Which term best describes an organism that feeds directly on producers?

• A. Autotroph
• B. Primary consumer
• C. Saprotroph
• D. Omnivore

Answer: (B)

Organisms that feed directly on producers occupy the primary consumer level in an ecosystem. Producers, or autotrophs, convert sunlight into chemical energy. When an animal eats those plants, it gains energy directly from that producer without consuming another consumer, placing it at the second trophic level—the primary consumer. This is typically herbivory; for example, rabbits eating grass or caterpillars munching leaves. Saprotrophs, by contrast, feed on decaying organic matter after life processes have ended, acting as decomposers. Omnivores eat both plants and animals, so they aren’t defined solely by feeding on producers, even though they may consume producers as part of their diet. So, the term that best describes an organism that feeds directly on producers is primary consumer.