Phylum |
Porifera |
Cnidaria |
Platyhelminthes |
Nematoda |
Tissue Layers |
2 germ layers- dipoblastic |
Diploblastic |
triploblastic |
triploblastic |
Cephalization |
None |
Ocelli, no brain but nerve net |
simple brain, ocelli, nerve ladder |
Simple brain, dorsal and ventral nerve cords |
Coelom |
Acoelomate, |
acoelomate |
acoelomate |
pseudocoelom between mesoderm and endoderm |
Symmetry |
none, irregular shape |
radial symmetry |
bilateral symmetry |
bilateral symmetry |
Reproduction |
Asexual with budding or gemmules, sexual with internal fertilization |
Asexually by budding, sexually through motile gametes |
asexually by regeneration, sexually by gametes, are hermaphrodites |
sexual reproduction, hermaphroditic and separate sexes |
Life cycle |
can live a very long time, |
Alternation of generations, between polyp and medusa |
can be free living or parasitic, alternating between hosts |
free living or parasitic, alternating between hosts |
Body Plan |
Filter feeds, body like large water pump, waste through osculum, sessile, no nerves |
sac-plan, nerve net, excretion using diffusion, one opening for mouth/anus, some sessile, some free swimming |
have a mouth(pharynx), use flame cells for excretion, flat body, free swimming, nerve ladder |
separate mouth and anus, round in shape, have a long tube for digestive tract, dorsal and ventral nerve cord |
Worms can either be parasitic or free living. Parasitic worms live inside a host. They require that host for obtaining food, protection, and reproduction. Without that host, they would die. Parasitic worms do not have many of the organs that free living worms have. They don't require these organs because the host does most of the work for the worm anyway. A free living worm can live all by itself in a habitat. They require more organs because they must carry out all processes by themselves
Elephantitis is caused by filarial worms. These filarial worms live in the lymphatic systems of birds and mammals, including humans. The worms may block the lymph passages and cause a buildup of fluid, which causes swelling, and thickening of skin and tissues. That is how it got its name, as the swollen limbs look like an elephant. The worms can live in the body for 6-8 years, and during this time, the release millions of tiny larvae into the blood. Some of these larvae are ingested by mosquitoes while sucking their blood, then the larvae are transferred by the mosquito into another persons blood and the cycle continues.
References
http://www.news-medical.net/health/What-is-Elephantiasis.aspx
http://www.who.int/mediacentre/factsheets/fs102/en/
http://www.news-medical.net/health/What-is-Elephantiasis.aspx
http://www.who.int/mediacentre/factsheets/fs102/en/