2 Subphylum Vertebrata Kingdom Animalia Phylum Chordata Have Backbone = vertebrae (plural) vertebra (singular)Dorsal row of hollow skeletal elements which enclose and protect the nerve cord.Spinal cord ends in a brain attached to spineFishAmphibiansReptilesBirdsMammals
3 Fish 24,000-30,000 species, ~15,000 are marine Most abundant vertebratesEukaryotic, multicellularOrgan level of organizationBilateral symmetryEndoskeleton, made of bone or cartilage
4 General Fish Characteristics GillsBackbone (vertebrae)Paired FinsSingle Loop CirculationTwo chambered heart
5 Fish have a two chambered heart and single loop circulation: blood is passed over the gills where it picks up oxygen, goes to the body and returns to the heart
6 Fish Respiration Water flows over gills as fish opens mouth and swims. Water flows opposite direction of blood flow.
7 Fish Respiration O2 diffuses from the water into the blood. Gills are made of thousands of gill filaments.Gills are covered by the 0perculum.
8 FISH 3 classes Agnatha Chondrichthyes Osteichthyes Jawless fish Cartilaginous fishesOsteichthyesBony fishes
9 The jawless fishes: Agnatha Most primitiveLack jaws and paired finsFeed by suction: teeth and muscular mouthsElongated cylindrical bodyCartilaginous skeletons
10 Hagfish“Slime eels”Secrete large amounts of mucus from skin when agitatedFeed on dead or decaying fishesBore into prey, eat them from inside out.Knot and slide techniqueHagfish Slime and sharksHagfish Info
11 Lamprey fresh and salt water Breed and hatch in freshwater rivers and lakesLive/feed at sea as adultsParasitic, suck blood from other fishPredators of bottom invertebrates
12 Chondrichthyes Include: Paired fins (often stiff) RAYInclude:SharksRaysSkatesRatfishPaired fins (often stiff)Skeleton made of cartilageLighter, more flexible than boneSKATERATFISHSHARK
13 Chondrichthyes Moveable jaws with well developed teeth “Conveyor belt” teeth replacementPlacoid scales- rough, sandpaper skinTeeth and skin composed of same material.
14 Spiracles: 1st pair of gill slits modified, used to take in water even when ventrally located mouth in sedimentHeterocercal caudal fin: upper lobe extends further than lower lobe
15 Sharks Paired pectoral fins Great predators (teeth and speed) great whites5 to 7 gill slitsTwo dorsal finsNictitating membrane = extra eye lid, protects eye during feedingNares for smellGreat whites can detect one drop of blood per every 1 million drop of water from 2 miles away!
16 Special senses Gel-filled sensory pores Detect weak electrical fields Ampullae of LorenziniLateral lineGel-filled sensory poresDetect weak electrical fieldsSuch as: muscular contractions, heart beats, nerve impulsesSense irregular swimmersPores along body that detect water vibrations and pressureAllows to avoid obstacles, orient to currents, detect prey
20 Shark Diversity Hammerhead Thresher Flattened head Eyes and nares separated for improved sensory intakeThresherVery long upper lobe of caudal finHerd and stun fish
21 Diversity: filter feeders Whale Shark: largest fishEat plankton!Basking Shark-2nd largest
22 Diversity: Body shape video Angel SharksSaw sharkFlattened bodyBury in sedimentAlternating tooth sizeBlade like snout
23 Rays and Skates Examples Often flattened Sting rays, electric rays, guitarfish, sawfish, skates, manta raysOften flattenedMostly live on bottom = demersalPectoral fins are flat, expanded, fused with headEyes on top of body typically.
24 Skates and Rays Feeding Teeth modified into grinding platesEat clams, crabs, anything in sedimentUncover prey by sifting sediment withpectoral fins
25 Ray gills 5 gill slits always on the underside of body Spiracles on top to pump water over gills when lying on sediment
26 Rays vs. Skates Whip like tail, often containing poison Stinging spinesGive birth to live youngLack whip like tail and poisonLay egg cases
27 Ratfish-chimieras Mostly deep water One pair of gill slits CartilaginousBottom dwellers oftenFeed on bottom dwellersSometimes, a snout-like nose
28 Videos Chondrichthyes diversity Which way to angel shark teeth curve? How do wobbegong sharks attract fish?What are the sensory organs used for on saw sharks?
29 Rays DiversityHow many species of rays are there?How do rays differ from sharks?
32 ReproductionMost fish lay eggs that are fertilized externally - called spawningSome fish bear live young
33 Fish AdaptationsLateral Line System- used to detect vibrations, orient the fish in water, it is a line of cells running down the side of the fish.Operculum- gill cover, movement of operculum allows more water to be drawn in.Swim Bladder- a gas filled sac that helps the fish maintain buoyancy. Sharks don’t have a swim bladderFins- Dorsal, Caudal, Pectoral, Pelvic, Anal.