Transfers of energy and nutrients are determined by trophic relationships within ecosystems - who eats whom. Food webs diagram these interconnected patterns of feeding relationships within ecosystems. Trophic levels specify the position of an organism within a food web with respect to its source of energy. Energy is lost during each transfer through the food web, due to thermodynamic effects and ecological relationships. As a result, the number of trophic levels in ecosystems is generally limited to a handful or less, and species at high trophic levels are rare compared to species at lower trophic levels.
Energy flows through ecosystems.
Trophic interactions transfer nutrients from producers to consumers. As producers and consumers die, the actions of decomposers breaks down the dead organic matter produced, and in doing so makes nutrients available to the producers once again. Describe why it is difficult to categorize some species into trophic levels. Big fierce animals are rare. Explain what this means.