Class Agnatha 80 species of hagfishes and lampreys Skin lacks scales and plates

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Class Agnatha 80 species of hagfishes and lampreys Skin lacks scales and plates Cartilaginous skeleton, unpaired fins Notochord remains throughout life Some are parasitic Hagfishes are marine; most lampreys live permanently in fresh water All lampreys reproduce in fresh water. - PowerPoint PPT Presentation

Text of Class Agnatha 80 species of hagfishes and lampreys Skin lacks scales and plates

  • Class Agnatha

    80 species of hagfishes and lampreysSkin lacks scales and platesCartilaginous skeleton, unpaired finsNotochord remains throughout lifeSome are parasiticHagfishes are marine; most lampreyslive permanently in fresh waterAll lampreys reproduce in fresh water

  • Figure 34.8 A hagfish

  • Figure 34.9 A sea lamprey

  • Class ChondrichthyesIncludes:SharksRaysSkates

  • Figure 34.11 Cartilaginous fishes (class Chondrichthyes): Great white shark (top left), silky shark (top right), southern stingray (bottom left), blue spotted stingray (bottom right)

  • Class Chondrichthyes

    Skeletons are made of cartilageSkin is covered with placoid scales

  • SharksMouth contains 6-20 rows ofteeth that point inward; when they break or wear down, the others move forward

    Paired nostrils on the snout have specialized nerve cells that connect with olfactory bulbs of the brain

    Largest brain of all fish

  • Adaptations of Cartilaginous FishMost pump water over their gillsby expanding and contracting their mouth cavity and pharynx

    Rays and skates have spiracles located behind their eyes

    Ammonia is converted to urea, which is much less toxic

  • Swimming generates lift and many cartilaginous fish can store large amounts of low-density lipids in their livers to maintain buoyancy

  • Reproduction in ChondrichthyesFertilization is internal, a male transfers sperm using a modified pelvic fin called a clasper.

    Sensory FunctionsThe lateral line system is present in nearly all fish, which is a row of sensory structures that runs the length of the fish to detect vibrations in the water

  • Class Osteichthyes Bony FishCharacteristics:BonesLungs or Swim BladderLungfishes have gills and lungs** All bony fish have an operculuma hard plate that opens at the rearand covers and protects the gillsScales

  • Lobe-Finned Fishes

    Have fleshy fins that are supported by a series of bones7 species of lungfishes and one species of coelocanth exist today

  • The lungfish resembles a short bodied eel. The base color of the fish is brown with small spots all over. They are carnivores. The dorsal and anal fins are long-based.

  • Figure 34.14 A coelocanth (Latimeria), the only extant lobe-finned genus

  • Ray-Finned Fishes

    Have fins that are supportedby long, segmented, flexiblebony elements called rays.includes eels, perch, salmon, guppies, bass

  • Figure 34.13 Anatomy of a trout, a representative ray-finned fish

  • Figure 34.12a Ray-finned fishes (class Actinopterygii): yellow perch

  • Respiratory and Circulatory Systems

    Water flows away from the head and the blood flows toward the head. This countercurrent flow allows more oxygen to diffuse into the gillsFish regulate their overall density by adjusting the amount of gas in their swim bladdersThere are four chambers in the heart

  • Buoyancy in FishSqualene (liver oil)

  • Buoyancy in Fish

  • Buoyancy in FishPhysoclistous bladderaaaaaaaaaaaaa

  • Respiration in Fish

  • Respiration in Fish

  • Osmoregulation in Fish

  • Reproduction

    Fertilization in most species is external

    If internal fertilization occurs, the maleinserts his sperm into the female usinga modified anal fin; the female carries the eggs inside her until the young are born

  • Diadromous - fish that make two runs in their life to live and reproduceAnadromous - fish that run up - salmonCatadromous - fish that run down - eelsParthenogenesis - no males required, females produce diploid eggs - Amazon mollyFish Reproductive Adaptations