Ecosystem is an open system and material can exchange from one ecosystem to another ecosystem. For ex. Frog move from the pond to the land and vice-versa. The ecosystem can be classified based on size, nature and duration;

(1)    Nature : On the basis of nature, it can be natural or artificial.

Natural Ecosystem: This ecosystem forms naturally without interference of human. Example include are pond, river, forest, village, hill etc.

Artificial Ecosystem: This ecosystem is developed and mainted by human. Example include are flowerbed, backyard, aquarium etc.

(2)   Duration: On the basis of duration, ecosystem can be classified as temporary or permanent.

Temporary ecosystem: it is short lived and man made or natural. Example include rain fed pond.

Permanent ecosystem: it is long lived and self supported natural ecosystem for very long period. Example includes forest, river etc.

(3)    Size: Ecosystem is classified as small or large ecosystem.

 

 

(1)             Small: it is small and also known as microecosystem. It can be temporary or permanent. For ex. Pond, flowerpot etc

(2)             Large: it is large in size and also known as macroecosystem. It is always permanent and mostly natural. For ex. Ocean, river, forest and desert.

(3)             STRUCTURE OF ECOSYSTEM: Each and every ecosystem has several components to sustain it for long duration. It needs matter (water, oxygen, mineral, carbon dioxide), different types of organisms and continuous recycling of energy (Figure 38.1). These requirements are met by two important components present in ecosystem; biotic components and abiotic components.

 

 

 

Biotic Components: The living organisms present in an ecosystem form the biotic component. They are connected through food. In this series, few organisms are producing food whereas others are consuling the food.

(i) Producers: The role of producers is to prepare food to provide nutrition to the other organisms present in the ecosystem. There are two types of producers; photoautotrophs and chemotrophs.

Photoautotrophs: These are green plants which can trap sun light to form carbohydrate, simple sugar from carbon di-oxide and water. This process is known as photosynthesis and these organisms are called as photoautotrophs.

Chemoautotrophs: Few bacteria such as sulfur bacteria, nitrifying bacteria, can be able to utilize free energy released from the chemical reactions to prepare organic food with it. They are called chemoautotrophs and the process is known as chemosynthesis.

(ii)   Consumers: These are mainly the animals. They are unable synthesize their own food and depends on producers. They utilize the oxygen being released from the producers as well. Several consumer doesn’t get the food from the producers but they are depended on consumers itself. As a result, consumers are related to each other through multiple food chains. There are many types of consumers and we will discuss in details about these consumer in the subsequent lecture. The consumers are known as heterotrophs.

(iii)   Decomposers: These are mainly bacteria and fungi. Their primary purpose in the ecosystem is to decompose the complex organic material into the simple inorganic material so that it can be use for producers to prepare food.

ABIOTIC COMPONENTS

 These factors include the non-living physiochemical factors of the environment. Abiotic factors are as follows:

(i)    Inorganic substances: Inorganic substances like carbon, nitrogen, oxygen, water, carbon di-oxide, calcium, phosphorus and their inorganic compounds. These are available as free form or dissolved in water and may be adsorbed on the soil particles.

(ii)  Organic compounds: These are carbohydrates, proteins, lipids, nuceltic acids etc. This material is present in dead organic matter. These are broken into the simple compounds by decomposers in ecosystem for recycling of matter.

(iii)   Climatic factors: These are factors present in the environment such as temperature, humidity, light, wind, rainfall an atomospheric gaseous etc.

Study of specific Ecosystem: Lets take a example of fresh water pond to understand the function of individual components.

1.   Abiotic Components: Non-living part of the pond includes: (1) water with dissolved gases, mineral and suspended organic matter. (2) air, CO2 and O2 on the water surface (3) sunlight.

2.   Biotic Components: The biotic constituents include the plants, animals and microorganisms. They play different role in ecosystem.

3.              Producers: Green plants act as producers.. As discussed previously, they utilized the sun light, CO2 and water to prepare the food for other organisms.

4.              Consumers: These includes crustaceans, worms, insect larvae and fishes.

5.              Decomposers: Dead plants and animals form the organic debris in the pond. The decomposer such as bacteria and fungi decay dead body into the simple organic and inorganic substances.