1. Phylum Nematoda

2. ROUNDWORMS Kingdom Animalia Phylum Nematoda
--Unsegmented worms --Pseudocoelom ("false coelom") -- body cavity contains organs

3. Characteristics Bilaterally symmetric
Body has more than two cell layers, tissues 
and organs
Body covered in a complex cuticle (protective
noncellular layer of roundworms)

4. Has a nervous system with pharyngeal nerve ring.
Has no circulatory system (no blood system)
Respiration= diffusion

6. Digestive tract with 2 openings: mouth & anus
Feeding Free-living - predators Parasites - humans and animals
Reproduction: Sexual reproduction, Separate sexes (male & female)

7. 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

8. https://www. youtube. com/watch

9. Filarial Worms - found in Tropical regions of Asia
-- usually transmitted by mosquitoes -- causes elephantiasis

11. 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

12. Hookworms
- burrow into the skin from soil - mature in the intestines --hooks used to attach and suck blood

14. C. elegans: A model organism
first organism to have DNA completely sequenced
It is a very simple, free living roundworm

16. References Biology Corner