Food Chain

A food chain is a model. A model can be used to represent events in nature and make these events easier to understand. A food chain is a model that shows where organisms in an ecosystem get their food.

A food chain has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism.

Matter enters a food chain when a producer makes its own food. This is how all of the matter eaten by organisms enters the food chain. Many producers make their own food using carbon dioxide, water, and sunlight. Producers do not eat other organisms, so there is no arrow pointing from another organism to the producer in a food chain.

Matter first moves up a food chain when the producer is eaten by a consumer. This is shown by an arrow pointing from the producer to a consumer.

Matter moves further up a food chain when a consumer eats another consumer. This is shown by an arrow pointing from one consumer to another consumer in the food chain. A food chain can have several kinds of consumers. Each kind of consumer can be described by what it eats:

A primary consumer eats the producer. So, there is an arrow pointing from the producer to the primary consumer in a food chain.

A secondary consumer eats the primary consumer. So, there is an arrow pointing from the primary consumer to the secondary consumer in a food chain.

A tertiary consumer eats the secondary consumer. So, there is an arrow pointing from the secondary consumer to the tertiary consumer in a food chain.

A top consumer is the animal at the top of a food chain. So, there is no arrow pointing to an organism that eats the top consumer.

A consumer that hunts and eats another consumer is a predator. The consumer eaten by a predator is its prey. Matter moves up a food chain when a predator hunts and eats its prey.

When a population of prey changes, their predators' food supply changes. Predators that have more food will be more likely to survive and produce offspring.

When a population of predators changes, their prey's chances of being eaten changes. Prey that have a greater chance of being eaten are less likely to survive and produce offspring.