NOTES ON OUR ENVIRONMENT BY Nagraj Sharma

NOTES ON OUR ENVIRONMENT ( Nagraj Sharma )

Environment : The physical, chemical and ‘ biological conditions of the region in which an organism lives is called its Environment. It includes air, light, soil, temperature, water and the presence or absence of other organisms, i.e., the conditions for development or growth.

Ecosystem : A community of organisms, interacting with each other, plus the environment in which they
live and with which they also interact. The examples of ecosystem are : a pond ; a desert; a forest; a lake ; a river ; a mountain ; the sea.
All the above ecosystems are made-up of two main components.

Food Chain :-  A food chain is a simple representation of transfer of energy from the sun to different biotic components of an ecosystem. When an animal takes food, this energy is supplied to the next level. and the process goes on. 

Food Web:-   In any ecosystem, there can be many food chains which are interlinked at various levels. Thus, many food chains form a network which is called food web.

Transfer of Energy through a food chain: Different levels in the food chain are called trophic level. Out of the energy consumed by an organism at a particular trophic level, 90% is utilised for its own need and rest 10% is left for the organism of the next trophic level.  

Biological magnification ::- “The increase in concentration of harmful chemicals in the body of living organisms at each trophic level of a food chain is called biological magnification”.

ENVIRONMENTAL PROBLEMS

(a) depletion of the Ozone Layer and waste disposal.
(b) pollution due to mismanagement of waste disposal.

I. Depletion of Ozone Layer

• (O3) layer is largely found in the stratosphere which is a part of our atmosphere from 12 km – 50 km above sea level.
• Ozone is a deadly poison at the ground level.
• Ozone is formed as a result of a following photochemical reaction.
  
• Ozone layer is a protective blanket around earth which absorbs most of the harmful U.V. (Ultraviolet) radiation of the Sun, thus protecting the living beings of the earth from health hazards like skin cancer, cataract in eyes, weaken immune system, destruction of plants etc.
• 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 Flouro Carbon) a synthetic, inert chemical E.g. Freon which are used as refrigerants and in fire extinguishers, caused Ozone depletion in the upper atmosphere.

Garbage Disposal

Industrialization and rise in demand of consumer goods have created a major problem in the form of wastes/garbage accumulation and its disposal specially in urban area. These are:-

1. Open dumping : A conventional method in which solid wastes dumped in selected areas of a town. It actually cause pollution
2. Land fillings : Wastes are dumped in low living area and are compacted by rolling with bulldozers
3. Composting : Organic wastes are filled into a compost pit (2m × 1m× 1m). It is then covered with a thin layer of soil. After about three months the same garbage filled inside the pit changes into organic manure.
4. Recycling : The solid wastes is broken down into its constituent simpler materials. These materials are then used to make new items. Even non-bio degradable solid wastes like plastic, metal can be recycled.
5. Reuse : A very simple conventional technique of using an item again& again. For e.g. paper can be reused for making envelops etc.