
Many fish swallow seawater
expel the solutes through kidneys and special cells on gills called chloride cells.
Kidneys conserve water-small amounts of urine.

23. Regulating Internal Environment: Cartilaginous fish
Blood is kept at about the same concentration as seawater
Keep urea in the bloodstream (this toxin is filtered out of the blood by other organisms)
Urea—product made when proteins broken down
This means no solutes are gained or water lost because the concentration internally and externally match

25. Reproduction Both sexes have paired gonads in the body cavity
Spawning happens during the most favorable conditions , timed with sex hormones
The release of them is triggered by environmental factors-many unknown
Day length, temperature, food availability
Nassau Grouper spawning

26. Reproductive Behavior
Many species migrate to breeding or spawning grounds at certain times
Color change to advertise readiness to breed
Courtship--series of behaviors to attract mates
Dances, displaying colors, swimming upside down
Each species has a unique courtship; this keeps them from mating with other species
Some fishes have internal fertilization
Mainly cartilaginous fishes, using the claspers
Most have external fertilization – gametes are releases into the water to fertilize (broadcast spawning)
Female can release millions of eggs
Most of the eggs released into the plankton don’t survive, but some do
Billfish spawning

27. Early Development Most fishes spawn eggs – oviparous
The yolk sac provides energy during development
After a few days they hatch into free-swimming larvae, or fry
Some fishes give birth to live young (the eggs hatches inside) - ovoviviparous
Mostly cartilaginous fishes
Some live embryos get nourishment from the uterus before born –Viviparous
Secret Lives of Baby Fish-TED Ed