carbon and water cycles

• Life on Earth has existed for billions of years
• Recycling on Earth includes molecules like water and carbon dioxide, as well as individual atoms like nitrogen, phosphorus, and carbon
• Atoms can be used repeatedly to create various organisms over millions of years
• An estimated six octillion atoms inside a person have been recycled from oceans, volcanoes, other animals, and even other humans
• Water Cycle
• Energy from the sun causes water to evaporate from various sources like lakes, oceans, rivers, puddles, soil, and plant leaves (transpiration)
• Evaporated water vapor accumulates in the sky and condenses into clouds, which eventually lead to precipitation (rain)
• Precipitated water can seep into the soil, flow into rivers, or be taken up by plants, completing the cycle
• Carbon Cycle
• Carbon is stored in the air as carbon dioxide, in plants as biological molecules, in the soil with bacteria and microorganisms, in fossil fuels underground, and in animals as biological molecules
• Photosynthesis is a crucial process where green plants and algae convert carbon dioxide into biological molecules like glucose
• Carbon can be released back into the atmosphere through respiration or passed on to animals that consume plants
• When plants and animals die, carbon can be released through microbial respiration in the soil or converted into fossil fuels in anaerobic conditions
• Fossil fuels can be burned by humans to produce carbon dioxide, closing the carbon cycle