Trophe comes from the Greek word “trope” meaning food or nourishment. Trophic diagrams show the relationship between organisms in an ecosystem. Comprising of levels, a trophic level is the position an organism occupies in a food chain, or food web.
August THienemann came up with terms: producers, consumers and reducers. Reducers are sometimes called decomposers.
Trophic level 1 is primary producers such as plants.
Trophic level 2 is usually Herbivores , usually called not primary producers, but primary consumers
Trophic level 3 is nromally carnivores, also called secondary consumers
Level 4 or 5 is apex predators, called tertiary consumers.
To draw a trophic level the wider the bar the more organisms there are at that level. As an example if one primary producer can feed many primary consumers the bar will be wider for whatever quantity is higher.
Some trophic level diagrams go by weight.