Can You Explain What Is Meant By “parasitism”?

Parasitism is an association between two organisms such that one organism (called the parasite) lives on or in the body of another organism (called the host). Since the parasite lives at the expense of its host, e.g. feeding on the host tissues, it normally does some harm to its host. Parasites are pathogens, i.e. they cause diseases and sometimes death to their host.Examples of parasites are hookworms which live in the intestines of vertebrates from which they suck blood. Aphids are parasites that suck plant juices.

Mistletoe is a parasitic plant living on tree trunks. Its roots pass through the bark of the host plant and penetrate the xylem, from which they absorb water and mineral salts. The mistletoe plants have green leaves and can manufacture food by photosynthesis so they are only partly dependent upon their hosts for food. They are known as partial parasites.
The parasite causing malaria in man is a protozoon (unicellular animal) called Plasmodium. Plasmodium spends one part of its life cycle in man and the other part in the Anopheles mosquito. It is a parasite of both man and mosquito. Many mosquitoes could feed on the blood of one man. Numerous plasmodium parasites could be found in the bodies of mosquitoes and man.

Add Comment

Report