Ecosystem

Ecosystem:the system resulting from the interaction of all the living and non living factors of the environment is called the ecosystem.

Types of ecosystem:

Natural
  Terrestrial
      Grassland
        Forest
        desert
  aquatic
      freshwater
           running water(lotic)
           stable water(lentic)
  marine
artificial(aquarium)
Here we have to study only lentic (pond) and grassland ecosystem.


Pond ecosystem:
It is a type of lentic freshwater ecosystem with complex interaction between its biotic and abiotic component. Upper part of pond is called littoral zone having shallow water , central is called limentic zone and lower part of pond is called as profundal zone with less biodiversity. Pond ecosystem consists of two major components:
abiotic components:
the abiotic component of pond includes:
Inorganic compounds like water, oxygen, carbon dioxide, carbon, calcium, phosphorus and their compounds.
Organic compounds like carbohydrates, protein, lipids, and amino acids. Only small amount of these are found in dissolved form rather they are found in base as sediment.
Ecological factors such as light, temperature, wind, rainfall etc regulates the functioning of pond ecosystem.
Biotic components: the living components of a pond are:
Producers: these are autotrophic aquatic green plants, photosynthetic bacteria etc. they fix solar energy during photosynthesis and make organic food from co2 and water. They are:
Emergent hydrophytes: it includes rooted emergent plants like ranunculus, typha etc.
Floating hydrophytes: it includes freely floating plants like pistia and azolla.
Submerged hydrophytes: it includes hydrilla and vallisnaria.
Phytoplanktons: it includes tiny plants like spirogyra and volvox.

Consumers: they are heterotrops which depends on their nutrients on producers. the consumers of pond are:
Primary: these are herbivores which feed on plants. They are microscopic animals like Cyclopes, daphria and other larger animals like insects, larvae, small fish etc.
Secondary: these are carnivores that feed on primary consumers. They are mainly crab, frog and snake.
Tertiary: these are some large fish, water birds etc.

Decomposers: after death of aquatic plants and animals; their bodies are acted upon by microorganism like bacteria and fungi(asprrgillus,rhizopus) etc. they are called decomposers. They convert complex organic substance into simple inorganic form; which can be utilized by green plants in nutrition.

Figure of pond ecosystem:

Grassland ecosystem:
The grassland ecosystem is a type of terrestrial ecosystem with open land grasses in which there is constant interaction between biotic communities and abiotic factors.
The grassland ecosystem consists of two major components:
Abiotic: the nonliving component of grassland ecosystem includes:
Inorganic compounds like carbondioxide, water, minerals, nitrate, phosphate, sulphate etc present in soil.
Organic compounds such as carbohydrates, proyein, lipid and amminoacids.
Environmental factors include light, temperature, wind, rainfall etc.

Biotic: the living factors of grassland ecosystem includes:
Producers: producers are those living organisms that can prepare food from inorganic substance .they are different types of species of grasses like cyanodon, imperata, oxalis, agropyron etc. In addition to this many herbs, shrubs are found in grassland.
Consumer: these are mainly heterotrophic animal which feed on producer. They are of following types:
Primary: they are herbivores feeding on grasses. They include mainly grazing animals like cow, buffalo, rabbit etc.
Secondary: they are primary carnivores like snake, frog, lizard, toad etc who feed on herbivores.
Tertiary: these are animals that depend upon secondary consumers for food. In grassland ecosystem, hawk, vulture are tertiary consumers.
Decomposers: these are saprophytic organism like bacteria and fungi. They decompose the dead bodies of plant and animal and convert the organic substance into simple form which is reused by green plants.

Functional aspects of ecosystem:
Functional aspects of ecosystem include flow of energy and the cycling of nutrients. The green plants fix solar energy in presence of CO2 and water to make organic food. From green plants, these organic compounds are passed into herbivores and from herbivore it transfer to carnivores.
All the living organisms have definite life span after which they die. The dead bodies provide food for saprophytic bacteria and fungi. During decomposition, energy is lost into environment as heat. Thus energy flow in ecosystem is noncyclic from sun to decomposers. Minerals from decomposed body are withdrawn by the root of plants and deposited in tissue of plants and again return to soil when plant dies. All the energy in ecosystem is recycled.