Learning about Food Chains

Most food chains in nature overlap.  Overlapping food chains form a food web.  A food web is a model that shows the many connected food chains and feeding relationships.  In a meadow ecosystem, you might find grass and other producers, rabbits, grasshoppers, eagles, mice, foxes, snakes, and owls.  Grass uses sunlight to make food.  Rabbits eat the grass, and eagles eat the rabbits.  However, mice and grasshoppers also eat grass.  Snakes, eagles, foxes, and owls all eat mice.  Eagles and owls eat almost all of the animals in the meadow.  These food chains are now part of a food web because several plants and animals are eaten by more than one thing.  This food web is composed of several overlapping food chains.  The food web shows how most consumers eat more than one kind of food and are eaten by more than one kind of animal themselves.  Food webs show how energy moves through all the organisms in an ecosystem.

In order to get a better understanding of the food webs, students dissected owl pellets to discover what owls eat.  During the investigation, the students had to draw and label each of the remains they found in their owl pellet.  Students used a poster in order to help identify each bone that was found in the pellet.  Following the dissection, students researched the different plants and animals that are eaten by the organisms the owl eats.  Finally, the students drew a diagram showing the flow of energy from the sun through the plants and animals and finally to the owl.  The students enjoyed the dissection all while gaining knowledge on how energy flows through an ecosystem.