Notes on "Natural Resources" by Nagraj Sir

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 Notes on "Natural Resources" by Nagraj Sir


Natural Resources

The resources available on the earth and the energy from the sun are necessary to meet the basic requirements of all life forms on the earth.

The stocks of nature which are useful to mankind are known as natural resources.
Examples: air, water, soil, minerals etc.

 Resources on the earth


→ The outermost crust of the earth is called the lithosphere.

→ Water covers 75% of the earth’s surface. It is also found underground. These comprise the hydrosphere.

→ The air that covers the whole of the earth like blanket is called the atmosphere.

Biosphere

→ All living things on earth together with atmosphere, the hydrosphere and the lithosphere interact and make life possible is known as biosphere.

• It may be:

(i) Biotic components: Plants and animals.
(ii) Abiotic components: Air, water and soil.

Air: It is a mixture of many gases like oxygen, nitrogen, carbon-dioxide, water vapour and other gases.

  • Nitrogen is used by plants for protein synthesis.
  • Oxygen sustains life used for respiration, combustion.
  • Carbon-dioxide used by plants for preparing food by photosynthesis.

Water vapour: provides moisture.

Atmosphere: Acts as a protective blanket around the earth. Maintains the temperature on the surface of earth. Winds are caused due to uneven heating of atmosphere, these winds maintains the pressure difference and causes cold and hot air, sea and land breeze, brings rain etc.

Rain: The clouds formed due to the evaporation of water condenses and precipitates as rain.

Water: Various sources of water are available i.e., surface water, underground water, snow, ice-bergs, water vapour in the atmosphere.

Use of Water

  • Water is used for transportation.
  • Sustain life
  • Used by plants and animals for life-processes. Water available for drinking should be conserved and used wisely.

Soil: Soil is formed by a very slow process i.e., by weathering of rocks. It consists of various nutrients. Plants grow in the soil, many microbe’s homes is soil.

Varieties of soil types are available

  • Sandy soil
  • Loamy Soil
  • Clayey Soil
  • Black soil
  • Red soil
  • Alluvial soil
  • Laterite soil.

Temperature: Temperature and light is also required for all biotic components.

Pollution: Contamination of natural sources with unwanted substances.

  • Air Pollution: Air contaminated with smoke, fumes, dust, pollen grain, etc.
  • Water Pollution: Water contaminated by sewage, industrial waste, excreta, chemicals, fertilizers etc.
  • Soil Pollution: Soil gets contaminated with fertilizers, pesticides, garbage, chemicals etc.
Environmental Problems Caused by Humans

Depletion of Ozone Layer


→ Ozone layer is present in the stratosphere which is a part of our atmosphere from 16 km to 60 km above sea level.

→ Ozone is an allotrope of oxygen. Its molecule is made up of three oxygen atoms. Molecular formula is O3.

→ Ozone layer absorbs the ultra-violet rays coming from the sun and protects living being from their harmful effects like skin cancer, cataract in eyes, weaken immune system.

→ The decline of ozone layer thickness in Antartica was first observed in 1985 and was termed as ozone hole.

Reason of Ozone Depletion

→ Excessive use of CFCs (Chloro Fluoro Carbon) in refrigeratos, jet planes, spray cans, fire extinguishers.

→ Nuclear explosion

Bio-geo-chemical Cycles: A constant interaction between biotic and abiotic components of the biosphere makes a system and these flow of components form a cycle called bio-geo-chemical cycle.

water cycle



Oxygen Cycle







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