Are there species that occupy several roles in the food hierarchy?

Question

Are there species that occupy several roles in the food hierarchy? By role, I am referring to producer, primary consumer, secondary consumer, tertiary consumer, quaternary consumer and so on. **Examples of more specific questions** - Are there species that are both primary and secondary consumer? - Are there species that are primary consumer, secondary consumer and a tertiary consumer? - Are there species that are both producer and primary consumer?

Answer 1

Yes. An example of a species that is both a producer and secondary consumer is a pitcher plant (or other carnivorous plant). Omnivores, which consume both plants as well as herbivorous animals (primary consumers), could be considered both primary and secondary consumers, though you may see them referred to simply as a type of secondary consumer. Depending on their diet, humans can act as primary, secondary, tertiary, or quaternary consumers. In reality, food webs within ecosystems are complicated, and rarely follow a simple linear hierarchy, but the categories are useful representations of energy transfer within a system.