What types of organisms typically make up the base, middle, and top of a food web

A producer and consumer are organisms that typically make up the base, middle, and top of a food web. 

Base - Always the Producers. Producers/ Plants are autotrops and make their own food.
Middle - The Herbivores ( Plant Eating)/ Omnivores ( Plant/ Animal Eating)
Top - Carnviores (Eat other animals)/ Omnivores
All organisms in middle and top sections are hetertrophs, or consume food.

Transfer of electrons. hope it !