Organisms are “evolved matter” whose form and function have been shaped by the environment that they have encountered. Compared to inorganic matter that reacts to external conditions in simple aimless ways, organisms exhibit far more complex responses to environmental stimuli, as seen in remarkable examples of morphological adaptations and behavioral strategies. These sophisticated responses reflect a knowledge of the environment that has been accumulated over the course of evolution as well as during individuals’ lifetime. Such knowledge can be described as an internal representation of the environment that organisms rely on to process information and react accordingly.

• epigenetic inheritance and evolutionary learning

In the example of bet-hedging, a population benefits from phenotypic diversity if the distribution of phenotypes matches the variability of the environment. In this sense, the amount of diversity maintained in the population is a representation of the environmental statistics. To attain the optimal phenotype diversity, however, organisms must overcome an apparent mismatch in timescale: the individual lifespan is too short for gathering information about the environmental statistics. We proposed an “evolutionary learning” process, by which the phenotype distribution of the population can be dynamically adapted [ref]. It happens if each organism alters the phenotype distribution of its offspring to increase the frequency of its own phenotype, analogous to Hebbian learning in neuroscience. This process may be realized through various mechanisms of epigenetic inheritance, which are actively studied in biology.

• phenotypic plasticity and environment-to-phenotype mapping

Phenotypic plasticity is the ability of organisms to develop alternative phenotypes depending on environmental cues. It is an important aspect of evolution, because in such cases the environment plays not only a selective but also a formative role. We proposed to describe phenotypic plasticity by a mapping from environmental cues to phenotypic traits, which is an abstraction of many possible mechanisms for gene regulation. Using this “environment-to-phenotype mapping”, we showed that the evolutionary benefit of phenotypic plasticity is determined by the predictability of future environment at the time of development [ref]. Moreover, depending on the noise in environmental cues and the strength of natural selection, phenotypic plasticity can give rise to different strategies for adapting to varying environments, including “unvarying” (where organisms express a constant “generalist” phenotype), “tracking” (where organisms match phenotypes to the environment), and “bet-hedging” [ref].