Parasites

    Parasitic Plants
 The dodder plant cannot makggjits own food as it has very little chlorophyll. It is totally dependent on its host for food and so is a total parasite. It grows on plants such as alfalfa, clover and cashew. It consists of a thin, golden yellow, twinning stem which bears small scale leaves. The stem attached itself to the host by means of suckers. Food is obtained by means of special absorbing organs called haustoria. The haustoria penetrate the stem of the host up to the region of the vascular bundles.

 They absorb water, mineral salts and food substances from the host. The mistletoe can manufacture food by photosynthesis but is dependent on the host for water and mineral salts. It is therefore, a partial parasite. T grows on cultivated trees like cacao. It has small green leaves.

A sucker at the base fixes the plant to the stem of its host. Haustoria develop from the sucker and penetrate to the xylem tissue where they absorb water and mineral salts. These are then used in the manufacture of food.

Parasitic animals
 Fleas, ticks, bugs and leeches are ectoparasites. Most ectoparasites have mouth parts that are modified for

• Piercing oR boring into the skin (animal) or epidermal layer (plant) and

 • Sucking the body fluid (animal) or sap (plant) of the host. (The female mosquito and aphid exhibit adaptations for this mode of feeding.) An Endoparasites is more highly specialized than an ectoparasites and shows more adaptations, many of which are related to its host's mode of life.

The liver fluke, hookworm and tapeworm are good examples of Endoparasites. Some important adaptations exhibited by Endoparasites are discussed in my previous write up. Ma y highly specialized Endoparasites that live in the gut absorb the digested food of the host through their body surfaces.

 Such parasites, like the tapeworms, have no feeding mouthparts or alimentary canals. Other Endoparasites, like the roundworms, that feed on the body fluids of the host usually have simple alimentary canals.