The word ecology, first proposed by German biologist Ernst Haeckel in 1869 (Greek oikos means house or place to live is the study of the relationship between organism and their environment. It is the science of the inter relations between living organism and environment.
Modern ecology focuses on the basic functional ecological unit, the ecosystem. The term ecosystem was proposed by the British ecologist A. G. Tansley in 1935. Its eco means environment and the systems part implies, a complex of coordinated units.
An ecosystem is a system formed by the interaction of variety of individual organisms with each other and with their physical environment. Therefore it is composed of all the associated organisms and the physical features that exist in a specific area.
E.P. Odum, the ecosystem is the basic functional unit of organisms and their environment, interacting with each other and within their own components.
An ecosystem is a sum total of living organisms, the environment and the processes of interaction between and within all part of the system, e.g. A forest, grassland, desert, lake etc. or it may man made like a farms. It may be very small (e.g. an aquarium) or vast (e.g. Ocean).
Structure of an Ecosystem
An ecosystem has two components the biotic components consisting of living things, and the abiotic portion, consisting of elements that are not alive.
The non living constituents are said to include the following category, habitat, gases, solar radiation, temperature, moisture and inorganic and organic nutrients.
The living organisms may be sub divided into producers, consumers and decomposers. From structural point of view all ecosystems consist of following four basic components.
Abiotic Components: These include basic inorganic and organic components of the environment or habitat of the organism.
The inorganic components of an ecosystem are carbon dioxide, water nitrogen, calcium phosphate all of which are involved in matter cycle (biogeochemical cycles).
The organic components of an ecosystem are proteins, carbohydrates lipids and amino acids, all of which are synthesized by the biota (flora and fauna) of an ecosystem and are reached to ecosystem as their wastes, dead remains etc. the climate ‘microclimate’ temperature, light soil etc. are abiotic components of the ecosystems.
In terrestrial environment soil is the major life-supporting element of terrestrial environments while in aquatic environment three major types fresh water, salt water and estuarine. Fresh water habitats include lakes, ponds, streams, rivers, .swamps and springs. Soils water habitats, which comprise most of the planet’s aquatic environment, include the seas and the oceans. Intermediate between the fresh water and salt water habitats is the estuary – a river mouth where salt water and fresh water mix.