2 What are fish? Aquatic vertebrates Most have Paired finsScalesGillsWide range of characteristicsBelong to different classes
3 Fish Evolution First fishes: armored bodies, no jaws Cambrian period (510 mya)505 mya to 410 mya: Adaptive Radiation of fishes – variation increased (no armor v. armor; jaws v. jawless)
4 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
5 Fish Evolution Fish evolved into two groups: Class Chondrichthyes Superclass OsteichthyesLobe finned (Class Sarcopterygii)evolutionary links point to the lobe finned fish sharing a common ancestor with early amphibiansRay finned (Class Actinopterygii)
6 Orders of Bony Fish Anguilliformes Order Salmoniformes Order Cypriniformes OrderSiluriformes OrderPerciformes OrderUse 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.
7 Fish Order: Body layout: Habitat Types of food eaten Modes of feeding Examples:
8 Fish Form and Function Adaptations for life in water Methods of feedingGillsPaired fins
9 Feeding Display all modes of feeding Herbivores, carnivores, omnivores, parasites, filter feeders, detritus feedersDepending on type of food availableSome fish are highly specialized (barracuda - carnivore)
10 External Fish AnatomyFins:DorsalPectoralPelvicAnalCaudal
11 External Structures Fins Lateral Line Operculum Nares steering, propulsion through waterLateral LineOperculumcovers/protects gillsNaresNasal openings
12 Lateral Line Senses changes in the water NO external ear CurrentElectricalHeatNO external earUtilizes lateral line for detecting sound vibrations
13 Key: External Fish Anatomy NaresEyeFins:DorsalPectoralPelvicAnalCaudalOperculumMouthLateral Line
14 Skeletal System Consists of bone and cartilage Skull Vertebrae Ribs Rays – within the fins
16 Muscular System Tail and Trunk Muscle Jaw Fin Myotomes – blocks of muscle that run up and down the fish’s bodySeparated by myoseptaJawFin
17 Digestive System Mouth Pharynx Esophagus Stomach Liver and pancreas Short, expandable (to enable swallowing of large food)StomachGastric glandsPyloric cecaFinger-like projections responsible for most digestionLiver and pancreassecrete enzymes to help with digestionIntestinesmajority of food absorption, length differs in herbivores a carnivoresGizzard
19 Digestive System Labeling MouthPharynxEsophagusLiverGall bladderIntestineAnusStomach
20 Respiratory System Gills on either side of the pharynx Made 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
21 Specialized Respiratory Systems Exception: Lungfish – need to go to surface of water to fill air sac (“lung”)Oxygen poor water
23 Also, describe how fish breathe. What happens to the operculum?What is the purpose of afferent/efferent blood vessels?
24 Nervous System VERY simplified Brain 3 lobesForebrain (smell)Midbrain (vision, learning, motor receptors)Hindbrain (medulla oblongata and cerebellum)CoordinationMovementBalanceSpinal cord – serves rest of the body
26 Circulatory System Closed circulatory system Single loop around body 4 part heart: (but considered 2 chambered)Sinus venosusAtriumVentricleBulbus arteriosus
27 Circulatory System – Blood Flow Sinus venosus receives unoxygenated blood from the bodyValve at the end of the sinus venosus opens into the atriumAtrium 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 arteriosus
28 Circulatory System – Blood Flow Bulbus 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 fish’s body.
29 Label the heart of a fish Sinus venosusAtriumVentricleBulbus arteriosusVeinVentral AortaAlso, draw in direction of blood flow.
32 Excretory System Release nitrogenous waste as ammonia GillsKidneys filter blood to excrete liquid wasteKidneys allow fish to maintain salt balanceSalt water fishFresh water fishCloaca
33 Reproduction External fertilization Oviparous – completely separate from both parentsFemales release eggs into waterMales release spermOvoviviparousOne 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
35 Growth and Development Fish are able to live independently when hatchedSome species build nests, care for young for long periods of timeAquatic life – minimal strain on organs, bone, muscleCan grow largeLimits on circulatory system, brain function
36 Life Cycle of Bony Fish Egg Larval fish/Alevin Fry Juvenile Adult Spawning adult
37 Other Structures Swim Bladder Between the stomach and the spine Allows for buoyancyFills with air to keep fish afloatIf the fish does not have a swim bladder, they will sink if they stop swimming
39 You will need to sketch and label the following systems: External fish anatomyRespiratory systemReproductive systemDigestive systemHeartI expect these to be turned in with the dissection packet and questions.
40 Also… You 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.