Fish (Chapter 30.2)Please set up your notebook for Cornell Notes

What is a fish?Characteristics

Aquatic vertebrates, most have paired fins, scales and gills

Form and functionFeeding

Herbivores, carnivores, parasites, filter feeders and detritus feedersFood enters mouth, passes through esophagus to stomach, goes through intestines and out anus

RespirationMost fish use gills

Gills are made up of feathery structures called filamentsWater is pulled in through mouth and pumped over the gills for gas exchange

ExcretionUse gills and kidneys to excrete ammonia wasteKidneys also help regulate amount of water in the body

CirculationClosed, single loopHeart – 4 parts (2 chambers)

Sinus venosus thin walled sac that collects blood before sending it to the atriumAtrium large, muscular chamber that holds blood before it enters the ventricleVentricle a think walled chamber that does the pumping of the bloodBulbous arteriosus large, muscular tube that connects to aorta, blood then goes to the body

ResponseWell developed nervous systemBrain with specialized regions

Olfactory bulbs sense of smellCerebrum processes information from olfactory bulbsOptic lobe processes info from eyesCerebellum coordinates body movementMedulla oblongata controls internal organs

Lateral line system a system of receptors on the side of the body that can detect changes in current and vibrations in the water

MovementMost move by alternating muscles in either side of the vertebral columnUse fins to propel forward and to steerFish are more dense that water, use swim bladder to adjust buoyancy

ReproductionFertilization occurs either internally or externallyAfter fertilization

Oviparous salmonOvoviviparous GuppiesViviparous some sharks

Classes of fishClass Agnatha jawless fish

Subclass Cyclostomata hagfish and lampreysLampreys filter feeders as larva and parasitic as adults

Have a circular sucking disk w/ a round mouth in centerAttach to fish, whales and dolphins, drill hole in side and suck up tissues and body fluids

Hagfish feed on dead and dying fishNo eyes but light detecting sensors on bodySecrete slime, have six hearts, open circulatory system and tie themselves into knots

Class Chondrichthyes Cartilaginous fishCartilage strong tissue that supports body but is softer and more flexible than boneSubclass Elasmobranchii sharks, skates and rays

Sharks torpedo shaped body, large curved tails and pointed snouts with mouth underneath

Rows of teeth that are constantly replacedSome sharks are filter feeders

Skates and rays diverse feeding habitatsGlide with flapping motion of large, wing-like pectoral fins

Subclass Holocephali chimaeras (ghost shark)Elongated, soft bodies with a bulky head and single gill opening

Class Osteichthyes bony fishSubclass Actinopterygii ray-finned fish

Have slender bones in finsMake up 99% of all fish speciesFreshwater and marine

Subclass Sarcopterygii lobe finned fishLung fish, coelacanthFleshy fins have stronger, jointed supporting bones