hetertotrophic nutrition

Heterotrophic nutrition

Heterotrophic (Gk. Hetero=different; trophe= nourishment) nutrition: this kind of nutrition is followed by all animals , fungi, some prosists, bacteria and nn green plants. These organisms obtain their food from other plants and animals beacuse they have no chlorophyll to trap solar energy and make their own food. Animals showing heterotrophic nutrition are called heterotrophs.

On the basis of nature of food heterotrophic nutrion is of three types:

1.     saprophytic nutrition

2.     parasitic nutrition

3.     holozoic nutrition

saprophytic nutrition is the mode of nutrition in which heterotrophs get their food from dead and decaying organisms

Saprophytic organisms produce digestive enzyme, these enzyme when released on the food material they breaks down to soluble food . this food in soluble form is absorbed. This method leads to the decay and decomposition of organic food material.

 Saprophytes are mainly bacteria and fungi. Yeast, mushrooms and moulds are saprophytic fungi.yeast feed on sugar solution which helps in its growth. Neottia and monotropa are flowering plants which are saprophyte.

Parasitic mode of nutrition is the phenomenon in which an organism(parasite) lives in or on the body of another organism(host). Parasite absorb the food from the body of their host, in thos process they make damage or even kill their host organism. This phenomenom is called parasitism. This mode of nutrition is showed by non-chlorophyllous plant, viruses and some fungi.

In fungi, mycelium go deep in the host tissue and secrete enzyme. The soli food in host body is converted in soluble form and then absorbed abd assimilated by fungal hyphae. For this purpose, tips of hyphae gets rounded and are called haustoria. Some parasitic bacteria cause diseases in plants and animals, these are pathogens.

Total stem parasite: cuscuta

Partial stem parasite: viscum, loranthus

e.g., puccinia (wheat and barberry plant), roundworms,

ectoparasite e.g., bedbug, head louse,

endoparasite e.g., trypanosome, malarial parasite(intracellular parasite)

taenia, ascaris (coelozoic parasite)or blood fluke, filarial worm (histozoic in body tissue)

green species of euglena, e.g., E.viridis, E.gracilis (autotrophic in light but saprophytic in dark). This dual mode is called myxotrophic nutrition.

Holozoic nutrition is the mode in which digestion is always inside the body, either intercellularly or intracellularly.  Organisms can feed on solid food material. The food may be whole plant animal or their part