Evolutionary developmental biologists categorize many different kinds of things, from ontogenetic stages to modules of gene activity. The process of categorization—the establishment of “kinds”—is an implicit part of describing the natural world in consistent, useful ways, and has an essentially practical rather than philosophical basis. Kinds commonly serve one of three purposes: they may function (1) as practical tools for communication; (2) to support prediction and generalization; or (3) as a basis for theoretical discussions. Beyond the minimal requirement (...) that classifications reflect biological reality, what sorts of kinds or classification will be useful in advancing a research program depends on the epistemological context. Thus, the important meaning of “natural” in “natural kinds” is not “natural with respect to nature,” but “natural with respect to the question.” This conclusion arises from the recognition that the proper role of concepts (e.g. natural kind, module, homology, model) is not to answer biological questions, but rather to help frame them. From a scientist’s perspective, arguing about the wording (or existence) of a single definition of “natural” or “kind” is beside the point: we get more work done by letting the question at hand determine what kinds of kinds are natural, on the basis of their ability to help answer it. We should be content to let “natural kinds” remain vague, multivalent, and–therefore broadly useful. For a philosopher like Hacking, the diverse, disparate, and ultimately incommensurable uses of the term “natural kind” have diluted its value so far that it loses all meaning. For practicing scientists, however, defining useful kinds in the context of particular questions and systems remains a productive epistemological strategy. (shrink)

Despite the productivity of basic cancer research, cancer continues to be a health burden to society because this research has not yielded corresponding clinical applications. Many proposed solutions to this dilemma have revolved around implementing organizational and policy changes related to cancer research. Here I argue for a different solution: a new conceptualization of causation in cancer. Neither the standard molecular biomarker approaches nor evolutionary biology approaches to cancer fully capture its complex causal dynamics, even when considered jointly. (...) These approaches map on to Ernst Mayr’s proximate–ultimate distinction, which is an inadequate conceptualization of causation in biological systems and makes it difficult to connect developmental and evolutionary viewpoints. I propose looking to evolutionary developmental biology to overcome the distinction and integrate the proximate and ultimate causal frameworks. I use the concepts of modularity and evolvability to show how an EvoDevo perspective can be manifested in cancer translational research. This perspective on causation in cancer is better suited for integrating the complexity of current empirical results and can facilitate novel developments in the investigation and clinical treatment of cancer. (shrink)

Although there are many historical and philosophical analyses of evolutionary developmental biology (EvoDevo), its development in the 1980s, when many individual or collective attempts to synthesize evolution and development were made, has not been examined in detail. This article focuses on some interdisciplinary studies during the 1980s and argues that they had important characteristics that previous historical and philosophical work has not recognized. First, we clarify how each set of studies from the 1980s integrated the results (...) or approaches from different biological fields, such as paleontology, developmental genetics, comparative morphology, experimental embryology, theoretical developmental biology, and population genetics. Second, after close examination we show that the interdisciplinary studies during the 1980s adopted different and conflicting views of genes, such as developmental-genetic, epigenetic, or population-genetic ones. We conclude that EvoDevo in the 1980s was a motley aggregation of various kinds of local integration. Finally, we discuss the implications of our analysis by comparing these early EvoDevo studies with those of the Modern Synthesis and with the present state of EvoDevo. (shrink)

Recent advances in genetics and neurobiology have greatly increased the degree of variation that one finds in what is taken to provide the biological foundations of our species-specific linguistic capacities. In particular, this variation seems to cast doubt on the purportedly homogeneous nature of the language faculty traditionally captured by the concept of “Universal Grammar.” In this article we discuss what this new source of diversity reveals about the biological reality underlying Universal Grammar. Our discussion leads us to support (1) (...) certain hypotheses advanced in evolutionary developmental biology that argue for the existence of robust biological mechanisms capable of canalizing variation at different levels, and (2) a bottom-up perspective on comparative cognition. We conclude by sketching future directions for what we call “comparative biolinguistics,” specifying which experimental directions may help us succeed in this new research avenue. (shrink)

Evolutionary developmental biology (or developmental evolution) is in the middle stages of its “development.” Its early ontogeny cannot be traced back to fertilization but pivotal developmental events included Gould’s (1977) treatment of heterochrony, Riedl’s (1978) analysis of “burden”, the Dahlem conference of 1981, a British Society of Developmental Biologists Symposium, as well as books that incorporated developmental genetics into older comparative themes. A major inductive process began with the discovery of widespread phylogenetic conservation (...) in homeobox-containing genes. One interpretation of these early developmental dynamics holds that an increasingly prominent problem agenda (e.g., how do novel structures and functions originate?), inherited from long-standing research programs in comparative embryology, morphology, and paleontology, was handed a powerful set of experimental tools from the lineage of experimental embryology. This allowed for an experimental probing of development and its evolution in an unprecedented fashion. Although the relationship between evolution and development has exhibited a protracted and complex history, we are still in the process of comprehending these early stages of “modern” EvoDevo’s ontogeny. (shrink)

Using the context of controversies surrounding evolutionary developmental biology (EvoDevo) and the possibility of an Extended Evolutionary Synthesis, I provide an account of theory structure as idealized theory presentations that are always incomplete (partial) and shaped by their conceptual content (material rather than formal organization). These two characteristics are salient because the goals that organize and regulate scientific practice, including the activity of using a theory, are heterogeneous. This means that the same theory can be (...) structured differently, in part because theory presentations (as idealizations) intentionally depart from different features known to be present in a theory. Since there are diverse and potentially incompatible theory structures derived from heterogeneous goals found in scientific practices, a question arises about the absence of a unifying theory structure in the background. The notion of a “theory façade” offers a fruitful perspective on this potentially unsettling result. (shrink)

The growing interest and major advances of the last decades in evolutionary developmental biology (EvoDevo) have led to the recognition of the incompleteness of the Modern Synthesis of evolutionary theory. Here we discuss how paleontology makes significant contributions to integrate evolution and development. First, extinct organisms often inform us about developmental processes by showing a combination of features unrecorded in living species. We illustrate this point using the vertebrate fossil record and studies relating bone (...) ossification to life history traits. Second, we discuss exceptionally preserved fossils that document rare ontogenetic sequences and illustrate this case with the patterns of heterochrony observed in Cambrian crustacean larvae preserved three-dimensionally. Third, most fossils potentially document the evolutionary patterns of allometry and modularity, as well as some of the (paleo)ecological factors that had influenced them. The temporal persistence of adaptive patterns in rodent evolution serves to address the importance of ecological constraints in evolution. Fourth, we discuss how the macroevolutionary patterns observed in the tetrapod limb, in the mammal molar proportions, and in the molluscan shell provide independent tests of the validity of morphogenetic models proposed on living species. Reciprocally, these macroevolutionary patterns often act as a source of inspiration to investigate the underlying rules of development, because, at the end, they are the patterns that the neo-Darwinian theory was unable to account for. (shrink)

Erratum to Using the context of controversies surrounding evolutionary developmental biology (EvoDevo) and the possibility of an Extended Evolutionary Synthesis, I provide an account of theory structure as idealized theory presentations that are always incomplete (partial) and shaped by their conceptual content (material rather than formal organization). These two characteristics are salient because the goals that organize and regulate scientific practice, including the activity of using a theory, are heterogeneous. This means that the same theory (...) can be structured differently, in part because theory presentations (as idealizations) intentionally depart from different features known to be present in a theory. Since there are diverse and potentially incompatible theory structures derived from heterogeneous goals found in scientific practices, a question arises about the absence of a unifying theory structure in the background. The notion of a “theory façade” offers a fruitful perspective on this potentially unsettling result. (shrink)

In a recent opinion piece, Denis Duboule has claimed that the increasing shift towards systems biology is driving evolutionary and developmental biology apart, and that a true reunification of these two disciplines within the framework of evolutionary developmental biology may easily take another 100 years. He identifies methodological, epistemological, and social differences as causes for this supposed separation. Our article provides a contrasting view. We argue that Duboule’s prediction is based on a one-sided (...) understanding of systems biology as a science that is only interested in functional, not evolutionary, aspects of biological processes. Instead, we propose a research program for an evolutionary systems biology, which is based on local exploration of the configuration space in evolving developmental systems. We call this approach—which is based on reverse engineering, simulation, and mathematical analysis—the natural history of configuration space. We discuss a number of illustrative examples that demonstrate the past success of local exploration, as opposed to global mapping, in different biological contexts. We argue that this pragmatic mode of inquiry can be extended and applied to the mathematical analysis of the developmental repertoire and evolutionary potential of evolving developmental mechanisms and that evolutionary systems biology so conceived provides a pragmatic epistemological framework for the EvoDevo synthesis. (shrink)

Morphological EvoDevo is a field of biological inquiry in which explicit relations between evolutionary patterns and growth or morphogenetic processes are made. Historically, morphological EvoDevo results from the coming together of several traditions, notably Naturphilosophie, embryology, the study of heterochrony, and developmental constraints. A special feature binding different approaches to morphological EvoDevo is the use of formalisms and mathematical models. Here we will introduce anatomical network analysis, a new approach centered on connectivity patterns formed by (...) anatomical parts, with its own concepts and tools specifically designed for the study of morphological EvoDevo questions. Riedl’s concept of burden is tightly related to the use of anatomical networks, providing a nexus between the evolutionary patterns and the structural constraints that shape them. (shrink)

With the advent of evolutionary developmental research, or EvoDevo, there is hope of discovering the roles that the genetic bases of development play in morphological evolution. Studies in EvoDevo span several levels of organismal organization. Low-level studies identify the ultimate genetic changes responsible for morphological variation and diversity. High-level studies of development focus on how genetic differences affect the dynamics of gene networks and epigenetic interactions to modify morphology. Whereas an increasing number of studies link independent (...) acquisition of homoplastic or convergent morphologies to similar changes in the genomes, homoplasies are not always found to have identical low-level genetic underpinnings. This suggests that a combination of low- and high-level approaches may be useful in understanding the relationship between genetic and morphological variation. Therefore, as an empirical and conceptual framework, we propose the causality horizon to signify the lowest level that allows linking homoplastic morphologies to similar changes in the development. A change in a system below the causality horizon cannot be generalized. In more concrete terms, homoplastic morphologies cannot be reduced to the same change in gene regulation when that change occurs below the causality horizon; rather, a higher-level mechanism should be identified. (shrink)

In recent years, several prominent biologists have pointed to the relatively new field of evolutionary developmental biology (EvoDevo) as evidence of an Extended Synthesis in evolutionary biology. More particularly, these biologists claim that theoretical and empirical EvoDevo research is extending the Modern Synthesis framework of evolutionary theory through investigation of evolutionarily important concepts that are not part of the framework developed during the 20th century. To describe the current changes in evolutionary (...) biology as an Extended Synthesis, however, is incorrect. Through review of Extended Synthesis arguments and analysis of the same biological concepts used to support these arguments, I argue that the foundation of the Modern Synthesis framework, theoretical population genetics, faces significant, perhaps insurmountable challenges from the concepts highlighted by EvoDevo research. As the foundation of the Modern Synthesis framework will require considerable remodeling—if possible—in light of the concepts emphasized by EvoDevo, it is incorrect to describe the ongoing changes in evolutionary biology as an Extended Synthesis. (shrink)

This thematic issue addresses questions of constraints on the evolution of form—physical, biological, and technical. Here, form is defined as an embodiment of a specific structure, which can be hierarchically different yet emerge from the same processes. The focus of this contribution is about how developmental biology and paleontology can be better integrated and compared in order to produce hypotheses about the evolution of form. The constraints on current EvoDevo research stem from the disconnect in the focus (...) of study for developmental geneticists and evolutionary morphologists; the former being interested in early developmental events at a molecular level in a model animal, the latter in late developmental events or comparison between adult forms, at a structural level in non-model animals. In order to truly integrate information from both fields in our understanding of evolutionary processes, morphology needs to be reintegrated in the study of gene expression, and its time frame needs to be extended beyond early developmental stages. Gene expression in non-model organisms also needs to be studied in order to gain perspective into primitive patterning at evolutionary nodes. Hypotheses formed by the comparison of expression patterns and morphologies seen in extant species can then be tested against forms found in the fossil record, coming closer to understanding the mechanisms underlying evolution. (shrink)

Traditional model systems such as fly, mouse, and chick have formed the foundation of the EvoDevo research program. These animal systems have provided a wealth of information on the patterns and mechanisms of developmental change over large phylogenetic scales. However, the almost exclusive focus on individual embryos as model organisms has also limited the field’s ability to address the central roles that natural selection and life history adaptation play in the evolution of developmental systems. Likewise, focus on (...) this small set of “unitary” model organisms may also constrain the explanatory reach and theoretical robustness of EvoDevo if we consider that many core developmental processes like homeostatic regulation, ontogenetic differentiation, and norms of reaction are also manifest at other levels of biological organization, such as colonial organisms. The study of social insect systems can help bridge these considerable gaps in EvoDevo’s current approach. Because social insect colonies span the fine line between simple associations of “unitary” organisms and full-fledged “superorganisms,” these systems help elucidate what kinds of processes fundamentally characterize developmental systems and their evolution. What is more, the traits of social insect colonies show high degrees of population-level variability that can be linked directly to selective factors in the environment, making them ideal systems in which to more fully integrate EcoEvoDevo approaches. (shrink)

The work of Pere Alberch is crucial to study the early stages of evo-devo. In particular, it illustrates very persuasively why developmental systems have so much to say about the course of evolutionary change. In addition to an important empirical work, he elaborated a stimulating framework of theoretical ideas on biological form, morphological variation, and how developmental processes establish possible evolutionary paths previous to the action of natural selection. In this framework, the study of development and (...) evolution are related through the notion of possible morphologies. In his view, the morphology of organisms shows internal coherence and structure, emergent from complex non linear interactions among parts and with the environment. (shrink)

In recent years, several prominent biologists have pointed to the relatively new field of evolutionary developmental biology as evidence of an Extended Synthesis in evolutionary biology. More particularly, these biologists claim that theoretical and empirical EvoDevo research is extending the Modern Synthesis framework of evolutionary theory through investigation of evolutionarily important concepts that are not part of the framework developed during the 20th century. To describe the current changes in evolutionary biology (...) as an Extended Synthesis, however, is incorrect. Through review of Extended Synthesis arguments and analysis of the same biological concepts used to support these arguments, I argue that the foundation of the Modern Synthesis framework, theoretical population genetics, faces significant, perhaps insurmountable challenges from the concepts highlighted by EvoDevo research. As the foundation of the Modern Synthesis framework will require considerable remodeling—if possible—in light of the concepts emphasized by EvoDevo, it is incorrect to describe the ongoing changes in evolutionary biology as an Extended Synthesis. (shrink)

There is a trend within philosophy of biology to concentrate on questions that are strongly related to particular biological research programs rather than on the general scope of the field and its relation to other sciences. Projects of the latter kind, of course, are followed as well but will not be the topic of this review. Shifting the focus to particular research programs reflects philosophers’ increased interest in knowledge of, and contribution to, actual biological research, which is organized in (...) such programs. It is accompanied by the increasing enthusiasm of biologists to involve philosophers in the conceptual work of theoretical biology. I concentrate on the philosophies of four biological research programs, three of which are devoted to evolutionary biology, which is still the main field of interest among philosophers of biology: adaptationism, EvoDevo, and the developmental systems approach. In addition, a short sketch of the newly emerging philosophy of systems biology is given. Several lines of philosophical inquiry can be found in all of the fields considered here: philosophy contributes to the conceptual development of biological research programs, it analyzes structures and delineations of particular research programs, and sometimes it is involved in a comparative assessment of biological programs as well. Philosophical projects that start from the level of a particular research program may give rise to a bottom-up perspective on biology and allow for an integrative view of biological research. This may open up the opportunity to tackle “larger” questions again in an altered and fruitful manner. (shrink)

Embryogenesis involves biochemical patterning as well as mechanical morphogenetic movements, both regulated by the expression of the regulatory genes of development. The reciprocal interplay of morphogenetic movements with developmental gene expression is becoming an increasingly intense subject of investigation. The molecular processes through which differentiation patterning closely regulates the development of morphogenetic movements are today becoming well understood. Conversely, experimental evidence recently revealed the involvement of mechanical cues due to morphogenetic movements in activating mechano-transduction pathways that control both the (...) differentiation and the active morphogenesis of fundamental events in embryonic tissue development. Here I will first focus on the central role the shape of biological structures of the molecular and mesoscopic cell scales plays in mechano-transduction. Then, after a short description of the genetic regulation of the Drosophila embryo mesoderm invagination at gastrulation—one of the best-understood morphogenetic movement of embryogenesis—I will detail the processes of differentiation and of active morphogenesis of Drosophila embryo gastrulation, which require mechano-transduction. Finally, I will explore the putative consequences in evolution of these mechano-transduction events. I speculate that the first ancient multicellular organisms might have emerged from primary morphological and differentiation patterns induced by primitive mechano-sensation effects allowed by mechano-transduction in response to their physical environment, such as touch by gravity or water flows, which might have acted as primitive motor–sensorial systems, thus conditioning the emergence of our primary animal ancestors. (shrink)

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. (shrink)