Fishour friends in the water

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Fishour friends in the water
Porcupine Fish
Great White Shark
Lamprey
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Characteristics of Fish

• 20,000 species
• Found in all types of water
• i.e Fresh, salt, sunless, polluted, warm, cold,
  etc.
• Ectothermic

• External features
• Paired fins
• Scales (protection)

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Respiration

• Respire using gills
• H2O enters mouth.
• Water passes over gills
• Water then passes out slits on side of fish
• O2 and CO2 are exchanged through capillaries
  (small blood vessels) in gills

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Circulation

• Two-chambered heart
• 1-chamber received deoxygenated blood
• 2nd-chamber pumps blood to gills.
• Oxygen picked up and dispersed to rest of body
• Carbon dioxide is released
• Slow process

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Nervous/Reproductive System

• Lateral line---mechanism that detects movements
  and vibrations.
• Some fish can smell
• Two sexes (male and female)
• External fertilization

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3 Classes of Fish

• Jawless (Agnatha)
• Cartilaginous (Chondrichthyes)
• Bony (Osteichthyes)

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Jawless Fish

• Sharp teeth used to drill hole in animal
• Blood sucked out of hole
• Endoskeleton made of cartilage
• Examples Lamprey, hagfish

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Cartilaginous Fish

• Endoskeleton made up of cartilage
• Skilled predators (typically found near floor of
  water source)
• Examples Sharks, rays

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Bony Fish

• Endoskeleton made up of bones
• Lateral line system (pressure change and swim
  with no light)
• Swim bladder (allows fish to float)
• Scales (reduces friction)
• Majority of fish
• Examples Salmon, Trout, Catfish