The earth used to be a lonely planet, until the first life appeared and brought the earth endless vividness and gradually formed the wonderful natural world. The most harmonious music in the world is played here every day: the hard-working planets are the ""producers"", taking energy from the sunlight and nurture others; the fierce animals play the ""consumers"", competing with each other leaving the weak eaten by the strong; the selfless microorganism bravely acts as ""decomposer"" to maintain a clean eco environment. Until one day, human beings use their own culture progression to conquer the nature and became its master... Although industrialization in the modern times helped to build humans' homes, the mother earth was deeply injured. For life's continuity, the alarm of the eco system is ringing.