A power point presentation on the class 10 science biology lesson"OUR ENVIRONMENT".It consists of more informations beyond syllabus.It will be more useful for IIT aspirants.

1. FOOD CHAIN, FOOD WEB,
10% LAW,
OZONE AND ITS DEPLETION,
MANAGING GARBAGE WASTE.

2. FOOD CHAIN
•The food can be transferred from one
organism to the other through food chains.
•In simple words, sequence of living organisms
in which another organism consumes is food
chain.
•Starting point of food chain is producers i.e
plants
•So all food chains begin with plants.

3. CONT…
•A food chain represents a single directional transfer of
energy.
•Example:
•The following chain tells that transfer of energy takes
place from grass to deer and not in the reverse
direction.
•The study of food chain in an area or habitat helps us
knowing interactions among different organisms and
also their interdependence.

4. EXAMPLES OF FOOD CHAIN
GRASSLAND FOOD CHAIN AQUATIC FOOD CHAIN

5. FOOD WEB
•The inter connected food chains operating in an
ecosystem which establishes a network of
relationship between various species is called a
food web.
•The food web has many intersrosses and
linkages among various species.This means the
various food chains in an ecosystem do not
operate in isolation

6. EXAMPLES OF FOOD WEB

7. DIFFERENCE BET. FOOD CHAIN FOOD
WEB
FOOD CHAIN
• A list of organisms showing who
eats whom is called food chain.
• A food chain represents a
unidirectional transfer of
energy.
• It represents single habitat.
FOOD WEB
• The network of a large number
of food chains existing in an
ecosystem is called food web.
• The food web has many
intersrosses and linkages among
various species.
• It represents many habitat.

8. EFFECT OF MAN’S ACTIVITIES ON
ECOSYSTEM
•The shortening of food chains due to mans
activities like hunting leads to an imbalance in
the functioning of an ecosystem and ultimately
in the functioning of the whole biosphere.
Example:
The formation of Sahara desert is an ex of ill
effect of man’s activities in the delicately
balanced ecosystem.

9. IF TROPHIC LEVELS ARE REMOVED
IF LIONS ARE REMOVED
• If all lions are removed by
hunting there will be no
predator which leads to
increase population of
deers.As a result deers eat
all grass and thus
Greenland turns as a
desert.
IF PLANTS ARE REMOVED
•If all plants are removed
then there will no deer
or lion as there is no
food for their survival.

10. TRANSFER OF
ENERGY IN
FOOD CHAINS
The food chain in a
community actually
represents a
stepwise transfer of
food and the energy
contained in food.

11. FOUR STEPS INVOLVED IN
TRANSFER OF ENERGY
•Energy is not created in the ecosystem,it is
converted from one to another.
•There is a continuous transfer of energy from
one trophic level to next trophic level.
•At trophic level some of the enrgy is utilized by
organisms.
•There is a loss of energy transfer in various levels
of organism and remains unutilized.

12. TEN PERCENT LAW
• It was proposed by Raymond Laurel Lindeman.
• Plants absorb 1 percent sun energy for primary production
and will give only 10% of the utilized energy as net
production available for the herbivores. When the plants are
consumed by animal, about 10% of the energy in the food is
fixed into animal flesh which is available for next trophic
level (carnivores or omnivores). When a carnivore or an
omnivore consumes that animal, only about 10% of energy is
fixed in its flesh for the higher level.

13. An Example..
• Sun releases 100000J of energy,
then plants take only 10,000J of
energy from sunlight and stores
1000J available for
herbivores/omnivores; thereafter,
a deer would take 100J from the
plant. A wolf eating the deer
would only take 10J. A human
eating the wolf would take 1J, etc.

14. BIOLOGICAL MAGNIFICATION
•Farmers spray pesticides
to plants to prevent pest
activities.
•These pesticides enter
food chain at producer
level and get transfer to
next trophic levels.
•This is known as
biological magnification.

15. OZONE LAYER
•Ozone layer in the
atmosphere protects us
from harmful UV radiation.
•This layer is essential
because it ensures the
survival of life on earth.
•The formula for ozone is O3
i.e oxygen combines with
one oxygen atom to form
ozone.

16. CAUSES FOR DEPLETION OF OZONE
• The main things that lead to destruction of the
ozone gas in the ozone layer. Low temperatures,
increase in the level of chlorine and bromine
gases in the upper stratosphere are some of the
reasons that leads to ozone layer depletion. But
the one and the most important reason for
ozone layer depletion is the production and
emission of chlorofluorocarbons (CFCs).
• There are many other substances that lead to
ozone layer depletion such as hydro
chlorofluorocarbons (HCFCs) and volatile organic
compounds (VOCs). Such substances are found
in vehicular emissions, by-products of industrial
processes, aerosols and refrigerants.

17. DEPLETION OF OZONE LAYER

18. EFFECTS OF DEPLETION

19. MANAGING THE
GARBAGE WE
PRODUCE
•The household waste
is called garbage.This
garbage includes left
over foods,fallen
leaves,waste
paper,and unwanted
paper etc.

20. METHODS OF WASTE DISPOSAL
RECYCLING
Recycling is a processing
of waste materials to
form new products.
Materials like tin,
metallic articles, rags,
paper, glass, polythene,
etc are recyclable

21. COMPOSTING
All organic materials decompose
with time. Food scraps, yard waste,
etc. make up one of the major
wastes we throw every day.
Sometimes these are buried under
beds of soil and left to decay under
the action of microorganisms such
as bacteria and fungi. This results in
the formation of nutrient rich
manure. This process is termed as
composting

22. VERMICOMPOST
Vermicomposting is the process of
using worms for the degradation
of organic matter into nutrient-
rich manure. Worms take the
organic matter as feed and digest
them. The excretory materials or
the by-products of digestion are
given out by the worms makes the
soil nutrient rich, thus enhancing
the growth of bacteria and fungi

23. INCINERATION
Incineration is the process of
controlled combustion of garbage to
reduce it to incombustible matter;
ash, waste gas, and heat. The waste
gasses thus generated are then
treated and released into the
environment. This process reduced
the volume of waste by 90 percent
and considered as one of the most
hygienic methods of waste disposal.
In some cases, the heat generated
used to produce electric power.

24. LANDFILLS
In this process, the waste that cannot
be reused or recycled separated out
and spread as a thin layer in some
low-lying areas across the city. A
layer of soil added after each layer of
garbage. Once this process is
complete, this area declared unfit for
building construction for the next 20
years and is only used as a
playground or a park.

25. SEWAGE TREATMENT
Sewage is carried to sewage
treatment plant STPs. Here the
sewage is filtered, organic
materials in the sewage sewage
is allowed settle down and
decompose in large tanks. The
water from these tanks is
cleaned and is released to water
bodies.

26. BIOGAS PRODUCTION
Biodegradable waste, such as food items,
animal waste or industrial waste from food
packaging industries send to bio-
degradation plants. In bio-degradation
plants, they are converted to biogas by
degradation with the help of bacteria, fungi,
and other biological means. Here, the
organic matter serves as food for the micro-
organisms. The degradation can happen
aerobically (with oxygen) or anaerobically
(without oxygen). Biogas is generated as a
result of this process which is used as fuel,
and the residue is used as manure.

27. WASTE MANAGEMENT
ADVANTAGES
This practice is highly lucrative
Keeps the environment clean and fresh
Saves the Earth and conserves energy
Reduces environmental pollution
Waste management will help you earn money
Creates employment
DISADVANTAGES
The process is not always cost-effective
The resultant product has a short life
The sites are often dangerous
The practices are not done uniformly
Waste management can cause more problems