Terrariums are considered artificial ecosystems. They're also an effective tool for teaching students about how plants and organisms interact. You likely won't be able to build a very complex ecosystem in a terrarium, but you can use one to show students the life cycle of plants and how the living things within the terrarium ecosystem interconnect. For example, if different plants are used in the terrarium, students can see how some plants develop expansive root systems to better capture water, compared to those that feature larger leaves to collect more sunlight.
Drawing out a diagram isn't as hands-on and interactive as a terrarium, but it is still an effective way for students to learn the basics about ecosystems. All you need is coloring tools, drawing utensils and a piece of paper. The students diagram the ecosystem environment of their choice. Some settings might include a beach, ocean, forest or grassland. After students are done with the project, they can arrange to visit the location they chose to study to see how their diagram matches up with the real thing.
Unlike terrariums, which are typically used to demonstrate how plants interact in an artificial ecosystem, an ecosystem in a bottle experiment can add animals such as worms, caterpillars and snails to the mix. This is best done in a two-liter soda bottle. After plant seeds begin to germinate in the bottle, add the animals. This project can show students how animals interact with plants in a controlled environment. Good Science Fair Projects recommends students log journal entries based on what they observe happening each day in the controlled environment.
All living and nonliving things work together in an ecosystem. A good way to teach this to students is by having them draw a food web. For example, in an ecosystem, plants use nutrients from the soil as food to grow. Small insects, such as beetles and caterpillars, eat plant leaves to survive, and larger animals, such as birds, eat the smaller insects. After students are done creating their food webs, they might take a field trip out into a forest, where they can watch animals feed or see signs of animal feeding firsthand.