Food Chains and Food Webs

What is a Food Chain? A food chain shows just one path of energy flow. The arrows indicate the direction of flow.

What is a Food Web? A food web shows all of the connections within an ecosystem. The flow of energy is shown between multiple organisms.

Components of Food Chains and Food Webs Energy Source Producers Consumers Decomposers

Energy Source The sun is a source of energy in all food chains.

Producers                                                     Plants that make their own food by trapping energy from the sun are called autotrophs. All plants are producers.

Energy from the sun is converted into food for plants in a process known as photosynthesis.

Consumers All the organisms that can not make their own food (and need producers). Also known as heterotrophs.

Consumers are classified into three categories based on what they eat: Herbivores Carnivores Omnivores

Herbivores Herbivores are consumers that eat plants or plant products.                                                     Herbivores are consumers that eat plants or plant products. Example are grasshoppers, mice, rabbits, deer, beavers, moose, cows, sheep, goats and groundhogs.

Carnivores Carnivores are those consumers that eat other animals. Examples are foxes, frogs, snakes, hawks, and spiders.

Omnivores Omnivores are the last type of consumer and eat both plants and animals. Examples are bears, turtles, monkeys, and some humans.

Levels of Consumers Organisms that feed directly from producers, i.e. organisms that eat plant or plant products are called primary consumers. Organisms that feed on primary consumers are called secondary consumers. Those organisms that feed on secondary consumers are called tertiary consumers.

Decomposers Organisms (mostly fungi and bacteria) that break down dead plant and animal material and return the nutrients to the soil to be used by plants.

Predators Animals that hunt and kill their food.

Prey Animals who are hunted by other animals for food.

Activity Find examples of herbivores, carnivores, and omnivores in the magazines provided. Find four examples for each category. Organize the images under the correct heading on the template provided. Pick one of the organisms you have cut out and create a food web for this species. Label all of the components of the food web that we have discussed.

References Interesting Facts about Ecosystems [Online] Available: http://www.arcytech7.org/java/population/facts_foodchain.html. November 7, 2005.