Abiotic elements of an ecosystem include sunlight, water, air, temperature, precipitation, water and soil chemistry. These elements help to make an ecosystem work. Sunlight, for instance, helps to make photosynthesis possible in plants. Photosynthesis is the process by which plants use the sunlight to make energy. A byproduct of this process is oxygen, which in turn helps make Earth hospitable to humans.
The biotic elements of an ecosystem include the plants, animals and microorganisms like fungi and bacteria. Biotic organisms can be classified as herbivorous (plant-eating), omnivorous (eating everything), detrivorous (waste-eating), carnivorous (meat-eating) and primary producers. Interactions in an ecosystem can be viewed in terms of the energy flowing through it. After plants, which are primary producers, capture sunlight and convert it to energy, herbivorous organisms harness that energy by eating the plants. Carnivores eat the herbivores. Bacteria and fungi, which are decomposers, feed on dead animals and waste.
Energy makes its way through an ecosystem when either living or dead material is consumed. Food chains in which dead material is the initial source of energy are called detritus food chains. Examples of such food chains occur on the ocean floor where sunlight cannot reach to sustain plant life. Food chains in which green plants are directly consumed are called grazer food chains.
The interactions in an ecosystem also involve the cycling of elements in that ecosystem. Biogeochemistry is the study of how living organisms are influenced by the chemistry and geology of the earth. An examination of these influences can reveal, to a degree, how chemical elements move through an ecosystem. For example, by using biogeochemistry, the effects of environmental pollution can be understood.