Parasitism

Parasitism is an association in which one organism (parasite) lives on or in the body of another organism (host).

Parasitic organisms include bacteria, fungi, viruses, protozoa and invertebrates like tapeworms, roundworms, liver flukes, mites, ticks, etc. Animals and plants are often hosts to these parasites. Parasites of plants also include other flowering plants like mistletoe and dodder.

The parasite obtains its nutrients and shelter from its host. Parasites benefit from the association at the expense of their host, while the host suffers.

Examples:

Tapeworm and Man:

Tapeworm is an intestinal parasite. It derives its nutrients from absorbing dissolved food substances from the intestine of the host (man).