Purpose Explore the interdependence of organisms by performing an experiment with lima bean
plants and earthworms.
Time Approximately 45 minutes
Question How can the presence of one species benefit another in the same ecosystem?
Hypothesis If plants grow in soil containing worms, then the plant growth will be greater, because
worms help decompose organic matter and distribute it through the soil in a form that
plants can use.
Summary You will grow two groups of plants. The experimental group will grow in soil with worms.
The control group will grow in soil without worms. After the plants grow, you will measure
the plant growth for both groups and compare them.
Variables Independent Variable: presence of worms
Dependent Variable: plant growth