Tutoring biology, you come across the concept of trophic level. The tutor defines it.
In an ecosystem, a tropic level can be thought of as a level of energy or of consumption.
The organisms at trophic level 1 are called primary producers. By photosynthesis, they harvest energy from the sun to produce carbohydrates. Grass is a primary producer; in the ocean, phytoplankton is an example.
At trophic level 2 are the plant-eaters.
At trophic level 3 are predators (carnivores).
Mader, Sylvia S. Inquiry into Life, 9th ed. Toronto: McGraw-Hill, 2000.
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.