This says that everything affects everything. If the predator (the red) dies, the medium tier (the blue), which contains animals like deer and birds, will overpopulate. That will make the plants die, thus the medium tier will die too.
This says that everything affects everything. If the predator (the red) dies, the medium tier (the blue), which contains animals like deer and birds, will overpopulate. That will make the plants die, thus the medium tier will die too.