Meaning of Ecosystem
An Ecosystem is a community of living organisms in conjunction with the nonliving components of their Environment (things like air, water and mineral soil), interacting as a system. These Biotic and Abiotic components are regarded as linked together through nutrient cycles and energy flows. As ecosystems are defined by the network of interactions among organisms, and between organisms and their environment, they can be of any size but usually encompass specific, limited spaces. (Some scientists say that the entire planet is an Ecosystem).
An ‘Ecosystem’ is a region with a specific and recognizable landscape form such as forest, grassland, desert, wetland or coastal area. The nature of the ecosystem is based on its geographical features such as hills, mountains, plains, rivers, lakes, coastal areas or islands. It is also controlled by climatic conditions such as the amount of sunlight, the temperature and the rainfall in the region. The geographical, climatic and soil characteristics form its non-living (Abiotic) component. These features create conditions that support a community of plants and animals that evolution has produced to live in these specific conditions. The living part of the Ecosystem is referred to as its biotic component.
The living community of plants and animals in any area together with the non-living components of the environment such as soil, air and water, constitute the ecosystem. Some ecosystems are fairly robust and are less affected by a certain level of human disturbance. Others are highly fragile and are quickly destroyed by human activities. Mountain Ecosystems are extremely fragile as degradation of forest cover leads to severe erosion of soil and changes in river courses. Island ecosystems are easily affected by any form of human activity which can lead to the rapid extinction of several of their unique species of plants and animals. Evergreen forests and coral reefs are also examples of species rich fragile ecosystems which must be protected against a variety of human activities that lead to their degradation. River and wetland ecosystems can be seriously affected by pollution and changes in surrounding land use.
Division of Ecosystem:
Ecosystems are divided into
- Terrestrial or land-based ecosystems, and
- Aquatic ecosystems in water.
These form the two major habitat conditions for the Earth’s living organisms. At a sub-global level, this is divided into bio-geographical realms, e.g.
- Eurasia called the Palaearctic realm;
- South and South-East Asia (of which India forms a major part) is the Oriental realm;
- North America is the Nearctic realm;
- South America forms the Neotropical realm;
- Africa the Ethiopian realm; and
- Australia the Australian realm.
At a National or State level, this forms bio-geographic regions. There are several distinctive geographical regions in India-
- The Himalayas,
- The Gangetic Plains,
- The Highlands of Central India,
- The Western and Eastern Ghats,
- The Semi-arid desert in the West,
- The Deccan Plateau,
- The Coastal Belts, and
- The Andaman and Nicobar Islands.
These geographically distinctive areas have plants and animals that have been adapted to live in each of these regions. At an even more local level, each area has several structurally and functionally identifiable ecosystems such as different types of forests, grasslands, river catchments, mangrove swamps in deltas, seashores, islands, etc. to give only a few examples. Here too each of these forms a habitat for specific plants and animals.