Final answer:
A food chain is a linear model that represents a single path of energy flow in an ecosystem, while a food web shows multiple pathways. Producers capture energy from the sun, which is then transferred through a series of consumers up to the apex predators, with decomposers recycling matter at each level.
Step-by-step explanation:
The flow of energy in an ecosystem is typically represented using models such as a food chain or a food web. In a food chain, which is a linear model, energy flow starts from the sun or inorganic chemicals into producers like grasses on land or phytoplankton in aquatic environments. These producers are consumed by herbivores, which are then eaten by carnivores, and eventually by an apex predator at the top. Each organism in the food chain occupies a specific trophic level. While the food chain is a simple way to understand energy flow, it is somewhat simplified compared to the actual complexities of nature, where organisms often eat and are eaten by multiple species.
A food web, on the other hand, represents multiple interacting pathways by which energy flows through organisms in an ecosystem. Energy enters ecosystems from the sun, and this energy then flows through the system from producers to various consumers before ending up with decomposers, which break down matter from all levels of the food chain, recycling it within the ecosystem. Food webs provide a more holistic and accurate representation, though they are more complex than food chains.