A food web is a diagram of many different types of plants and animals with arrows connecting them to show which animals eat each organism. Food webs help scientists to see the relationships between all of the elements of an ecosystem.

Energy Flow

When an organism eats another organism, it gains energy from that food. Food webs depict the flow of energy from one organism to another by using arrows that point in the direction the energy is flowing. The arrow points to the animal that is eating the other.

Producers

The elements in the food web that do not have arrows pointing to them are called producers. Most producers are plants and algae that use light energy to grow.

Consumers

Any element on the food web that has an arrow pointing to it is called a consumer because it consumes other elements of the food web. Primary consumers are herbivores that eat only plants, secondary consumers are carnivores that eat herbivores and tertiary consumers are carnivores that eat carnivores.

Significance

Food webs help show what might happen if one species overruns an area or goes extinct. Either situation will disrupt the amount of food available for other animals in the food web to eat.

Food Chain

Food chains are simplified versions of food webs that only show one line of energy transfer. For example, a food chain would just say that owls eat rabbits and rabbits eat grass, while leaving out all the other organisms in the ecosystem that eat grass and rabbits.

Source:

Bigelow Laboratory for Ocean Sciences: Fitting Algae Into the Food Web

Virtual Teacher Aide: Food Chains and Food Webs

More Information:

Food Web Game