Definition

Environment:
The term environment has been derived from a French
word “Environ” means to surround. It refers to both
Abiotic (Non-Living) and Biotic (Living)
Environment. The word environment means
surroundings, in which organisms live.

Environmental Studies:
A group of multiple and inter-disciplinary studies, studying
the relations of humans and the environment, and the
impact of humans on nature. It is the branch of science
concerned with the relations between organisms and
their environment. It is a part of the broader field of
environmental education, which integrates the basics of
Biology, Chemistry, Physics, Mathematics, Geology,
Statistics, Sociology, History, etc.
Objectives
According to UNESCO (1971), the objectives of
environmental studies are:

Creating the awareness about

environmental problems among people.
Imparting basic knowledge about the
environment and its allied problems.
Developing an attitude of concern for the
environment.
Motivating public to participate in
environment protection and environment
improvement.
Acquiring skills to help the concerned
Importance
To clarify modern environmental concept
like how to conserve biodiversity.
To know the more sustainable way of
living
To use natural resources more
efficiently.
To know the behavior of the organisms
under natural conditions.
To know the interrelationship between
organisms in populations and
communities.
To aware and educate people regarding
Scope
Biosphere: Indicates the realm of living
organisms and their interactions with
environment, viz Atmosphere, Hydrosphere and
Lithosphere
Scope
The
Atmosphere
It implies the
protective
blanket of
gases,
surrounding the
earth. The
atmosphere
may be divided
into four
regions namely:
Scope
Troposphere: It surrounds us on the earth up to a height of
around 15 kilometers. The troposphere contains a mixture of
gases of varying composition, mainly consisting of Nitrogen-
78%, Oxygen-20%, Argon- 0.9%, Carbon dioxide- 0.03%
and other gases such as helium, hydrogen etc

Stratosphere: The layer of atmosphere above the

Troposphere is called Stratosphere. It consists of a thick
blanket of Ozone stretched to a length of about 40
kilometers. This layer is also called Ozonosphere. It
protects all the living beings on earth from the dangerous
ultraviolet rays emitting from the sun. Ozone in the ozone
layer absorbs the ultraviolet radiation.

Mesosphere or Ionosphere: The layer of atmosphere up

to about 100 Km above the ozonosphere is called the
Ionosphere. It is named so because any neutral atom or
molecule is stripped off its electrons by the ultraviolet rays to
 Scope
Thermosphere: The region (100-800 km) above the
Ionosphere is called Thermosphere, rightly so as temperature in
this zone increases gradually up to 1200°C. The region above
the thermosphere is called Exosphere. It rarely contains any
atoms, molecules or ions.

The Hydrosphere : It Comprises All Types of Water

Resources Oceans, Seas, Lakes, Rivers, Streams, Reservoirs,
Lakes, Rivers, Streams, Reservoirs, Polar Ice Caps, Glaciers, and
Ground Water. Hydrosphere forms a very prominent part of the
environment as water is an essential item required for all the
living beings. Three fourth of the earth is covered with water in
the form of oceans.
 Scope
The Lithosphere:
The earth we live on forms the Lithosphere. More
precisely the solid outer layer of the earth is called
Lithosphere. It is somewhat loose in texture and acts as
the main source of nutrients for plants that grow on it.

The composition of the top soil is as follows. Inorganic salts and

oxysalts such as sulphates, silicates, carbonates etc-60%,
organic matter in the form of putrefied plants, animal products-
30%, water-5%, air-5%. The structure of the earth appears as
follows. The top soil alone is suitable for the growth of
plants and for agriculture. The diameter of the earth we
live on is 12,756 K.M.

The centre of the earth called the core is still a boiling cauldron
(large pot or kettle) with the oxides and pure metals such as
Nickel and Iron in liquid state at about 3000°C. These metals in
large quantities at the centre of the earth are responsible for
Scope
The Lithosphere:
The hot centre of the core of the earth thus accounts for
the existence of volcanoes and hot water springs even at
the coldest areas such as the foot of the Himalaya
mountains. At first the top soil was a solid rock but
gradually it crumbled into fine particles due to weathering
process.

Lithosphere – Crust and Upper part of mantle

(Asthenosphere)

Layers of the Earth

Crust: the outer layer of rock on which humans and
animals live and plants grow (0-100 km thick) (O2 –
46.6%, Silicon-27.7%, Al – 8.1, Fe-5.0%.
Mantle: a semi-solid magma layer consisting of iron,
magnesium, and silicon (100-2900 km thick) (45% O2,
 Scope
Biosphere:
All the living organisms of plants or animal origin
constitute the Biosphere. Besides these two, the
Biosphere also contains very small living organisms invisible
to naked eye called the microbes. There are more than one
million known animal species on the earth. Similarly there
are more than 1 Lakh plant species. Biosphere maintains
the oxygen cycle, carbon dioxide cycle and nitrogen
cycle constant i.e., Biosphere helps to maintain the
quantities of nitrogen (78%), oxygen (21%), and
carbon dioxide (0.03%) constant in the atmosphere.

Example: Animals and plants utilize oxygen in the

respiration process where organic wastes are oxidized to
carbon dioxide. Plants also take part in the photosynthesis in
which carbohydrates are produced by the reaction between
carbon dioxide and water in the presence of sunlight and
Need For Public Awareness
• Growing Population
• Poverty
• Agricultural Growth
• Need to Ground Water
• Development and Forests
• Degradation of Land
• Reduction of Genetic Diversity
• Increasing of Urbanization
• Pollution
Need For Public Awareness
To bring awareness about environmental sciences,
Supreme Court of India recently directed all the
State Governments and Universities to make it a
subject of compulsory study at school and college
level.
To promote awareness about protection of an environment
Central Government is spending a lot of money through
Ministry of Forests and Environment in organizing
eco-clubs and to run National Green Council (N.G.C)
The Central Government is also funding several Non-
Governmental Organizations (N.G.O’s) to organize
public awareness programmes on important issues like
plastic and solid waste, conservation of water for future,
public health and hygiene, minimizing the release of
Ozone Depleting Substance (O.D.S).
The responsibility now rests on the younger generations to
educate the illiterate about the dangers of pollution and
Resources
• A resource may be defined as a material that is of value and useful to the living
beings.
• A resource may also be defined as an abstract entity such as intelligence, skill and
labor useful to the living beings.
• Material resources can be obtained from Nature
Ex: Water, Minerals and Forests are Tangible Resources and
Skills, Labour and Intelligence are Intangible

Resources can be classified as Renewable and Non-renewable.

Renewable Resources:
These are permanent and perennial. Ex: Forests, Water and Solar Energy etc.
Non-Renewable Resources:
These are available in limited. Ex: Fuels such as Coal and Petroleum
 Classification of Natural Resources
Natural Resources
Anything required by us for living and provided by nature
is known as natural resource. They classified as follow
based on their availability and abundance.
In Exhaustible Resources:
The resources which will not decrease on use are called in
exhaustible resources. Ex: Rainfall, Solar energy, Hydro
power etc.
Exhaustible Resources:
The resources which will decreases on use are called
exhaustible resources and further classified into
exhaustible renewable resources and exhaustible non-
renewable resources.
Exhaustible Renewable Resources:
The resources which regain their original quantities are
called exhaustible renewable resources. Ex: Water, Soil,
Plant, Wild life, Animals.
 I. FOREST RESOURCES
Forests are spread over nearly 35% of the earth all over
the world including India. Forest resources are classified
as:
• Evergreen Forests
• Semi Evergreen Forests
• Tropical Forests

Uses of Forest Resources:

• Trees are the sources of Carbohydrates and Oxygen
which are formed by Photosynthesis.
• Oxygen are essential for life.
• Wood as Fuel, Furniture etc., are essential needs.
• Forests are gradually dwindling by these activities.
• Deforestation is the Major Concern
• In order to conserve the forest resources, Deforestation
should be stopped forthwith.
 I. FOREST RESOURCES
Dangers of Deforestation:
The consequence of deforestation is
• Increase of carbon dioxide causes global warming. This is
also known as “Green House Effect”.
• The destruction of the forest treasure will lead make the
wild life end.
• There are more than 75,000 species of animals and
about 50,000 species of plants.
• It also lead to Global Warming results
• Melting of Ice in the Polar Regions causing, rise of the
levels in the Oceans
• Shifting of the fertile agricultural areas and converting
some of the land into deserts.
• To prevent these disastrous consequences by planting
and growing as many green trees as possible.
• More importantly, the illiterate masses should be
educated about the impending dangers of deforestation.
 II. WATER RESOURCES
Water resources form an important renewable part of
environment. Water exists as 1) Oceans 2) Lakes and
Rivers 3) Glaciers 4) Ground water. These may be
described as follows
Oceans:
• Oceans cover nearly 70% of the total surface area of the
earth.
• The oceans are treasures of several sea animals.
• Life is believed to have been originated in the oceans.
Lakes and Rivers:
• Lakes and rivers form the sources of water on the earth’s
surface.
• They form good sources of potable water.
• The abundance of water in these depends upon the
rainfall of the region. Some of the rivers form perennial
sources of water. Ex: River Ganges or Ganga By
constructing dams and reservoirs we can generate
 II. WATER RESOURCES
Glaciers:
• A glacier is a moving mass of ice. The largest glacier in
the world is Antarctica’s lambert glacier which is nearly
more than 500 Km long.
• The world’s largest perennial rivers originate from these
glaciers only for example in India, Ganga, Brahmaputra
etc.

Ground Water:
• About 97% of the total water of the earth is in the form
of oceans. 2% of the water is in the form of glaciers and
solid ice in polar regions.
• Only the remaining 1% of the available water is potable.
• All the living beings need water for their survival.
• Human and animal bodies contain 70% of water.
• Water thus forms an essential resource.
 II. WATER RESOURCES
Benefits and Problems Concerned with Dams:
A “Dam” is a construction across a river to store water
and regulate the flow and divert into the channels of
needy areas for irrigation purposes.
Dams are thus intended for the increased distribution and
utilization of the excess water flowing through the rivers
and avoiding wastage of water. India has many perennial
rivers such as the Ganga, Sindhu Godavari, Krishna Kaveri
etc., distributed all over India.
• The following are the advantages of “Dams”:
• Prevention of water wastage
• Irrigate those areas on the land which otherwise are not
in the path of the water flow of the rivers.
• Use the water reservoirs for the production of electricity.
• Create more fertile areas of the land and make the
people in those areas occupied and employed.
• There are some disadvantages also in the construction of
 III. MINERAL RESOURCES:
Minerals:
• Non-renewable Natural Resources.
• They are naturally occurring inorganic, crystalline solids
with definite chemical composition and particular
physical properties.
Types of Minerals:
Non-metallic minerals like diamond, graphite, quartz etc.
Metallic minerals like Bauxite, Laterite etc.
Uses:
• For development of industrial plants and machinery.
• Coal, Lignite and Uranium are used for generation of
energy.
• Used in defense systems weapons and ornaments.
• Used in communication system like cables and telephone
wires.
• Used in many medicines.
• Gold, Silver, Platinum, Diamond are used as jewellery.
III. MINERAL RESOURCES:
Effects of Extraction Of Mineral Resources:
• Extraction of mineral resources from the earth is called Mining or Quarrying.
• Mining of minerals, coal and petroleum from the soil results in the damage to
the natural texture and composition there by bringing a major ecological
change of nature.
• Depending on the nature of the material extracted and the various
metallurgical processes the effluents contaminate the atmosphere and cause
pollution.

Environmental affects of mineral extraction:

Mining or extraction and processing of minerals and their disposal pollutes the
soil, air and water

Ill Effects of Mining In India:

People residing near the (Uranium mine), Jharkhand are exposed to nuclear
hazards.
 III. MINERAL RESOURCES:
Ill Effects of Mining In India:
• High sulphur contamination of groundwater is taking place in
North eastern coal fields (Assam).
• River pollution is cause of concern due to Kudremukh iron ore
in Karnataka.
• Health hazards in mines due to appearance of diseases black
lung disease, asbestosis etc.
• Disappearance of vegetation.
• Defacing land scope and subsidence
IV. FOOD of land.
RESOURCES:
• Food is essential for growth and development of living
organisms.
• These essential materials are called nutrients and these
nutrients are available from variety of animals and plants.
• There are thousands of edible plants and animals over the
world, out of which only about three dozen types constitute
major food of humans.
Food Sources:
• The majorities of people obtain food from cultivated plants
Food Crops:
• At global level; only 20 species of crops are used for
food.
Ex: Wheat, Rice, Corn, Potatoes; Barley, Sweet Potatoes,
Cassavas, Soybeans, Oats, Sorghum, Millet, Sugarcane,
Sugar Beets, Rye, Peanuts, Field Beans, Chick-peas,
Pigeon- Peas, Bananas And Coconuts.
Livestock:
• Domesticated animals are an important food source.
(e.g. cattle, sheep, goats, camel, reindeer, llama, etc.).

Aquaculture:
• Fish and seafood contributes 17 million metric tonnes of
high quality protein to provide balance diet to the world.
 IV. FOOD RESOURCES:
Changes Caused by Agriculture and Overgrazing:
• Deforestation
• Soil Erosion
• Depletion of nutrients
• Impact related to high yielding varieties (HYV)
• Fertilizers related problems include micronutrient
imbalance, nitrite pollution and eutrophication.
• Pesticide related problems include creating resistance in
pests and producing new pests, death of non-target
organisms, biological magnification.
• Water logging, salinity problems and such others.
• The carrying capacity of land for cattle depends upon
micro climate and soil fertility. If carrying capacity is
exceeded than land is overgrazed.
• Because of overgrazing the agricultural land gets
affected as follows:
• Reduction in growth and diversity of plant species
 V. ENERGY RESOURCES:
There are two types of energy resources

1) Renewable Resources:
The resources that are being continuously consumed by
man but renewed by nature are called renewable
resources. These resources are inexhaustible; these may
be also called as non-conventional sources of energy.
Ex: Solar Energy, Wind Energy, Tidal Energy, Hydro
Power, Geo Thermal Energy, Bio-Mass Energy, Bio-Gas,
Bio-Fuels and Hydrogen.

2) Non- Renewable Resources of Energy:

These are not renewable. They are not replenished by
nature if exhausted.
Ex: Coal, Petroleum, LPG (Liquified Petroleum Gas),
Natural Gas, CNG (Compressed Natural Gas), SNG
(Synthetic Natural Gas) and Nuclear Energy:
 VI. LAND RESOURCES:
• Soil may be defined as the portion of earth’s surface
suitable for growing plants and for agriculture.
• When the earth formed billions of years ago, it was only
a ball of solidified minerals or rocks.
• As time passed, these rocks are sudden freezing along
with fast flowing water and high winds and transformed
into what the land looks like today.

Soil Erosion:
• Thus soil erosion is defined as the process of loss of top
soil under the influence of certain external factors some
of which are natural and some are manmade.
Natural Factors:
• Weather and climatic conditions. Ex: High temperature
and Pressure).\
• Heavy rains
• Waves of the sea.
 VI. LAND RESOURCES:
Man Made:
• Diversion of the natural course of river flow.
• Faulty agricultural activity and faulty procedures.
• Unusually fast flow if irrigating water due to non levelling
of soil.
• Extensive mining of soil.

Prevention Measures of Soil Erosion:

• River and canal flows should be controlled with proper
bunds and reinforced edges.
• Check dams should be constructed in pre determined
areas to control the flow rate of rivers.
• Growing grass or deep rooted plants on the coastal line
or along the river bunds to prevent soil erosion.
 VI. LAND RESOURCES:
Desertification:
The process of rendering once fertile lands into waste lands is
called desertification.
Reasons:
• Irregular monsoon and improper temperature and pressures
on land causing drought.
• Heavy rains and heavy floods causing depletion of soil
nutrients or water clogging and flooding.
• High tides and cyclones causing layering of fertile lands with
salts and sand thus rendering the soil unfit for cultivation.
• Green house effect and global warming creating conditions
unfit for agriculture.
Precautions:
• Using ground water for irrigation during dry seasons.
• Arranging proper drainage system in agricultural soils to avoid
water logging and over irrigation. If there is deposition of salts
and sand on fertile soils the deposits should be removed by
human effort or man power.
Ecology and Ecosystem
Ecology:
• The branch of science which deals with the relationship
of organisms with their Environment is known as Ecology.

• Today, Ecology has become one of the most important

branches of Biology it deals with the consequences of
inter relationship between organisms and Environment.

Ecosystem:
• The term ecosystem was coined by a British Ecologist,
A.G. Tanslay in 1935.

• “Ecosystem is a basic functional unit of Ecology

consisting of abiotic and biotic factors which
interact with each other and exchange materials”.
The Ecosystem may be
 Types of Ecosystem
Natural:
Operating under natural conditions without any major
interference by man.

Terrestrial: Grass Land, Desert, Forest etc., and

Aquatic :
Fresh Water: Ponds, Lakes and Streams
Marine : Open Sea, Coastal and Estuarine
Ecosystems

Artificial: Man-made Ecosystems

Example : Croplands, Space Ecosystems etc.

• An important feature of an Ecosystem is that it is

capable of self maintenance and self regulation.
 Ecosyst
em
Artificial
Natural Ecosystem
Ecosystems
Terrestrial Man-Made
Ecosystem Crop Fields etc.
1. Forest Aquatic
Ecosystem Ecosystem
2. Grassland
Marine
Ecosystem
Ecosystem
3. Desert Fresh Water
Lotic 1. Oceanic
Ecosystem Ecosystem
Ecosystem Ecosystem
Lentic
(Flowing 2. *Estuaries
Ecosystem
Water) (Stagnant
1. River Water)
Ecosystem 1. Lake
2. Stream Ecosystem
Ecosystem 2. Pond
3. Spring
 Concept of an Ecosystem
• The Organisms and the Environment are interrelated and
interdependent with each other.

• Animals depend on Plants because they cannot

synthesize their food material.

• Plants depend upon the Abiotic environment for Light,

Water, CO2, Mineral Salts and inorganic, organic
substances for the synthesis of food.

• After the death of animals microorganisms covert their

dead bodies into inorganic and organic substances.
These substances are absorbed by plants for the
existence of plant community.

• Thus a dynamic and delicate balance exists between the

 Structure and Function of an Ecosystem
Structure:
• The Composition of Biological Community including
Species, Number, Biomass, Life History and Distribution
in Space etc.
• The quantity and distribution of the non-living materials
such as nutrients, water etc. and
• The range of conditions of existence, such as
temperature, light etc.

Function:
• The Rate of Biological Energy Flow i.e., the Production
and Respiration Rates of the Community
• Rate of Materials or Nutrient Cycles and
• Biological or Ecological Regulation including both
• Regulation of Organisms by Environment
(Photoperiodism etc) and
•
Structure of Ecosystem: (Components of an
Ecosystem)
The Ecosystem comprises two major components
Abiotic Component and
Biotic Component

Abiotic Component:
All non-living factors of Ecosystem is called Abiotic
component, which includes
Organic Substances:
• These are Proteins, Carbohydrates, Lipids, Amino Acids
etc present either in the biomass or in the environment.
Inorganic Substances:
• These include elements like C, H, O, N, P, Mg, Fe, Cd, Cu,
Na, H2O, CO2 etc.
• They are present either in free state or in the form of
compounds dissolved in water and present in the soil.
Climatic Regime:
 A Scheme of the Structure of a Unit of Typical
Ecosystem

Sun

Producers

Nutrients

Decompos Consumer
ers s
Structure of Ecosystem: (Components of an
Ecosystem)
Biotic Components:
All living organisms constitute of biotic components. They
are

Producers:
Ex: Autotrophic Green Plants and some Photosynthetic
Bacteria.
• Only green plants are capable of trapping the solar
energy which is the ultimate source of energy for all the
organisms of an ecosystem.
• Only Green Plants (Producers) are capable of preparing
food materials for animals growth and development.

Consumers:
• They are Heterotrophic Organisms.
• All the animals which directly or indirectly depend upon
Structure of Ecosystem: (Components of an
Ecosystem)
Primary Consumers:
• These are Herbivorous Animals. They feed on Producers
(Green Plants)
Ex: Deer, Sheep, Goat, Horse, Rabbit, Cattle, insects etc.
Secondary Consumers:
• These are Carnivorous animals. They feed on Primary
Consumers.
Ex: Wolves, Dogs, Cats, Frog, Fox etc.
Tertiary Consumers:
• They feed on both Primary and Secondary Consumers.
Ex: Lion, Vultures, Eagle, Hawks etc.

Decomposers:
Ex: Micro organisms such as Bacteria, and Fungi.
• They secrete enzymes to decompose the dead bodies of
plants and animals (Producers and Consumers),
•
 Types of Ecosystem
Natural:
Operating under natural conditions without any major interference by
man.

Terrestrial: Forest, Grass Land, Desert etc., and

Aquatic :
Fresh Water : Ponds, Lakes and Streams
Marine : Open Sea, Coastal and Estuarine Ecosystems

Artificial: Man-made Ecosystems

Example : Croplands, Space Ecosystems etc.

• An important feature of an Ecosystem is that it is capable of self

maintenance and self regulation.

• It has a tendency to resist change and to remain in a state of

equilibrium.
 Forest Ecosystem
• Forest Ecosystem is the one in which a tall and trees grow that
support many animals and birds.

• The forest are found in undisturbed areas receiving moderate to hi

rainfall. The forest occupies nearly 40% of the world’s land area.

• In India it occupies only 19% of its total land area.

Types of Forest Ecosystem:

Depending upon the climate conditions, forests can be classified into
the following types.
Tropical Rain Forests (receives abundant rain).
Tropical Deciduous Forests (which shed the leaves).
Tropical Scrub Forests (bushy).
Temperate Rain Forests.
Temperate Deciduous Forests
 Forest Ecosystem
Tropical Rain Forests :
• Found near the Equator.
• Characterized by High temperature.
• Broad Leaf Trees like Teak and the animals like Lion, Tiger and
Monkey.
Tropical Deciduous Forests:
• Found little away from the equator.
• Characterized by a Warm Climate and Rain is only during Monsoon.
• Have Deciduous Trees like Maple, Oak and Hickory and Animals like
Deer, Fox, Rabbit and Rat.
Tropical Scrub Forests
• Characterized by a Dry Climate for Longer Time.
• Small Deciduous Trees Maple, Oak, Hickory and Animals Like Deer,
Fox, etc.,
Temperate Rain Forests
• Found in Temperate Areas with Adequate Rainfall.
• Characterized by Coniferous Trees like Pines, Firs, Red Wood etc.,
and animals like, Squirrels, Fox, Cats, Bear etc.,
 Forest Ecosystem
Temperate Deciduous Forests:
• Found in areas with Moderate Temperatures.
• Major Trees including broad leaf Deciduous Trees like
Oak, Hickory and Animals like Deer, Fox, Bear etc.,

Characteristics of Forest Ecosystems:

• Forests are characterized by warm temperature and
adequate rainfall, which make the generation of number
of ponds, lakes etc.,
• The forest maintains climate and rainfall.
• The forest support many wild animals and protect
Biodiversity.
• The soil is rich in organic matter and nutrients which
support the growth of trees.
• Since penetration of light is so poor, the conversion of
organic matter into nutrients is very fast.
 Forest Ecosystem
Structure and Function of forest ecosystem
Abiotic Components
• Climatic Factors (Temperature, Light, Rainfall) and Minerals
• The Abiotic components are Inorganic and Organic Substances
found in the Soil and Atmosphere.
• In addition Minerals, the occurrence of Litter is characteristic
features, majority of Forests.

Biotic Components
Producers:
• The plants absorb Sunlight and produce Photosynthesis Trees,
Shrubs and Ground Vegetation.
Consumers:
• Primary Consumers (Herbivores) :
• They directly depend on the plants for their food.
Ex: Ants, Flies, Insects, Mice, Deer, Squirrels.
 Forest Ecosystem
Consumers:
• Secondary Consumers (Primary Carnivores):
• They directly depend on the herbivores for their food
Ex: Snakes, birds, fox.
• Tertiary Consumers :
• They depend on the primary carnivores for their food
Ex: Animals, like tiger, lion, etc.,
Decomposers:
• Bacteria and Fungi.
• They decompose the dad plant and animal matter of
decomposition in tropical and subtropical forests is in
rapid than in the temperate Forests.
Forest Ecosystem
Food Web
 Grass Land Ecosystem
• Grass Land occupies about 20% of earth’s surface
addition to grass species, some trees and shrubs are also
present in grasslands.
• Limited grazing helps to improve the net primary
production of the grasslands.
• But, overgrazing leads degradation of these grasslands
resulting in desertification.

Types of Grassland Ecosystem

Depending upon the climate conditions grassland
classified into three types
1.Tropical grasslands.
2.Temperate grasslands.
3.Polar grasslands.
 Grass Land Ecosystem
Tropical Grass Lands:
• Found near the borders of Tropical Rain Forests.
• Characterized by High Temperature and Moderate Rainfall (40-100
cm).
• Are also known as Savanna type.
• Tall Grasses with Scattered Shrubs and Stunted Trees and Animals
like Zebras, Giraffes, Antelopes etc.,
Temperate Grass Lands:
• Are usually found in the Centers of Continents, Oil Sloped Hills.
• Characterized by Very Cold Winters and Hot Summers.
• Intense Grazing and Summer Fires, do not allow Shrubs or Trees to
Grow.
Polar Grass Lands:
•Are found in Arctic Polar Regions.
•Characterized by severe cold and strong winds along with ice and
snow.
•In summers several small annual plants grow.
•Animals like Arctic Wolf, Weasel, Arctic Fox etc.,
 Grass Land Ecosystem
Characteristics of Grassland Ecosystems
• Grassland ecosystem is a plain land occupied by grasses.
• Soil is very rich in nutrients and organic matter.
• Since it has tall grass, it is ideal place for grazing animals.
• It is characterized by low or uneven rainfall.

Structure and Function of the Grassland Ecosystems

Abiotic Components:
Nutrients, H, O, A, P, S, etc.,
These are supplied by C02, H2, C, Nitrate, Phosphates and
Sulphates.
Biotic Components:
Producers:
They produce food.
Ex: Grasses, Herbs and Shrubs.
 Grass Land Ecosystem
Consumers:.
Primary Consumers (Herbivores) :
They depend on grasses for their food
Ex: Cows, Buffaloes, Deer, Sheep etc.,

Secondary Consumers (Carnivores) :

They feed on herbivores.
Ex: Snakes, Lizards, Birds, Jackals, Fox etc.,

Tertiary Consumers:
They feed on secondary consumers
Ex: Hawks, eagle, etc.,

Decomposers :
They decompose the dead organic matter
Ex: Fungi and Bacteria.
Grass Land Ecosystem
Grass Land Ecosystem
 Dessert Ecosystem
Desert occupies about 35% of our World’s Land Area.
Characterized by less than 25 cm Rainfall.
The Atmosphere is Dry and hence it is a Poor Insulator .

Types of Desert Ecosystems:

Based on the climatic conditions, deserts are classified
three types.
Tropical Deserts.
Temperate Deserts.
Cold Deserts.
 Dessert Ecosystem
Features of Different Types of Deserts
Tropical Deserts:
Africa : Sahara Desert.
Rajasthan : Thar Desert.
• They are characterized by only few species.
• Wind blow sand dunes are very common.

Temperate Deserts
South California : Majave.
• Characterized by Very Hot Summer and Very Cold
Winter Time.

Cold Deserts
China: Gobi
desert.
• They are
 Dessert Ecosystem
Characteristics of Desert Ecosystem
• The desert air is Dry and the Climate is Hot.
• Annual Rainfall is Less than 25 cm.
• The Soil is Very Poor in Nutrients and Organic Matter, Vegetation
is Poor.

Structure And Functions Of The Desert Systems

Ecosystems
Abiotic Components
Ex: Temperature, Rainfall, Sunlight, Water, etc.,
• The Temperature is Very High and the Rainfall is Very Low.
• The Nutrient Cycling is also Very Low.
Biotic Components
Producers:
Ex: Shrubs, Bushes, Some Grasses and Few Trees
• Deserts are Mostly Succulent Plants (Cacti).
• They have Water Storing Capacity to stay alive.
• They have Wax Cuticle Protect them from the sun.
 Dessert Ecosystem
Consumers
Ex: Squirrels, Nice Foxes, Rabbits, Deer and Reptiles.
• These animals dig holes in the ground to live in.
• They come out at night to find food.
• Most of the animals can extract water from the seeds
they eat.

Decomposers
Ex: Fungi and Bacteria
• Desert has poor vegetation with a very low amount
of dead organic mater.
• They are decomposed by few fungi and bacteria.
Dessert Ecosystem
 Aquatic Ecosystem
The aquatic ecosystem deals with water bodies. The major types of
organism found in aquatic environments are determined by the
water’s salinity.
Types of Aquatic Life Zone
Aquatic Life Zones are Divided into Two Types.
• Fresh Water Life Zones : Ex: Pounds, Streams, Lakes, Rivers.
• Salt Water Life Zones: Ex: Oceans, Estuaries.

Fresh Water Ecosystem

Pond Ecosystems
• A pond is a fresh water aquatic ecosystems, where water is
stagnant.
• It receives enough water during rainy season.
• It contains several types of algae, aquatic plants, insects, fishes
and birds.
Characteristics of Pond
• Pond is temporary, only seasonal.
• It is a stagnant fresh water body.
• Ponds get polluted easily due to limited amount of water.
 Aquatic (Fresh Water) Ecosystem
Structure and Functions of Pond Ecosystems
Abiotic components
Ex: Temperature, Light, Water and Organic and Inorganic Compounds
Biotic Components
Producers:
Include Green Photosynthetic Organism. They are of two types.
Phytoplankton:
Microscopic Aquatic Plants which freely float on the surface of water.
Ex: Algae, Floating Plants like Volvox, Pandorina, Anabaena,
Cosmarium
Microphytes:
Ex: Large Floating Plants and Submerged Plants Like Hydrilla,
Jussiaea, Wolfia, Demna.
Consumers:
Primary Consumers
Zooplanktons:
These are microscopic animals which freely float on the surface of
water.
 Aquatic (Fresh Water) Ecosystem
Zooplanktons:
These are microscopic animals which freely float on the
surface of water. Zooplanktons are found along with
phytoplankton. They feed on plants (Phytoplankton).
Ex: Protozoa, Very Small Fish, Ciliates, Flagellates and
Protozoans.
Secondary Consumers (Carnivores):
They feed on Zooplankton
Ex: Insects like Water Beetles and Small Fish.
Tertiary Consumers :
They feed on smaller fish
Ex: Large Fish Like Game Fish.
Decomposers:
They decompose the dead plant and animal matter and
their nutrients are released and reused by the green
plants. Ex: Fungi, Bacteria and Flagellates
Aquatic (Fresh Water) Ecosystem
 Aquatic (Fresh Water) Ecosystem
Lake Ecosystem:
• Lakes are large natural shallow water bodies used for various
purposes.
• Lakes are supplied with water from rainfall, melting snow and
streams.
Types of Lakes:
Oligotrophic : Have Low Nutrient Concentrations
Eutrophic : Over Nourished by Nutrients Like N and P
Dystrophic : Have Low pH, High Humid Content and Brown
Waters.
Volcanic : They receive Water from Magma after Volcanic.
Zones of Lake:
Depending upon their Depth and Distance from the Shore, Lakes
Consists of Four Distinct Zones.
Liftoai Zones : It is the top layer of the lake. It has a shallow
water.
Lininetic Zone : Effect penetration of solar light takes
place.
Préfundal Zone : The deep open water, where it is too
dark.
 Aquatic (Fresh Water) Ecosystem
Characteristics of Lake Ecosystem
1.Lake is a shallow fresh water body;
2.It is a permanent water body with large Water
resources.
3.It helps in irrigation and drinking.
Structure and Function of Lake Ecosystem
Abiotic Components:
Temperature, light, proteins and lipids, O2CO2
Biotic Components:
Producers:
Are Green Plants may be Submerged, Free Floating and
Amphibian Plants.
Ex: Phytoplankton's, Algae and Flagellates.
 Aquatic (Fresh Water) Ecosystem
Consumers:
Primary Consumers:
Zooplanktons: They feed on Phytoplankton.
Ex: Ciliates, Protozoans, etc.,
Secondary Consumers (Carnivores) :
They feed on Zooplankton. Ex: Insects and small
fishes.
Tertiary consumers:
They feed on smaller fish. Ex: Large Fishes like
Game Fish.

Decomposers:
They decompose the dead Plants and Animals
Ex: Bacteria, Fungi and Actinomycetes.
.
Aquatic (Fresh Water) Ecosystem
 Aquatic (Fresh Water) Ecosystem
River or Stream Ecosystem:
The running water of a stream or a river is usually well
oxygenated, because it absorbs oxygen from the air. The
number of animals are low in river or stream.

Characteristics of River or Stream.

• It is a fresh water, and free flowing water systems.
• Due to mixing of water, dissolved oxygen content is.
more.
• River deposits large amount of nutrients.
 Aquatic (Fresh Water) Ecosystem
Structure and function of River or Stream Ecosystem
Abiotic components
Ex: River, Light, Temperature, Chemistry, Substrate

Biotic Components
Producers:
Phytoplankton, Algae, Water Grasses, Aquatic Masses other
Amphibious Plants.

Consumers:
Primary Consumers:
They feed on phytoplankton. Ex: Water insects, snails, fishes:
Secondary Consumers:
They feed on primary consumers Ex: Birds

Decomposers:
They decomposes the dead animals and plants. Ex: Bacteria and
fungi.
 Aquatic (Salt Water) Ecosystems
Characteristics of Ocean Ecosystem
Ocean or Marine Ecosystems
• Covers more than two third of the earth’s surface.
• Characterized by its high concentration of Salts and Minerals.
• Supplies huge variety Products like Drugs, Iron, Magnesium Natural
Gas etc.
• Ship, Submarines Sail for Commercial Activities.
• It is Rich in Biodiversity.
Zones of Oceans: The oceans have two major life zones.
Coastal Zone: It is relatively warm, nutrient rich shallow water.
It has high primary productivity because of high nutrients and
sunlight.
Open Sea: It is the deeper part of the ocean.
It is vertically divided into three regions.
Euphotic Zone : It receives abundant light with High
Photosynthetic Activity
Bathyal Zone : It receives dim light and is usually geologically
active.
Abyssal Zone : It is the dark zone and is very deep (2000 to
metres).
 Aquatic (Salt Water) Ecosystems
Structure and Function Ecosystems:
Abiotic Components: Temperature, Light, Na Cl, K, Ca, and Mg Salts
alkalinity

Biotic Components
Producers:
Phytoplanktons: Ex: Diatoms, Unicellular Algae etc., and Marine
Plants: Sea Weeds, Chlorophycela, Phaeophyceae.
Consumers
Primary Consumers (Herbivores) :
They feed on Producers. Ex: Crustaceans, Mollusks, Fishes
Secondary Consumers (Carnivores) :
They feed on Herbivores. Ex: Herring Sahd, Mackerel, etc.,
Tertiary Consumers:
They are the top consumers. They feed on small. Ex: Cod, Haddock
etc.,
Decomposers:
They decompose the dead organic matter. Ex: Bacteria and Fungi.
Aquatic (Salt Water) Ecosystems
 Aquatic (Salt Water) Ecosystems
Estuarine Ecosystem
Characteristics of Estuarine Ecosystem
• An estuary is a partially enclosed coastal area at the’
mouth of a river, where sea water mixes with
freshwater.
• They are transition zones, which are strongly affected
by tides of the sea.
• Water characteristics are periodically changed.
• They are generally abundant of nutrients.
• The living organism in estuarine ecosystems have wide
tolerance.
• Salinity remains highest during the summer and lowest
during the winter
• They are useful to human beings due to their high food
potential.
• It is essential to protect the estuaries from pollution.
 Aquatic (Salt Water) Ecosystems
Structure and Function of Estuarine Ecosystem
Abiotic Components
Ex: Temperature, pH, Sodium, Potassium Salts and Various
Nutrients.

Biotic Components
Producers:
Ex: Marsh Grasses, Sea Weeds , Sea Grasses and
Phytoplankton.

Consumers:
Ex: Oysters, Crabs, Sea Birds, Small Fishes

Decomposers
Ex: Bacterias, fungi and actenomycetous.
 Ecological Succession
Definition:
An Ecological Succession includes a Series of Orderly, Progressive and
Predictable Changes that a Biotic Community Undergoes in its
Development Towards a Stable or Climax Condition.

According to Smith (1966),“Ecological Succession is an Orderly and

Progressive Replacement of one Community by Another Until a
Comparatively Stable Community Occupies the Area”.
 Kinds of Ecological Succession:
Ecological succession may be of the following two types.
Primary Succession:
When Succession begins on an area which has not been
previously occupied by a community i.e., area devoid of
organisms, it is called Primary Succession.
 Kinds of Ecological Succession:
Secondary Succession:
When community development is proceeding in an area
from which a community was removed and where
nutrients and conditions for existence are already
favorable. For example succession in a forest area where
vegetation has been devastated by fire or by flood.
 Kinds of Ecological Succession:
On the basis of successive changes in nutritional and
energy contents, successions are classified into
autotrophic succession and heterotrophic succession.
Autotrophic Succession:
It is characterized by early and continued dominance of
Autotrophic Organisms like green plants.

It begins in a predominantly inorganic environment and

the energy flow is maintained indefinitely.

Heterotrophic Succession:
It is characterized by an early dominance of Heterotrophs
i.e., fungi, bacteria, and animals.

This begins in a predominantly organic environment and

there is a progressive decline in the energy content.
 Trends in Ecological Succession:
• In an area, the plant and animal communities undergo
succession side by side. It is so because vegetational changes
in turn affect the food and shelter for various types of animals.
• Biotic succession is according to specific laws and towards
particular direction so future seral communities (an
intermediate stage in an ecosystem moving towards climax
stable community) can be predicted.

CAUSES OF ECOLOGICAL SUCCESSION

Initial or Initiating causes:
These may be climatic factors (such as erosion and deposits,
wind, Drought, Snow, Fire etc) or may be biotic factors (Such as
various activities of organisms).
These causes produce the bare area or destroy the existing
populations in an area.
Continuing Causes:
These are the process as migration, aggregation,
competition, reaction etc. which cause successive waves of
 Energy
• Energy can be defined as the capacity to do work.
• The existence of living world depends upon the flow of
energy and circulation of materials through the
ecosystem.
• The energy is required for the performance of all the life
activities.
• The source of energy in the atmosphere is the solar
energy.
• The expenditure and storage of energy is described by
two laws of thermodynamics.
The First Law of Thermodynamics (Law of
Conservation of Energy):
States that “energy is neither created nor destroyed and
is converted from one form to another. Ex: Solar energy
changes into energy of food and heat.
 Energy
• Plants (Producers) store the energy in the form of
Potential Energy.
• When an Herbivore Animal eats a Plant and these
organic compounds are oxidized, the energy liberated is
just equal to the amount of energy used in synthesizing
the substances (First Law of Thermodynamics), but some
of the Energy is heat and not useful energy (Second Law
of Thermodynamics).

• If this Animal in turn is eaten by another one, along with

transfer of energy from a herbivore to carnivore, a
further decrease in useful energy occurs. As the second
animal (Carnivore) oxidizes the organic substances of
the first (Herbivore) to liberate energy to synthesize its
own cellular constituents.

•
 Food Chains
• The transfer of food energy from the producers, through
a series of organisms (Herbivore to Carnivores to
Decomposers) with repeated eating and being eaten is
known as a food chain.
Plant Herbivore Carnivore
• This is one form of Trophic relationship in which Plants
are Producers, Herbivores are Primary Consumers and
the Carnivores Secondary Consumers. There may exist
Tertiary Consumers also.
• The Plants are said to be at the First Trophic Level. The
Herbivores represent Second Trophic Level. Similarly,
Primary Carnivores constitute the Third Trophic Level
where as Secondary Carnivores (Ex: Large Fish, Man etc)
constitute the Fourth Trophic Level in an Ecosystem.
• Thus the energy is transferred through series of stages in
an ecosystem and this is explained as Food chain.
 Food Chains
• The transfer of energy from the source in plants through
a series of organisms by eating and being eaten
constitutes food chains.

• At each transfer, a large proportion of energy is lost in

the form of heat.

• These food chains are not isolated sequences, but are

interconnected with each other.

• This interlocking pattern is known as the Food Web.

• Each step of the food web is called a Trophic Level.

• Hence green plants occupy the first level, Herbivores the

Second Level, Carnivores the Third level and Secondary
 Food Chains
There are two types of food chains found in terrestrial
ecosystem.
They are
Grazing Food Chain and
Detritus Food Chain

Grazing Food Chain:

• This food chain begin with a Green Plant which is the
original source of all food and goes through smaller to
larger animals, i.e., Grazing Herbivores to Carnivores.

• with such type of Food Chains are directly dependent on

an influx of Solar Radiation.

• Most of the Ecosystems in nature follow this type of Food

Chain.
Food Chains
Food Web
• In an Ecosystem usually each
organism feeds on two or
more different kinds of
organisms and is in turn
eaten by two or more
different animals. This means
that there is an interaction
and inter connection between
different Food Chains. This
interconnection of number of
Food Chains forms a Food
Web. So a Food Web can be
defined as a network of Food
Chains which becomes inter
connected at different Tropic
Levels so as to form a
 Ecological Pyramids
• An ecological pyramid is a graphic representation of an
ecological parameter like number, biomass or energy at
different trophic levels in a food chain in an ecosystem.
• Pyramid is a conical structure and in ecological pyramid
the first trophic level forms the base and the successive
trophic levels above the base makes up the apex.
• Ecological pyramids are classified into three types
depending upon their nature.

Pyramid of Number
Pyramid of Biomass
Pyramid of Energy
 Ecological Pyramids
Pyramid of Number:
• It is graphic representation showing the
arrangement of number of individuals of
different Trophic Levels in a Food chain in
an ecosystem.
• We find that the largest number is of
producers and the number keeps on
decreasing as we move forward in the food
chain. For example in a grass land
ecosystem, the producers which are mainly
grasses, are always maximum in number.
• This number then shows a decrease
towards the apex, as the primary
consumers (herbivores) like rabbits, mice
etc, are lesser in number than the grasses;
the secondary consumers, snakes and
 Ecological Pyramids
Pyramids of Biomass:
Biomass may be defined as the total weight of dry matter
present in the ecosystem at any one time. By using the
weight of organisms in the different trophic levels a
pyramid of biomass results. Pyramid of biomass is a
graphic representation of biomass present per unit area in
different trophic levels. In grass land and forest
ecosystem, there is a gradual decrease in biomass of
organisms at successive trophic levels from the producers
to the carnivores. Thus the pyramid is upright. But in
pond ecosystem, producers are small organisms
therefore, biomass shows an increasing tendency. Thus
making the pyramid inverted in shape.
 Ecological Pyramids
Pyramid of Energy:
It is a graphic representation of amount of energy trapped
per unit time and area in different trophic levels of a food
chain. This pyramid represents the number of calories
transferred from one trophic level to the next. This
pyramids is always upright as the energy that flows
always decreases with every trophic level. It is maximum
in producers and least in carnivores.