Ecosystems, Energy Flow and Trophic Levels

An ecosystem is a community of interacting organisms together with the non-living (abiotic) environment they occupy. Ecology examines how these biotic and abiotic components exchange energy and matter. A key distinction in biology is that energy flows through an ecosystem in one direction and is ultimately lost as heat, whereas matter (nutrients) is recycled. This lesson focuses on the one-way flow of energy from sunlight to the organisms that capture, transfer, and dissipate it.

Producers and Consumers

Producers (autotrophs) synthesize their own organic molecules from inorganic raw materials. On land and in the surface waters of oceans, most producers are photosynthetic, using light energy to convert carbon dioxide and water into glucose. Producers form the foundation of nearly every ecos