STRUCTURE OF AN ECOSYSTEM

STRUCTURE OF AN ECOSYSTEM

ODUM(1971) described that an ecosystem is formed of two major components:

A.     Biotic (living) components

B.      Abiotic (non-living)components.

A.     Biotic components. These include the living elements of the ecosystem and are divided into two categories on the basis of their  nutritional relationship :

1.      Autotrophic components.

2.      Hetrotrophic components.

1.      Producers or Autotrophic components. These include the green plants , photosynthetic bacteria and cyanobacteria which are capable of manufacturing their organic food (e.g glucose) from simple inorganic substances (e.g co₂ and H₂O) by the process of  photosynthesis. These are also called producers. These may be herbs, shrubs, larged sized trees or microscopic,free floating phytoplanktons. These are called photoautotrophs.

6co₂ + 6H₂O   ---------àC₆ H₁₂ O₆  + 6O₂

Certian  bacteria e.g  sulphur bacteria  and  nitrifying bacteria synthesize their organic food from inorganic compound in the presence of chemical energy and are called  chemoautotrops.

2.      Consumers or hetrotrophic components: these include those organisms which consumes either readymade organic food or decompose the complex organic compounds . These are also called   consumers. Depending upon their size,  hetrotrophs are divided into two categories:

(a)   Macroconsumers : these include the animal , which eat the producers directly or indirectly. These are divided in to four categories:

(i)Primary consumers. These includes the  herbivores  which really eat upon the plant e.g rabbit deer , goat cattel grasshopper etc.

(ii) Secondary consumers.  These include the primary carnivores which eat upon the herbivorous animals e.g. fox ,frog.centepede fishesh,wild cats, snakes etc.

(iii) Teritiary consumers .  these includes the  secondary carnivores  which eat  upon the teritiary consumers e.g lion,tiger etc

(b)   Microconsumers.  These are also called decomposers or saprotrophs or reducers which break down the complex organic compounds of dead bodies of both plants and animals, absorbs some of the decomposed products while release most of inorganic compounds into the environment from where these are refused by the producers. So these help in  material recycling. These include bacteria and fungi.

(B). Abiotic component.these include the non-living physic-chemicals factors of environment.theseare divided in to three categories :

1.      Inorganic material.these are involved in the material cycles e.g Carbon,nitrogen oxygen, phosphorus,H₂O,etc.

2.      Organic compounds. These are present in dead organic matter and include  carbohydrates,proteins,lipids,nucleic acids,etc.

3.      Climatic and Edaphic factors. Climatic factors include physical factors of environment e.g light temperature, wind,etc .the edaphic factors are soil factors.