The whole Earth has a total of four very important cycles. Living beings need these four cycles to survive. There is the water cycle, the carbon cycle, the nitrogen cycle, and the phosphorus cycle. These four cycles help the Earth and the organisms on Earth live.
All living things require water to survive. Water moves between the ocean, atmosphere, and land, called the water cycle. The process by which water changes from liquid form to an atmospheric gas is called evaporation, occurring by the sun’s heat. During the day, the water becomes into moist air because of the sun, and then it cools. Eventually, the water vapor condenses into tiny droplets that form clouds. When the droplets become large and heavy enough, the water falls to earth, which is called precipitation in the form of rain, snow, sleet, or hail. Much of the precipitation on land runs along the ground until it enters a river or stream which carries it to an ocean and the water cycle begins again.
Carbon is important to living systems because it is the key ingredient in all living organisms. There are four different kinds of processes involved in the carbon cycle. 1, biological processes, such as photosynthesis, respiration, and decomposition of plants and animals. 2, geochemical processes, such as the release of carbon dioxide gas to the atmosphere by volcanoes. 3, mixed biochemical processes, such as the burial of carbon-rich remains of organisms and their conversation into coal and fossil fuels by the pressure of the overlying earth. 4, human activity, including mining, the burning of fossil fuels, and the cutting and burning of forests.
Carbon dioxide is released into the atmosphere and plants take in carbon dioxide and use the carbon to build carbohydrates during photosynthesis. The carbohydrates are passed along food webs to animals and other consumers.
All organisms require nitrogen to make amino acids, which in turn are used to build proteins. Although nitrogen gas is the most abundant form of nitrogen Earth, only certain types of bacteria can use this form directly. Some bacteria, which live in the soil and on the roots of plants called legumes, convert nitrogen gas into ammonia in a process known as nitrogen fixation. When organisms die, decomposers return nitrogen to the soil as ammonia. Other soil bacteria convert nitrates into nitrogen gas in a process called denitrification. This process releases nitrogen into the atmosphere once again.
Phosphorus is essential to living organisms because it forms part of important life-sustaining molecules such as DNA and RNA. Unlike carbon, oxygen, and nitrogen, phosphorus does not enter the atmosphere. Instead, phosphorus remains mostly on land in rock and soil minerals, and in ocean sediments. There phosphorus exists in the form of inorganic phosphate. As the rocks and sediments slowly wear down, phosphate is released. When plants absorb phosphate from the soil or from water, the plants bind the phosphate into organic compounds. Organic phosphate moves through the food web, form producers to consumers, and to the rest of the ecosystem.
All of these cycles are very important to us. They are the building blocks of organisms. They also help sustain life Earth and we would not be able to live without water, carbon, nitrogen, and phosphorus. These elements are crucial to every human's life. But the cycles make it not harm to us.