Trophic Level - Ecosystem
In an ecosystem, the various biotic components are related to each other and form food chains. If we group all the organisms in a food chain according to their general source of nutrition, we can assign them different trophic (feeding) levels - Figure. The producer organisms belong to first trophic level, primary consumers (herbivores) to the second trophic level, secondary consumers (carnivores) to the third trophic level and tertiary consumers (top carnivores) to the fourth trophic level.
Figure: Diagrammatic representation of trophic levels in an ecosystem