Organisation of an ecosystem - AQAHow materials are cycled in an ecosystem
The feeding relationships between organisms in an ecosystem can be seen in food chains. Sampling allows us to measure the abundance and distribution of these species.
Atoms exist in different forms or compounds at different times in history and cycle between them. We can see this cycling in the elementA substance made of one type of atom only. carbon and the compoundA substance formed by the chemical union of two or more elements. water. Just as rocks can cycle between igneousRocks that formed under very hot conditions within the Earth., sedimentary rockA type of rock formed by the deposition of material at the earth's surface. and metamorphicA type of rock formed under intense heat or pressure., carbon and water can exist in different forms at different times.
Other elements and compounds also exist in cycles. Many humans eat protein in the form of meat from other animals. Our bodies break this down into its constituent parts called amino acids and then use these to make proteins within our own bodies for growth and repair. When we eventually die these building blocks are returned to the environment to be used by other living organisms.
Decomposing bacteria and fungi help dead organisms break down and rot. They help recycle minerals and nutrients to the environment, which can then be used by other organisms. As they decomposeIf a substance decomposes, it breaks down into simpler compounds or elements. dead matter, the decomposers also respireTo engage in respiration, the energy-producing process inside living cells. and so release carbon dioxide to the environment, contributing to the carbon cycleThe processes and events involved in recycling carbon in the environment..