Fish

FishWhat are fish?Aquatic vertebratesMost havePaired finsScalesGillsWide range of characteristics Belong to different classes Fish EvolutionFirst fishes: armored bodies, no jawsCambrian period (510 mya)505 mya to 410 mya: Adaptive Radiation of fishes variation increased (no armor v. armor; jaws v. jawless)

Fish EvolutionJaw evolution and paired fins seem to have come about togetherMade out of bone or cartilagePaired finsMore control during swimmingTail finsMore muscle mass along trunk of body

Fish EvolutionFish evolved into two groups:Class ChondrichthyesSuperclass OsteichthyesLobe finned (Class Sarcopterygii)evolutionary links point to the lobe finned fish sharing a common ancestor with early amphibiansRay finned (Class Actinopterygii)

Orders of Bony FishAnguilliformes OrderSalmoniformes OrderCypriniformes OrderSiluriformes OrderPerciformes Order

Use your computers to research characteristics of one order (body layout, habitat, types of food eaten, modes of feeding, examples).You will present your findings to the class.

Fish Order:Body layout:

Habitat

Types of food eaten

Modes of feeding

Examples:

Fish Form and FunctionAdaptations for life in waterMethods of feedingGillsPaired finsFeedingDisplay all modes of feedingHerbivores, carnivores, omnivores, parasites, filter feeders, detritus feedersDepending on type of food availableSome fish are highly specialized (barracuda - carnivore)External Fish AnatomyFins:DorsalPectoralPelvicAnal Caudal

External StructuresFinssteering, propulsion through water

Lateral Line

Operculumcovers/protects gills

NaresNasal openings

Lateral LineSenses changes in the waterCurrentElectricalHeatNO external earUtilizes lateral line for detecting sound vibrations

Key: External Fish AnatomyNaresEyeFins:DorsalPectoralPelvicAnal CaudalOperculum MouthLateral Line

Skeletal SystemConsists of bone and cartilage

SkullVertebraeRibsRays within the fins

Skeletal System

Muscular SystemTail and Trunk MuscleMyotomes blocks of muscle that run up and down the fishs bodySeparated by myoseptaJawFin

Digestive SystemMouthPharynxEsophagusShort, expandable (to enable swallowing of large food)StomachGastric glands Pyloric cecaFinger-like projections responsible for most digestionLiver and pancreassecrete enzymes to help with digestionIntestinesmajority of food absorption, length differs in herbivores a carnivoresGizzardDigestive System

Digestive System Labeling

MouthPharynxEsophagusLiverGall bladderIntestineAnusStomachRespiratory SystemGills on either side of the pharynxMade up of filamentsFeathery structures with large number of capillaries for increased gas exchangePull water in through the mouth, over the gills, out the openings on the side of the pharynx

Specialized Respiratory SystemsException: Lungfish need to go to surface of water to fill air sac (lung)Oxygen poor water

Respiratory System

Afferent blood vesselsEfferent blood vesselsGillsOperculumHeartDorsal aortaVentral aortaAlso, describe how fish breathe.What happens to the operculum?What is the purpose of afferent/efferent blood vessels?

Nervous SystemVERY simplifiedBrain3 lobesForebrain (smell)Midbrain (vision, learning, motor receptors)Hindbrain (medulla oblongata and cerebellum)CoordinationMovementBalanceSpinal cord serves rest of the body

Nervous System - Brain

Circulatory SystemClosed circulatory systemSingle loop around body4 part heart: (but considered 2 chambered)Sinus venosusAtriumVentricleBulbus arteriosusCirculatory System Blood FlowSinus venosus receives unoxygenated blood from the bodyValve at the end of the sinus venosus opens into the atrium Atrium has thick, muscular wallsAtrium receives unoxygenated blood and pumps it into the ventricleVentricle is the largest and most muscular chamber of the heartVentricle fills with blood it constricts and forces the blood through the bulbus arteriosusCirculatory System Blood FlowBulbus arteriosus is a valve or series of valves that control blood flow out of the ventricle and into the ventral aorta. Blood passes through the bulbus arteriosus to the ventral aorta. From the ventral aorta, blood flows to the gill filaments, where it is oxygenated.Blood flows out of gills through the dorsal aorta and through the fishs body.

Label the heart of a fish

Sinus venosusAtriumVentricleBulbus arteriosusVeinVentral Aorta

Also, draw in direction of blood flow.Circulatory SystemRed blood cell productionSpleen KidneyBonesBlood Flow

Excretory SystemRelease nitrogenous waste as ammoniaGillsKidneys filter blood to excrete liquid waste

Kidneys allow fish to maintain salt balanceSalt water fishFresh water fish

Cloaca

ReproductionExternal fertilizationOviparous completely separate from both parentsFemales release eggs into waterMales release spermOvoviviparous One parent carries fertilized eggs until they hatch no direct connection to the parent (yolk sac is nourishment)ViviparousCarry fertilized eggs internally direct connection between mother and offspring (no yolk sac)Live birthSharks

Growth and DevelopmentFish are able to live independently when hatchedSome species build nests, care for young for long periods of time

Aquatic life minimal strain on organs, bone, muscleCan grow largeLimits on circulatory system, brain functionLife Cycle of Bony FishEggLarval fish/AlevinFryJuvenileAdultSpawning adult

Other StructuresSwim BladderBetween the stomach and the spineAllows for buoyancyFills with air to keep fish afloatIf the fish does not have a swim bladder, they will sink if they stop swimming Dissection of the PerchYou will need to sketch and label the following systems:External fish anatomyRespiratory systemReproductive system Digestive systemHeart

I expect these to be turned in with the dissection packet and questions.AlsoYou will be removing organs from your perch.Throughout the dissection I will be circulating to see which organ(s) we will save for future comparisons.

You will be graded on the dissection as well as the post-dissection packet. I will collect 1 packet from each personThe answers to the questions throughout the procedure should be on a separate sheet of paper these can be completed after the dissectionEach group will receive a dissection grade.Dissection of the Perch

Dissection of the Perch