Parasitic Nutrition is a mode of heterotrophic nutrition where an organism (known as a parasite) lives on the body surface or inside the body of another type of organism (known as a host).
The parasite obtains nutrition directly from the body of the host.
Since these parasites derive their nourishment from their host, this symbiotic interaction is often described as harmful to the host.
Parasites are dependent on their host for survival since the host provides nutrition and protection. As a result of this dependence, parasites have considerable modifications to optimize parasitic nutrition and therefore their survival.
A few examples of parasites are tapeworms, fleas, and barnacles.
Tapeworms are segmented flatworms that attach themselves to the insides of the intestines of animals such as cows, pigs, and humans.
They get food by eating the host's partly digested food, depriving the host of nutrients. Fleas harm their hosts, such as dogs, by biting their skin, sucking their blood, and causing them to itch.
The fleas, in turn, get food and a warm home. Barnacles, which live on the bodies of whales, do not seriously harm their hosts, but they do itch and are annoying.