Heterotrophs are therefore consumers. Chemicals are recycled. Energy is not recycled. Energy and trophic dynamics Trophic refers to nutrition. Organisms can be arranged into trophic levels in accordance with these interactions.
Plants represent the first trophic level.
Animals which are consumers constitute higher trophic levels. Herbivores are the second trophic level and graze on plants. A simple linear model that depicts the nutritional interactions of organisms in an ecosystem is the food chain. The nutritional interactions are rarely so simple because organisms may have varied diets and eat both plants and animals. A more realistic way to depict the nutritional connections is with a food web.