SimEarth: The Living Planet is a simulation computer game designed by Will Wright and published in 1990 by Maxis, in which the player controls the development of an entire planet. The player can vary its atmosphere, temperature, landmasses, etc, then place various forms of life on the planet and watch them evolve. Although as a software toy, the game does not have any required goals, the big (and difficult) challenge is to evolve intelligent life and an advanced civilisation. Although the game was much admired when it came out, it was not a big seller compared to its hit predecessor SimCity.

The game models the Gaia hypothesis of James Lovelock (who assisted with the design and wrote an introduction to the manual), and one of the options available to the player is the simplified "Daisyworld" model.

The player's control of the planet in the game is quite comprehensive; display panels allow the player to regulate everything from atmospheric gases, with percentages to three decimal places, to the rate of continental drift. The list of natural disasters ranges hurricanes to population-dependent plagues.

An interesting feature of the game is that most phyla of multicellular organisms are on an equal footing, and thus it is possible to evolve intelligent molluscs and the like. In addition to the familiar types, the long-extinct "trichordates" are included, because "we felt sorry for them, and are giving them a chance for survival in SimEarth". (A small number of mysterious fossils seem to exhibit trilateral symmetry, but this is controversial; see Vendian faunas, in particular Tribrachidium .) As an "Easter egg", machine life can appear in the game if a city of the highest technology level is destroyed by a nuclear explosion. Machine life can thrive in any biome or environmental conditions, generally out-competing any other life forms present, and can itself eventually evolve intelligence and build cities.

Despite the humor, both in game and manual, game play itself can be somewhat mystifying; species may appear thrive or die out for no apparent reason. Mass extinctions, however, are often followed by periods of renewed evolutionary diversification, allowing the player to experiment with new sets of species and ecosystems. The open-ended nature of the game and the lack of a clear end-point may help explain its lack of popularity, since players prefer to feel in control of events.

Versions were made for the Super Nintendo, Apple Macintosh, Commodore Amiga and IBM PC.

External links

• The MobyGames' entry on this game