What defines consumers in an ecosystem?

Consumers in an ecosystem are defined by their role as organisms that obtain their energy by feeding on other organisms. This includes a diverse range of species, such as herbivores, carnivores, and omnivores, all of which rely on other living beings (plants, animals, or both) for sustenance. This feeding behavior is essential for the flow of energy through food webs, as consumers play a crucial role in transferring energy from producers—organisms that create their own food through processes like photosynthesis—to higher trophic levels.

The other options describe different roles within an ecosystem: producers generate energy, decomposers break down organic matter and recycle nutrients, and organisms that only feed on plants (herbivores) are a subset of consumers. However, the defining characteristic of consumers is their dependence on other organisms for energy. This concept is fundamental to understanding ecosystem dynamics and energy flow.