Herbivores obtain nitrogen primarily by consuming plants that have absorbed nitrogen compounds from the soil.

Nitrogen Pathway

Plants take up nitrates and ammonia—fixed from atmospheric nitrogen by soil bacteria—through their roots and incorporate them into proteins, amino acids, and nucleic acids. Herbivores ingest these nitrogen-rich plant materials during feeding, breaking them down via digestion to recycle the nitrogen for their own protein synthesis and growth.

Role in Ecosystem

This process is part of the nitrogen cycle, where nitrogen fixed by bacteria like Rhizobium in plant roots becomes available to primary consumers such as herbivores. Decomposers later return nitrogen to the soil from animal waste and remains, sustaining the cycle.