Deconstructing

The corpse of a leaf lies deconstructing on the concrete.  I remember, ever since my first terrarium, always being fascinated at the circular cycle of life.  Most everything that is consumed by the living in the process of life is returned to be used by the next generation.  Of course, there are small losses from the system--some tiny percentage of body heat that manages to be radiated into space, for example--but for the most part, the lid of the giant glass container is sealed, and the critters inside go right on with their lives.