Class Osteichthyes
Operculum – a gill cover that protects the gills
Swim Bladder – a gas-filled sac above the stomach allows for adjustments in buoyancy
Fins
Upper and lower lobes of Caudal Fin almost always the same size
Fin rays – rigid spines that support a thin membrane
Mouth & Jaws
Mouth of most bony fish is terminal or anterior end
Overall jaw movement is more than that of sharks with teeth that are fused to jaw
Feeding
Most bony fish are carnivores
Well developed teeth used for capture and holding
Roof of mouth, gill rakers, and pharynx may have teeth to help hold
Feeding
Grazers – fish that feed primarily on seaweeds and other plants
Some develop beaks to help scrape off algae or pieces of coral
Feeding
Filter feeders filter plankton through their gills
Tend to be smaller, schooling fish such as herrings, anchovies, and sardines
Digestive System
Digestive System: stomach, intestine, pancreas, liver, pyloric caecae
Pyloric caecae – slender tubes that secrete digestive enzymes
Plant eaters = long intestine, Meat eaters = short intestines
Gill Irrigation Gills share a common
gill chamber Mouth opens,
operculum closes, and pharynx expands to allow in water and the opposite is true
Fast swimmers just open their mouths
Nervous System
Brain & spinal cord Olfactory sacs or bulbs located on either side of
the head and connected to nostrils (smell) Taste buds located in mouths or barbels
Vision
Better eyes than chondrichthyes
Fish eyes focus by moving closer or farther away from subject
Many have color vision
Hearing
Presence of inner ears Chambers similar to the
lateral line Located on either side of
the head just behind the brain
Can resonate/amplify sound through swim bladder
Behaviors
Territories – home areas that fish defend against intruders
Most common in crowded environments
Some defend as groups
Behaviors Schools – well defined
groups of fishes Well coordinated with no
leaders Used a protection by
confusion Increase swimming
efficiency Advantageous in feeding No single reason and
vary species to species
Behavior Migration – regular
mass movements from one place to another
Anadromous fish – live mostly at sea and migrate to freshwater to breed (salmon)
Catadromous fish – breed a sea and live in rivers (eels)
Subclass Dipnoi
“Lungfish” Jaw fused to brain
case Caudal, dorsal, and
anal fin connected Pectoral fins long and
tubular Air breathing organ
attached to esophogus
Subclass Crossopterygii
“Coelacanths” Cosmoid scale Two dorsal fins and
fleshy paired fins with skeletal elements
Thought to be extinct till found
Sometimes grouped with lungfish in Subclass Sarcopterygii
Subclass Actinopterygii
Ray-finned fishes Most familiar fish Have fin rays, swim
bladders, and a symmetrically lobed caudal fin
Cartilaginous Fish
Lungfish
Ray-Finned Fish
Lobed-Finned Fish
Jawed Vertebrates
Birds, lizards, turtles, dinosaurs, mammals
Subclass Actinopterygii
Superorder Teleostei
Bass
Goldfish
Guppies
Seahorses
Sturgeons
Tuna
Etc.
Superorder Holostean
Garpikes
Bowfins
Superorder Chondrostei
Freshwater Sturgeon
Bichirs
Paddlefish
Reedfish
Superorder Chondrostei
Lack bone Sometimes classified
with sharks Though more in
common with the telosts
Superorder Telostei
Most prolific class 96% of all fish 12 suborders Symmetrical caudal
fin Spines on fins
Elopomorpha
Order Elopiformes Order Albuliformes Order Notacanthiformes Order Anguilliformes Order
Saccopharyngiformes
Ostariophysi
OrderGonorynchiformes Order Cypriniformes Order Characiformes Order Gymnotiformes Order Silurioformes
Paracanthopterygii
Order Percopsiformes Order Batrachoidiformes Order Lophiiformes Order Gadiformes Order Ophidiiformes
Acanthopterygii
Order Mugiliformes Order Atheriniformes Order Beloniformes Order Cetomimiformes Order Cyprinodontiformes Order Stephanoberyciformes Order Bericiformes Order Zeiformes
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