Food chain
A food chain refers to the sequence of events in an ecosystem, where one organism eats another and then is eaten by another organism. It starts with the primary source like the sun or hydrothermal vents where producers make food, continues with consumers or animals who eat the food, and ends with the top predator.
While the trophic level of an organism is the number of steps it is from the start of the chain. The biomass and food pyramid do not indicate the preying and being preyed pattern in an ecosystem.