Strictly for the classroom, with pauses and questions for thought and discussion, this is essentially a string of definitions--of food chain, cycle, niche, species, etc.--tied together with a few ecological home truths: ""When plants make food they really make it"" . . . ""even predators have their place in the web"" . . . ""everything changes"" . . . . Ending up with a definition of consequences might be a neat trick, but the trivializing example--""If people throw a lot of litter around a park, it stops being a place where anyone wants to go. That's a consequence""--is likely to stifle any larger thoughts or discussion.