host-parasite
A host-parasite relationship is also known as a parasitic relationship. A parasitic relationship is when one organism, the parasite, lives off another organism, the host, and harms it and can even cause it death. The parasite lives on or in the body of a host.
Nematodes: Round worms
Nematodes have skinny worm-like bodies found in marine biomes, they are internal parasites on many species of algae and animals such as fish. Most species are about less than 3mm long. They have distinctive heads with buccal cavity (inner mouth) features that are important taxonomic characters. there are about 100,000 known species known and over 400 of them are know to the Arctic Ocean.
Trichinella: ringworms
Trichinella is a very harmful microscopic organism. It can be a major harm to its host which is often the polar bears. This parasite can enter the body by infections in the gut when larvae ingested through infected raw meat. The larvae enter the blood and flow through the body infecting everything. The larvae grow to be about 1 mm long. Trichinella will sit in the polar bears body for several years and cause many infections.