Difference between Food Chain and Food Web

Food chain refers to a linked feeding series in an ecosystem. A food chain illustrates the order in which a chain of organisms feed upon each other and the  sequence of organisms through which energy and materials are transferred, in the form of food, from one tropic level to another. The following graphics shows a simple food chain.

The food chains are not isolated and are inter-linked to each other. For example, a Hawk can eat snakes as well as other smaller birds. A mouse can eat grass, bread or even grasshoppers. A Lizard can eat insects of different types. Thus, various food chains are intertwined in each other making a food web. A Foodweb is thus a system of interlocking and interdependent food chains. A typical Foodweb is shown in the below graphics.