Biology 201

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Biology 201

• Lab

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LAB 2

• Fish Locomotion and Equilibrium

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Gas Bladder Types
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Physoclistous

• Gas Bladder
• C) Gut

The Fish in this example has a physoclistous gas
bladder because there in an absence of the
pneumatic duct (the connection from the gut to
the gas bladder)
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Physostomous

• Gas Bladder
• Pneumatic Duct
• Gut

The Fish in this example has a Physostomous Gas
Bladder (Pneumatic Duct present) These Bladders
are essentially an envagination of the gut. Air
may be released out of the mouth at anytime.
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When Artificially Inflated

• The goldfish (Physostomous) were able to release
  this extra oxygen as air bubbles and were able to
  remain in the same spot. This is because their
  gas bladder is connect to the pneumatic duct
  which is connected to the gut allowing them to
  release air
• Other fish do not have the pneumatic duct
  connecting the two organs therefore can only
  release the extra air through the circulatory
  system, which takes a longer amount of time to
  do. This causes the fish to rise when the air is
  taken out of the tank.

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Locomotory Styles

• Cruising (Mackerel)
• Maneuvering (Triggerfish)
• Accelerators (Barracuda)

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Cruisers

• Steady, high speed swimmers.
• Help reduce drag by limiting movement to the
  caudal fin.
• Streamliners body tapers toward the tail
• Contain high percentage of aerobic muscle (red),
  limits fatigue.
• Usually Have a Forked Tail.
• Example Tuna

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Maneuvers

• Flat, oval, disc shaped bodies key in rotating
  about their axis in a small space.
• They are aerobic (Red Muscle Fibers)
• Pectoral fins are crucial to movement, they are
  often triangular.
• Forked Tails
• Example Reef Fish

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Accelerators

• Anaerobic (White Muscle Fibers)
• -Therefore they fatigue very easily, but have
  bursts of energy.
• Usually have a flat body or large tails
• Very Flexible.
• -They either bend in a C shape (not as much
  control as an
  escape mechanism) or an S shape (more
  control)
• Example Gars and Pike

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• Specialized fish can only be one of the 3, while
  generalists can be a combination of them all
• The main difference between accelerators and
  maneuvers is the pectoral fin
• All fish have more white muscle fibers than red,
  just in some, they have unordinary high
  percentages of red fibers.

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Fin Names
M Midline P Paired
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Muscles

• Aerobic Red
• Anaerobic White
• Aerobic Muscles contracts slowly, but does not
  fatigue easily Anaerobic muscle contracts
  quickly, but has no endurance.

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Modes of Swimming

• Body/Caudal Fin Propulsion

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Anguilliform Mode

• While Swimming, the body contorts into a smooth
  sine wave form with more than one wavelength in
  the body length
• Example Eel, Lamprey

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Subcarangiform Mode

• The body forms a sigmoidal shape of just less
  that one wavelength in body length
• The head Does move from side to side but not in
  as a pronounced fashion as the Anguilliform
• Example Salmon, Trout, Cod

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Carangiform Mode

• Fish in this group are stiffer and faster-moving
  than the previous groups. The vast majority of
  movement is concentrated in the very rear of the
  body and tail. Carangiform swimmers generally
  have rapidly oscillating tails.

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Thunniform Mode

• Undulate only a portion of their body, posterior
  to a hinge area within the caudal peduncle.
• Head tracks an almost straight line.
• Extremely Narrow Necking
• Lunate Tail
• Examples Tuna

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Ostraciform Mode

• Have a Body Incapable of Lateral Flexure
• Propulsion is generated by oscillation of the
  typically rigid tail, which pivots on the caudal
  peduncle.
• Poorly Streamlined, not capable of high speeds.
• Example Lumpsucker.

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Median/Paired Fin Propulsion
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Labriform Mode

• Well Developed pectoral fins with narrow, nearly
  vertical bases.
• Fins Oscillate and may move independent of one
  another.
• Examples Gar and Reef fish

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Rajiform Mode

• Very Large Pectoral fins, undulated
  dorsoventrally at the anterior end.
• The rest of the flexible fin follows the anterior
  edge, forming a sigmoidal pattern that drives
  water posterior while driving the animal forward.
• Examples Rays

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Amiiform Mode

• Undulation of only the dorsal fin along its
  length
• Long Dorsal Fin.
• Example Bowfin

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Balistiform Mode

• Similar to Amiiform mode except that both the
  dorsal fin and anal fin are undulated along their
  length simultaneously.