The atmosphere provides organisms found within ecosystems with carbon dioxide for photosynthesis and oxygen for respiration . The processes of evaporation , transpiration , and precipitation cycle water between the atmosphere and the Earth's surface. Solar radiation is used in ecosystems to heat the atmosphere and to evaporate and transpire water into the atmosphere. Sunlight is also necessary for photosynthesis . Photosynthesis provides the energy for plant growth and metabolism, and the organic food for other forms of life.
Water is the medium by which mineral nutrients enter and are translocated in plants.
It is also necessary for the maintenance of leaf turgidity and is required for photosynthetic chemical reactions. Plants and animals receive their water from the Earth's surface and soil. The original source of this water is precipitation from the atmosphere. Ecosystems are composed of a variety of living organisms that can be classified as producers , consumers , or decomposers . Producers or autotrophs , are organisms that can manufacture the organic compounds they use as sources of energy and nutrients .