Alejandro Fábregas-Tejeda

In recent years, biologists and philosophers of science have argued that evolutionary theory should incorporate more seriously the idea of ‘reciprocal causation.’ This notion refers to feedback loops whereby organisms change their experiences of the environment or alter the physical properties of their surroundings. In these loops, in particular niche constructing activities are central, since they may alter selection pressures acting on organisms, and thus affect their evolutionary trajectories. This paper discusses long-standing problems that emerge when studying such reciprocal causal processes between organisms and environments. By comparing past approaches to reciprocal causation from the early twentieth century with contemporary ones in niche construction theory, we identify two central reoccurring problems: All of these approaches have not been able to provide a conceptual framework that allows maintaining meaningful boundaries between organisms and environments, instead of merging the two, and integrating experiential and physical kinds of reciprocal causation. By building on case studies of niche construction research, we provide a model that is able to solve these two problems. It allows distinguishing between mutually interacting organisms and environments in complex scenarios, as well as integrating various forms of experiential and physical niche construction.

Dietary changes can alter the human microbiome with potential detrimental consequences for health. Given that environment, health, and evolution are interconnected, we ask: Could diet‐driven microbiome perturbations have consequences that extend beyond their immediate impact on human health? We address this question in the context of the urgent health challenges posed by global climate change. Drawing on recent studies, we propose that not only can diet‐driven microbiome changes lead to dysbiosis, they can also shape life‐history traits and fuel human evolution. We posit that dietary shifts prompt mismatched microbiome‐host genetics configurations that modulate human longevity and reproductive success. These mismatches can also induce a heritable intra‐holobiont stress response, which encourages the holobiont to re‐establish equilibrium within the changed nutritional environment. Thus, while mismatches between climate change‐related genetic and epigenetic configurations within the holobiont increase the risk and severity of diseases, they may also affect life‐history traits and facilitate adaptive responses. These propositions form a framework that can help systematize and address climate‐related dietary challenges for policy and health interventions.

Against the common historiographic narratives of evolutionary biology, the first decades of the 20th century were theoretically far richer than usually assumed. This especially refers to the hitherto neglected role that early theoretical biologists played in introducing visionary research perspectives and concepts before the institutionalization of the Modern Synthesis. Here, we present one of these scholars, the German theoretical biologist and ecomorphologist Hans Böker, by reviewing his 1935 paper “Artumwandlung durch Umkonstruktion, Umkonstruktion durch aktives Reagieren der Organismen”, published in the inaugural volume of the journal Acta Biotheoretica. While largely forgotten today, this work represents a melting pot of ideas that adumbrate some of today’s most lively debated empirical and conceptual topics in evolutionary biology: the active role of organisms as actors of their own evolution, environmental induction and phenotypic plasticity, genetic assimilation, as well as developmental bias. We discuss Böker’s views on how species change through "Umkonstruktion," and how such reconstruction is exerted through active reactions of organisms to environmental perturbations. In addition, we outline the aims and wider context of his "biological comparative anatomy," including Boker’s reprehensible political affiliation with the Nazi Party. Finally, we highlight some of the historical reasons for why Böker’s views did not have a larger impact in evolutionary biology, but we also recount some of the direct and indirect legacies of his approach in research areas such as ecomorphology and EvoDevo. Böker’s paper is available as supplementary material in the online version of this article, as part of the journal's "Classics in Biological Theory" collection; the first translation of the paper into English, by Alexander Böhm and Jan Baedke, is also being published in this volume.

Biologists and philosophers of science have recently called for an extension of evolutionary theory. This so-called ‘extended evolutionary synthesis’ seeks to integrate developmental processes, extra-genetic forms of inheritance, and niche construction into evolutionary theory in a central way. While there is often agreement in evolutionary biology over the existence of these phenomena, their explanatory relevance is questioned. Advocates of EES posit that their perspective offers better explanations than those provided by ‘standard evolutionary theory’. Still, why this would be the case is unclear. Usually, such claims assume that EES’s superior explanatory status arises from the pluralist structure of EES, its different problem agenda, and a growing body of evidence for the evolutionary relevance of developmental phenomena. However, what is usually neglected in this debate is a discussion of what the explanatory standards of EES actually are, and how they differ from prevailing standards in SET. In other words, what is considered to be a good explanation in EES versus SET? To answer this question, we present a theoretical framework that evaluates the explanatory power of different evolutionary explanations of the same phenomena. This account is able to identify criteria for why and when evolutionary explanations of EES are better than those of SET. Such evaluations will enable evolutionary biology to find potential grounds for theoretical integration.

Contemporary evolutionary biology comprises a plural landscape of multiple co-existent conceptual frameworks and strenuous voices that disagree on the nature and scope of evolutionary theory. Since the mid-eighties, some of these conceptual frameworks have denounced the ontologies of the Modern Synthesis and of the updated Standard Theory of Evolution as unfinished or even flawed. In this paper, we analyze and compare two of those conceptual frameworks, namely Niles Eldredge’s Hierarchy Theory of Evolution (with its extended ontology of evolutionary entities) and the Extended Evolutionary Synthesis (with its proposal of an extended ontology of evolutionary processes), in an attempt to map some epistemic bridges (e.g. compatible views of causation; niche construction) and some conceptual rifts (e.g. extra-genetic inheritance; different perspectives on macroevolution; contrasting standpoints held in the “externalism–internalism” debate) that exist between them. This paper seeks to encourage theoretical, philosophical and historiographical discussions about pluralism or the possible unification of contemporary evolutionary biology.

The Extended Evolutionary Synthesis (EES) debate is gaining ground in contemporary evolutionary biology. In parallel, a number of philosophical standpoints have emerged in an attempt to clarify what exactly is represented by the EES. For Massimo Pigliucci, we are in the wake of the newest instantiation of a persisting Kuhnian paradigm; in contrast, Telmo Pievani has contended that the transition to an EES could be best represented as a progressive reformation of a prior Lakatosian scientific research program, with the extension of its Neo-Darwinian core and the addition of a brand-new protective belt of assumptions and auxiliary hypotheses. Here, we argue that those philosophical vantage points are not the only ways to interpret what current proposals to ‘extend’ the Modern Synthesis-derived ‘standard evolutionary theory’ (SET) entail in terms of theoretical change in evolutionary biology. We specifically propose the image of the emergent EES as a vast network of models and interweaved representations that, instantiated in diverse practices, are connected and related in multiple ways. Under that assumption, the EES could be articulated around a paraconsistent network of evolutionary theories (including some elements of the SET), as well as models, practices and representation systems of contemporary evolutionary biology, with edges and nodes that change their position and centrality as a consequence of the co-construction and stabilization of facts and historical discussions revolving around the epistemic goals of this area of the life sciences. We then critically examine the purported structure of the EES—published by Laland and collaborators in 2015—in light of our own network-based proposal. Finally, we consider which epistemic units of Evo-Devo are present or still missing from the EES, in preparation for further analyses of the topic of explanatory integration in this conceptual framework.