A phylogenetic, ontogenetic, and epigenetic view of bio-inspired hardware systems

If one considers life on Earth since its very beginning, three levels of organization can be distinguished: the phylogenetic level concerns the temporal evolution of the genetic programs within individuals and species, the ontogenetic level concerns the developmental process of a single multicellular organism, and the epigenetic level concerns the learning processes during an individual organism's lifetime. In analogy to nature, the space of bio-inspired hardware systems can be partitioned along these three axes, phylogeny, ontogeny, and epigenesis, giving rise to the POE model. This paper is an exposition and examination of bio-inspired systems within the POE framework, with our goals being: 1) to present an overview of current-day research, 2) to demonstrate that the POE model can be used to classify bioinspired systems, and 3) to identify possible directions for future research, derived from a POE outlook. We first discuss each of the three axes separately, considering the systems created to date and plotting directions for continued progress along the axis in question. We end our exposition by a discussion of possible research directions, involving the construction of bio-inspired systems that are situated along two, and ultimately all three axes. This could give rise to novel systems endowed with evolutionary, reproductive, regenerative, and learning capabilities.