Fish-Sharks - Jefcoed

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					 Fish-Sharks
  Kingdom Animalia
  Phylum Chordata
Subphylum Vertebrata
           Phylum Chordata
► Single  dorsal, hollow nerve cord
► Gill or pharyngeal slits
► A notochord
         Subphylum Vertebrata
► Have  a backbone-vertebral column-spine
► Nerve cord-spinal cord
► Complex brain with skull for protection
► Bilaterally symmetrical
► endoskeleton
         General characteristics
► Fishfirst appeared 510 million years ago
► Feed on all types of plants and animals
► Many fish are home to some invertebrates
► 22,000 species
► 50% of vertebrates on earth are fish
► 58% of fish are marine
Most Economically Important Marine
           Organisms
1.   Vital Source of Protein for millions
2.   Ground up as fertilizer or chicken feed
3.   Leather, glue and vitamins are obtained
     from fish
4.   Sport fishing
5.   pets
► Class   Agnatha
   Jawless fish
► Class   Chrondrichthyes
   Cartilaginous fishes
     ►Subclass Elasmobranchii (sharks & rays)
     ►Subclass Holocephali (ratfishes)

► Class   Osteichthyes
   Bony fishes
     ►Subclass Dipnoi (lung fish)
     ►Subclass Crosspterygii (colecanth)
     ►Subclass Actinopterygii (ray-finned fish)
              Class Agnatha
► Jawless
► Most primitive
► Feed by suction
   Round muscular mouth
   Rows of teeth
► Body is cylindrical and elogate like an eels
► Lack paired fins
► Lack scales
          Hagfish-Slime Eels
► Feed  on dead or dying fish
► Can bore into prey and eat from the inside
  out
► 2.6 feet maximum length
► Skin is used in leather goods
► Most known for attacking fish on lines and
  in nets
Hagfishes- Slime Eels
                 Lamprey
► Primarily freshwater as juveniles
► Attach to other fish and suck out their blood
  and organs
► Also eat bottom dwelling invertebrates
Lamprey
         Class Chondrichthyes
► Skeleton   is made of cartilage
   Lighter than bone
   More flexible than bone
► Moveable   jaws
► Well-developed teeth
► Mouth is ventral and curved downward
► Paired lateral fins
► Rough sandpaper like skin
   Skin is modified from teeth
External Covering

         ► AllChondrichthyes
           have placoid scales in
           one form or another
         ► Placoid scale
           modifications
             Spine of stingray, dorsal
              spine of dogfish,
              defensive spines in the
              skate, and teeth
                  Sharks
► Fast swimmers, predators
► Changed very little over time because they
  are so successful as they are
► Spindle shaped bodies
► 2 dorsal fins on back
► Paired pectoral fins
              Sensory Systems
► Hearing
► Olfaction
► Lateral   line
   Detects
    vibrations
           Sensory Systems
► Visual systems
  are well
  developed for
  use during
  night and day
► Nictitating
  membrane
   Clear eyelid
    for protection
              Sensory Systems
► Ampullae   of
 Lorenzini
   Detect
    weak
    electrical
    fields
   Look like
    little pores
    all over the
    sharks
    nose
            Shark Breathing

► 5-7  gill slits
► Most must swim continuously to force water
  over the gills
► When caught in fishing nets sharks ‘drown’
  because they can’t force water in to breathe
► All sharks do not have to swim to breathe
   Nurse shark and a few others can obtain
    enough oxygen without swimming
                       Buoyancy
►   Huge oil-filled liver
     A shark that has an air weight of 1,000 kg. weighs only 3.3kg in water
►   Lift created by a heterocercal tail
► Found  throughout the oceans
► Found at all depths
► Most prevalent in tropical coastal waters
► Several sharks are restricted to deep water
► Shark fishing is strictly managed in the US
                Uses of Sharks
1.   Shark meat is eaten world wide
     ► Sold as scallops
2.   Fished for oil
3.   Fished for skin
4.   Fins used in soup in Orient
     ► Sharks are caught, fins removed, then thrown
       back to die
5.   Shark cartilage may be used as a cancer
     treatment
             Powerful Jaws
► Numerous   sharp, triangular teeth
► Teeth are imbedded in a tough, fibrous,
  membrane
► Lost or broken teeth are replaced
► Conveyor belt-like system moves teeth
  forward
► Can have 30,000 teeth in their lifetime
Chondrichthyes Reproduction

► Mostspecies
 have extended
 gestation
 periods in egg
 cases or in the
 body cavities of
 females
                    •Internal fertilization,
                    through the use of
                    claspers on the male
Oviparity - Egg Laying
              ► Oviparity
              Viviparity-live birth
► Yolk-sac Viviparity (Ovoviviparity)
   Eggs are produced and retained inside the mother
   Shell disappears and young are retained until fully
    developed
► Uterine   Viviparity
   Mother secretes nutrient rich fluid which is taken up
    through the skin of the embryo
► Cannibal    Viviparity
   Young in each oviduct consume unfertilized eggs or
    other siblings
► Placental   Viviparity
   Nutrients are supplied to the embryo directly from the
    mother via a umbilical cord
         Hammerhead Shark
► Flattened head
► Eyes at the tips
► Head serves as a rudder
► Separates eyes and nostrils which improves
  senses
Hammerhead
                  Sawsharks
► Long  flat blade with teeth on the edges
► Distinguished from sawfish by the location
  of the gill slits
   Shark gill slits are always on the sides of the
    body
Sawshark
              Thresher Sharks
► Upper  lobe of tail is very long
► Use tails to herd and stun schooling fishes
             Spiny Pygmy
► 10inches maximum
 length
Whale Shark
       ► Can  be 60 ft long
       ► Largest of all fish
       ► Most are ~40 ft
       ► Pose no danger to
         humans
       ► Filter feeders
            Basking Sharks
► Second   largest sharks
► Filter feeders
► Up to 50 feet long
► Most are ~ 33 feet long
Basking Shark
          Great White Shark
► Most dangerous
► Up to 20 feet long
               Bull Shark
► Possiblyestablished in some freshwater
 rivers and lakes
  Angel Shark
► Flattenedbody
► Link between
  sharks and rays
              Rays and Skates
► Flattened    bodies
► Live on the bottom
► Rays, skates and related fishes have 5 pairs
  of gill slits on the underside of the body
► Pectoral fins are flat and expanded
   Look like wings
   Fused to the head
► Eyes   on top of head
             Guitarfish
•True Ray
•Looks like a shark
                   Sawfish
► Look like a saw shark except the gill slits are
  ventral
► Feed by swimming through schools of fish
  and swinging their blades back and forth
► Grow up to 36 feet long
Saw fish
                  Stingrays
► Eagle,bat cow-nosed
► Have a whip-like tail
   Usually equipped with stinging spines
   Poison glands produce venom
   Sting to the abdomen can be deadly
► Cover  themselves with sand
► Eat clams, crabs, small fish and sediment
  dwelling animals
► Teeth are modified into grinding plates
Bat Ray
Cow nosed Ray
               Electric Rays
► Specialorgans that produce electricity
► Up to 200 volts
   Stun prey
   Discourage predators
       and Romans used shocks to cure
► Greeks
 headaches
Electric Ray
   Eagle, Manta and Devil Rays
► Don’t   live on the bottom
► ‘fly’ through the water
► Eagle’s feed on the bottom
► Manta and Devil Ray are the same animal
► Manta’s feed in mid-water on plankton
► Can leap out of the water
► Up to 23 feet wide
Eagle Ray
Manta Ray
         Skate
► Lack whip-like tail
► Some have electric
  organs
► Egg cases
► Larger species are
  fished for food
Ratfish-Chimaeras
         ► 30  species
         ► Strange looking
         ► Deep water
         ► Gill slits are covered
           with a skin flap
         ► Long rat-like tail
         ► Feed on bottom
           dwelling crustaceans
           and molluscs
  Bony Fish- Class Osteichthyes
► Skeleton  is made of bone
► 23,700 species
► 98% of all fish
► Thin flexible overlapping scales
   Develop from bone
   Ctenoid scales
► Flap   of bony plates protects the gills
   Gill cover-operculum
                 Bony Fish Fins
► Caudal   fin
   Homocercal
   Both lobes are close to the same size
► Fins are thin membranes supported by bony
  spines or fin rays
► May consist of rigid spines to act as a rudder or
  protection
► Some are flexible for propulsion and
  maneuverability
► Streamlined shape-fusiform
          Other characteristics
► Mouth  is terminal
► Jaws have freedom of movement
► Teeth are fused to the jawbone
► Teeth can be replaced but not like sharks
   More similar to how our teeth are replaced
► Swim   bladder-gas filled sac that allows the
  fish to adjust its buoyancy
► Ichthyology- study of fish
              Fast swimmers
► Tunas, mackerels,
  marlins, sharks
► Streamlined bodies
         Laterally Compressed
► Leisurely  swimming
► Bursts of speed if
  needed
► Snappers, wrasses,
  damselfishes and
  butterflyfishes
      Flattened Top to Bottom
► Rays, skates, sea moths
► Live on the bottom
                   Flat Fish
► Look  flattened top to bottom but actually
  laterally compressed
► Flounders, soles, halibuts, hogchokers
► When juveniles they swim upright
► 8-12 days old
   Eye migrates
   Begin to swim on their side
   countershading
Flatfish have the remarkable ability to blend with
                their surroundings
                   Flatfish Ontogeny
► All flatfish start life as
  bilaterally symmetrical
  larvae
    *Metamorphose*
    Change from pelagic
     bilaterally symmetrical
     larvae to a benthic
     asymmetrical juveniles
        ► Change usually occurs at
         a given size (varies from
         4 – 120 mm.)
            Right-eye
             Dextral




Left-eye
Sinistral
Elongate bodies
        ► Eels, trumpet fish,
          pipefish
        ► Live in narrow spaces
          between rocks, reefs
          or vegetation
        No generalized shape
► Seahorses
► Seadragons
    Body shape for camouflage
► Pipefish resembles eel grass
► Trumpet fish resembles tube sponges
► Blennies and sculpins have growths that
  resemble seaweeds
► Stonefish resembles a rock
   Shallow water
   Most potent venom known in fish
   Can be deadly
                      Coloration
►   Chromatophores
    ►   Contain colored pigments
    ►   Irregular in shape
    ►   Variety of colors and hues
    ►   Allow for rapid color changes
        ►   Contract and expand the pigment
►   Structural colors
    ► Result from a surface reflecting certain colors
    ► Special crystal like chromatophores-
      iridophores
    ► Make the fish shiny
                      Coloration
► Warning    coloration
   Mood
   Reproductive condition
   Advertise that they are dangerous, poisonous or
    taste bad
► Cryptic   coloration
   Blending with environment
     ►Flatfish,   blennies, sculpins, rockfish
   Change colors depending on environment
   Common among coral reed fish
                  Coloration
► Countershading
   Open water fish and shallow water predators
   Silver or white bellies
    ►When   you look up from underneath this helps hide
      them in the lightness of the sky
   Dark backs
    ►When   you look down from above this helps hide
      them in the ocean depths
   Deep water fish use color for concealment, they
    tend to be black or red which are hard to see in
    the ocean depths
         Why do fish swim??
► To obtain food
► Escape predators
► Find mates
     Bony fish v/s cartilaginous
► Swim   bladder           ► Stiff pectoral fins
                           ► Oil in liver
► Ctenoid scales           ► Placoid scales
► Scales modified from     ► Scales modified from
  bone                       teeth
► Fusiform body            ► Spindle shaped body
► Urogenital opening for   ► Cloacal opening for
  urine and gametes          digestive, excretory
► Anus for waste             and reproductive
► External fertilization   ► Internal fertilization
                 Purpose of fins
► Bony   fish pectorals   ► Pelvic   Fins
     Not for buoyancy       Turn
     Maneuverability        Balance
     Hover                  brake
     Swim backwards
► Dorsal-anal   fins
   Rudders
   Steer and stability
                   Digestion
► Mouth->esophagus->stomach->intestine
► Liver   secretes bile to help the breakdown of
  fats
► Spiral valve in sharks increases the surface
  area of the large intestines so more
  nutrients can be removed from the food
        Circulatory-Respiratory
►2  chambered heart   ► Gills
► Arteries, veins,        Structure where oxygen
  capillaries              is removed from the
                           water
► Gas exchange
                      ► Gill   slits
► Hemoglobin- red
                          Openings on the sides
  protein                  or underneath for water
   Carries oxygen         to exit
                      ► Spiracles
                          Openings by the eyes
                           for water to enter
                    Reproduction
► Seasonal   migrations
   Some migrate up stream
   Controlled by sex hormones
► Some    are hermaphrodites
   Can self fertilize
   Usually don’t
► Sex   reversal
   All juvenile fish are female, at a certain age about half
    within a population will become male
   Anytime a population does not have enough females
    some of the males will revert back to female
► External   reproduction
   Spawning

				
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