Here I give an essay on the ecosystem and its description.
An ecosystem is one community consisting of living organisms
in a non-living environment. Living
organisms (biotic components) are animals, plants, microbes etc. Environment (not biological or abiotic
components) includes soil, soil minerals, nitrogen, water, air etc. All these
components interact with one another as a system in total.
These interactions and their effect on the total ecosystem
on the Earth are of interest to us and to scientists.
The nutrient cycles and energy flows in the
ecosystem involve the living and non-living components. A lake can be treated
as an ecosystem or India as a country or even the entire Earth can be studied as an ecosystem. Through
these interactions, energy and matter flow through the ecosystem in cycles.
Energy comes into our ecosystem from the Sun through
photosynthesis by plants. Plants absorb
carbon, nutrients and nitrogen from soil or atmosphere and releases oxygen into
atmosphere. Animals feed on plants and on other weaker animals. Dead organic
matter is decomposed by bacteria, fungi and worms. Carbon and other nutrients
are released back into atmosphere and soil respectively. They are converted to
their original form in the atmosphere and soil.
So the plants and microbes use these nutrients again.
The ecosystems are dynamic. They are periodically perturbed
by disturbances and recover from them slowly in time. Climate, parent material (underlying
geological material) of the soil, time, new non-native species and topography
(terrain, location, geography) are the external factors influence and control
the ecosystem at a location. Topography affects local atmosphere, soil
development and flow of water through the system.
Decomposition, root competition and shading are internal
factors affect availability of resources within ecosystem. People affect the
internal resources and also external factors like climate. Climate in turn
affects the ecosystem. More internal factors affecting an ecosystem are
biodiversity or the variation in life forms, temporary disturbances and the
succession in the gradual evolution of species.
Energy flows happen as follows. Primary production of organic matter from
inorganic carbon matter occurs through photosynthesis. Primary consumers or secondary producers are
those which consume plants (herbivores). Microbivores are organisms that feed on
microbes (bacteria and fungi). Carnivores feed on primary consumers. Plants occupy the tropic level 1, herbivores
occupy level2 and carnivores occupy level 3 in the food chain (sequence) of the
ecosystem. In reality, the sequences form food web rather than a simple sequence of food production and consumption.
Management of natural resources in the entire ecosystem is
the ecosystem management.
Questions and answers:
1. What is an ecosystem?
An ecosystem is one community consisting of living organisms in a non-living environment along with the interactions among these biotic and abiotic components.
2. Give examples of some ecosystems.
A lake, Indian subcontinent, the ocean-bed , the Earth
3. What are primary producers? what are secondary consumers ?
Plants are primary producers. Carnivores are secondary consumers.
4. Which organisms are decomposers ?
Baceria, worms and fungi.
5. Which things flow through the ecosystem ?
Matter, food, energy