Today, third world countries use DDT widely. We condone the liquidation of ancient forests around the world by doing little to stop it. We don't know the answers to these questions - perhaps we can't know them, until it's too late. Sunlight is converted into chemical energy by green plants. Part of that energy is captured by herbivorous insects and vertebrates when they eat the plant.
Carnivores then eat herbivores.
In reality, however, the flow of energy through an ecosystem is more like a web. Species share energy back and forth in subtle ways. Each member of your class will play one or more parts in a Craters food web. Have the kids sit cross-legged on the ground in a circle. Give each of them a slip of paper from the enclosed list of Craters species.