Fish Form and Function

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Fish Form and Function

• Why does it look like that?

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The Basic Fish
A Bony Fish
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The Basic Shark
A Cartilaginous Fish
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Scales

• The Fish
• Scales Made from bone and look like shingles

• The Shark
• Scales or Dermal Denticles tiny toothe like
  structures smooth and feel like sandpaper

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Fins

• Move, Stabilize and Protect
• Paired pectoral and pelvic
• Unpaired anal, caudal, and dorsal
• Placement and purpose varies
• Bony fish visible supporting rays and spines
• Cartilaginous no visible support

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Gills

• Oxygen enters at gills
• Found along the side of the head Feathery in
  structure
• Appear bright red when healthy
• Sharks have 5-7 gill slits that allow water to
  pass out of the gill cavity
• Bony fish gills covered by a bony plate the
  operculum

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Gills and Breathing
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Eyes

• Most well developed
• Sharks Pupils that dilate and constrict, eyelid
  that closes from the bottom up
• Fish Lack both

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The Mouth
Location and Size can determine food and
ecosystem.
Terminal can chase and capture things or pick
at things. Located on the front end
Up-Pointing long lower jaw feeds near the
surface. The mouth opening is toward the top of
the head.
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Sub-Terminal on the underside of the head,
usually feed on the bottom.
Some fish have specialized mouths. The seahorse
has a tiny mouth at the end of a straw-like snout
that is used to "slurp"zooplankton.
The Sharks mouth is located on the underside of
its head.
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Body Shapes
Fusiform or streamlined - capable of swimming
very fast, usually live in open water.
Laterally compressed usually do not swim
rapidly, exceptionally maneuverable.
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Depressed flattened from top to bottom (like
stingrays) live on the bottom.
Eel-like snake-like body shape
Some fish fit into no categories, they tend to
have protective outer coverings and are slow
swimmers.
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Tails indicate speed
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Color

• Red Common color in fish deep water or
  nocturnal
• Countershading Dark on top light on bottom
• Disruptive coloration camouflage
• Eyespot mimicry, spot usually near tail
• Warning Coloration- advertise defense mechanism
• Camouflage blend into the background

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Senses

• Sight Most have good sight.
• Smell nares are two blind sacs that detect
  odor.
• Taste Taste buds are in lining of mouth and
  gills, Barbels are whiskers that are covered
  with taste buds
• Hearing Inner ears are well developed and pick
  up sound waves through the fishs body
• Lateral Line Feel movements in the water
• Electricity Some have special pores that detect
  electricity.

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Several methods for getting around

• Waves passing down the body
• Flex the posterior (caudal) portion of the body
• Flap pectoral fins and (sometimes) tail
• Move just the tail

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Getting Around