Cycles & The Earth
1. Describe the characteristics of the water, carbon, energy, and nitrogen cycles.
2. Analyze how humans interact with the different cycles.
cycle water cycle evapotranspiration carbon cycle energy cycle solar energy geothermal energy tidal energy
As we discussed earlier, Earth functions as a closed system. In order for the system to continue to thrive the Earth must cycle its resources so that it can renew its supply of needed constituents such as water, carbon, nitrogen and energy.
The Water Cycle
As you can see from the above image there are many paths for the water cycle. Here is one scenario.
The Carbon Cycle:
The carbon cycle is considered to b a biogeochemical cycle. Bio because of the sugars and molecules that are made from it and geo from the CO2 that is produced as a result of cellular respiration and the burning of organic compounds. Carbon is the building block of life.
The Nitrogen Cycle:
Nitrogen is an important building block used in the formation of DNA and proteins. Nitrogen is contained in the waste of every living organism as well as in the decaying organic material plants and animals. Nitrogen uptake is primarily via ingestion. Nitrogen is returned to plants through the process of nitrogen fixation that is performed by bacteria involved in the breakdown of dead organic material.
The Energy Cycle:
Earth's energy cycles are often referred to Earth's energy budget. If the Earth takes in more energy than it uses the climate on Earth will get warmer and if it releases more than the sun gives it will get cooler. No matter where the energy comes from it is important to remember that the laws of thermodynamics apply to each situation. (Energy is neither created nor destroyed, only change from one form to another.) There are three main sources for Earth's energy.
1) Solar Energy
2) Geothermal Energy
3) Tidal Energy
Last modified: January 30, 2003