GE8291 CHAPTER2 STRUCTURE AND FUNCTIONS OF ECOSYSTEM

GE8291 CHAPTER2 STRUCTURE AND FUNCTIONS OF ECOSYSTEM

STRUCTURE  (or) COMPONENTS  OF AN ECOSYSTEM

The structure of an ecosystem explains the relationship between  the abiotic (Non-living) and the biotic (Living) components.

The two major components of an ecosystem are

*Abiotic components

* Biotic components

Abiotic component:  The non-living components of an ecosystem collectively form a community called abiotic components. Non-living components can  be  physical components , chemical components.

Eg: climate, soil, water, energy, nutrients etc.

Physical components: They include energy, climate, raw materials and living space that is needed  for a biological community. It is useful for the growth and maintenance of its member. Eg: Air,water, soil, sunlight etc.

Chemical components: They are the sources of essential nutrients.

(i) Organic substance: Protein, lipids, carbohydrates etc.

(ii) Inorganic substance: All Micro elements(need in trace amount) Al,Co,Zn,Cu are some of the micro elements and Macro elements (need in more amount) C,H,O,P,K,N are some of the macro elements.

Biotic component: The living organisms of an ecosystem is collectively called as Biotic components. Based on the nutritional relationship the biotic components are

(i) Autotrophic components: The member of autotrophic components are producers,they are self nourishing organisms(Autotrophs).  Eg: Green plants, algae etc

(ii) Heterotrophic components:  Consumers and Decomposers comes under heterotrophic components, they depends on others for food. They consumes autotrophs(producers). The heterotrophs are:

(i) Macro consumers: They are Herbivores(plant eating animal), Omnivores(animals that feed on both plants & animals) or Carnivores(animal that feeds on other animals)

(ii) Saprotrophs(Micro consumers): They are Decomposers (Bacteria,Fungi etc)

CLASSIFICATION OF BIOTIC COMPONENTS:

On the basis of mode of food the members of biotic community is classified as:

* Producers(plants)

* Consumers(Animals)

* Decomposers(Micro-organisms)

Producers: They prepare their own food through photosynthesis.(Autotrophs) examples are green plants, trees etc.

Photosynthesis is the process in which the green pigment in  leaves of plant converts Co2 and H2O  in the presence of sunlight  into  starch.

hν(sunlight)

6CO2+ 12H2O —–————> C6H12O6+6O2+6H2O

chlorophyll

This process is called as PHOTOSYNTHESIS.

CONSUMERS:

The organisms that depends  directly or indirectly on producers for their  food.

examples are (i) plant eating ( insect , rabbit, goat) (ii) animal eating(lion,tiger etc)

Types Of Consumers:

* Primary consumers(Herbivores ), they depends on plants for their food they are called as plant eaters. (eg: insects, rat ,goat, deer)

*Secondary consumers(primary carnivores/Meat eaters), they feed on primary consumers.

eg: Frog, Cat, Snakes etc.

*Tertiary consumers(Secondary carnivores/Meat eaters) , they feed on secondary consumers.

eg: Tiger, lions etc.

DECOMPOSERS:

The organisms that feed on dead  organisms like plants , animals  and decompose it into simpler compounds.During decomposition inorganic nutrients are released. These  inorganic nutrients with organic substances are then utilized by producers(plants)  for the preparation of their own food.

FUNCTION OF AN ECOSYSTEM:

The main function of an ecosystem is to allow flow of energy and cycling of nutrients.

TYPES OF FUNCTIONS:

1. Primary function or Primary production: The primary function of all ecosystem is the manufacture of starch(photosynthesis)

2. Secondary function or Secondary production:  The secondary function of all the ecosystem is distributing energy (food) to all consumers.

3. Tertiary function: Decomposition of the dead matters  in an ecosystem  namely “cycling”.