The possible evolutionary significance of epigenetic memory and codes is a key problem for extended evolutionary synthesis and biosemiotics. In this paper, some less known original works are reviewed which highlight theoretical parallels between current evolutionary epigenetics, on the one hand, and its predecessors in the eco-physiology of higher nervous activity, on the other. Recently, these areas have begun to converge, with first evidence now indicating the possibility of transgenerational epigenetic inheritance of conditional associations in the mammalian nervous system, and (...) related findings in other taxa. This can serve as an interesting example of evolutionary code-making, where the molecular mechanisms underlying arbitrary associations between stimuli involve lasting changes in gene expression that may be transmitted epigenetically across generations, and which in some cases could be further assimilated into the genome over subsequent evolution. Although preliminary, such epigenetic scenarios would also offer an interesting, if so far overlooked parallel to earlier research carried out by one of I.P. Pavlov’s leading students, acad. P.K. Anokhin, and his colleagues, but also by eminent eco-physiologists of the time, several of whom offered arguments for the possibility of unconditional reflexes representing evolutionarily later, specialized, and reduced forms of associative reflexes, from which they may be derived. Although discarded under the growing dominance of modern synthesis, these early epigenetic investigations may deserve renewed attention in the modern context, and if further confirmed, could open essentially new perspectives on the morphofunctional evolution of the nervous system. (shrink)

Despite several decades of criticism, dichotomous thinking about behavioral development remains widespread and influential. This is particularly true in study of birdsong development, where it has become increasingly common to diagnose songs, elements of songs, or precursors of songs as either innate or learned on the basis of isolation-rearing experiments. The theory of sensory templates has encouraged both the dichotomous approach and an emphasis on structural rather than functional aspects of song development. As a result, potentially important lines of investigation (...) have been overlooked and the interpretation of existing data is often flawed. Evidence for a genetic origin of behavioraldifferencesis frequently interpreted as evidence for the genetic determination of behavioralcharacters. The technique of isolation rearing remains the methodology of choice for many investigators, despite the fact that it offers only a rather crude analysis of the contribution of experience to song development and provides no information at all about genetic contributions to development. The latter could in principle be elucidated by the application of developmental-genetic techniques, but it is unlikely that these can easily be applied to the study of birdsong. Because developmental questions are so often posed in terms of the learned–innate dichotomy, “experience” is taken to be synonymous with “learning” and the possible role of nonobvious contributions to song development has largely been ignored. An alternative approach, based on Daniel Lehrman's interactionist theory of development, permits a more thorough appreciation of the problems that have yet to be addressed, and provides a more secure conceptual foundation for theories of song development. (shrink)