Ecosystem

INTRODUCTION
An ecosystem is a natural unit consisting of all plants,
animals and micro organisms (biotic factors) in an area
functioning together with all the physical (abiotic) factors
of the environment. An ecosystem is a unit of
interdependent organisms which share in same habitat.
Ecosystems ecosystem usually form a number of food webs
which shows the interdependence of the organisms within
ecosystem. Ecosystem is also known as basic functional unit
of ecology. An ecosystem needs only the input of sunlight
energy for its functioning. The example of ecosystem is
grassland, a forest, a desert, a mountain, a pond, a lake, a
river and a sea. When we say that a pond or a lake is an
ecosystem, then the word pond also include all the aquatic
life (plants and animals) which occurs in the pond water.
This is because the living organisms are found every where.
Similarly when we say that a forest is an ecosystem then it
means the physical environment of the forests like soil, air
and water along with all the plants and animals which occur
in forest. The desert, grassland, forest, crop field and
mountains represents terrestrial ecosystem, where as pond,
lake, river, sea and aquarium represent aquatic ecosystem.

TYPES OF ECOSYSTEM
Ecosystems are of following types-
a) Permanent and natural ecosystem-These ecosystems
operate under natural conditions without the
interference of human beings. These are of two types-
 Terrestrial ecosystem-these operate on land example
forests ecosystem, grassland and desert ecosystem.
 Aquatic ecosystem-These operate in water and are
again of two types:-
 Fresh water ecosystem-Operate in ponds, lakes,
rivers etc
 Marine ecosystem-Operate in sea water having high
salt concentration (3.5%) example open sea, coastal
and estuaries.
b) Artificial or anthropogenic ecosystem-These are main
made ecosystem example cropland, space ecosystem,
large dams, lakes canal, etc. A balanced aquarium is also
an example of artificial ecosystem.
COMPONENTS OF ECOSYSTEM
The entire ecosystem is made up of two main
components: abiotic components and biotic components.
Abiotic components mean non living components and
biotic components means living components. Thus we
can say that the ecosystem consist of nonliving
environment and the living biological community.
 Abiotic components of an ecosystem-The abiotic
components of an ecosystem or non-living components
of an ecosystem include the physical environment like
soil, water and air along with the inorganic substances

like carbon dioxide, nitrogen, oxygen, water, phosphorus
and other elements present in them. The physical factors
like light, temperature, pressure and humidity are also
considered as abiotic components of the ecosystem
 Biotic components of an ecosystem- The biotic components
of an ecosystem or living component of ecosystem is a
community of organisms like plants and animals which
is made up of many different interdependent populations.
The biotic community of an ecosystem includes three
types of organisms:
a) Producer organisms (autographs) which synthesize
their own food. All the green plants are producers.
b) Consumer organisms (heterotrophs) which are
dependent on others for food. All animals are
consumers
c) Decomposer organisms (saprotrophs) which consume
the dead remains of other organisms. Certain bacteria
and fungi are decomposers
FUNCTIONING OF AN ECOSYSTEM
The ecosystem has non living components like soil,
water and air which contain inorganic nutrient elements,
and the living components called producer, consumer
decomposer organisms. All this components make the
ecosystem function as follows-from the nutrient pool of
earth (soil, water and air) carbon dioxide and water are
absorbed by the producer organisms (green plants).with
the help of sunlight energy, the producer organisms
convert this inorganic substances into organic
compounds like carbohydrates which acts as a food.
Thus, producers trap the solar energy and then provide

the basic food or energy for all other life in the
ecosystem. The consumers derive their energy needs
directly or indirectly from producers. When the
producers and consumers die, then the decomposer
organisms act on their dead bodies to return the various
elements back to the nutrient pool (soil, water and air).
Thus an ecosystem involves input of energy and matter
which are exchanged between living and non living
components
PRODUCERS, CONSUMERS AND
DECOMPOSERS
According to the manner in which the organisms
obtain their food from the environment, all of them can be
divided into three groups: - producers, consumers and
decomposers.
1) Producers: - The organisms which can produce food are
called producers. Producers are the organisms which
can prepare their own food from simple inorganic
substances like carbon dioxide and water by using
sunlight energy in the presence of chlorophyll. The
examples of producers are green plants and certain blue
green algae. The green plants synthesize their own food
during photosynthesis by taking raw materials from the
earth and the energy from the sun. The green plants
produce carbohydrates by photosynthesis and also
synthesize fats and proteins. Thus the green plants are
called producers in the living world. Producers are the
autotrophic organisms in the ecosystem upon which

other organisms depend for food. Thus, producers are
autotrophs
2) .Consumers:- Those organisms which consume food
prepared by producers are called consumers. The
consumers depend on producers for food, directly or
indirectly. The consumers get their food by eating other
organisms or products. All the animals are consumers.
Even the microscopic lives of water called protozoa are
consumers. The example of common consumers are
man, goat, deer, fish, lion, cow, buffalo etc. The cow and
buffalo eat green grass and other green fodder because
green grass and other green plants are producers of food.
The bio mass of grass and plants supplies food and
energy to these animals like cow and buffalo. The
consumers like animals can not prepare food from simple
inorganic substances through photosynthesis. The
consumers need readymade food for their survival which
they get from producers directly or indirectly. If an
animal eats grass and other green plants or their products
itself we can say that it gets the food from producers
directly. It eats grass. On the other hand, if animals eat
the meat of another animal then we can say that it gets
the food from the producer indirectly. For example, a
lion gets food by eating goat which in turns eats grass.
So in the case the lion gets its food indirectly from the
producer grass (through the goat). Consumers are also
called hetrotrophs. Consumers can be further divided
into three groups: herbivores, carnivores and omnivores.
 HERBIVORES: - Some animals eat only plants. Those
animals which eat only plants are called herbivores.

The herbivores may eat grasses, leaves, grains, fruits or
the bark of the trees. Some of the examples of herbivores
are: Cow, Buffalo, Goat, Sheep, Horse, Deer, Camel,
Monkey, Rabbit etc. Cow is a herbivore because it eats
only plants as food. Herbivores are also known as
herbivorous animals. The animals which get their food
by eating the producers directly are called primary
consumers. Since herbivores obtain their food directly
from plants, therefore herbivores are primary
consumers.
 CARNIVORES: - Some animals only eat other animal. They
do not eat plant food at all. Those animals which eat
only other animals as a food are called carnivores.
The carnivores eat the meat of other animals. Some of
the examples of carnivores are: Lion, Tiger, Vulture,
Lizard, Snake, Wolf, Hawk etc. Lion is the carnivore
because it eats only the meat or flesh of other animals
like deer, rabbit, goat etc. carnivores are also known as
carnivorous animals. The carnivores are usually of two
types: small carnivores and large carnivores. The
small carnivores which feed on herbivores (primary
consumers) are called secondary consumers. For
example, a grasshopper, rat, seed eating bird and frog,
etc are secondary consumers. The large carnivores which
feed upon the small carnivores (secondary consumers)
are called tertiary consumers. For example lion, tiger,
birds of prey and humans are some of the tertiary
consumers.
 OMNIVORES: - Some animals eat both, plants as well as
other animals. Those animals which eat both, plants
and animals are called omnivores. Some of the

examples of omnivores are: Dog, Crow, Sparrow, Bear,
Mynah, Ant etc. Man is called an omnivore because he
eats both, plant food (such as grains, pulses, fruits and
vegetables) as well as meat of animals (such as goat,
chicken and fish). Omnivores are also called omnivorous
animals.
3) Decomposers: - the non green micro-organisms like some
bacteria and fungi, which are incapable of producing their
food, live on dead and decaying plants and animal bodies,
and are consumers of special type, called decomposers.
Thus we can say that the micro-organisms which break
down the complex organic compounds present in the
dead organisms like dead plants and animals and their
products like faeces, urine, etc into simpler substances
are called decomposers. The examples of decomposers are
certain bacteria and fungi. The bacteria which act as
decomposers are called putrefying bacteria. The bacteria
and fungi act as decomposers by the secretions of their
body surfaces which decompose the organic matter present
in the dead plants and animals, into simpler substances and
liberate ammonia, carbon dioxide etc. they absorb some of
these simpler substances for their own maintenance and
release the remaining into the soil, water and air to be used
by the producers again. The decomposers are also known as
micro-consumers or saprotrophs.
INTERACTIONS BETWEEN BIOTIC AND
ABIOTIC COMPONENTS OF ECOSYSTEM

Biotic and abiotic components of the ecosystem
interact with one another and are interdependent example
 The amount of annual rainfall greatly affects the
vegetation as well as animal population of a particular
area. Example tropical areas having plenty and uniform
rainfall throughout the year are with evergreen forest
while the areas with scanty rainfall have deserts with
xerophytes vegetation. But the amount of rainfall also
depends upon the forests which also affects the
temperature and soil. More rain means more trees and
more trees means more rainfall.
 In the ecosystem, the living components i.e. the
producers (plants), consumers (animals), decomposers
(bacteria and fungi) also interact with one another for
their production and consumption. These are related
with one another through food chains in which there is
repeated eating and eaten by so to transmit the food
energy. So in a food chain there is a nutritive interaction
between biotic components of an ecosystem. The
various steps of food chain are called tropic levels
example in a grazing food chain of grass land, grasses acts
as producers and are autotrophic. These synthesis their
own organic food by the process of photosynthesis. The
grasses are taken up by the herbivores (primary
consumers) like rabbit, deer, sheep, goat etc. and then
by different kinds of carnivores involving repeated
eating. The plants, herbivores and carnivores undergo
natural death. Their dead bodies are decomposed by
decomposers (bacteria and fungi) which return the
chemicals nutrient to the environment from where these
are reused by producers

Thus there is a perfect interaction between abiotic and
biotic components which help in energy flow and
material cycling.
ENERGY FLOW
Energy flow is the key function of an ecosystem. It is
determined by two basic laws of thermodynamics. First
law of thermodynamics states that energy is neither
created nor destroyed, but can be transferred from one
component to another, or transformed from one state to
another .Second law of thermodynamics states that energy
transformation is not cent percent as at each step, there
occurs dissipation of energy due to metabolic functions
like respiration, locomotion, biosynthesis etc.
 Energy flow in a food chain – primary source of
energy is sun which produces different types of
electromagnetic radiations. Only a part of these
radiations reaches the earth’s atmosphere in the form
of light and heat. Light falling on leaves of the plants
is trapped by the producers in the presence of green
pigment chlorophyll and is used in assimilating the
organic food (glucose) by the process of photosynthesis.
The total food manufactured by the plants during
photosynthesis is called Gross primary productivity (PG).
On average, it is about 1-5 percent of incident
radiations. A part of it is used by the plants in the
process of respiration (R) while remaining energy is
used in the synthesis of plant biomass and is called Net
primary productivity (PN) or apparent photosynthesis. An

average it is about 0.8 to 4 percent energy incident
radiations .So it is represented as –
PN = PG - R
NUTRIENT CYCLING (BIOGEOCHEMICAL
CYCLE)
Biogeochemical cycles are the cyclic pathways through
which chemical element move from environment to
organisms and back to environment. Such cycling is
essential as the earth and its environment, with reference
to these elements, are considered as closed system and
there is no inflow of such elements form outside the
earth and their amounts are limited.
There are two types of biogeochemical cycles-
a) Gaseous cycles – eg. Carbon, nitrogen and oxygen
cycles.
b) Sedimentary cycles- eg. Calcium, phosphorous and
sulphur.
 Carbon cycle-it is an example of gaseous cycles.
 Significance – carbon is the basic component of all
the organic compounds like carbohydrates, proteins,
lipids, enzymes and nucleic acid of the protoplasm.
In atmosphere, it is present as carbon dioxide.
 Carbon dioxide utilization – carbon dioxide is
utilized by the photosynthetic organisms like green
plants, photosynthetic bacteria, diatoms and blue
green algae in the process of photosynthesis. It
occurs in the presence of chlorophyll and radiant

energy of sunlight. Glucose synthesized in
photosynthesis is used to synthesized other organic
compounds
 Carbon dioxide production-
 Carbon dioxide is released during respiration of both
producers and consumers.
 During decomposition of organic compounds of dead
bodies.
 During burning of fossil flues like wood, coal,
petroleum etc.
 Volcanic eruptions and hot springs.
 During weathering of rocks by acids produced by
micro organisms and roots of higher plants.
 Phosphorus cycle – It is an example of
sedimentary cycles
 Significance-Phosphorus is the component of
energy compounds like ATP, phospholipids of
cellular membranes, bones, teeth and nucleic acids.
 Phosphorus utilization-Reservoir pool of
phosphorus is phosphate rocks which contain
phosphate in combination with calcium and iron.
The chemical weathering and erosion of phosphate
rocks add the phosphate compounds into the soil.
The plants absorb orthophosphate from the soil
through their root system and utilize them in their
metabolism. But a large part of phosphorus is lost to
sea through fresh water bodies where most of it is
lost by physical abortion and sedimentation. But a

part of this phosphate (only 0.5%) is added to the
soil mainly thorough sea birds.
 Phosphorus production-
 During decomposition of dead bodies of plants and
animals.
 Phosphate fertilizers added to the soil to increase the
soil fertility.
 Excreta of marine birds, called guana, contain large
amount of phosphorus` .
BALANCE IN NATURE
The food chains, energy flow and material or nutrient
cycling are continuously going on all around us. In a
forest, large number of plants grows. These plants are the
sources of food and shelter for animals. There live the
herbivores, carnivores and omnivores in the forests. The
herbivores are produced in a large numbers. The
carnivores and omnivores are produced in lesser
numbers. So herbivores, which are the food for the rest,
survive even after they are consumed in large numbers.
Thus “The Balance in Nature” remains unaffected.
If a link in this food chain is broken, then all the animals
will have to die. If we decide to eliminate sparrows from
our area by killing them one by one. Then the result of
this action will be very harmful. We know that the crops
are destroyed by insects. These insects become food of
sparrows. When sparrows are killed, the insects will be
on the rampage and the crops will be destroyed. And so
this will affect the human beings and animals and this

lead to their death. By this example we come to know
that:
 Destroying any part of the food chain would disturb the
balance in nature.
 All forms of life not only depend upon one another, but
also keep a check on all others.
The whole process results in a balance, which exists in
nature. This is called the Balance in Nature.
CAUSES OF DESTRUCTION OF
ECOSYSTEM
Destruction of ecosystem is caused by interplay of many
contributing factors:-
1) Changing pattern of land use: - Land is the basic natural
resource which provides nourishment to the entire
human population. There is changing pattern of land
use in both the urban and rural areas. Urban land
misuse is one of today’s most severe environmental
concern due to which there is urban sprawl. In this trend,
major cities get surrounded by wide rings of suburb
where squatter built makeshift shelters on the unused
land. These suburbs generally lack the basic facilities of
water supply, drainage, roads, transport, etc and
generally transforms into slums. Now residential
colonies are being built at the cost of agriculture in the
plains and forests in hilly areas these human activities
causes land-degradation and desertification.
Deforestation also causes loss of habitat of various
animals and unfavorable change in the climate in the
climate which increases their enhance of extinction

2) Population growth:- Presently worlds human populations
more than 6 billion and is increasing at the rate of 70
million per year. Such a large growth rate of human
population is called population explosion. India has
15.6%of the world population through it has only
2.42%of total land area of the world. In India about 60
million people added every year. Overpopulation
causes many socio-economic problem like increase
unemployment, increased industrialization, decreased
availability of natural resources and basic needs of life,
increased unhygienic condition, eco-degradation etc. So
population pressure is a trade to nations well being
and to its environment
3) Urbanization: - uncontrolled rise in human population
forces a large number of rural people to migrate to
towns and cities, called urbanization. Main reasons for
urbanization are- better facilities for employment,
education and medical-aid, most important being
increased chances of employment. Some of the major
problems associated with urbanization are-poor
sanitation, improper municipal solid waste management
or garbage disposal, decreased space for parks, green
belts and payments, slum development etc. Other
serious psychological health problems are depression,
alcohol and drugs abuse, suicide etc.
.
4) Migration-It involves the movement of people from an
area with scarce resources to another area with plenty
of resources. It is of two types:-
a. Emigration in which the people move out of an area.
b. Immigration in which the people enter a new area.

Human population is called an open population in
which individuals undergo both immigration and
emigration. Migration decreases the population size and
density in an area of emigration while increases the
population size and density in the area of immigration.
Due to migration, the population ratio of different
countries has changed.
5) Industrialization- To meet the increasing needs of rapidly
growing human population, there was rapid increase in
the number of industries which started about 1600AD
called industrial revolution. Though industrialization has
made many positive contributions in the economic
growth of a country but the industrial wastes released in
the forms of gaseous or particulate form in the air or
liquid effluents in the water bodies or as solid wastes in
the soil are responsible for many adverse health effects.
Industrial effluents are the largest sources of water
pollution. The industrial air pollutants causes
environmental degradation and are responsible for
respiratory disease like bronchitis, emphysema, asthma
etc. the solid wastes of paper, cement, sugar textile,
pesticides add solid wastes in the soil and causes soil
pollution. A number of industrial accidents (eg. Bhopal
gas tragedy of dec 1984) and nuclear accidents killed
large number of human being.
6) Shifting cultivation-it is a unique farming system
followed in certain tropical area where the soil is
exhausted after continued cultivation of crops. In India
this practice is followed more commonly in jhum
forests of north-east. In this farming system forest land
is cleared by falling trees and burning of trunks and

branches. After the land is cleared crops are grown for
2-3 years then the land is abundant as their fertility of
soil decreases. The farmers then move into new areas
and the process is repeated. This can lead to
degradation.
7) Construction of large dams:- Big river valley projects like
hirakud dam (Orissa), Bhakra nagal dam(Punjab), Tehri
dam (Uttaranchal), Sardar sarovar project(Gujarat) have
caused large scale destruction of ecosystem and
displacement of local people. It is estimated that during
the last 50 years, these dams have displaced more than
20 million people similarly, construction of Aswan dam
in Egypt has decreased the fish harvesting by about two
thirds
8) Mining:-Mining is the process of extraction of various ores
from the earth’s crust and produces large amount of
debris, causes loss of habitats and causes the
displacement of native people. It is so due to accidents
occurring in the mined area like subsidence of land that
often leads to shifting of people example jharia coal
fields of Jharkhand, there is a big problem to the local
residents due to underground fires which necessitates
the large scale evacuation of about 0.3 million
population of jharia community which would require
about 18000 crores while the cost for extinguish the fire
would be around 8000 crores.
IMPACT OF ECOSYSTEM DESTURCTION
Ecosystem destruction adversely affects the people
of the developed as well as developing countries but the
persons who are most seriously affected by

environmental degradation in India are the poor. They
are the first victims of poor sanitation, bad air, and
contaminated water and scare natural resources. Some of
ill effects of environmental degradation are the
following:-
i. Loss of habitat:-
The entire tribal population and millions of other forests
dwelling people depend on the forests for their very
existence. Destruction of forests for various non-forestry
activities like housing, agriculture, etc has caused the
social cultural and economic destruction of the tribal
population in particular. The important cause of loss of
habitat is environmental pollution especially green house
effect due to increasing load of GHG’s environmental
pollution is also responsible for increased extinction of
many species of flora and fauna. Other causes of habitat
destruction are construction of river projects, minig etc.
which cause displacement of local community which in
turn, causes loss of land, job food, increased mortality
and social isolation of the tribal.
ii. Stress on natural resources:-
Natural resources include both renewable and non-
renewable resources of nature. By the end of 19th
century, about 80% of India’s natural resources were
common property resources is greatest in the tribal area,
less in rural area and least in urban areas. Increasing
human population associated with increased human
needs and human activities have exerted tremendous
stress on our heading towards depletion and man may
find himself incapable to find their substitute. There is

ever increasing human dependency upon the natural
resources for energy, building material, water, land
forests etc. there is also persistent misuse of land and
water resources which has also decreased the soil
rejuvenation capacity and ground water recharge
capacity.
Similarly there is net loss of forests cover which offers
natural habitats for other biological resources and also
has ecological, meteorological and environmental
importance. In 1997, India’s forests cover was less than
18% then the required 30% for ecological stability. Due
to land abuse, it is estimated that about 60% of the
world’s agricultural land is being afflicted with
desertification. According to a UN estimated, if the
deforestation continued at the same pace, then by 2010,
about two-thirds of landmass may be desertification.
CONSERVATION OF ECOSYSTEM
Ecosystem refers to both abiotic and biotic
components and involves the interrelationship between
air, water and land including the human beings a stable
ecosystem is a necessity for the survival and
maintenance of life in an area. It provides us many
essential goods like energy, water air, food etc to
support. Destruction of ecosystem has many adverse
effects on sustainable development. So it is the
fundamental duty of every citizen to converse our
ecosystem so that we may enjoy our fundamental rights of
healthy environment.
Conservation is the management of the bio-sphere
in such a way that it may field the greatest sustainable

benefit to present generation while maintaining its
potential to meet the needs and aspiration of future
generations. Conservation has three objectives:-
 To maintain essential ecological process and life
supporting system.
 To pressure the biodiversity and ecological balance in
the ecosystem.
 To ensure continuous use of species.
This can be achieved by:-
1) Population stabilization: - As the land and other non
renewable resources are finite and there is an upper limit
to the capacity of the landmass and resources which
shrink as the population increases, so the population
must be stabilized. The future population growth should be
related to the resources base in order to have sustainable
development. Zero population growth holds the key to
well being and prosperity of nation. It can be achieved
through public awareness by environmental education
programmes, increasing the marriage, sincere
implementation of family planning programmes,
increased use of contraceptives etc.
2) Control in air pollution: - control of air pollution by using
lead free and sulphur fuel in the automobiles, installation of
catalytic converters in the automobiles, afforestation and
reforestation programmes, increased use of non-
combustible sources of energy etc. these are some of the
methods to control air pollution which is causing the
destruction of ecosystem.

3) Control of water pollution: - This is also another type of
pollution which causes destruction of ecosystem. Control of
water pollution can be done by treating the industrial and
sewage waste water in effluent treatment plants (ETPS) before
their discharge in water bodies, judicious use of pesticides
and fertilizers etc.
4) Proper land use: - land forms a basic site of number of
human activities like agriculture, forestry, grasslands, urban
and industrial development, transport etc and is one of the
important components of life support systems. So there is
an urgent need of integrated land use planning. Present
croplands and grasslands must be kept in healthy condition
otherwise pressure would be built for additional croplands
which will be possible only at the cost of forests or many
nomadic groups in the country when their grazing land will
be transformed into agricultural land. Sufficient space
should provided for waste treatment plants, oxidation
ponds, land fills and other means of degrading or recycling
wastes and water are some of the method that will help in
proper land use.
5) Conservation of natural resources: - conservation of natural
resources to avoid their scarcity. Conservation involves the
management in such a way that a balanced cycle is
maintained between their harvest and renewal. It usually
lies into mantras of
3- R approach which demands-
 Reduction in the use of raw materials.
 Reuse of waste material.

 Recycling of materials.
CONCLUSION
Ecosystem is very important in our life, without it we
cannot live. Ecosystem is a natural unit which consists of
many biotic and abiotic factors. Since we know that
population is growing day by day so it affects the
ecosystem directly or indirectly. It also gives birth to many
other problems like overuse of resource that may cause the
exploitation of resource, water pollution, air pollution, land
degradation and many other factors that affects the
ecosystem. All this affect the ecosystem and lead to the
destruction of ecosystem. And so we should try to control
population growth which is the root cause of these
problems which will help in the conservation of the
ecosystem. So conservation of ecosystem is very important
because “ECOSYSTEM IS VERY IMPORTANT FACTOR IN OUR LIFE”.
REFERENCE
 Holy Faith Environmental Education – IX
 S.Chand - X

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