FISH

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FISH
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CHORDATES

• PHYLUM ? CHORDATES CHORDATA
• 7 CLASSES
• JAWLESS FISH AGNATHA
• CARTILAGINOUS FISH CHONDRICHTHYES
• BONY FISH OSTEICHTHYES
• AMPHIBIANS AMPHIBIANS
• REPTILES REPTILIA
• BIRDS AVES
• MAMMALS MAMMALIA

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Other terms associated with chordates

• Vertebrae a strong but flexible column of bones
  that enclose the dorsal nerve cord
• Endo means within
• Endoskeleton the vertebrae, skull, and the rest
  of the internal skeleton

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Lancelets Tunicates

• Simpler than other chordates
• Do NOT have a backbone
• Do NOT have a well-developed head

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Chordate Body Parts

• Tail some only have a tail in the embryo stages
• Notochord becomes the backbone
• Hollow Nerve Cord spinal cord of nerves that
  runs along backbone
• Pharyngeal Pouches develop into gills or other
  body parts as the embryo develops

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Vertebrates

• Animals that have a backbone
• Well-developed head
• Skull protects head
• Made of bone OR cartilage a tough material that
  is flexible (nose, ears)
• Bones ? fossils (hard)

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Cold or Warm-blooded?

• Cold-blooded this means that the animals body
  temperature changes with the temperature around
  it (ectotherms)
• Warm-blooded animals that have a body
  temperature that stays the same in any
  environment (endotherms)

Fish (3 classes) Reptiles Amphibians
Birds Mammals
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Back to FISH!!!

• 25,000 species (more than any other chordate)
• Cold-blooded
• 3 adaptations to live in water
• GILLS take oxygen from the water and put carbon
  dioxide into the water
• FINS fanlike structures that are used for
  steering, balancing, and moving
• SCALES hard, thin, overlapping plates that
  cover and protect the fishs body

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Fish Sense

• Vision
• Hearing
• Smell
• Lateral lines row or rows of tiny sense organs
  that detect water vibrations
• Lateral lines run from the head down the sides of
  the body

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Reproduction

• Sexually
• Usually external fertilization unfertilized
  eggs laid in the water and the male drops sperm
  on them
• Internal fertilization the eggs are inside the
  female and the male deposits sperm inside the
  female
• Eggs are laid after internal fertilization or
  they are developed inside the female

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3 CLASSES of FISH

• Jawless Fish
• Cartilaginous Fish
• Bony Fish

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Jawless Fish

• Class Jawless fish
• Round mouth
• Tube-like bodies
• No scales
• Slimy skin

HAGFISH
LAMPREY
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Cartilaginous Fish

• Skeletons are made of cartilage
• Cartilage is a tough, flexible, tissue that is
  not as hard as bone
• Sharks
• Skates Rays
• Some must keep moving to swim and breathe
• Liver filled with oil to help float

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More on Cartilaginous Fish

• Have moveable jaws and scales
• In most species, the eggs are fertilized inside
  the females body, and the young are born alive
  (similar to humans)

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Bony Fish
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Bony Fish Facts

• Have skeletons made of bone
• 95 of all fish are in this class
• Sizes from 1cm to 8.6m
• Have a swim bladder this allows the fish to
  suspend at a certain depth by adjusting the
  amount of gas in the swim bladder
• Swim bladders are similar to those used in
  submarines

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2 Groups of Bony Fish

• Lobe-finned fish have fins that resemble arms
  or legs and are fleshy
• Lungfish have both gills and lungs can live
  where the water dries up in the summer and they
  bury themselves in the mud and breathe through
  lung-like organs
• Ray-finned fish (most common) fins made of
  long, thin bones covered with skin