Chapter 39 Fish

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Chapter 39Fish

• Section 2
• Jawless and Cartilaginous Fish

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Fish Adaptations

• Stream-lined body muscular tail
• Paired-fins allow fish to manuver
• Secrete mucus around body to help move in water
  and protect against infections
• Store lipids (fat) to help aid in buoyancy
• Use gills for gas exchange

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Homeostasis

• Freshwater fish hypertonic (higher
  concentration of solutes than the surrounding
  water- gain water)
• Saltwater fish hypotonic (contain lower
  concentrations of solutes than their
  surroundings- lose water)

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Sensory Functions

• Fish can sense light, chemicals, sound
• Some can sense electrical magnetic fields
• Many fish can see in color, but most
  cartilaginous fish can not see in color

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Sensory Functions

• Chemoreception- ability to detect chemicals in
  the environment
• Sharks have great sense of smell taste
• Barbels- whisker-like organs near mouth

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Barbels
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Sensory Functions

• Lateral line- allows fish to sense vibration in
  the water
• Cartilagenous fish (sharks rays)- ampullae of
  Lorenzini- detect weak electrical fields- help
  locate prey

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Lateral Line
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ampullae of Lorenzini
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Jawless Fishes

• Hagfish lamprey
• Have an eel-like body, cartilaginous skeleton,
  and unpaired fins
• Hagfish live in oceans
• Lampreys live in freshwater

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Hagfishes

• Bottom-dwellers in cold marine water, no jaws
• Isotonic- same ion concentration as sea water
• Feed on small invertebrates or dead dying fish
• Burrow in dead fish consume internal organs

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Hagfish
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Lampreys

• ½ parasites, ½ free-living
• Attaches to host with disk-shaped mouth
• After feeding, lampreys drop off host may
  recover, bleed to death, or die from infection
• Fertilization occurs outside body (external
  fertilization)

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Lamprey
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Cartilaginous Fish

• Class Chondrichthyes
• Sharks, skates, rays, ratfish
• Cartilage- flexible, lightweight material made of
  cells surrounded by tough fibers of protein
• Skin is covered with placoid scales- feels like
  sandpaper

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Sharks

• Whale shark- largest shark (60 feet)
• Feed on plankton floating plants animals
• Filter water using gill rakers
• 6 to 20 rows of teeth that point inward

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Whale Shark
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Sharks

• One shark uses 20,000 teeth in a lifetime
• Each tooth is shaped based-on diet

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Great White Shark
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Hammer Head Shark
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Black-tip Reef Shark
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Bull Shark
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Lemon Shark
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Tiger Shark
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Rays Skates

• Flatten-bodies with wing-like pectoral fins and
  whip-like tails
• Rays have diamond or disk-shaped bodies
• Skates have triangular bodies
• Bottom-dwellers
• Feed on crustaceans

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Rays
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Skates
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Ratfishes

• Deep-water
• Have gill slits covered by a flap of skin
• Some have a rat-like tail
• Feed on crustaceans or mollusks

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Ratfish
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Adaptions

• Gas exchange in gills
• Some sharks need to constantly move in order for
  gas exchange to occur
• Rays usually take in water from ventral side, but
  when on bottom, they use spiracles located behind
  eye to draw in water

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Adaptations

• Sharks have an oil in their liver called squalene
  oil that contributes to their buoyancy
• Convert ammonia to urea which is a less toxic
  waste

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Reproduction

• Internal fertilization- male transfers sperm to
  females body
• No cartilaginous fish provides parental care once
  young are born

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REVIEW!!!

• Identify three characteristics of fish that makes
  them well suited to aquatic life.
• Contrast the feeding behavior of hagfish to the
  feeding behavior of lampreys.
• Identify the advantages of internal fertilization
  vs. external fertilization.