Biomass is the total amount of living organic material in an ecosystem. See also food pyramid. The part of the earth in which living species are found is called the biosphere. Most organisms are found within a few metres of the earth's surface, either in the soil, water or atmosphere. The living,or biotic, part of the environment includes the various populations of living plants, animals and microbes which together form the communities of the environment.
Green plants get carbon from the carbon dioxide in the atmosphere.
Through photosynthesis the carbon is changed into carbohydrates. The carbon is transferred to animals when the plants are eaten. Carbon is returned to the atmosphere through animal respiration and through decomposition when the plants or animals die. Animals that eat other animals are called flesh-eaters, or carnivores. Carnivores that feed on other carnivores are called second-order carnivores.