- 10 packs
of 100 beans/marbles/paper dots (something that can
be counted easily)
designated members of the food chain- sun, grass/trees,
Assign students as members of the
food chain: one as the sun, ten as grass/trees, five as
rabbits, one as an eagle.
The only constant condition in an
ecosystem is the amount of energy that comes from the
sun. In this activity, sun energy comes in the form of
beans/marbles/paper dots. Each packet of 100 beans (or
whatever is used) is enough to support one member of the
plant category. Have the sun give one packet of energy
to each member of the plant group.
Remember that only one percent of
the sun's energy that hits the Earth is used by plants.
Have each plant take one bean out of their packet, returning
the rest to the teacher. This represents energy lost to
Two beans are required to support
each rabbit. How many rabbits can be supported?
Have each rabbit give one bean to
the teacher. This represents energy lost to the system.
Secondary consumers, like eagles,
require a lot of energy. Five beans are needed to support
one eagle. How many eagles can be supported?
When eagles die, most of the remaining
energy would be released, but a small amount would stay
with parts of the eagle that would not decompose quickly.
Have the eagle give up 4 beans to the teacher.
Why are fewer organisms found as you
move along a food chain? What would happen to other organisms
if eagles left the area? If rabbits left?
Where would all of the energy that
was lost (given to the teacher) go?