Ecosystems

An ecosystem is different from a habitat. In an ecosystem, the biotic organisms and their abiotic environment are inseparably related, and they interact with others. Groups of organisms interact to form communities in a particular area. These communities are linked to their environment through the transfer of matter and energy to form an ecosystem. So, an ecosystem includes not only the physical habitat but also the flow of energy and materials.

Structure of an ecosystem: The structure includes both biotic and abiotic components such as:

1)      The composition of the biotic community including species, number of organisms, distribution and life cycles. 

2)      The quantity and distribution of non-living materials such as soil and the basic inorganic elements and compounds like nitrogen, oxygen and carbon dioxide. It also includes organic compounds such as proteins, carbohydrates and lipids which are by-products of organism activities. 

3)      The physical conditions such as moisture or solar radiation. 

The structure of an ecosystem is directly related to the species diversity. The two major categories are Autecology and Synecology.

• Autecology is the study within the target species for their geographic distribution, physical form, biological classification, life cycle and food relationships. The study is generally not limited to a specific geographical location.

• A synecological approach studies organisms on different levels including the individuals within a single species (population), between species (community) and between different communities (biome).

4)      Population ecology: A population is a group of interbreeding individuals within a single species living in the same habitat at the same time. An example is all salt water crocodiles. 

5)      Community ecology: A community may be composed of many different species. The type and patterns of interdependies between various interacting populations are studied in community ecology. For example, the interactions between the populations of pangash fish, Pallas fishing eagle and sundry trees. 

6)      Biome ecology: A biome is composed of different communities existing within a specific region distinguished by specific geographical and climatological characteristics. For example, whole Sundarbans is a biome.