The three lines of reasoning built up above have resulted in the following model system of ``metazoan'' evolution. In the system articifial ``metazoans'' are selected for the ability to develop and to maintain cellular diversity. The ``metazoans'' are allowed to make use of differential adhesion driven cell rearrangement and contact signalling in the development and maintenance of cellular diversity. It is examined how the complex genotype-phenotype mapping of these ``metazoans'', being a model of the complex genotype-phenotype mapping of multicellular animals, influences evolutionary dynamics. The mechanisms the ``metazoans'' use to build up cellular diversity are studied.
In this report the following style convention is used. In the model several entities have names like ``gene'' or ``metazoan''. In order to indicate that these names refer to model entities rather than to biological concepts, they are printed in slanted style.