Natural ecosystems include the forests, grasslands, deserts,
and aquatic ecosystems like ponds, rivers, lakes, and the sea. Man-modified
ecosystems include agricultural land and urban or industrial landuse patterns.
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 very fragile and
are quickly destroyed by human activities.
All living organisms and their non-living environment,
interact with each other at different points in time and at different
places. At a global level this forms the biosphere. At a sub-global level,
this is divided into bio-geographical realms, e.g. Eurasia - Palaeartic
realm; South and South-East Asia (of which India forms a major part) - the
Oriental realm; North America -Nearctic realm; South America - Neotropical
realm; Africa - Ethiopian realm; and Australia - Australian realm.
At a national or state level, this forms biogeographic
regions. There are several distinctive 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.
At an even more local level, each area has several
structurally and functionally identifiable ecosystems- such as forests,
grasslands, river catchments, mangrove swamps in deltas, seashores, islands,
An ‘ecosystem’ is a region with a specific and recognizable
landscape form, such as a forest, grassland, desert, wetland or coastal area.
The nature of the ecosystem is based on its geographical features like hills,
mountains, plains, rivers, lakes, coastal areas or islands. It is also
controlled by climatic conditions-the amount of sunlight, the temperature and
the rainfall in the region.
The geographical, climatic and soil characteristics form its
non-living or 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
The ecosystem functions through several biogeochemical cycles
and energy-transfer mechanisms. Observe and document the components of the
ecosystem, which consist of its non-living or abiotic features such as air,
water, climate and soil and its biotic components, the various plants and
Both these aspects of the ecosystem interact with each other
through several functional aspects to form nature’s ecosystem (ants, herbivores
and carnivores can be seen to form food chains. All these chains are joined
together to form a ‘web of life’ on which man depends. Each of these food chains
use energy that comes from the Sun and powers the 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.