3 classes of fish 5 th grade. there are 3 main classes of fishes can you guess the 3?
TRANSCRIPT
3 classes of FISH5th Grade
There are 3 main classes of fishes
Can you guess the 3?
1) Bony Fish
2) Cartilaginous Fish
3) Jawless Fish
3 Classes of Fishes
What is a Bony fish?
Bony Fish:
Has a skeleton made from bone
Have scales Single pair of gill openings
Swim bladder Over 20,000 species
Bony Fish:
Bony Fish:
What is a cartilaginous fish?
Cartilaginous Fish
Have skeletons made of cartilage instead of bone
Do not have typical fish scales
Their skin is tough and abrasive
Have between 5 and 7 gills
What types of fish are Cartilaginous Fish?
Sharks
Rays
Skates
Chimaeras
Cartilaginous Fish
Cartilaginous Fish
Cartilaginous Fish
Jawless Fish
“Agnatha” = means “no jaw” in Ancient Greek
Have long bodies and look like eels
Skeletons are made of cartilage, not bone
They have no scales
Only 50 species left worldwide
This group is made of lampreys and hagfish
Jawless Fish
Jawless Fish (Agnatha)
Lampreys: Parasitic Instead of a jaw they have a sucking
disc that they attach to their fish host and rasp away at the flesh
Hagfish:
What can the SHAPE of a fish’s body tell us about the fish?
The body shape can tell us:
Where it lives
How it feeds
How it moves through the water
Demersal Fish “bottom-dwelling” fish
Flat in shape
Do not swim continuously so do not need to be streamlined
A flat, pancake-like shape means that the fish is able to stay very close to the sea floor where they feed
Ex. Flounder or Wobbegong
Other slow-moving fish have rounded bodies (often have poisonous flesh since they cannot move quickly)
Blowfish
White-barred boxfish
Fish with elongated bodies are able to swim very fast for a long time so do not have any special body protection (ex. sea mullet)
How do FINS work?
Pectoral Fins –used to maneuver the fish up, down, and sideways –act as brakes and the fish can use them to swim backwards
Pelvic Fins –used for braking and steering
Dorsal fin –stabilizer so that that fish does not roll on its side
Caudal Fin –speed and strength
Parts of a bony fish
Lateral Line
Lateral Line: a sensory organ that runs along the sides of the fish’s body under the skin
A series of tiny, sensitive cells called “neuromasts”
Tiny vibrations in the water pass through the lateral line to help the fish detect differences in pressure and movement in the water
Nerves connect the lateral line to the ears and the brain
What is special about a fish’s Swim Bladder?
Swim Bladder:
Swim Bladder: an oval-shaped sac found in the fish’s abdominal cavity
Neutral Buoyancy: the ability of an organism to use little or no energy to stay at particular levels of water, and is achieved through the expanding and shrinking of the swim bladder due to varying gas pressure
At different times it can be filled with varying amounts and composition of gases
Swim Bladder:
Fish can have more control over their movements while expending minimal amounts of energy
Helps fish stay floating all day long without using up too much energy
Do freshwater or salt water fish require a larger swimbladder?
Freshwater!
Freshwater fishes require a larger swimbladder than those in salt water because freshwater is less buoyant than salt water
Buoyant: ability to float
Objects float better on SALT water than freshwater