Phylum Nematoda

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Phylum Nematoda

• Roundworms
• Means Thread

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Aaugh! They are Everywhere!

• Every fist-full of dirt
• Every rotten apple
• Each square meter of lake
• bottom
• Most are free living
• Most are parasites

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Nematooooda!

• One study in Colorado estimated that nematodes
  consumed about as much grass as a prairie dog
  colony.

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Characteristics

• Tough outer covering- Cuticle
• No circular muscles- run lengthwise (move with a
  crazy thrusting movement)
• Smooth, round, nonsegmented
• Tube within a tube
• Separate sexes
• 15,000 known species

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Muscle Diagram
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Examples

• Hookworm-
• Sucks blood in intestine
• Enters between the toes by boring in the skin

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Filaria

• Causes Elephantiasis
• Transfer by mosquito

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Trichinella

• Causes trichinosis
• Found in pork

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Pinworm

• Common among children
• Intense rectal itching
• Worms are visible near the anus at night or early
  in the morning

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Horsehair Worm

• Parasites on grasshoppers, crickets, locusts,
  katydids, and beetles
• Other hosts include dragonflies, spiders,
  millipedes, centipedes, and leeches

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Persistent

• Many nematodes are able to suspend their life
  processes completely when conditions become
  unfavorable in these resistant states they can
  survive extreme drying, heat, or cold, and then
  return to life when favorable conditions return.

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