Caron and Nitrogen Cycles Blog

Bio in organisms when it enters the animals' bodies through eating.  Geological when it goes back into the soil (ex: waste).  Chemical when it enters back to the air through the cycles.

Carbon is in a cycle because it needs to exit organism's bodies as well.  It is a part of all organisms and plants use it as food.  If there was no cycle, the plants would have too much carbon inside them, that when animals ate the plants, the carbon would stay in the animals' bodies forever.  Also, the carbon would stay in the soil forever (geological).  Both of these situations are unhealthy.

http://en.wikipedia.org/wiki/File:Carbon_cycle-cute_diagram.svg

The Nitrogen cycle is important because it puts nitrogen into the ground and the air (chemical & geological).  Nitrogen is necessary for all living things, and our atmosphere is made up of about 75% nitrogen.  Bacteria takes the nitrogen out of the air and transforms it into nutrients for the soil.  The nutrients provided by bacteria helps the plants to grow.  When the animals eat the plants grown in nitrogen soil, nitrogen enters their body.  It then exits to the earth through their waste.

http://en.wikipedia.org/wiki/File:Nitrogen_Cycle.svg

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