Natural Resources - Key Points

(1)     Natural Resources : -

Resources provided by nature for use of living organisms. Eg. - Sun, Air, etc.


(2)     Atmosphere : -

Blanket of air surrounding the Earth.


(3)     Hydrosphere : -

The total amount of water content on the planet whether in the form of oceans, rivers, lakes, ponds, or underground water.


(4)     Lithosphere : -

The outer crust of the Earth.


(5)     Biosphere : -

Life supporting zone of the Earth where the three zones atmosphere, hydrosphere and lithosphere makes life possible.


(6)     Abiotic Components : -

The non-living things that are essential for survival of the living organisms. Like - Air, Water, Soil etc.


(7)     Biotic Components : -

Living organisms on the Earth. Like - Plants and Animals.


(8)     Composition of Air : -

Mixture of Nitrogen (78%), Oxygen (21%), Carbon dioxide (0.03%), small amount of CO, He, Ar, H, other gases and water vapour.


(9)     Importance of Atmosphere : -

(a) One of the components of air i.e. oxygen supports life as used in Respiration process by animals.

(b) Air being bad conductor of heat acts as insulator and maintains the increase or decrease of heat on Earth.

(c) Ozone layer present around Earth protects it from harmful Ultra-Violet radiations.


(10)   Sea Breeze : -

Due to uneven heating of the land and sea by Sun, at day times hotter air above the land rises up creating a low pressure area above the land. The breeze flowing from high pressure region of air (sea) to low pressure region (land) is known as sea breeze.


(11)   Land Breeze : -

The breeze flowing from land to sea at night is known as land breeze.


(12)    Air pollution : -

Addition of harmful gases like oxides of nitrogen, oxides of sulphur, carbon monoxide, and other particulates to the atmosphere is known as Air pollution.


(13)   Acid Rain : -

Rain containing acid formed from the reactions of pollutants like oxides of sulphur and water, which causes damage to plants and buildings and decreases soil fertility.


(14)   Smog : -

Fog combined with smoke is smog, a indicator of Air pollution formed in winters.


(15)   Lichens : -

A bio-indicator growing at the bark of tree forming thin greenish white crust is sensitive to air pollution.


(16)   Water Pollution : -

Undesirable changes in water like addition of harmful substances and removal of useful substance from water, or even temperature variations in water causes water to pollute.


(17)   Soil : -

Portion of earth surface that consists of disintegrated rock and decaying organic materials.


(18)   Soil Pollution : -

Addition of harmful substances and removal of useful substances from soil causing useful organisms to die in soil causes soil pollution.


(19)   Soil Erosion : -

It is a process of removal of top layer of soil i.e. Top soil.


(20)   Biogeochemical Cycles : -

The cyclic flow of nutrients in abiotic and biotic components.


(21)   Water Cycle : -

The cyclic flow of water in the Biosphere with different forms like underground water, vapour in atmosphere.


(22)   Nitrogen Fixation : -

Conversion of atmospheric nitrogen into nitrogenous compounds by nitrogen fixing bacteria.


(23)   Ammonification : -

Conversion of nitrogen containing proteins of dead and decayed organisms into ammonia by microorganisms like bacteria, fungi.


(24)   Decomposers : -

Convert complex nitrogen containing compound into ammonia. Example - Fungi and bacteria.


(25)   Nitrification : -

Conversion of ammonia to nitrites and further to nitrates by nitrogen fixing bacteria.


(26)   Denitrification : -

Conversion of nitrates to atmospheric nitrogen.


(27)   Green House Effect : -

When light from sun enters earth's atmosphere, some radiations are reflected, some are absorbed and some are captured by the gases present in the atmosphere like CO2, CH4, Nitrogen oxide, Chlorofluoro carbons (CFCs). This capturing of heat in the atmosphere makes the Earth warmer, leading to global warming.


(28)   Global Warming : -

With the increase in green house gases in the atmosphere due to burning of fossils and CFCs from air conditioners and refrigerators the entrapment of radiations of sunlight had also increased. This results in the excessive heating of the Earth, making the Earth Warmer. Causing the glaciers to melt which would in return increase the content of water on Earth making it submerged.


(29)   Ozone Layer : -

Ozone layer is a protective covering around the Earth which protects it from harmful UV-radiations coming from Sun.


(30)   Depletion of Ozone Layer : -

Excessive production of compounds like CFCs, freons, halons on Earth causes damage to the ozone layer by reacting with ozone (O3).


(31)   Ozone Hole : -

Above Antarctica thinning of Ozone layer occurred causing UV-radiations to pass through this area named Ozone hole.


(32) Global Warming and Diseases like skin cancer are two major harmful consequences of Ozone layer depletion.


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