Biodiversity and cycling materials GapFill

Materials in an ecosystem are limited and, in most cases, will be repeatedly recycled through the system; without recycling, resources such as carbon and water will not be available for other organisms. The carbon cycle removes  carbohydratesstarchdustcarbon dioxide from the atmosphere to be used by plants, while returning it to the environment in processes such as  transcriptiontranslationrespirationphotosynthesis and decay.

Decay, or decomposition, occurs by the action of microorganisms, whose metabolism can be affected by temperature, oxygen availability and  humiditypressurewind speedsunlight. Farmers take advantage of this to produce  pesticidesirrigation systemsgreenhousescompost, which can help them maintain healthy soil and reduce the need for expensive fertilisers.

Human activities, including that of farmers, can directly affect the cycling of substances, and, if not appropriately controlled, can have a damaging impact on ecosystems. Particular ways in which humans can affect the environment and their own sustainability include:

• waste management, such as causing pollution to land, air and  watercellsgenessoil;
• the excessive removal of trees from Earth – a process known as  dephotosynthesisdeforestationoverchoppingculling;
• the burning of  acid rainfusion reactorssolar powerfossil fuels, which contributes to global warming; 
• the increasing demand for  fur and woolvegan productsmeat and fishhoney, which means animal farming must occur at a greater rate to counteract food insecurity;
• and the introduction of  symbioticparasiticnon-indigenousmutualistic species to different environments, which can destabilise ecosystems.