Editing SimEarth (section)

===Civilization===
Once an organism on the SimEarth planet becomes sentient and develops civilization, it will gradually go through different stages of development with each successive stage being more technologically advanced than the last.

* [[Stone Age]], characterized by the use of stone tools and [[paleolithic]] lifestyles.
* [[Bronze Age]], characterized by the use of bronze tools, the invention of farming, the development of writing, and urbanization.
* [[Iron Age]], characterized by the use of iron tools and is slightly more advanced than the Bronze Age.
* [[Industrial Age]], characterized by rapid industrialization and improving living standards. This stage is where resources are being rapidly consumed. Once this stage is achieved, energy requirements are high and [[global warming]] starts to threaten the planet's habitability.
* [[Atomic Age]], characterized by the use of nuclear energy.
* [[Information Age]], associated with the mass use of [[telecommunications]] technologies and computers.
* [[Nanotechnology|Nanotech Age]], the most challenging stage to reach due to depleting resources and the growing threat of global warming. It is associated with the use of nanotechnology and interplanetary [[Spaceflight|space travel]].

It is only possible for one species to reach sentience at a time on the planet. If the current sentient species becomes extinct, another species can achieve sentience. Once the sentient species reaches advanced Nanotech Age, they will begin the Exodus and launch all of their population into space. This entirely removes that species from the world, allowing other species to reach sentience.