In any given environment there are hundreds of varieties of plants and animals living together, creating ecosystems. Bill Nye literally sets up office in an ocean, a forest and a field to commune with nature and show what happens when one link falls out of nature's chain.The DVD has extra features: fully indexed "chapters" correlated to national science standards, interactive glossaries and quizzes, bonus footage of never-before-seen segments, interviews and demos, Spanish translation, and on-disk implementation guide. .