Food chains are simple, a chain showing the flow of energy from one organism to another in predation. It starts off with a producer, and then an arrow is drawn to a primary consumer, then a secondary consumer, then a tertiary, and on and on and on until you reach the top predator. A food web on the other hand is a little more difficult. This is a large collection of all the food webs in a certain area. This means there can be multiple producers and multiple top predators even though a food chain has only one.