The level within a food chain in which all members are equally far removed
from the primary food producers. The first trophic level is occupied by primary producers, which are green plants that use photosynthesis to obtain energy from sunlight. Herbivores (primary consumers), which eat the plants, occupy the second level. Secondary consumers, on the third trophic level, are carnivores, which eat the herbivores. There may be a fourth level (tertiary consumers) occupied by other carnivores that eat those on the third level.