Class 7 lesson 1 (Maharashtra board)

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Natural Resources

2. Needs of Human beings
Man gets air to breathe from atmosphere. Gets
water for drinking and for day to day use from
rivers, wells, lakes, reservoirs. Food, clothes,
shelter and medicines these needs are met by
plants and Animals. Plants are grown in soil.
Minerals in soil are hence useful for man.
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3. Natural Resources
The things through which Mans basic
need are met are called as resources.
Air, Water, soil, minerals, Plants and
animals together provide for all our
needs. These are the part of Nature.
Man cannot produce them and hence
they are called Natural resources.
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4. Renewable resources
Animals live for certain years. Most of the plants also
live for specific years. Because of reproduction
animals are born again, plants are grown. We can
grow plants by sowing them again. Plants and animals
even if destroyed can be reproduced. Those natural
resources even if destroyes can be produced again
and again are called Renewable resources.
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5. Non-renewable resources
The resources like Air, water, soil, minerals
can never be produced by any method, they
are called non-renewable resources.
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6. Use of Natural resources
We all human beings make use of
Natural resources for meeting our
needs. Sometimes even when there is
no need just for leisure purpose we
make use of them. Examples like
having things, food, clothes. Notebooks,
pencils, boxes, Water bottles more then
we need. Natural resources should be
used sparingly, they should not pollute
the environment, is our utmost
responsibility to ensure it.
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7. Preserving Non-renewable resources
Air - A balanced mixture of Oxygen,
Nitrogen, Carbon dioxide and some
other gases. We cannot produce Air in
any laboratory. Growing Businesses
and inturn unlimited growth in the
number of factories – the poisonous
gases coming out of them, increase in
number of vehicles and the fuel used in
it are all responsible for increasing air
pollution.
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8. Air Pollution bad effects
The increase in the proportion of
carbon dioxide in the air causes more
heat to be retained in the
atmosphere. That is why, we are
facing the crisis called ‘global
warming’ . Life cycle of seasons is
getting affected because of increase
in temperature. Respiratory problems
other diseases, skin problems are
increasing because of this.
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9. How to reduce air pollution?
Use vehicles only when required.
Use Public transport as much as
possible.
Use CNG(Compressed Natural gas)
instead of Petrol and diesel.
Process the gas coming out of
factory before letting it out in air.
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10. Water – Why to conserve water ?
Water Non-renewable resource–
Because of water cycle water on earth
itself comes back to earth.
Limited reserves of water.
Available reserves of water are getting
polluted.
Melting of ice due to increasing
temperature which in turn evaporates
and becomes a part of water cycle
creating pollution.
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11. How to conseve water ?
To prevent rainwater from flowing
away,allow it to percolate into the earth.
To build dams for the same.
Use water sparingly only as much it is
needed.
Not to waste water.
Prevent the sources of water from
getting polluted.
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12. Importance of soil
The life cycle of all living things begins
from and ends in soil.
We get minerals from soil only..
The bacteria necessary for growing
crops are available in soil.
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13. Why to Protect Soil ?
Mountains, trees in jungle hold soil because of it’s roots.
Because of cutting down of forests and trees, soil gets
carried away by wind and water. The interior of rock fall
open.This is called as erosion of soil. Soil becomes saline
due to excessive watering, and crops doesn’t grow in it. For
growing crops chemical fertilizers are used on wide scale.
These gets mixed in soil and creates soil pollution. Release
of polluted water, chemicals and slag from factories gets
mixed in soil .Overuse of insecticides sprayed on soil gets
mixed in it. If garbage is buried in soil it creates soil
pollution. It takes of thousands of years to form a layer of
soil, but rain or winds carry away or ‘erode’ this layer in few
hours.
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14. Measures for protecting soil
Planting trees on mountains and on plains.
Use of organic fertilizers and organic insecticides.
Preventing the cutting down of trees.
Water the soil only as much as needed. For this make use
of sprinkle and drip irrigation.
To separate out wet and dry garbage and use it again by
recycling in proper way.
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15. Importance of Minerals
Minerals can never be produced by any
method..
There deposits are limited..
For production of various day to day
things, use of minerals should be done in
controlled manner.
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16. Effects of using minerals and Mineral oils in uncontrolled manner.
Deposits are dwindling/depleting.
When these fuels are burnt, carbon dioxide gas is given out which is
responsible for trapping of heat in earth’s atmosphere. As a result, global
temperatures are slowly rising.
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17. How to save minerals and mineral fuels ?
Use them sparingly.
Making use of alternative sources of energy such as solar energy, wind
energy, energy from tidal waves, biogas, etc.
Making people aware of this alternative sources of energy.
For this making a practice of observing 20 August as ‘Akshayya Urja
Din’
To take steps like reducing their use, reusing them, using them without
any wastage and avoiding their use whenever possible.
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18. Renewable resources generation and
conservation—Why ?
Cutting down of forests on large scale for
urbanisation, new construction(dams,
roads), land for agriculture .
Many rare species of animals and plants
are on the verge of extinction.
Indian Cheetah, birds and animals like
dodo have disappeared from Nature’s
chain.
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19. Tendency to grow only those crops
which have greater demand in
global market such as rubber,
medicinal plants or plants from
which cosmetics are made.
This has the adverse effect on the
environment. It is difficult to create
forests exactly like a natural forests.
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20. Attack on natural habitats of animals
Breeding only useful species animals
killing of animals
Poaching for the money that some
animal parts bring.
Because of this many animal species
have become extinct or are in danger of
becoming extinct.
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21. Biotechnology
By studing genes of plants and
animals and using scientific
experiment it is possible to save and
conserve certain desired
characteristics. Using this, it is now
possible to produce any plant ,
animals too in a laboratory. This is
called ‘biotechnology’.
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22. By using biotechnology
Food grains problem can be resolved
Growth period of crops, plants can be reduced.
Generating species having power to create
antibodies possible.
Possible to grow species having useful properties.
Whenever required availability of time of the latter.
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23. Biotechnology must be used with great prudence
Limitations to the use of biotechnology.
Possibility of making mistake in experiement.
In Nature’s chain every living being has some
place and hence it necessary to conserve them.
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24. Get Additional information
Nulla building
Soilless agriculture
Clowning
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