Ecosystem : Meaning and Definition

Ecosystem

        The term ecosystem was first used by A. G. Tansley in 1935 who defined ecosystem as 'a particular category of physical systems, consisting of organisms and inorganic components in a relatively stable equilibrium, open and of various sizes and kinds'.
       An Ecosystem is a community of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment (things like air, water, 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 (although some scientists say that the entire planet is an ecosystem)-From http://en.wikipedia.org/wiki/Ecosystem

        According to Tansley the ecosystem is comprised of two major parts viz. biome and habitat and thus 'all parts of such an ecosystem-organic and inorganic, biome and habitat may be regarded as interacting factors which, in a mature ecosystem, are in approximate equilibrium, it is through their interactions that the whole system is maintained'-                                                                                                                 (A. G. Tansley, 1935)
        F. R. Fosberg (1963) has defined ecosystem as 'a functioning, interacting system composed of one or more living organisms and their effective environment, both physical and biological'.
        According to R. L. Lindeman (1942) the term ecosystem applies to 'any system composed of physical-chemical-biological processes, within a space-time unit of any magnitude'.
        According to A. N. Strahler and A. H. Strahler (1976), 'the total assemblage of components interacting with group of organisms is known as ecological system or more simply, an ecosystem. Ecosystems have inputs of matter and energy, used to build biological structure, to produce and to maintain necessary internal energy levels. matter and energy are also exported from an ecosystem. an ecosystem tends to achieve a balance of the various processes and activities within it'.

Based on the contents of above definitions of ecosystem provided by various scientists it may be pointed out that ' ecosystems are therefore unities of organisms connected to one another and to their environment'.

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Ecology : Meaning and Definitions

Ecology meaning

Ecology in a very simple term. The word ‘ecology’ (‘oecology’ or ‘oekology’) derived from two greek words, ‘oikos’ meaning house or dwelling as habitat and ‘logos’ meaning the study of.

Ecology definitions

The term ‘ecology’ was first coined and used by the German biologist, Ernst Haeckel in 1869, a few conceptual terms were already proposed to reveal relationships between organisms and their environment. ecology is a science that studies the interdependent, mutually reactive and interconnected relationships between the organisms and their physical environment on the one hand and among the organisms on the other hands.

For Example, French zoologist, Isodore geoffroy St. Hilaire used the term ecology in 1859, for the study of the relations of the organisms within the family and society in the aggregate and in the community.

It may be summarized that : ecology is a science that studies interrelationships between biotic and abiotic components  of a natural ecosystem of one hand and among organisms on the other hand.

Reference:

• S. Singh, Environmental Geography

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What is environment ?

Meaning Of Environment

The word environment’ has been derived from the French word ‘environer’ meaning to encircle or to surround. The Dictionary meaning of the word ‘environment’ is a ‘surrounding’ ; external conditions influencing development or growth of people, animals or plants; living or working conditions etc.

definition

Environment may refer to the physical and biological factors along with their chemical interactions that affect an organism.

Primarily,the concern of all geographers is with the environment of man. But man cannot exist or be understood in isolation from the other forms of life and from plant life’

-(A.N. Strahler and A.H. Strahler,1976, p.4)

Environment refers to the sum total of conditions which surround man at a given point in space and time’

-(C.c. Park,1980, p.28)

Environment is defined more comprehensively by others “as a holistic view of the world as it functions at any point of time, with a multitude of spatial elemental and socio-economic systems distinguished by quality and attributes of space and mode of behaviour of abiotic and biotic forms’ -(K. R. Dikhshit, 1984)

Thus environment is defined as ‘(1)The circumstances and conditions (physical conditions) that surround (and affect) an organism or group of organisms , or  (2) the social and cultural conditions that affect an individual or community.Since human inhabit the natural world as well as the ‘built’ or technological, social and cultural world, all constitute parts of our environment’

-(W. P. cunnigham and M.A. Cunnigham, 2004)

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what is environmental geography

Meaning of Environmental Geography

‘Environmental geography is basically the study of Environment’. If this is so, why it should not be termed as “geography of environment” ? The answer is easy, the term of Environmental geography lays more emphasis on man-environment relationships.Probably K. Hewitt and F. K. Hare first used the term of  ‘environmental geography’ in Man and Environment.

Environmental Geography definition -: Define Environmental Geography

Environmental geography is the study of systematic description of different components of environment and interactions of man with these components.

Thus the definition of Environmental geography may be further broadened as follows:

“Environmental geography is the study of characteristic features of various components of the Environment, the interactions between and among the components in a geoecosystem in terms of ecosystem of varying spatial and temporal scales.”

Savindra Singh  defined Environmental Geography in 1989 as follows :

“Thus broadly speaking, environmental geography may be defined as the study of spatial attributes of interrelationships between living organisms and natural environment in general and between technologically advanced ‘economic man’ and his natural environment in particular in temporal and spatial framework.”

The final definition of environmental geography may be formulated as follows :

“environmental geography may be defined as that branch of geography  which studies the characteristics, compositions and functions of different components of the natural environmental system, mutual interdependence  of different components, various processes that link the components, the interactions of different components with each other and among themselves and consequent responses (environmental problems) in spatial and temporal context in terms of ‘geoecosystem.’ as well as interactions of technologically advanced ‘economic man’ with different components of natural ‘geoecosystem’ and resultant modifications and changes in the natural geoecosystem leading to environmental degradation and pollution, the techniques and strategies of pollution control measures and management of ecological resources” .

-(Savindra Singh,1989)

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Food Web ?

Food Webs

A food web is made up of interconnected food chains. Most communities include various populations of producer organisms which are eaten by any number of consumer populations. The green crab, for example, is a consumer as well as a decomposer. The crab will eat dead things or living things if it can catch them. A secondary consumer may also eat any number of primary consumers or producers. This non-linear set of interactions which shows the complex flow of energy in nature is more easily visualized in the following diagram.

 In a food web nutrients are recycled in the end by decomposers. Animals like shrimp and crabs can break the materials down to detritus. Then bacteria reduce the detritus to nutrients. Decomposers work at every level, setting free nutrients that form an essential part of the total food web.

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Food Chain ?

Food Chains

All living organisms (plants and animals) must eat some type of food for survival. Plants
make their own food through a process called photosynthesis. Using the energy from the
sun, water and carbon dioxide from the atmosphere and nutrients, they chemically make
their own food. Since they make or produce their own food they are called producers.
Organisms which do not create their own food must eat either plants or animals. They are
called consumers. Some animals get their energy from eating plants while other animals
get energy indirectly from plants by eating other animals that already ate the plants.
Animals that eat only plants are called herbivores. Animals that eat both plants and other
animals are called omnivores. Animals that eat only other animals are called carnivores.
Some animals eat only dead or decaying materials and are called decomposers.
In the marine food web, special producers are found. They are tiny microscopic plants
called phytoplankton. Since the water is the home for these special tiny plants; it is also
the home for tiny microscopic animals called zooplankton. And of course, zooplankton
eat phytoplankton. Sometimes zooplankton and phytoplankton are collectively referred to
as plankton.
Food chains show the relationships between producers, consumers, and decomposers,
showing who eats whom with arrows. The arrows show the movement of energy through
the food chain. For example, in the food chain shown below, the small fish (silverside)
gets its energy by eating the plankton and the large fish (bluefish) gets its energy by
eating the small fish. Finally, the bacteria eats the fish after it dies, getting its energy from
the large fish. The bacteria also returns nutrients back to the environment for use by the
phytoplankton.

PHYTOPLANKTON ~~> ZOOPLANKTON ~~> SILVERSIDE ~~> BLUEFISH

                                    NUTRIENTS <~~ BACTERIA

Thus the food chain becomes a complete circle. Animals may eat more than one type of
food. They may eat many different types of plants or many different animals. This makes
everything more complicated and the food chain becomes a food web.

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