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27-2 Roundworms
Kingdom Animalia  Phylum Nematoda
Unsegmented worms
Pseudocoelom (“false coelom”)
– body cavity contains organs
Digestive tract with 2 openings, mouth & anus
Feeding
Free-living – predators
Parasites – humans and animals
Reproduction: Sexual reproduction,
Separate sexes (male & female)
Roundworms & Disease
Trichinosis (trichinella worm)
– cysts within the muscles are consumed
(undercooked food)
-- worm grows in intestine
-- forms cysts in the muscles of the new host
-- symptom: terrible pain in muscles
Filarial Worms – found in Tropical regions of
Asia
-- usually transmitted by mosquitoes
-- causes elephantiasis
Ascarid Worms (common roundworm)
- lives in intestine
- eggs are passed out in the feces
Hookworms
- burrow into the skin from soil
- mature in the intestines
--hooks used to attach and suck blood
Research on C. elegans
- first organism to have DNA completely
sequenced