A Food Chain
All living things get energy from food.
There are two ways living things can get
food. They can either make their own food,
or they can eat other organisms for food.
Plants make their own food. Some animals
get food by eating plants. Some animals get
food by eating other animals.
When an animal eats a plant, it gets energy
from the plant. When an animal eats an
animal, it gets energy from the animal.
We can show the flow of energy between
organisms in a food chain. For example, a
snail can get energy by eating grass. Then a
bird can get energy by eating the snail, and
a fox can get energy by eating the bird.
In this way, energy flows from the grass to the fox.
All living things need energy to survive and grow.
Think of each organism as one link in the food chain. Plants are the
first link, followed in turn by each animal. When plants make food
from sunlight, they turn light energy into chemical energy. But what
happens to this chemical energy if a plant is eaten?
When a snail eats a plant, it takes in the
chemical energy from the plant. It uses
some of this chemical energy and turns
it into the energy of motion. Even
though snails are slow, they still need
energy to move! The snail may also store
some energy in its body. This stored
energy is also a form of chemical energy.
When a bird catches and eats a snail, it
also turns the energy stored in the
snail’s body into the energy it uses to
stay alive. Birds turn the energy in food
into energy of motion, as well as heat
energy. As you can see, energy changes
forms many times as it travels through
the food chain in an ecosystem.
Discovery Education Science
Like most living things, a red fox eats a variety of foods to get energy.
© 2007 Discovery Communications, LLC