Do organisms fulfill requirement of food in same way.classify organismson basis of mode of nutrition

Asked by  | 28th Mar, 2009, 11:44: AM

Expert Answer:

No. It is fulfilled in different ways.

All living organisms require food to carry out their life processes, i.e., growth, repair and for production of energy. There are two main groups of living organisms on the base of mode of nutrition.

1.      Autotrophic organisms

2.      Heterotrophic organisms

 

1) Autotrophic organisms:

Autotrophs are organisms that are able to synthesize their own organic substances using an external energy source from simple inorganic substances. eg.  plants,some prokaryotes.

2) HETEROTROPHIC ORGANISMS

These are organisms which can not prepare their food. They take prepared food, digest it and then utilize it after absorption i.e., animals, fungi etc. Heterotrophic organisms are further classified into:

i) Holozoic organisms:

In these organisms, the nutrients that are taken into the body are passed down some form of alimentary canal. Holozoic organisms can be divided into two groups herbivores and carnivores.

a) Herbivores - They feed only on plant material.

b) Carnivores - They feed on the flesh of animals.

 

ii) Saprotrophs - 

They are decomposers. They get their food by digesting dead and decaying organisms. Digestion is by the release of extracellular enzymes on to the dead matter and absorption of the soluble products of enzymatic digestion. eg - fungi and bacteria

 

iii) Parasites -

This is a relationship between parasite and host. The parasite is dependent on the host for nutrition and protection and will generally harm the host. eg - tapeworm.

 

 

iv) Symbionts / Mutualists -

The relationship in which living organisms which are partners are mutually beneficial is called symbiosis. Such animals are called symbionts. Eg -   Man and bacteria found in the intestine of man are symbionts.

Answered by  | 29th Mar, 2009, 08:10: AM

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