A good answer would be "caste". A caste system is the social hierarchy in India in which people are first assigned one of the four main castes (scholars, warriors, farmers, servers) and then additionally often also to smaller castes (farmers of rice, of bananas). The social mobility is very low.
Producers obtain energy from photosynthesis as they are the plants, bacteria, and algae that form the initial layer of energy transfer. Producers then transfer a percentage of energy to first tier consumers (herbivores/omnivores).
