Trophic level - the position of an organism in a food chain
The first organisms in a food chain are always producers (plants). The second level in a food chain are the primary consumers (first to eat the producers). Thereafter you have the secondary consumers (who eat the primary consumers), the tertiary consumers (who eat the secondary consumers) and sometimes the quaternary consumers (who eat the tertiary consumers). Note that the terms 'herbivore' and 'carnivore' are not used to describe the trophic level, these terms instead refer to the diet of the organism.
