An ecosystem is a self sufficient interacting system in the biosphere. Eg. forest, desert, pond etc. almost, all the ecosystem have more or less similar fundamental plan for their gross organization(i.e. structure and function); but they differ in respect of their species, composition, environment, geographical location etc.

 Some of important ecosystem of world-

1.              Forest ecosystem

2.              Grassland ecosystem

3.              Desert ecosystem

4.              Pond ecosystem

1. Forest ecosystem:

 A close strand of trees growing on vast area and associated with other plants and animal is called forest.

Component of these ecosystems:

         Abiotic: temperature, light, rainfall and soil etc.

         Biotic: (a)     producers: trees and shrubs like teak, pine, oak, mango, babool etc.

                     (b)    Consumers:

(i)                 Primary consumers: herbivores eg elephants, neeligai, deer, squirrels flies, beetles ant etc.

(ii)               Secondary consumers: Carnivores; e.g. snakes, lizards, foxes etc.

(iii)             Tertiary consumers: lion, tiger etc.

(iv)             Decomposers: Micro organism-Bacteria fungi.

There are many types of forest ecosystems:

(i)           Tropical evergreen (equatorial regions, rainfall more than 200cm).

(ii)         Mediterranean forests (area around  Mediterranean sea)

(iii)       Coniferous forest or taiga(rainfall 10 to 35 cm)

(iv)       Deciduous forest: hot summer and cold winter rainfall 75-125 cm.

2.  Grassland ecosystem:

This is an example of terrestrial ecosystem. Various components:

       Producer: grass, shrubs, bush and few trees.

         Composer: rat, snake, deer, sheep, bear, elephant, tiger etc.

         Decomposer: bacteria and fungi.

The major grass land of world. Prairies of canada and U.S.A., pampas of south America, the steppes of Europe and Asia and velds of Africa. Annual average rain -fall is 25-75 cm.

1.      Desert ecosystem:

Desert are areas where rainfall is extremely low (less than 25 cm per year) and rate of evaporation in very high. The flora and fauna are very scanty.

Producers: cacti, acacias, babool, khejri, succulents and hard grasses.

Consumers: rats, camel, foxes, spider, lizards, scorpions etc.

Decomposers: bacteria and fungi major deserts of world are in Asia (thar, gobe, tibet) north America (Sahara) etc.

Aquatic ecosystem:

The range of aquatic ecosystem can be from open pond to ocean. It can be fresh water and marine water. Eg. Lake, ponds, rivers, streams, sea.

Various components:

 Producers: phytoplanktons like diatoms, microscopic algae, floating and submerge plants.

         Consumers: zooplanktons, insects etc.

         Decomposers:  bacteria and fungi etc.