Cycles of matter: Carbon
Carbon is everywhere in the desert. It flows through the ecosystem like a circle. Carbon starts in the atmosphere as carbon dioxide, and is taken in by plants, like the cactus. Plants use this carbon dioxide and water in photosynthesis to create glucose and oxygen. After a while, a primary consumer, like the desert sheep, eats the plant and obtains its glucose. A secondary consumer, like the bobcat, can eat this primary consumer to obtain its glucose. The consumer uses this glucose and oxygen in the process of cellular respiration to make ATP, water, heat, and carbon dioxide. This carbon dioxide is released into the atmosphere where it goes through the process again. Carbon can also be released into the atmosphere by combustion. Carbon dioxide is released into the atmosphere when wood is being burned or fossil fuels are being used.
Cycle of matter vs. Energy Pyramid
The cycle of matter differs from how energy flows. As you can see from the diagram, matter moves in a cycle, or like a wheel, where matter is never destroyed or made new. The energy flow is different because energy moves in a straight line, like stairs. The energy starts from the sun and works its way down until there is none to little energy left.