Adaptation through organism-induced environmental transformations—a systems representation

Environments affect phenotypes through two elementary functions: modifying (by affecting the development of individuals’ phenotypes) and adaptive (by determining the phenotypes’ adaptive significance). Adaptation may be perceived to coordinate the two functions, which may even be performed by the same environmental factor. Organismic transformation of the environment can again affect both functions, where the adaptive functions are commonly addressed via notions of “niche/habitat construction” or “extended phenotype” and modifying function are largely ignored. The multi-causal role of these transformations in evolution and adaptation is hard to model and formalize using standard tools. To arrive at a more comprehensive representation, a systems approach is taken that allows classification and generalization of earlier results and the outlining of new insights. These include the following: \(*\) $\ast$  Temporary transformation (restricted to one adaptational episode) is structurally equivalent to adaptation without transformation and therefore provide no new insights. \(*\) $\ast$  Prolonged transformation (extending over several episodes) in either adaptive or modifying environments promotes adaptational coordination between the two functions but ultimately prevents persistent adaptedness. \(*\) $\ast$  The success of transformations of the adaptive environment that do not affect the modifying environment depends on the diversity in the system states rather than on phenogenetic plasticity. \(*\) $\ast$  A substantial difference between transformation of the adaptive and of the modifying environment is that adaptation can be reached within a single episode via transformation of the modifying environment, even if the adaptive environment has no modifying effect. The evolutionary consequences await explicit model analysis. \(*\) $\ast$  Migration can be interpreted in terms of environmental transformation of either function, modifying or adaptive, by replacing transformation between environments by migration between them. Established results from migration models can help to reassess existing models of adaptation by environmental transformation and to design new models.