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The Earth System's Four Spheres


    1.    Describe the four spheres of the Earth system.

    2.    Explain how the spheres interact and change.

Key Terms:

    atmosphere        geosphere        hydrosphere        biosphere


Earth supports life unlike any planet that has been discovered this far.  This unique ability rests in the formation of an atmosphere that contained and allowed the geosphere, hydrosphere, and biosphere to flourish.  

The Atmosphere:

The atmosphere is the area around the planet that contains the gases of our planet.  Our atmosphere is unique among the planets because it contains oxygen which is what we depend on for our life systems.  Although we will go into further detail later here are a couple of the functions of our atmosphere.

area around Earth containing the gases
protects us from harmful radiation
traps in water supporting the water cycle
absorbs and reflects heat supporting a mild climate
varying areas of pressure allow us to experience weather

(starryskies.com/solar_system/ Earth_html/atmosphere.jpg)

The Geosphere:

The geosphere is the Earth excluding the water.  Contained in the geosphere are:

geographical structures - rocks, mountains, beaches, ...
underlying structures - mantle, ocean basins, core, magma, ....
mineral resources - iron, copper, ...

(ess.geology.ufl.edu/ess/Introduction/ Geosphere.gif)

The Hydrosphere:

The hydrosphere is the name give to all of the water contained within the Earth system. The system is continually recycled.  This becomes very important as the amount of useable fresh water is only about 0.5% of the total hydrosphere which includes:

water bodies - oceans, lakes, rivers, streams, ground water, ...
frozen structures - ice caps, snow, ...
water vapor in the atmosphere

(www.math.montana.edu/.../ess/ hydrosphere/topex01.gif)

The Biosphere:

All of the living things on the Earth and in the sky make up the biosphere.  From bacteria to people all are members.  Within the four spheres no one has impacted the Earth system as human beings have.  Our green house gases have raised the temperature and changed the composition of the atmosphere.  Our construction and mining have altered the face of the geosphere, our consumption, irrigation and water diversion practices have changed the composition and location of the hydrosphere, and our increasing incursion into the open spaces of the planet have caused the extinction of a large portion of the biosphere.

(www.exitfive.com/dahlov/ images/biosphere.jpg)









Last modified: January 28, 2003