Exploring Gaia Theory: Artificial Life on a Planetary Scale

Gaia theory, the view that the biota can both affect their environment and do so in a manner that benefits life in general, is an extremely controversial interpretation of the complex relationships between the biota and biosphere. Since individual Gaian phenomena can span spatial scales from cellular to planetary, they evade thorough analysis and empirical validation. Consequently, a good deal of Gaian thinking revolves around an abstract computer model, Daisyworld [24]. However, this model fails to properly account for natural selection's role in Gaian emergence. Although we propose an alternate scheme that offers some improvement - one based on evolutionary computation and individual-based simulation - the field remains wide open for investigations from the alife perspective. This paper reviews both models along with a few natural Gaian phenomena before generalizing a set of common primitive features and emergent properties from the real and artificial examples. These shared characteristics will hopefully provide a backbone for a muchdesired “Gaia-logic” and assist other alife researchers in the search for additional Gaian models