This document discusses ecosystems and their components. An ecosystem is defined as the living and nonliving interactions within a specific environment. It includes biotic components like producers, consumers, and decomposers, as well as abiotic factors such as climate, soil, water and sunlight. Producers use photosynthesis to convert sunlight into chemical energy, consumers eat producers or other consumers to obtain energy, and decomposers break down dead organic matter. Key ecosystem functions that maintain balance and life processes are productivity, decomposition, energy flow between organisms, and nutrient cycling.