4Be.03: Food chains are built from producers and consumers; consumers can be…

Food Webs: Who Eats Whom? Grade 5

Where a plant's food comes from, what happens when the wolves disappear, who cleans up, and how much life hides under a log. Four lessons on how energy and matter move through living things.

• Where does a plant get its food? 50–60 min, plus 10 min to weigh seedlings two weeks later

  Students sink spinach leaf disks in baking soda water and watch them float back up in the light as they make oxygen, then start bean seedlings with no soil at all and weigh them two weeks later. They explain that plants build their food from air and water using light, not from the soil.

• What would happen if the wolves disappeared? 45–60 min

  Students become species in a northern forest or a prairie and connect themselves with yarn into a living food web. When one species is removed, everyone who feels the yarn tug finds out how far the change spreads, and students explain why no species lives on its own.

• Who cleans up? 45 min to set up, 5 min check-ins twice a week, then 30 min after 2 weeks (bread) and 20 min after 4 to 6 weeks (leaves)

  Students seal bread and fruit in taped zip bags to watch mould grow without ever opening them, and bury mesh bags of dry leaves in soil to weigh what's left weeks later. They explain how decomposers break down dead things and return matter to the soil for plants to use again.

• Can we count the life under a log? 50–60 min

  Teams mark out a 1 m square in two different parts of the schoolyard, tally every kind of living thing they find, and compare the two sites. They explain which place supports more life and why, using the food webs and decomposers from earlier lessons.