Students' eyes might roll when you ask, Who eats grass for breakfast? Seize the opportunity to challenge them to bring in empty boxes, wrappers, or containers of things they ate for breakfast that week.
Ask, What part of the plant do you think we eat when we eat grasses? Offer a hint by passing around some familiar items that come from grasses: popcorn and rice. Ask, What plant parts have you observed that also look like these? Explain that while animals can digest the leaves and stems of grasses, humans worldwide depend on grass seeds for survival.
Half of the world's population, in fact, depends on the seeds of one grass alone for food: rice. The ground seeds of wheat, believed to have been grown for food for 10,000 years, are a major ingredient in breads, breakfast cereals, and a range of other products. Corn, also cultivated for thousands of years, is used for animal feed, cereals and breads, not to mention corn syrup, corn oil, paint, plastics, soaps, whiskey, and a host of other products. Sugarcane, one of the largest grasses, is raised for the sweet juice in its stem. Two-thirds of the sugar we eat comes from the crushed, boiled, and crystallized solid stems of this plant. Molasses is the thick syrup that also comes from the cane. When you factor in the indirect ways we depend on grass for food -- via grass and grain-eating cows, chickens, pigs, and other animals whose products we rely on -- it becomes even more evident how important grasses are to our survival.
Consider asking student groups to pool the breakfast items they brought in. Have each group list all the ingredients they find that come from grasses, then also identify ingredients that indirectly depend on grass (milk products, for example, because cows depend on grass and other grains; eggs because most chickens are fed corn and other grass seeds).