Ecosystems
An ecosystem is a segment of nature consisting of a community of
living beings and the physical environment both interacting and
exchanging materials between them.
The
two components of nature, organisms and the environment are not only
highly complex and dynamic but also interdependent, mutually reactive
and interrelated. Ecology deals with the various principles which govern
relationships between organisms and their environment.
At about the same time the English naturalist, St. George Jackson
Mivart coined the term hexicology, and defined as the study of the
relations which exist between the organisms and their environment with
respect to the nature of the locality, the temperature and the amounts
of light, and their relations to other organisms as enemies, rivals, or
accidental and involuntary benefactors. Thus, ecology is literally the
study of organisms and their relationship with environment.
Scope and Importance:
Taylor
(1936), in an attempt to define ecology, has very rightly pointed out
that scope of ecology by stating that ecology is the science of all the
relations of ecosystems, all organisms to all their environments.
Ecology
plays an important role in agriculture crop rotation, weed control,
management of grasslands, range management forestry, biological surveys,
pest control, fishery biology, and in the conservation of soil,
wildlife, forest, water supplies, water bodies like rivers, lakes and
ponds,
Ecosystem is defined as a dynamic entity composed of a biological
community and its associated abiotic environment. Often the dynamic
interactions that occur within an ecosystem are numerous and complex.
Ecosystems
are also always undergoing alterations to their bio-tic and antibiotic
components. Some of these alterations begin first with a change in the
state of one component of the ecosystem, which then cascades and
sometimes amplifies into other components because of relationships.
Ecosystem Productivity:
The productivity in an ecosystem are of two kinds—primary productivity
and secondary productivity. The primary productivity of an ecosystem is
the rate at which organic matter is produced during photosynthesis. During the process of production and consumption, energy is passed
along, or flows, from one organism to another. For example, solar energy
is converted to chemical energy within the leaves of green plants. The
leaves can then be eaten by some herbivore, and the herbivore may, in
turn, be eaten by a carnivore.
Consider a hypothetical ecosystem that receives 1,000 Kilocalories of
light energy in a given day. Most of this energy is not
absorbed at all. Some is simply reflected back into space. Of the energy
that is absorbed, most is stored as heat or used for evaporation of
water. A small amount is assimilated by plants.
Energetic Efficiency :
The movement of energy through the community depends on the
efficiency with which organisms consume their food resources and convert
them into biomass. This efficiency is referred to as the food chain or
ecological efficiency.
Ecological efficiency are determined by both internal,
physiological characteristics of organisms and their external,
ecological relationships to the environment. To understand the
biological basis of ecological efficiency, one must dissect the
individual link of the food chain into its component parts
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