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EVS ||Lesson 1: INTRODUCTION Cheat Sheet (DRAFT) by

LESSON-1 INTRODUCTION TO ENVIRONMENTAL STUDIES

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Components of Envrio­nment

4 Major Components
Lithos­phere
Litho = Rock
Hydros­phere
Hydro = Water
Atmosphere
Atmo = Air
Biosphere
Bio = Life
The planet Earth is catego­rised into different spheres which represent solid [rock/­soil], liquid [water], and gaseous [air] phases. The overla­pping zone of the three spheres is called the biosphere, where life can exist.

Atmosp­here: (Greek: Atmos means vapor)

✦gaseous mixture which envelops the planet earth is called atmosphere
✦Content of water vapor, density of the air mass and atmosp­heric pressure decreases rapidly with the increase in altitude
Compos­ition of dry air
Component
Volume %
Nitrogen
78%
Oxygen
20%
Argon
0.9%
CO2
0.04%
Gases in Traces
Remaining

Layers of atmosphere & temper­ature

The rate of change of temper­ature with the altitude is called lapse rate. The atmosphere has
been stratified into major four layers where temper­ature decreases (negative lapse rate) or
increases (positive lapse rate).
  

Lithos­phere: (Greek: Lithos means rock)

✦Litho­sphere is the outermost layer of the crust which represents the land mass of the planet.
✦consists of rocks, soil, sediments and minerals.
✦geolo­gical structures or landforms like high mountains, plateau, deep valleys and sea beds make the surface of lithos­phere uneven
✦geolo­gical processes like weathering & erosion, volcanic eruptions, biogeo­che­mical cycles take place at the lithos­phere
✦Different terres­trial ecosystems like forests, grassl­ands, deserts etc. are found on the lithos­phere

Cross Section of Lithos­phere

Earths structure can be stratified into
-Outer Crust
-Middle Mantle
-Inner Core

4 Major Layers of Atmosphere

rate of change of temper­ature with the altitude is called lapse rate
✦Tropo­sphere
upper layer is called tropopause
✦Strat­osphere
Ozone layerin this region absorbs harmful UV radiation, partic­ularly UV-B radiation because of which life is possible on earth’s surface
✦Mesos­phere
Density of air is very low and important chemical species found in this region are O2 + and NO+
✦Therm­osphere
ionic oxygen atoms and other ions in this layer absorb short wave solar radiation which increases the temper­ature in this layer
 

Hydros­phere: (Greek: Hydor means water)

✦repre­sents water masses in solid (ice cover, glaciers etc.), liquid (water bodies) and gaseous (water vapors) phases
✦covers almost three-­fourth of the total surface area of the earth.
✦is an integral part of the water cycle and plays a crucial role in mainta­ining normal climatic, meteor­olo­gical, physical, chemical and biological functions on the planet
✦Oceans and seas are the largest sink of carbon in the enviro­nment.
Total water
97% Salt Water + 3% Fresh Water

Total Fresh water = 2% Ice Caps + 1% Surface and Ground Water

Biosph­ere­:(G­reek: Bios means life)

✦self-­reg­ulating overla­pping region of atmosp­here, lithos­phere and hydros­phere
✦the enviro­nment where life sustai­nably exists, nourished and flourished by the healthy intera­ction between biotic and abiotic components
✦biotic (autot­rophs and hetero­trophs)
 
✦abiotic components (air, water, sunlight, soil, rock etc.)