Those organisms in all the trophic levels , with the exception of the producers . These include herbivores , carnivores , omnivores , and parasites .
Primary consumers subsist on plant material alone.
Secondary consumers feed on primary consumers, and so on. One who uses goods and services. Certain assumptions are made in economics about the consumer. He or she will use goods commensurate with their price such that a fall in the price of commodity will lead to increased consumption. So will a rise in income, and the reverse is held to be true.