An ecosystem is a community of living organisms like plants, animals and microbes in union with the nonliving components of their environment  like air, water and mineral soil and interacting as a system.

Producers or autotrophs are organisms that make their own organic material from simple inorganic substances. For most of the biosphere the main producers are photosynthetic plants and algae that synthesis glucose from carbon dioxide and and water.

Glucose is produced which along with other nutrients is used to produce biomass. This biomass that provides the total theoretical energy available to all organisms coming in the trophic levels after the producers.

Consumers  or heterotrophs are organisms that obtain nutrition by eating or digesting other organisms. These are the herbivores and carnivores of the ecosystem. By eating other organisms they gain both food as an energy supply and nutrient molecules from within the biomass ingested.

Decomposers are the waste managers of any ecosystem. The are the final link in a foodweb breaking down dead organic matter from producers and consumers and ultimately returning energy to the atmosphere in respiration and inorganic molecules bake to the soil during decomposition. Decomposers can be divided into two groups based on their mode of nutrition.

1. Detritivores are organisms that ingest non-living organic matter. These can include earthworms, beetles and many other invertebrates.
2. Saprotrophs are organism that lives on or in non- living organic matter, secreting digestive enzymes into it and absorbing the products of digestion. These include Fungi and bacteria.