Evolution by habit: Peirce, Lamarck, and teleology in biology.

In our paper, we analyse the relationship of the evolutionary philosophy of Charles Sanders Peirce to Lamarckian natural philosophy and link it to concepts of teleology, focusing especially on Aristotelian and Peircean conceptions of the final cause. Peirce commented on evolution in many of his writings, especially in 1891-1893 in essays such as 'Evolutionary Love' (1893) or 'Man's Glassy Essence' (1892). After introducing the three types of evolution distinguished by Peirce, we compare Peirce's and Lamarck's views on evolution, habit, and teleology. From a synthesis of concepts formulated by Peirce, Aristotle, nineteenth-century neo-Lamarckians, and current knowledge regarding epigenetics, there should emerge our own concept of biological teleology unburdened by panpsychism, subjective intentions, or determinism. We believe it could be a concept acceptable to current biology.

Transgenerational Epigenetic Inheritance of Traumatic Experience in Mammals.

In recent years, we have seen an increasing amount of evidence pointing to the existence of a non-genetic heredity of the effects of events such as separation from parents, threat to life, or other traumatising experiences such as famine. This heredity is often mediated by epigenetic regulations of gene expression and may be transferred even across several generations. In this review, we focus on studies which involve transgenerational epigenetic inheritance (TEI), with a short detour to intergenerational studies focused on the inheritance of trauma or stressful experiences. The reviewed studies show a plethora of universal changes which stress exposure initiates on multiple levels of organisation ranging from hormonal production and the hypothalamic-pituitary-adrenal (HPA) axis modulation all the way to cognition, behaviour, or propensity to certain psychiatric or metabolic disorders. This review will also provide an overview of relevant methodology and difficulties linked to implementation of epigenetic studies. A better understanding of these processes may help us elucidate the evolutionary pathways which are at work in the course of emergence of the diseases and disorders associated with exposure to trauma, either direct or in a previous generation.

The phylotypic stage as a boundary of modular memory: non mechanistic perspective.

The concept of the phylotypic stage has been strongly integrated into developmental biology, thanks mostly to drawings presented by Haeckel (Anthropogenie oder Entwicklungsgeschichte des Menschen, 1874). They are printed in every textbook as proof of the existence of the phylotypic stage and the fact of its conservation, albeit many times criticized as misleading and simplifying (Richardson in Develop Biol 172:412-421, 1995, Richardson et al. in Anat Embryo 196:91-106, 1997; Bininda-Emons et al. in Proc R Soc Lond 270:341-346, 2003). Although generally accepted by modern biology, doubt still exists concerning the very existence or the usefulness of the concept. What kind of evolutionary and developmental horizons does it open indeed? This article begins with the history of the concept, discusses its validity and draws this into connotation with the idea of a memory activated throughout the development. Barbieri (The organic codes. An introduction to semantic biology, 2003) considers the phylotypic stage to be a crucial boundary when the genetic program ceases to suffice for further development of the embryo, and supracellular memory of the body plan is activated. This moment clearly coincides with the commencing of the modular development of the embryo. In this article the nature of such putative memory will be discussed.