Nematoda
-The nematodes or roundworms constitute the phylum Nematoda. They are a diverse animal phylum inhabiting a broad range of environments.
-Nematodes have successfully adapted to nearly every ecosystem from marine (salt water) to fresh water, to soils, and from the polar regions to the tropics, as well as the highest to the lowest of elevations.
- more than half are parasitic, the total number of nematode species has been estimated to be about 1 million.
Structures and Functions
roundworms have a complete digestive tract, a tough transparent cuticle, and only reproduce sexually
Classes
Filarial - can block lymph vessels causing elephantiasis
Ascarid - can fill the hosts intestines causing malnutrition.
Hookworms - suck blood causing weakness to the host.