Types of Worms

earthworm picture
image credit

The earthworm is probably the most familiar worm to all of us. They are very beneficial by improve the soil by loosening and aerating it. Other worms like tapeworms are parasites. They feed off living things and live in the intestines of many animals including humans. All types of worms are invertebrates and although they are all similar, they are separated into three different phyla: flatworms, roundworms, and segmented worms.

Characteristics of Flatworms

tapeworm picture
image credit

  • Flattened body, distinct head and tail.
  • May be free-living or live as internal parasites.
  • Free-living: Planaria
  • Light-sensitive eyespots.
  • Tubelike mouth.
  • Internal parasites: tapeworm.
  • Head with sucking mouthparts surrounded by many hooks.
  • Parasites in many animals, including humans.

Characteristics of Roundworms

hookworm picture
image credit

  • Cylindrical body without segments.
  • May be free-living or live as parasites.
  • Can cause disease in humans.
  • Hookworm - enters through the soles of the feet, then travels to the intestine and sucks blood from the intestinal wall.
  • Trichina worm - enters by way of undercooked meat (usually pork); causes disease called trichinosis.

Characteristics of Segmented Worms

leech picture
image credit

  • Cylindrical body divided into segments.
  • Well-developed organ systems.
  • May be free-living or live as parasites.
  • Free-living: earthworms
  • Important in producing soil.
  • Parasitic: leeches.
  • Live in water.
  • Attach to fish and other animals and suck blood from veins in the skin.

Any fans of worms out there?

..