The Earth is unique in the solar system in that, as far as we know, it is the only place that sustains life. Some people even like to view the Earth, or Gaia after the Greek Earth goddess, almost as a living thing itself. Life on Earth has passed through many stages of dynamic evolotion. Human beings represent just the latest snapshot in evolutionary time. Humans, however, through pollution and over consumption, may now be beginning to threaten the sustainability of Earth’s life support systems. How we chose to respond will depend on how we view our relationship with the environment.