Chapter 39 Fishes

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Chapter 39Fishes

• Section 3
• Bony Fishes

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Characteristics

• Class Osteichthyes
• Bone- harder heavier than cartridge
• Lungs- early bony fishes
• Swim bladder- gas-filled sac that is used to
  control buoyancy
• Scales- protect fish and reduce friction when
  swimming

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Lobe-finned fishes

• Fleshy fins supported by a series of bones
• Lungfish and coelacanth
• Lungfish- exchange gas through lungs and gills
  (Live in tropical ponds)
• Coelacanth- live deep in the ocean

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Lungfish
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Coelacanth
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Ray-finned fishes

• Do not have fins with a central bony axis- fins
  supported by bony-rays
• Evolved from scales
• Familiar fish- trout, goldfish, eels, bass,
  guppies, salmon, perch, etc.

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Trout
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Perch
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Goldfish
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External Anatomy

• Operculum- hard plate that opens at the rear and
  covers and protects gills
• Fins- swimming and navigation
• Caudal fin- tail fin
• Two dorsal fins (anterior posterior)
• Ventral anal fin- helps move in a straight line
• Pelvic fins- orient body

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External Anatomy

• Skin- scales
• Scales grow with fish
• Scales overlap like shingles on roof

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Internal Anatomy

• Skeleton- skull, spinal column, pectoral girdle,
  pelvic girdle, and ribs
• Pectoral girdle- supports pectoral fish
• Digestive Jaws, pharynx, esophagus, stomach,
  intestine, liver, gallbladder, pancreas, anus

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Internal Anatomy

• Circulatory- gills, heart, capillaries

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Respiratory and Excretory

• Countercurrent Flow- causes more oxygen to
  diffuse into the blood
• Urine
• Urinary bladder

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Swim Bladder

• Sac filled with oxygen, carbon dioxide, and
  nitrogen
• Adjust their buoyancy based on swim bladder

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Nervous System

• Brain
• Optic tectum- receives and processes information
  from the fishs visual, auditory, and
  lateral-line systems

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Reproduction

• External
• Lay large numbers of eggs to ensure survival of
  species
• Spawning- reproduction
• Migrate to warm waters to spawn

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REVIEW!!!

• List three key features that characterize bony
  fishes.
• Describe the external anatomy of fish.
• Name the importance of swim bladder.