Download ROUNDWORMS

Phylum Nematoda
https://www.youtube.com/watch?v=X1YiIiPUQR8
ROUNDWORMS
Kingdom Animalia
Phylum Nematoda
--Unsegmented worms
--Pseudocoelom
("false coelom")
-- body cavity contains
organs
Characteristics
• Bilaterally symmetric
• Body has more than two cell layers, tissues
and organs
• Body covered in a complex cuticle (protective
noncellular layer of roundworms)
• Has a nervous system with pharyngeal nerve
ring.
• Has no circulatory system (no blood system)
• Respiration= diffusion
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
https://www.youtube.com/watch?v=DC4ozHnm9bY&index=3&
list=PLLACj7guzqJpyi94ecdzg2mzHdVb6NYDR
Filarial Worms - found in Tropical regions of
Asia
-- usually transmitted
by mosquitoes
-- causes elephantiasis
https://www.youtube.com/watch?v=dnWwHthkGkY
Ascarid Worms (common
roundworm)
- lives in intestine
- eggs are passed out in the feces
Most roundworms infect
dogs, but occasionally they
find their way into human
hosts
Hookworms
- burrow into the skin from soil
- mature in the intestines
--hooks used to attach and suck blood
https://www.youtube.com/watch?v=8zqSLIUv_oQ
C. elegans: A model organism
●first organism to have DNA completely
sequenced
●It is a very simple, free living roundworm
https://www.youtube.com/watch?v=v4ePpLoS6xw
References
•
•
Biology Corner
http://www.earthlife.net/inverts/nematoda.html