Food Chains and Food Webs

What You'll Learn

Food webs show the complex feeding relationships in an ecosystem. Unlike a simple food chain, a food web shows that most organisms eat more than one type of food.

Key Words

biome
symbiosis
mutualism

Materials Needed

cotton balls
zip-lock bags
labels
seeds
soil
cups

Safety First

Do not taste any materials.
Wear safety goggles when mixing liquids.

Steps

Step 1 — Read

Review the background information on Ecosystems before starting.

Step 2 — Do

Set up a composting experiment: place food scraps in one sealed bag and leaves in another. Observe decomposition over two weeks and record changes.

Step 3 — Observe

Look for patterns in your observations.

Step 4 — Record

Make a graph or chart showing your results.

Check Your Understanding

Question 1

1 of 3

What is the main source of energy for most food chains?