Computers can be used to mimic ancient marine-organism communities with surprising effectiveness.

In a series of special programs designed for the I.B.M. 7090/7094 computers, fossil communities and their environments have been symbolically simulated in a three-dimensional mathematical model. In constructing the model, each community was assigned specific properties which governed their response to environmental factors such as depth of water, distance from shore, substrate, turbulence, turbidity, temperature, and salinity. The environmental conditions in turn were varied by adjusting numerical data fed to the computer which regulated the model.

The properties assigned to the computer communities were finely adjusted by trial and error in order to make them "behave" more or less like their actual counterparts, adapting to changing conditions and even competing with each other. One of the most useful aspects of the program was the ability to advance the model through increments of geologic time where the responses of the communities and the long-term effect of environmental and evolutional factors could be observed in a way heretofore not possible.

Recent work with the model has dealt with environmental responses of leaf-like calcareous algae of late Paleozoic age. These algae were widespread in shallow Pennsylvanian and Early Permian seas, locally creating thickened banks or reefs. Today, some of these reefs serve as large oil reservoirs in southeastern Utah, northern Oklahoma, and West Texas. Exploration for such reservoirs will be greatly enhanced if the environmental response of the organisms that created them can be experimentally determined and this knowledge effectively used for exploration purposes.

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