ENVIRONMENTAL SCIENCE

Multidisciplinary Nature of EVS

1. Environment
The surrounding in which all the living( plants, animal etc.) and non-living things( air, water, land
etc) are inter related through physical, chemical or biological means, is called as environment.

2. What is environmental studies?

Environmental studies related with every issues that affect living organism. It is an applied
science with multi disciplinary approach that finds how human civilization sustainable on the
limited natural resources.

3. SCOPE

Environmental studies is an integration of several subjects like biology, chemistry, physics,

geography, economics sociology etc, that help us to understand different environmental issues.
The scope of environmental studies is extremely wide that covers every major disciplines.
i. The living being with their surrounding create the environment and they all are
dependent on other for producing food using natural resources. In this way the web of
life is formed and to maintain it we have to keep natural system intact.
ii. Environment studies create awareness among the people to know about various
renewable and non-renewable resources of a region . This knowledge helps to balance
of uses such resources.
iii. It provides the knowledge about ecological system, causes, effects and relationship
between these components.
iv. It provides necessary information about biodiversity richness and the danger of
degradation of different species.
v. The study makes to understand the causes and the effects of manmade environmental
disaster, pollution and minimise their effects.
vi. The study enables citizens to protect and improvements of their surroundings .
vii. This study identify and develop eco-friendly skills and technology to various
environmental issues.
viii. The study enables theoretical knowledge into practical environmental issues.

4. Importance

In the earth natural resources are limited. Water, soil, product from forest, ocean,rivers,
agriculture , livestock are all part of our life support systems. Human population keep increasing
 so the increase in use of resources though the earth resources are fixed. The overuse and
misuse of resources with a large waste product and pollution lead to threat to the quality of life
for all. This situation only improve if all will taking care of preserving natural resources. There is
also direct and indirect values of environmental ecosystem.( see fig. 1.1 of book).

5. Need for public awareness

• As the earth’s natural resources are rapidly dwindling and our environment is being degraded by
human activities, it is evident that something needs to be done.

• It’s not only government job to think about these issues. Its responsibility of every individual.

• Public awareness is best way to mitigate the effect of environmental issues.

Activity we can do for public awareness

• Organize some cultural event on some specific day (days related to environmental issues) like
play, nuked, etc to aware the people.

• We can also take help of mass media such as radio television, newspapers to strongly influence
the public opinion.

• We can join several NGO which is working towards environmental protection in our country.

• Practice and promote good civic sense and hygiene such as enforcing no spiting or tobacco
chewing, no throwing garbage on road, no smoking in public.

• Join local movements that support activity like saving tree, recycle waste, buy environment
friendly product.

6. WELL KNOWN ENVIRONMENTAL THINKER (write their important work from book)
 Indira Gandhi
 Darwin
 Salim Ali
 Medha patkar (Narmada bachao andolan)

 Sunderlal bahuguna (Chipko movement)

 Narendra modi (Clean India campaign )

 Madhav gadgil (Well known ecologist)

 M swaminathan

7. Institution of Environment and their basic functions . (write their important function
from book)
  Bombay natural history society(BHNS): Important NGO based research organization
that influences conservation policy such as wild life policy , law building in India. There
campaign is save the silent valley.

 Ministry of environment and forest

 Botanical survey of India(BSI)

 Central pollution control board(CPCB)

 Bharatiya Vidyapeeth institute of environmental education and research

 Centre for science and environment(CSE) ,New Delhi

 Zoological survey of India(ZSI)

 Wildlife institute of India (WII),Dehradun

****************************** MULTIDICIPLINARY NATURE of EVS and

NEED FOR PUBLIC AWARENESS CHEK FROM CLASS NOTE****************
 NATURAL RESOURCES

The environment provides various goods and services that is necessary for sustain in the earth.
These are called as natural resources which includes abiotic part like water, soil, air, solar energy
along with the biotic part like plants, animals, microbes etc. All the living being only survive in
the communities of different organism with a suitable surrounding is called as habitat. The
interaction between the abiotic component of nature with the specific living component of any
particular habitat forms the ecosystem. Basically the living organism forming ecosystem
depending on food resources.

1. EARTH RESOURSES
Human depends on various resources which are provided by various sources or spheres.
The different spheres are atmosphere, hydrosphere, lithosphere, biosphere.

Atmosphere: It is the lowest layer of troposphere, composed of various gases like oxygen,
nitrogen, carbondioxide, water vapour etc., keep the earth surface warm to survive for living
being, providing oxygen for respiration,

HYDRO SPHERE : It is the water bodies on the earth, two types of water bodies are marine
water and fresh water.

LITHOSPHERE : It is the land or soil resource of earth, give facility for agriculture and food
resource.

BIOSPHERE: All the living being on the earth such as plants and animals.

2. Classification of resources
• Renewable resources
A renewable resource is a natural resource which can be regenerated after use such as forest ,water,
soil, grass land etc.. Solar energy is the main driving force for ecological system responsible for growth of
plants as well as existence of animals. These resources renewable until certain limit of use.

• Non renewable resources

A non renewable resource is a natural resources that takes millions of years to regenerate and is
therefore irreplaceable after consumption, such as coal, fossil fuel, mineral etc.

Some important natural resource

 Forest resources
 Water
 Mineral
 Energy
 Land
Forest Resource
Forest is the important renewable resource which directly or indirectly providing lives and livelihood to
all biotic components on the earth.

Utilization of Forest resources

• Local use : Food for animals, Fodder for cattle, Fuelwood for cooking, Timber for construction,
Sericulture for silk, Medicinal plants for medicine, Apiculture of bees for honeys

• Water and watershed and soil conservation : Present surface run-off water, Preventing soil and
flash flood, Preventing drought, Maintaining water retention of soil

Controlling Air pollution: Producing oxygen or clean air to the environment and absorbing
carbon di oxide.

• Temperature Regulation: Absorption of solar heat and make the environment cool by
evaporation and transpiration, maintain carbon di oxide level for plant growth and controlling
global warming,

• Market Value : Timber extraction for construction, industrial uses, homes furniture, making
paper, Source of income by selling fuel wood, gum, fibre, cotton, some medicine which comes
directly from forests.

• Biodiversity maintain : Forest serves as a biodiversity reserve and gene reserve for a variety of
species which is very vital resource for maintain balance in ecosystem and supporting new
economic varieties in agriculture , horticulture, veterinary and medical fields.

• Forrest regulates earth’s temperature variations, controlling rainfall occurrences, regulates

stream flows, CO2 –O2 balance, nutrient and water cycles on the earth.

• Conservation of soil : Forest prevent the soil erosion by bind the soil particle with the network of
roots of different plants and protect the soil from the harsh effect of wind and rain.

Deforestation and degradation – threats to forest

• Deforestation refers to removal of plants from the forest. Deforestation involves a loss in area
covered by forests degradation on other hand refers to condition of forest involving in reduction
in its quality. Scientists estimate that India should ideally have 33% of its land under forest
cover. Today we only have about 12%. Thus we need to not protect only our existing forest but
also increase our forest cover.

Causes of deforestation
• One or more component such as soil ,vegetation of a forest affected thereby impacting the
overall functioning of forest ecosystem.

• The expansion of agriculture land, rapid industrialisation urbanisation, illegal logging and mining
are serious causes of loss and degradation of forest in India and all over world .
 • Commercial agriculture, to cater the high population only several plants are farming for food
production..

• Cattle ranching and livestock grazing.

• Mining and fossil fuel extraction.

• Infrastructure development, urbanization.

Effects / Consequences of Deforestation

It is a threat to biodiversity due to loss of natural habitat of different plants and animals.

Hydrological cycle and atmospheric conditions drastically affected.

Increase rate of global warming as well as climate change.

Induces chance of land slide.

Enhance soil erosion and flood.

Economic loss, aesthetic loss.

Prevention from deforestation

Expansion of forest area by implanting trees in the forest with people’s participation.

Increase public awareness through different social activity such as celebrating environment day to make
them understand the importance of aforestation and bad impact of deforestation.

Encourage people for recycle and reuse of forest product.

Use alternate source of energy instead of wood.

Effect of Mining and Dams on forest and Tribal people

Mining is the extraction of valuable minerals or other geological materials from the earth crust usually as
a form of ore which are generally covered by dense forest on the earth surface.

The adverse effect of mining on forest :

Vast areas of forest are directly cleared to accommodate mining sites, construction roads, processing
industry and township for workers.

Forest land is also used to store the waste raw materials after extraction of usable resourece.

Mining also responsible for soil erosion as a result fertile land destroyed and forest get degraded.

Pollution of nearby water, soil and air due to mining are directly harming the habitat of forest and
resident tribal people.
Effect of Dam

A Dam is constructed across a river which requires a huge artificial lake in attachment to the dam. This
lake are building with great compromise of forest area which creates some harmful effect on the
environment. Dams built for hydroelectric power or irrigation have submerged large tracts of forest a
and have displaced tribal people whose lives are closely knit to the forest .

A large forest area become submerged under the backwater from the dam. The great loss of forest leads
to habitat loss for resident wildlife as well as biodiversity loss.

As the fertile land get degraded , then cultivation process affected as a result food and fodder
production disrupted for tribal people.

Water logging and canal irrigation are creating salinity in the nearby land which decreasing the soil
fertility severely.

Water resources
Water cycle: READ FROM BOOK : PG 26

Use and over utilization of water

 All aquatic system is used by large no of people for their daily needs such as drinking water
washing, cooking, watering animal and irrigating field.

 However the world depends upon limited quantity of fresh water. Water covers 70% of the
earth surface but only 3% percent of it is fresh water.

 At global level 70% of the water is used for agriculture, about 22% for industry and only 8% for
domestic purposes .however this varies for different country .India use 87% of water for
agriculture, 8% for industry and 5% for domestic purposes.

 Over utilization of water is going to lead a severe shortage of water in coming future .however
more than one billion people worldwide have no access of water and many more water supply
are unreliable .

Conflict over water

• One of greatest challenges facing the world this century is the need of rethink of overall
management of water resources.

• India is expected to face critical level of water stress by 2025.At global level, 31 countries are
already short of water of water and by 2025 there will be 48 countries.

• Currently more than 1 billion people worldwide have no access of clean water, and many more,
water supply are unreliable.
 • UN estimated that by the year 2050, 4 billion people will be seriously affected by water shortage
.this will lead multiple conflict between countries over sharing of water.

Ground Water

Surface water and rain water precipitation infiltrates the ground and fills the pores in soil and rock.
Under the surface of the earth behind the soil and rock spaces an area is filled with water. This water
filled area is called as ground water.

Surface Water

Water precipitation that does neither soak into the ground nor evaporate to the atmosphere is called
surface water. It forms streams, lakes, wetlands and artificial reservoir.

Dams- Their benefits and problems

Dams are the construction, built across the river to hold extra water during rain and use the stored
water for supply throughout the year for irrigation, generating hydroelectric power and flood control.

Managing a river system is best done by leaving its course undisturbed .Dams and canal lead to major
flood during the monsoons and drainage of wetland seriously affect the area that get flooded when
there is high rainfall.

Today there are more than 45000 large dams around the world, which plays an important role in
communities and their economic development.

Current estimates show that about 30-40% of the irrigated land worldwide relies on dam.

Hydropower supplies 19% of world total electric power supply and used in more than 150 countries.

Benefits

Dam is storing water during rain which can control flood.

Dam can supply water for irrigation and domestic use throughout the year.

Dams are built for generating hydro electric power.

Navigation and fishery can be developed in the dam area.

Problems caused by dams

• The fragmentation and physical transformation of rivers.

• Serious impact on riverside ecosystems.

• Social consequences of large dams due to displacement of people.

• Water logging of the surrounding lands.

• Dislodging of animal population, damaging their habitat.

 • Managing a river system is best done by leaving its course undisturbed .Dams and canal lead to
major flood during the monsoons and drainage of wetland seriously affect the area that get
flooded when there is high rainfall.

• Currently there are more than 45000 large dams around the world, which plays an important
role in communities and their economic development.

Flood

• It is caused in low lying areas witnessing heavy rainfall during the monsoons.

• It is causes widespread destruction of life and property.

• Besides the natural causes of that being heavy rainfall, sometimes they are also caused due to
man-made causes such as breakdown of storage capacity of the dams.

• A flood normally results when heavy rainfall causes submergence of low-lying areas or the areas
that are ill equipped to handle large scale volume of water and drainage systems.

• India since times immemorial has witnessed/witnesses large scale floods every year. Some of
the recent examples of the floods can be seen from the Mumbai floods of 2006. Every year
North Bihar also experiences widespread floods every year.

Drought

• In the recent years widespread drought and rainfall is caused by the El-Nino effect

• Drought results in cracking of soil, thus symbolising insufficient water penetration in the soil,
causing destruction of the crop cultivation.

• In order to encounter drought, food storage capacity and refrigeration facilities need to be
improved upon.

• Solutions like rainwater harvesting can be used to encounter drought in areas experiencing
insufficient rainfall.

• In order to save farm lands from drought and its side effects, crops requiring less water can be
looked into and cultivated.

• Drought is caused by widespread deforestation. An example is that of cherrapunji, which at one

time experienced rainfall throughout the year but now hardly witnesses any, due to
deforestation.
Mineral resources
• A mineral is naturally occurring substance of definite chemical composition and identifiable
physical properties .an ore is a mineral combination of mineral from which a useful substance,
such as metal can be extracted and used to manufacture useful products.

Utilisation of mineral resources

• For working in our day-to-day life, minerals come handy for a lot of purposes. Some of them are
discussed as follows:

• Iron, aluminium, zinc, manganese and copper are important row material for industrial use.

• Important non metallic resources include coal, salt, clay, cement and silica is used for various
purposes.

• Stone used for building material such as granite, marble and limestone.

• Mineral with some special property is used for ornamental purposes like gold, silver, platinum,
diamond, emerald, rubies etc.

Environmental Problems during Mineral Extraction

• Mining is considered as environmentally hazardous.

• Mining results in landfills and water pollution affecting marine life.

• Industrial waste cause pollution of land, air and water, due to usage of non-renewable mineral
sources.

• Accidents like oil spills during oil extraction cause water pollution.

******* EXPLOTATION OF MINERAL RESOUCE is given in class note **********

Food resources
World food problem

• In many developing country where population are expanding rapidly ,the production of food is
unable to keep pace with the growing demand
 • Food production in 64 out of 105 countries is lagging behind their population growth level,these
countries are unable to produce more food ,or do not have the financial mean to import it

• India is one of the countries that has been produce enough food by cultivating a large
proportion of its arable land through irrigation. The green revolution of the 60s reduced the
starvation in the country

Effect of modern agriculture

• our fertile soil are being exploited faster than they can recuperate

• Forest ,grassland and wetland have been put to agricultural use, which has led to serious
ecological consequences

• Our fish resources both marine and inland , show evidence of exhaustion

• There is great disparity in the availability of nutritious food ,

Problem due to Fertilizer and pesticide

• Excessive use of fertilizer leads degradation fertile capability of land

Energy resources
Energy is available on the earth in a number of forms and some forms may be use immediately while
others require some transformations. It is difficult to imagine life without energy. All the developmental
activities in the world are directly or indirectly depend on energy. Energy production and utilization are
the key index of development of any country.

Growing energy need

• Energy has always been closely linked to man’s economic growth and development .The
present strategies for development ,focussed on rapid growth to achieve rapid growth the
energy demand also increases rapidly

• In now days per capita energy consumption is one of the major parameter of economic
development and living standard of any country or society

• Between 1950 to 1990, the world’s energy need increased four fold. The world’s demand of
electricity doubled over last 22 year

• The world’s total primary energy consumption in 2000 was 9096 million tons of oil ;a global
average per capita that works out to be 1.5 tons of oil.

• Electricity is at present fastest growing form energy world wide

What is energy and use of energy?

Energy is the capacity for doing any work. Energy can be present in everywhere, such as in livestock as
chemical energy, from sun as heat or light energy, for moving object as mechanical energy or electrical
energy etc.
Energy or specifically electrical energy generation and application is the primary unit in industrial or
household application. It is the main driving force of different sectors such as commerce, transport,
telecommunication etc.

ENERGY RESOUCE

According to the law of conservation one energy form can be converted to other form. Currently most of
the machineries are run by the electrical energy. It is the target to produce any form of energy into
electrical energy. According to the various source of energy, it broadly classified into renewable and non
renewable energy resources.

Renewable/ Alternate energy sources

Renewable energy resources are the natural resources from which basically electrical energy can be
generated again and again as when required. These energy resource are cleanest and safest for energy
production.

• Hydroelectric power

• Solar energy

Solar energy is used commonly for heating, cooking and electricity production. For solar cooker
and water heater concave mirror is used to trap solar energy for heating purpose. For
generation of electricity and light photo voltaic solar cells are used to convert solar energy into
electricity.

Advantage : i) Solar energy is a renewable resource, therefore no risk of depletion of source.

ii) Solar power generation not causing air or water pollution.

iii) Can be efficiently used for heating , lighting and energy generation cost is very less.

Disadvantage: i) Energy is available only in the day time. Energy generation is not stable as it
depending on sun light which may be affected by weather conditions.

ii) Solar power generation station is expensive and very skilful scientific knowledge is required.

• Biomass energy

• Tidal energy

• Wind energy

Wind energy harness the power of the wind energy to propel the blades of wind turbines which
can generate electrical energy through a generator. Wind energy can be directly used in wind
mill to rotate the milling wheel.

Advantages: i) It can produce energy throughout the year.

ii) Available at day and night

iii) Eco-friendly, non-polluting, renewable less cost.

 Disadvantage: constant wind flow is required always and generated energy is less.

• Geothermal energy

Geothermal means heat of the earth. The energy is harnessed from the heat energy present in
molten rock under the earth surface. This energy is used to produce steam to generate electrical
energy using steam turbine.

It is a renewable resource of energy and does not produce any polluting components to the
environment. This energy mainly used in power production, space heating industrial processing,
green house maintaining etc.

This energy production is very much prone to attach risk factors. The improper drilling into the
earth can release hazardous minerals and gas.

• Bio gas energy

Use of alternate energy sources

• Conventional energy sources affects nature and humane society in different ways. India needs
to rapidly move towards a policy to reduce the use of conventional energy source and focus on
cleaner energy production .

• A shift to alternative energy use and renewable energy sources that are used judiciously and
equitably would bring about environmentally friendly and sustainable life style . This will reduce
India’s dependency on imported oil.

• This can achieved by small hydrogenation units, enhancing fuel wood plantation, using energy
efficient cooking stoves and other devices ,using solar irrigation, using public transport and
bicycle ,more focus on biomass and biogas energy for rural area.

Non renewable energy

• Coal(55%)

• Oil (31%)

• Natural gas(8%)

• Nuclear fuel (1%)

Land resources
 • Landform like hills ,valleys, plains, river basins and wetland include different resources
generating area that the people living in them depend on it .

• If land is utilised carefully ,it can be utilised as a renewable resources and its also can be
converted into non-renewable resource when highly toxic industrial and nuclear waste is
dumped on it.

• Land on earth is as finite as any other natural resources so proper utilisation of land is very
much important .we need land for building homes, cultivating food ,developing industries.
Equally importantly, humans need to protect forest, grasslands, wetland, mountain coasts to
protect our critically valuable biodiversity.

Land degradation

• Farmland is under treat due to more and more intense utilisation . Every year ,between 5-7 mha
of land worldwide is added to existing degraded farmland .

• When soil is used for more intense farming ,it is eroded more rapidly by wind and rain .

• Over-irrigating farmland leads to salination as the evaporation of water brings the salt to the
surface of soil on which crops can not grow . Over irrigation also creates water logging of the
topsoil ,so that crop roots are affected and the crop deteriorates .

• The use of more and more chemical fertilisers poisons the soil and eventually the land becomes
unproductive .

Ecosystem
What is ecosystem?

 An ecosystem is the interactive relation between the all living organisms or biotic components
such as plant and animal, and the non living ,or abiotic component such as air, soil, water and
sun light, in a particular area .

 The ecosystem functions through several biogeochemical cycles and energy transfer
mechanism. The various biotic components forming different food chains through which energy
from sun passing to different living organism. All the food chains joined together form web of
life.

Classification

Ecosystem basically consists two factor

a. Biotic factor : living part of ecosystem is referred as the biotic component

b. Abiotic factor :non living part of ecosystem is characterised as a biotic factor

Biotic factor

a) Primary producer

b) Herbivorous

c) Carnivorous

d) Omnivorous

e) Detrivorous

A biotic factor

a) Sunlight

b) Temperature

c) Water or moisture

d) Soil or chemical content

e) Climatic condition

Structure aspects of ecosystem

 This refers to all the elements that make up an ecosystem –the individuals and communities of
plants and animals as well as the non living natural resources present in the ecosystem

a) Inorganic compounds – C, N,CO2 ,H2O

b) Organic compounds –proteins, carbohydrates, lipids, which link abiotic to biotic aspects
c) Climate regimes –temperature ,moisture ,light and topography
d) Producers –plants
e) Macro consumers –photographs that is large animals
f) Micro consumers- saprotrophs that is absorbers like fungi

 Functional aspects of ecosystems

 Energy cycles

 Food chains

 Diversity –interlinks between organisms

 Nutrient cycles –biogeochemical cycles

 Evolution

Producers, consumers, decomposers

  Plants are the producers in the ecosystem, as they manufacture their food by using energy from
the sun. In forests these forms community of plant. In the sea these forms tiny algal forms large
seaweed

 The herbivorous animals are primary consumers, as they live on producers. In a forest these are
the insects, amphibians, reptile’s bird and mammals. The herbivorous animal includes for
example, the hare, deer and elephant that live on plant life.

 At high tropic level, there are carnivorous animals, or secondary consumers, which live on the
herbivores .in our forests; the carnivorous are tigers, leopards, jackals, foxes and small wild cats.

 Decomposers or derivers are a group of organisms consisting of small animals such as worms,
insects, bacteria and fungi which break down dead organic material into simpler substances that
are used by plants as nutrition. Thus decomposition is a vital function of nature, as without
this ,all the nutrients would be tied up in dead matter and no new life would be produced

Energy flow in ecosystem

 Every ecosystem has several interrelated mechanism that affects human life. These are water
cycle , carbon cycle , oxygen cycle and energy cycle .while every ecosystem is controlled by these
cycles

 All the function of ecosystem is in some way related to growth and regeneration of plant and
animal species. These interlinked process can be depicted as various cycle; all these process
depends on energy from sunlight. During the photosynthesis , carbon dioxide is absorbed by plant
and oxygen is released into the atmosphere . Animal depends on these oxygen for their
respiration . the energy cycle nutrients into soil on which plant life grows. Our own lives are
closely linked to proper functioning of these cycles of life. If human activities go on altering them ,
humanity cannot survive on earth.

Ecological succession

 Ecological succession is process through which ecosystems tend to change over a period of time.
Succession can be related to seasonal environmental changes, which creates changes in the
community of plants and animals living in the ecosystem.
 Other succession events may take much longer periods of time, extending to several decades .if a
forest is cleared, it is initially colonised by a certain group of species of plants and animals, which
gradually change through an orderly process of community development.
 The most frequent example of succession changes occur in pond ecosystem ,where fluctuates
from a dry terrestrial habitat to early colonisation stage by small aquatic species after the
monsoon

Dynamics of Ecosystem

 The various components of the ecosystem constitute an interacting system. They are connected
by energy, nutrients and minerals. The nutrients and minerals circulate and recirculate between
 the abiotic and biotic factors of the ecosystem several times. Whereas, the flow of energy is one
way, once used by the ecosystem, it is lost. Thus the continuous survival of the ecosystem
depends on the flow of energy and the circulation of nutrients and minerals in the ecosystem.

 Thus the dynamics (functions) of the ecosystem includes the following.

1. Energy

2. Primary production

3. Secondary production

4. Food chain

5. Trophic levels

6. Food web

7. Energy flow

8. Ecological pyramids

9. Biogeochemical cycles

1. Energy

a) Energy is the ability to do work.

b) The main source of energy for an ecosystem is the radiant energy or light energy derived from
the sun.
c) This light energy is converted into chemical energy in the form of sugar by plants by the
process of photosynthesis. Plants utilize only 0.02% of Sun’s light energy reaching the earth.
d) 6CO2 + 6H2O (+ sunlight & chlorophyll) àC6H12O6 + 6O2 (+673cal)
e) Plants use most of the energy they make for themselves. Consumers get their energy from the
plants (producers).
2. Primary production
a) The amount of light energy converted to chemical energy by plants during a given period of
time per unit area is called primary productivity.
3. Secondary production
a) The energy that is not used by producers can be passed on to organisms that cannot make their
own energy. The producers are directly consumed by the herbivores that are eaten by the
primary carnivores that in turn are consumed by the secondary carnivores. The consumers store
some amount of energy in their tissues. This energy, stored by the consumers, is called
secondary production. Only about 10 to 20% of the primary production is converted into
secondary production.
4. Food chain
A food chain tells us what is eaten by what in an ecosystem and flow of energy from one living
organism to other.

Example of a food chain

  Many insects feed on nectar which they gather from flowers.
 The insect is eaten by the frog.
 The frog is eaten by the heron.
 What does this food chain show?
 The producers form the food for the herbivores. The herbivores form the food for the
carnivores. The sequence of the eaters being eaten is called food chain.
 Producers herbivores Carnivores
 The arrow means “is eaten by”.

 The insect is eaten by the frog.

5. Trophic level
Each food chain contains many steps like producers, herbivores, primary carnivores and so on.
Each step of the food chain is called tropic level. The number of tropic levels in a food chain is
always restricted to 4 or 5. But very often the chains are very much complicated with many tropic
levels.

First Tropic level 2nd Tropic level 3rd Tropic level

6. Food Webs:
a) In an ecosystem the various food chains are interconnected with each other to form a net
work called food web.
b) This is because each organism may obtain food from more than one tropic level. In other
words, one organism forms food for more than one organisms of the higher tropic level.
7. Energy flow
a) Solar energy is trapped by the green plants, and converted into chemical energy and stored as
carbohydrates. This happens during photosynthesis.
b) A part of this chemical energy is used up by the green plants themselves. The major portion of
the energy is consumed in the form of food by the consumers at different tropic level.
c) Thus there is energy flow through the biotic components in an ecosystem.
d) The transfer of energy from one tropic level to another tropic level is called energy flow.
e) -The flow of energy in an ecosystem is unidirectional. That is, it flows from the producer level to
the consumer level and never in the reverse direction. Hence the energy can be used only once
in the ecosystem.
f) But the minerals circulate and circulate many times in the ecosystem.
g) -A large amount of energy is lost at each tropic level. It is estimated that 80% to 90% of the
energy is lost when it is transferred from one tropic level to another.

8. Ecological Pyramids
a) The number, biomass, and energy of organisms gradually decrease from the producer to the
consumer level. This can be represented by a pyramid called ecological pyramid.
b) Ecological pyramid is the graphic representation of number, biomass, and energy of the
successive tropic levels of an ecosystem.
c) Types of ecological pyramids

1. The pyramid of number

2. The pyramid of biomass

3. The pyramid of energy.

The pyramid of number

The number of individuals at the tropic level decreases from the producer level to the consumer
level.

In any ecosystem the number of producers is far high. The number of herbivores is lesser than the
producers. Similarly, the numbers of carnivores is lesser than the herbivores.

Example: Pond ecosystem.

The number in a pond ecosystem decrease in the following order.

Phytoplankton Zooplankton Fishes Snakes.

The pyramid of biomass

a) Biomass: Biomass refers to the total weight of living matter per unit area.
b) In an ecosystem the biomass decreases from the producer level to the consumer level.

Pyramid of energy

a) The energy flows in an ecosystem from the producer level to the consumer level.
b) At each tropic level 80% to 90% of energy is lost. Hence the amount of energy decreases from
the producer level to the consumer level.
According to the 2nd Law of Thermodynamics, the energy is not transferred from one
object/organism to the next with 100% efficiency

 Some of the energy is lost to the environment

Energy Pyramid

 Energy Pyramid shows the amounts of energy that moves from one level to the next.

 Only about 10% of energy is transferred from one level to the next

 The other 90% is used by the organism to carry out its life processes or it is lost to the
environment

Forest Ecosystem
Forest are formed by a community of plants which is composed of various trees, shrubs, climbers ,
ground covers and flora. The different landscapes make different types of forest. Each forest is the
habitat of a specific community of animals.
  Forest ecosystem has two parts
(i) The non living or abiotic aspect : The type of forest depend on the abiotic
conditions, such as landscape like mountains, river valleys , soil, rainfall,
surrounding temperature, latitude, altitude etc.
(ii) The living or biotic aspect : The plants and animals are living on the specific forest,
from large macrophytes to microscopic plants and animals therefore a highly
diverse population.

 Stability of ecosystem in forest is essential as plant and animal species and also the human
being are closely depend on each other , directly for food or indirectly for services.

Types of Forest

 Tropical evergreen forest

 Tropical deciduous forest

 Temperate evergreen forest

 Temperate deciduous forest

 Taiga

Features of Forest Ecosystem

 Forest canopy

 Forest floor

 Forest soil

Function of forest ecosystem

 Watershed Protection

 Atmospheric regulation

 Soil Erosion Control

 Wind Erosion Control

Aquatic Ecosystem
 Low temperature and sunlight
 Soil and vegetation is submerged
 Flora and fauna had adapted
 Densely populated.
  Types of Aquatic ecosystem
 Ocean
 Wetland
Features of aquatic ecosystem

 Light and temperature

 Current
 Chemistry
 Competitive organism
Function of Aquatic Ecosystem

 Recycles nutrients
 Purify water
 Responsible for proper rainfall
 Attenuate floods

****** chk Hand written note *****

BIODIVERSITY

Biodiversity:

Biological diversity is a part of nature which includes genetic differences of different plants and animals
at different places and ecosystems, like locally, region , country and the world.

The word BIODIVERSITY Originates from the Greek word BIOS = LIFE And Latin word DIVERSITAS =
VARIETY or DIFFERENCE. The whole word BIO DIVERSITY generally therefore means: VARIETY OF LIFE.

The variety can be observed in three different levels

I. Genetic Diversity: It considers the differences of individual specific characteristics of

different plants and animals within the same species due to different gene
combinations.

• Adaptation to particular environmental conditions may weed out genetic variants that are not
successful.

• But populations benefit from some genetic diversity, so as to avoid inbreeding or disease
epidemics.

ii. Species Diversity : The no. of species of plant and animals presents in a region creates
species diversity. The area with very rich of species diversity is called hotspot.
 iii. Ecosystem Diversity : The all variety of plants and animals of a specific global or political region .
It can also classified as Community diversity, Habitat diversity, Landscape diversity.

Why is biodiversity important?

Everything that lives in an ecosystem is part of the web of life, including humans. Each species of
vegetation and each creature have a place on the earth and play a vital role in the circle of life. Plant,
animal, and insect species interact and depend upon one another for what each offers, such as food,
shelter, oxygen, soil and enrichment.
Maintaining a wide diversity of species in each ecosystem is necessary to preserve the web of life that
sustains all living things. In his 1992 best-seller, "The Diversity of Life," famed Harvard University
biologist Edward O. Wilson -- known as the "father of biodiversity," -- said, "It is reckless to suppose that
biodiversity can be diminished indefinitely without threatening humanity itself.

" Ecosystem diversity refers to the diversity of a place at the level of ecosystems. The term differs
from biodiversity, which refers to variation in species rather than ecosystems.

Species diversity is the effective number of different species that are represented in a collection of
individuals.

Genetic diversity, the level of biodiversity refers to the total number of genetic characteristics in the
genetic makeup of a species.

Biodiversity in India

i. India is known for its rich heritage of biodiversity.

ii. India is one of the 17 mega-diverse countries in the world.
iii. With only 2.4 % of the world’s area, India accounts for 7–8 % of the world’s recorded plant and
animal species.
iv. India’s ten biogeography zones possess an exemplary diversity of ecological habitats like alpine
forests, grasslands, wetlands, coastal and marine ecosystems, and desert ecosystems.
v. Amongst the existing biota, 91,307 species of animals of which 2,557 Protest, 12,470 general
invertebrates, 69,903 arthropods, 4,994 vertebrates, and 45,500 species of plants as well as
5,650 microbial species have been documented in its 10 bio-geographic regions.
vi. India has four out of thirty-four global biodiversity hotspots, which is an indicator of high degree
of endemism (of species) in India.
vii. About 5,150 plant species and 1,837 animal species are endemic to India.

viii. India’s biodiversity includes wild relatives of agricultural crops and domesticated animals.

Biogeographically classification of India

i. The cold mountainous ,snow covered trans Himalayan region of leach

 ii. The Himalayan ranges and valleys of Kashmir ,hibachi padres , uttarakhand,assam and other
north-eastern states

iii. The terrain, the lowland where the Himalayan rivers flow into plains

iv. The genetic and Brahmaputra plains

v. The that desert of Rajasthan

vi. The semi arid grassland region of the Deccan plateau , Gujarat, Maharashtra, Andhra
Pradesh ,Karnataka and Tamil nadir

vii. The northeaster state of India

viii. The western Ghats in Maharashtra ,Karnataka and Kerala

ix. The Andaman and microbar islands

x. The long western and eastern coastal belts with sandy beaches and forests

Value of biodiversity

Biodiversity provides a variety of environmental services from its species and ecosystems that are
essential at global regional and local levels. The important services provides by biodiversity are
production of oxygen, reduction of carbon di oxide, maintenance of water cycle , preserving
ecological processes etc. The preservation of biodiversity is important for survival of humans and
improving the quality of human life. The values of biodiversity can be categorizes as

 Consumptive Use Value : The various live stock directly used by human.
i. Timber , food, fuel wood, fodder, medicines consumes by local communities and
forest dwellers..
ii. Fisher folks consuming fish and edible aquatic animal and plants.

 Productive use value: this category comprised of marketable group.

i. Bio technologist uses bio rich areas to find better genetic plants and animals to
develop better livestock for farming and plantation.
ii. Pharmacist produces medicines from plants and of bio diversified natural forest
area.
iii. Genetic diversity enables scientists to develop better crop and animals through
careful research and breeding program.
  Social Values : Bio diversity is preserved by the different traditional societies that values as a
resources by consider different plants animals like tulsi, banyan, cow, snake are sacred.

 Ethical and moral values : this value related to conservation of biodiversity is based on
importance of protecting all form of life. Most religions believe that all form of life have the
right to exist on the earth.

 Aesthetic Value : Biodiversity is a beautiful and wonderful aspect of nature, which can
enhance human imagination, creativity, knowledge, mental peace of mind also can promote
eco tourism.

 Option Value: It is keeping future possibilities open for their use as we do not knowing
future which species will be proven important for human.

BIODIVERSITY HOTSPOTS:

 A region with high biodiversity with most of spices being Endemic.

 India has basically three Biodiversity Hotspots- East Himalayan Region , Western Ghat, and
andman nicobar Iceland.

THREATS TO BIODIVERSITY

Increase in human population and their applied knowledge and skills using extensively natural
biodiversity for their purpose. The human activities destroys and depletes the basics of an ecosystem as
well as genetic and species diversity. The threat to biodiversity are mostly due to human activity and
some are the natural causes.

Natural causes:

 Narrow geographical area

 Low population

 Low breeding rate

 Natural disasters

Anthropogenic causes: ####### (meaning : environmental degradation by human activities)

 Habitat loss :

The loss of wild habitats, due to rapid human population growth and short term economic
benefit are the major reason of rapid global destruction of biodiversity. Man has begun to
 overuse and misuse of natural ecosystems, such as forest and grassland for agriculture and
residential purposes, mangroves cleared for fuel wood or prawn farming, wetlands converted to
agricultural lands and the biodiversity rich tropical forest and coral reefs are destroyed. This very
intense threat to biodiversity worldwide leads to millions of species loss.

 Human-wildlife conflicts:

The loss of species occurs due to destruction of natural ecosystems for conversion to agriculture
or industry or through pollution of air and water. Wild forest and grassland are deforested for
timber and agriculture which are replanted with single type of plants. This monoculture
plantation does not support the natural biodiversity of multi-storeyed natural forest with
undergrowth vegetations and not properly nourished soil. Due to loss of forest canopy, cattle
leaving and retard the regeneration of the forest, young seedling are constantly trampled.

 Overexploitation of selected species:

The increasing human population also occupying protected areas, degrades forest ecosystem
and reducing buffer zones of forest area. Repeated cultivation of same type of crops and fodder
as well as increase the growth of grass for grazing , ultimately reduces regeneration lower the
plants and related animal diversity.

 Introduction to exotic species:

The biodiversity adversely affected by the introduction of exotic weeds which are not a part of
natural vegetation. Like lantana grass imported to India, that weed grows in a large manner
which affect the growth of indigenous undergrowth species. The over harvesting of fish , using
large trawling boats is leading to serious depletion of fish stocks and turtles.

 Pollution

 Hunting / Poaching :

It is a specific threat to certain animals for the economic benefits. The skin and bones of tiger,
ivory of elephants, horns of rhinos, perfume and meat for deer, corals and shells are collected
by illegal hunting of such animals. The garden plants, various fern and mosses along with
medicinal plants are also collected illegally for economic purposes.

 Global warming and climate change

 Agriculture
EX-situ and IN-situ conservation chk from class note

Difference between EX-situ and IN-situ conservation

In-situ EX-situ
It is done in natural habitats of the biodiversity
It is done outside the natural habitat of
components. biodiversity components.
It is more dynamic It is more stable, less affected by environmental
changes.
It involves designation management and It involves sampling, transform and storing of
maintaining species in their natural habitat. species from their natural habitat.
Here conservation population remain within the In this conservation natural evolution process are
same ecosystem. Involving the process of not followed.
evolution.
This conservation is time consuming but This conservation method is aimed to use in
sustainable. conserving gentle components in immediate
occasion.

Endangered Species

It is a group of population of animals, plants or other organisms that is reducing very rapidly or
becoming extinct very soon because they are threaten by changing environmental conditions and they
are available in very few places on the earth.

Eg: rhinoceros, elephant, tiger etc

Endemic Species:

The endangered plants or animals which are exist in only one geographical area on the earth and they
are adversely threaten by any unsuitable environmental condition becoming extinct.

Eg. Lemurs of Madagascar, Nicober pigeon, fan throated lizard etc.

Diversity of subspecies

 Endangered golden lion tamarin, endemic to Brazil’s Atlantic rainforest, which has been almost
totally destroyed.
 Within species, diversity exists in subspecies, or geographic variations.
 The tiger, Panthera tigris, had 8 subspecies.
 5 persist today, including Panthera tigris altaica, the Siberian tiger.

Biodiversity loss and species extinction

• Extinction = last member of a species dies and the species vanishes forever from Earth

• Extirpation = disappearance of a particular population, but not the entire species globally
 • These are natural processes.

• On average one species goes extinct naturally every 500–1,000 years—this is the background
rate of extinction.

• 99% of all species that ever lived are now extinct.

Benefits of biodiversity: Basophilic

Basophilic = human love for and attachment to other living things; “the connections that human beings
subconsciously seek out with the rest of life”:

• Affinity for parks and wildlife

• Keeping of pets

• Valuing real estate with landscape views

• Interest in escaping cities to go hiking, birding, fishing, hunting, backpacking, etc.

Conservation biology

• Scientific discipline devoted to understanding the factors, forces, and processes that influence
the loss, protection, and restoration of biological diversity within and among ecosystems.

• Applied and goal-oriented: conservation biologists

intend to prevent extinction.

• This discipline arose in recent decades as biologists grew alarmed at the degradation of natural
systems they had spent their lives studying.

Conservation approaches: Captive breeding

• Many endangered species are being bred in zoos, to boost populations and reintroduce them
into the wild.

• This has worked so far for the California condor

(in photo, condor hand puppet feeds chick so it imprints on birds, not humans).

• But this is worthless if there is not adequate habitat left in the wild

Conservation approaches: Biodiversity hotspots

Biodiversity hotspot = an area that supports an especially high number of species endemic to the area,
found nowhere else in the world

CONCLUSION
Biodiversity is our life. If the Biodiversity got lost at this rate then in near future, the survival of human
being will be threatened. So, it is our moral duty to conserve Biodiversity as well our Environment. Long-
term maintenance of species and their management requires co-operative efforts across entire
landscapes. Biodiversity should be dealt with at scale of habitats or ecosystems rather than at species
level.