D’Arcy Thompson’s drawings showing coordinated differences between the shape of an individual of one species and the shape of an individual of another have been reproduced and discussed countless times. However, while they have been widely regarded as inspirational, their interpretation in causal terms has proved difficult, and there is as yet no consensus on this matter. Here, I approach these Thompsonian transformations from a particular angle, namely their dimensional insufficiency. I argue that this problem must be solved before the (...) issue of causality can be considered. This approach leads to the conclusion that Thompsonian transformations—or “morphological transformations”—have not taken place in evolution, and logically can never do so, because they involve the direct conversion of the adult form of one species into that of another. In contrast, “developmental transformations” do occur in the short term, within the lifetime of a single individual. And “evolutionary transformations” occur in the long term, in a context that can be described, following Scott Gilbert, as five-dimensional. I argue that these two kinds of transformation—developmental and evolutionary—have different causal agencies. I consider the possible nature of these agencies and, related to that, the way in which Thompson’s work connects with Darwinian evolutionary theory. (shrink)

Processes produce changes: rivers erode their banks and thunderstorms cause floods. If I am right that organisms are a kind of process, then the causally efficacious behaviours of organisms are also examples of processes producing change. In this paper I shall try to articulate a view of how we should think of causation within a broadly processual ontology of the living world. Specifically, I shall argue that causation, at least in a central class of cases, is the interaction of processes, (...) that such causation is the exercise of a capacity inherent in that process and, negatively, that causation should not be understood as the instantiation of universal laws. The approach I describe has substantial similarities with the process causality articulated by Wesley Salmon and Phil Dowe for physical causation, making it plausible that the basic approach can be applied equally to the non-living world. It is an approach that builds at crucial points on the criticisms of determinism and universal causality famously articulated by Elizabeth Anscombe. (shrink)

We describe an approach to measuring biological information where ‘information’ is understood in the sense found in Francis Crick’s foundational contributions to molecular biology. Genes contain information in this sense, but so do epigenetic factors, as many biologists have recognized. The term ‘epigenetic’ is ambiguous, and we introduce a distinction between epigenetic and exogenetic inheritance to clarify one aspect of this ambiguity. These three heredity systems play complementary roles in supplying information for development. -/- We then consider the evolutionary significance (...) of the three inheritance systems. Whilst the genetic inheritance system was the key innovation in the evolution of heredity, in modern organisms the three systems each play important and complementary roles in heredity and evolution. -/- Our focus in the earlier part of the paper is on ‘proximate biology’, where information is a substantial causal factor that causes organisms to develop and causes offspring to resemble their parents. But much philosophical work has focused on information in ‘ultimate biology’. Ultimate information is a way of talking about the evolutionary design of the mechanisms of development and inheritance. We conclude by clarifying the relationship between the two. Ultimate information is not a causal factor that acts in development or heredity, but it can help to explain the evolution of proximate information, which is. (shrink)

Developmental systems theory (DST) is a wholeheartedly epigenetic approach to development, inheritance and evolution. The developmental system of an organism is the entire matrix of resources that are needed to reproduce the life cycle. The range of developmental resources that are properly described as being inherited, and which are subject to natural selection, is far wider than has traditionally been allowed. Evolution acts on this extended set of developmental resources. From a developmental systems perspective, development does not proceed according to (...) a preformed plan; what is inherited is much more than DNA; and evolution is change not only in gene frequencies, but in entire developmental systems. (shrink)

Biology is seen not merely as a privileged oppressor of women but as a co-victim of masculinist social assumptions. We see feminist critique as one of the normative controls that any scientist must perform whenever analyzing data, and we seek to demonstrate what has happened when this control has not been utilized. Narratives of fertilization and sex determination traditionally have been modeled on the cultural patterns of male/female interaction, leading to gender associations being placed on cells and their components. We (...) also find that when gender biases are controlled, new perceptions of these intracellular and extracellular relationships emerge. (shrink)

The concept of plasticity has always been present in the history of developmental biology, both within the theory of epigenesis and within morphogenesis studies. However this tradition relies also upon a genetic conception of plasticity. Founded upon the concepts of ‘‘phenotypic plasticity’’ and ‘‘reaction norm,’’ this genetic conception focuses on the array of possible phenotypic change in relation to diversified environments. Another concept of plasticity can be found in recent publications by some developmental biologists (Gilbert, West-Eberhard). I argue that these (...) authors adopt a ‘‘broad conception of plasticity’’ that is closely related to a notion of development as something that is ongoing throughout an organism’s lifecycle, and has no clear-cut boundaries. However, I suggest that given a narrow conception of plasticity, one can define temporal boundaries for development that are linked to specific features of the morphological process, which are different from behavioral and physiological processes. (shrink)

Stem cell biology and systems biology are two prominent new approaches to studying cell development. In stem cell biology, the predominant method is experimental manipulation of concrete cells and tissues. Systems biology, in contrast, emphasizes mathematical modeling of cellular systems. For scientists and philosophers interested in development, an important question arises: how should the two approaches relate? This essay proposes an answer, using the model of Waddington’s landscape to triangulate between stem cell and systems approaches. This simple abstract model represents (...) development as an undulating surface of hills and valleys. Originally constructed by C. H. Waddington to visually explicate an integrated theory of genetics, development and evolution, the landscape model can play an updated unificatory role. I examine this model’s structure, representational assumptions, and uses in all three contexts, and argue that explanations of cell development require both mathematical models and concrete experiments. On this view, the two approaches are interdependent, with mathematical models playing a crucial but circumscribed role in explanations of cell development. (shrink)

Morphogenesis is a key process in developmental biology. An important issue is the understanding of the generation of shape and cellular organisation in tissues. Despite of their great diversity, morphogenetic processes share common features. This work is an attempt to describe this diversity using the same formalism based on a cellular description. Tissue is seen as a multi-cellular system whose behaviour is the result of all constitutive cells dynamics. Morphogenesis is then considered as a spatiotemporal organization of cells activities. We (...) show how this formalism relies on Reaction–Diffusion/Positional Information approach and how it permits to generalize its modelling possibilities. Three quite different applications for concrete morphogenetic processes are presented. The first one is a model for epithelial invagination, the second is a model of cellular differentiation by local cell–cell signalling. The last example is the secondary radial growth of conifer trees. From the mathematical point of view, different modelling tools are used according to the specificity of each process. (shrink)

This paper focuses on a running dispute between Werner Callebaut’s naturalistic view and Filip Kolen and Gertrudis Van de Vijver’s transcendentalist view on the nature of philosophy of biology and the relation of this discipline to biological sciences. It is argued that, despite differences in opinion, both positions agree that philosophy of biology’s ultimate goal is to ‘move’ biology or at least be ‘meaningful’ to it. In order to make this goal clear and effective, more is needed than a polarizing (...) debate which hardly touches upon biology. Therefore, a redirection in discussion is suggested towards a reflection on the possibilities of incorporating philosophy in interdisciplinary research, and on finding concrete research questions which are of interest both to the philosopher and to the biologist. (shrink)

Determinism and unpredictability are compatible since deterministic flows can produce, if sensitive to initial conditions, unpredictable behaviors. Within this perspective, the notion of scenario to chaos transition offers a new form of predictability for the behavior of sensitive to initial condition systems under the variation of a control parameter. In this paper I first shed light on the genesis of this notion, based on a dynamical systems approach and on considerations of structural stability. I then suggest a link to the (...) figure of epigenetic landscape, partially inspired by a dynamical systems perspective, and offering a theoretical framework to apprehend developmental noise. (shrink)

The theory of concepts advanced in the dissertation aims at accounting for a) how a concept makes successful practice possible, and b) how a scientific concept can be subject to rational change in the course of history. Traditional accounts in the philosophy of science have usually studied concepts in terms only of their reference; their concern is to establish a stability of reference in order to address the incommensurability problem. My discussion, in contrast, suggests that each scientific concept consists of (...) three components of content: 1) reference, 2) inferential role, and 3) the epistemic goal pursued with the concept's use. I argue that in the course of history a concept can change in any of these three components, and that change in one component—including change of reference—can be accounted for as being rational relative to other components, in particular a concept's epistemic goal.This semantic framework is applied to two cases from the history of biology: the homology concept as used in 19th and 20th century biology, and the gene concept as used in different parts of the 20th century. The homology case study argues that the advent of Darwinian evolutionary theory, despite introducing a new definition of homology, did not bring about a new homology concept (distinct from the pre-Darwinian concept) in the 19th century. Nowadays, however, distinct homology concepts are used in systematics/evolutionary biology, in evolutionary developmental biology, and in molecular biology. The emergence of these different homology concepts is explained as occurring in a rational fashion. The gene case study argues that conceptual progress occurred with the transition from the classical to the molecular gene concept, despite a change in reference. In the last two decades, change occurred internal to the molecular gene concept, so that nowadays this concept's usage and reference varies from context to context. I argue that this situation emerged rationally and that the current variation in usage and reference is conducive to biological practice.The dissertation uses ideas and methodological tools from the philosophy of mind and language, the philosophy of science, the history of science, and the psychology of concepts. (shrink)

A crucial question for a process view of life is how to identify a process and how to follow it through time. The genidentity view can contribute decisively to this project. It says that the identity through time of an entity X is given by a well-identified series of continuous states of affairs. Genidentity helps address the problem of diachronic identity in the living world. This chapter describes the centrality of the concept of genidentity for David Hull and proposes an (...) extension of Hull’s view to the ubiquitous phenomenon of symbiosis. Finally, using immunology as a key example, it shows that the genidentity view suggests that the main interest of a process approach is epistemological rather than ontological and that its principal claim is one of priority, namely that processes precede and define things, and not vice versa. (shrink)

It is widely recognized that the innate versus acquired distinction is a false dichotomy. Yet many scientists continue to describe certain traits as “innate” and take this to imply that those traits are not acquired, or “unlearned.” This article asks what cognitive role, if any, the concept of innateness should play in the psychological and behavioural sciences. I consider three arguments for eliminating innateness from scientific discourse. First, the classification of a trait as innate is thought to discourage empirical research (...) into its developmental origin. Second, this concept lumps together a number of different biological properties that ought to be treated as distinct. Third, innateness is associated with the outmoded folk biological theory of essentialism. In response to these objections, I consider two attempts to revise the concept of innateness which aim to make it more suitable for scientific explanation and research. One proposal is that innateness can be defined in terms of the biological property of environmental canalization. On this view, a trait is innate to the extent that it is developmentally buffered against a range of different environments. Another proposal is that innateness serves as an explanatory primitive for cognitive science. This view holds that there exist a sharp boundary between psychological and biological explanations and that to identify a trait as innate means that it falls into the latter explanatory domain. This essay ends with some questions for future research. (shrink)

In 2011, Peterson suggested that the main reason why C.H. Waddington was essentially ignored by the framers of the modern evolutionary synthesis in the 1950s was because they were Cartesian reductionists and mathematical population geneticists while he was a Whiteheadian organicist and experimental geneticist who worked with Drosophila. This paper suggests a further reason that can only be seen now. The former defined genes and their alleles by their selectable phenotypes, essentially the Mendelian view, while Waddington defined a gene through (...) its functional role as determined by genetic analysis, a view that foresaw the modern view that a gene is a DNA sequence with some function. The former were interested in selection, while Waddington focused on variation. The differences between the two views of a gene are briefly considered in the context of systems biology. (shrink)

The traditional practice of establishing morphological types and investigating morphological organization has found new support from evolutionary developmental biology (evo-devo), especially with respect to the notion of body plans. Despite recurring claims that typology is at odds with evolutionary thinking, evo-devo offers mechanistic explanations of the evolutionary origin, transformation, and evolvability of morphological organization. In parallel, philosophers have developed non-essentialist conceptions of natural kinds that permit kinds to exhibit variation and undergo change. This not only facilitates a construal of species (...) and higher taxa as natural kinds, but also broadens our perspective on the diversity of kinds found in biology. There are many different natural kinds relevant to the investigative and explanatory aims of evo-devo, including homologues and developmental modules. (shrink)

This paper focuses on a running dispute between Werner Callebaut’s naturalistic view and Filip Kolen and Gertrudis Van de Vijver’s transcendentalist view on the nature of philosophy of biology and the relation of this discipline to biological sciences. It is argued that, despite differences in opinion, both positions agree that philosophy of biology’s ultimate goal is to ‘move’ biology or at least be ‘meaningful’ to it. In order to make this goal clear and effective, more is needed than a polarizing (...) debate which hardly touches upon biology. Therefore, a redirection in discussion is suggested towards a reflection on the possibilities of incorporating philosophy in interdisciplinary research, and on finding concrete research questions which are of interest both to the philosopher and to the biologist. (shrink)

The discovery by Hans Spemann of the “organizer” tissue and its ability to induce the formation of the amphibian embryo’s neural tube inspired leading embryologists to attempt to elucidate embryonic inductions’ underlying mechanism. Joseph Needham, who during the 1930s conducted research in biochemical embryology, proposed that embryonic induction is mediated by a specific chemical entity embedded in the inducing tissue, surmising that chemical to be a hormone of sterol-like structure. Along with embryologist Conrad H. Waddington, they conducted research aimed at (...) the isolation and functional characterization of the underlying agent. As historians clearly pointed out, embryologists came to question Needham’s biochemical approach; he failed to locate the hormone he sought and eventually abandoned his quest. Yet, this study finds that the difficulties he ran into resulted primarily from the limited conditions for conducting his experiments at his institute. In addition, Needham’s research reflected the interests of leading biochemists in hormone and cancer research, because it offered novel theoretical models and experimental methods for engaging with the function of the hormones and carcinogens they isolated. Needham and Waddington were deterred neither by the mounting challenges nor by the limited experimental infrastructure. Like their colleagues in hormone and cancer research, they anticipated difficulties in attempting to establish causal links between complex biological phenomena and simple chemical triggering. (shrink)

Conrad Hal Waddington was a British developmental biologist who mainly worked in Cambridge and Edinburgh, but spent the late 1930s with Morgan in California learning about Drosophila. He was the first person to realize that development depended on the then unknown activities of genes, and he needed an appropriate model organism. His major experimental contributions were to show how mutation analysis could be used to investigate developmental mechanisms in Drosophila, and to explore how developmental mutation could drive evolution, his other (...) deep interest. Waddington was, however, predominantly a thinker, and set out to provide a coherent framework for understanding the genetic bases of embryogenesis and evolution, developing his ideas in many books. Perhaps his best-known concept is the epigenetic landscape: here a ball rolls down a complex valley, making path choices. The rolling ball represents a cell’s development over time, while the topography represents the changing regulatory environment that controls these choices. In its later forms, the role of each feature in the landscape was controlled by the effects of sets of interacting genes, an idea underpinning contemporary approaches to systems biology. Waddington was the first developmental geneticist and probably the most important developmental biologist of the pre-molecular age. (shrink)

This article examines and rejects the claim that 'innateness is canalization'. Waddington's concept of canalization is distinguished from the narrower concept of environmental canalization with which it is often confused. Evidence is presented that the concept of environmental canalization is not an accurate analysis of the existing concept of innateness. The strategy of 'biologicizing the mind' by treating psychological or behavioral traits as if they were environmentally canalized physiological traits is criticized using data from developmental psychobiology. It is concluded that (...) identifying innateness with environmental canalization can only result in adding unhelpful associations from 'folkbiology' to the relatively precise idea of canalization. (shrink)

An increasing number of biologists are expressing discontent with the prevailing theory of neo-Darwinism. In particular, the tendency of neo-Darwinians to adopt genetic determinism and atomistic notions of both genes and organisms is seen as grossly unfair to the body of developmental theory. One faction of dissenteers, the Process Structuralists, take their inspiration from the rational morphologists who preceded Darwin. These neo-rationalists argue that a mature biology must possess universal laws and that these generative laws should be sought within organismal (...) development. Such a rational biology will only be possible once the neo-Darwinian paradigm, with its reliance on inherently stochastic processes, is overthrown.To facilitate this revolution, process structuralism launches a broad attack on the theoritical adequacy of its opponent. It is charged that neo-Darwinism is untestable and therefore its hypotheses are nothing more than adaptive stories. Further, the lamentable tendencies toward genetic determinism and atomism by modern biologists is seen as the inescapable consequences of adopting the neo-Darwinian outlook. (shrink)

We discuss N. I. Vavilov’s 1922 landmark publication, “The Law of Homologous Series in Variation,” and highlight its salient points. Vavilov drew upon his considerable experience in the field with wild and cultivated crop plants and summarized what he noticed in the form of a law. The law stated that comparable variant forms tended to appear in different varieties of the same species, different species of the same genus, different genera of the same family, and so on. His survey of (...) the older literature suggested that the law applied to multicellular animals as well. Vavilov acknowledged that such “parallel” series might be the outcome of convergent evolution (as conventionally understood). At the same time, by way of an alternative hypothesis, he posed a question that continues to engage evolutionary biology to this day. Namely, does the existence of such parallelisms reflect underlying structural and developmental principles (based on the laws of physics and chemistry) which constrain the range of possible plant and animal forms? Vavilov’s original 1922 paper from the _Journal of Genetics_ (12:47–89) is available as supplementary material in the online version of this article. (shrink)

Everyone has heard of ‘epigenetics’, but the term means different things to different researchers. Four important contemporary meanings are outlined in this paper. Epigenetics in its various senses has implications for development, heredity, and evolution, and also for medicine. Concerning development, it cements the vision of a reactive genome strongly coupled to its environment. Concerning heredity, both narrowly epigenetic and broader ‘exogenetic’ systems of inheritance play important roles in the construction of phenotypes. A thoroughly epigenetic model of development and evolution (...) was Waddington’s aim when he introduced the term ‘epigenetics’ in the 1940s, but it has taken the modern development of molecular epigenetics to realize this aim. In the final sections of the paper we briefly outline some further implications of epigenetics for medicine and for the nature/nurture debate. (shrink)

Developmental biology is a theory of interpretation. Developmental signals are interpreted differently depending on the previous history of the responding cell. Thus, there is a context for the reception of a signal. While this conclusion is obvious during metamorphosis, when a single hormone instructs some cells to proliferate, some cells to differentiate, and other cells to die, it is commonplace during normal development. Paracrine factors such as BMP4 can induce apoptosis, proliferation, or differentiation depending upon the history of the responding (...) cells. In addition, organisms have evolved to alter their development in response to differences in temperature, diet, the presence of predators, or the presence of competitors. This allows them to develop the phenotype, within the limits imposed by the genotype, best suited for the immediate habitat of the organism. Most developing organisms have also evolved to expect developmental signals from symbionts, and these organisms develop abnormally if the symbiont signals are not present. Thus Hoffmeyer’s “vertical semiotic system” of genetic communication and “horizontal semiotic system” of ecological communication are integrated during development. (shrink)

Ecological developmental biology (eco‐devo) explores the mechanistic relationships between the processes of individual development and environmental factors. Recent studies imply that some of these relationships have deep evolutionary origins, and may even pre‐date the divergences of the simplest extant animals, including cnidarians and sponges. Development of these early diverging metazoans is often sensitive to environmental factors, and these interactions occur in the context of conserved signaling pathways and mechanisms of tissue homeostasis whose detailed molecular logic remain elusive. Efficient methods for (...) transgenesis in cnidarians together with the ease of experimental manipulation in cnidarians and sponges make them ideal models for understanding causal relationships between environmental factors and developmental mechanisms. Here, we identify major questions at the interface between animal evolution and development and outline a road map for research aimed at identifying the mechanisms that link environmental factors to developmental mechanisms in early diverging metazoans.Also watch the Video Abstract. (shrink)

This special issue of Biological Theory is focused on development; it raises the problem of the temporal and spatial boundaries of development. From a temporal point of view, when does development start and stop? From a spatial point of view, what is it exactly that "develops", and is it possible to delineate clearly the developing entity? This issue explores the possible answers to these questions, and thus sheds light on the definition of development itself.

Conrad Hal Waddington integrated genetics with embryology and evolution by formulating and providing experimental evidence for the mechanisms of canalization and genetic assimilation in the context of stabilizing selection, and by fostering an epigenetic rather than the prevailing gene-centered view of embryonic development and of evolutionary change in development and adult form. Waddington saw phenotypes as processes, not static structures and behaviors. Trained in geology at Cambridge, Waddington turned to experimental studies on the chemical nature of the primary organizer and (...) developed the concepts of evocation and individuation as separable components of embryonic induction. A move after WW II to Edinburgh provided Waddington with his professional home for the rest of his career, during which he integrated genetics and development into an evolutionarily relevant discipline. Our conception of embryonic development as a highly integrated series of canalized pathways owes much to Waddington’s development of the concepts of canalization, chreods, epigenetics, and the epigenotype. The integrated, heritable, epigenetic organization of embryonic development is Waddington’s lasting legacy to development. He demonstrated organismal response to environmental change and hidden genetic variation, integrated environmental responsiveness into heritable change in response to selection, and coupled development, environment, and evolution. (shrink)

I attempt to raise questions regarding elements of systematics—primarily in the realm of phylogenetic reconstruction—in order to provoke discussion on the current state of affairs in this discipline, and also evolutionary biology in general: e.g., conceptions of homology and homoplasy, hypothesis testing, the nature of and objections to Hennigian “phylogenetic systematics”, and the schism between Darwinian descendants of the “modern evolutionary synthesis” and their supposed antagonists, cladists and punctuationalists.

Organic selection (the Baldwin Effect) by which an environmentally elicitedphenotypic adaptation comes under genotypic control following selectionwas proposed independently in 1896 by the psychologists James Baldwinand Conwy Lloyd Morgan and by the paleontologist Henry Fairfield Osborn.Modified forms of organic selection were proposed as autonomization bySchmalhausen in 1938, as genetic assimilation by Waddington in 1942, andas an explanation for evolution in changing environments or for speciationby Matsuda and West-Eberhard in the 1980s. Organic selection as amechanism mediating proximate environmental effects on the (...) evolution ofmorphology and behaviour is the topic of this essay. Discussion includesthe context in which organic selection was proposed, Lamarckian or neo-Lamarckian implications of organic selection, Waddingtons experimentalstudies demonstrating the existence and efficacy of genetic assimilation,stabilizing selection and norms of reaction favoured by Schmalhausen, andMatsudas search for a mechanism of organic selection in endocrine changesand in heterochrony. (shrink)

The 17th and 18th centuries were the theatre of the fight between two main theories concerning the development of organisms: preformationism (or preformism) and epigeneticism (or epigenesis). According to the first, the formation of new features during organisms’ development can be seen as the result of a mere unfolding of features that were preformed in the sperm, the egg, or the zygote. According to epigeneticism, there is no pre-existing form, and development is a process where genuinely new characters emerge from (...) formless matter. The debate involved naturalists, anatomists, physiologists, microscopists, medical doctors, and philosophers as well. Current developmental biology is, according to some, still inspired (or haunted) by the age-old controversy. The aim of this contribution is twofold. First, to discuss in which guise, if any, the old controversy is still shaping the contemporary debate in biology and philosophy of biology; and, second, to sketch Schelling’s position on that debate, suggesting that it may contain some still valuable philosophical insight. (shrink)

Biological mimicry is regarded by many as a textbook illustration of Darwin’s idea of evolution by random mutation followed by differential selection of reproductively fit specimens, resulting in gradual phenotypic change in a population. In this paper, I argue that some cases of so-called mimicry are probably merely look-a-likes and do not gain an advantage due to their similarity in appearance to something else. In cases where a similar appearance does provide a benefit, I argue that it is possible that (...) these forms of mimicry were created in a single generation. An interpretive response to an appearance as a sign can make a new structure perform drastically differently in an environment. In such cases, Darwin’s natural selection mechanism only helps to explain gradual the spread of these new forms, not the creation of them. I argue that biosemiosis should be regarded as a much more powerful mechanism for affecting evolutionary trajectories than the gradualist view allows. I focus on two cases of butterfly mimicry: the Viceroy (Nymphalidae: Limenitis archippus) and Monarch (Nymphalidae: Danaus plexippus) butterflies, supposed Müllerian mimics, and deadleaf mimic butterflies (Kallima). (shrink)

In 1956, in his Principles of Embryology, Conrad Hal Waddington explained that the word “epigenetics” should be used to translate and update Wilhelm Roux’ German notion of “Entwicklungsmechanik” to qualify the studies focusing on the mechanisms of development. When Waddington mentioned it in 1956, the notion of epigenetics was not yet popular, as it would become from the 1980s. However, Waddington referred first to the notion in the late 1930s. While his late allusion clearly reveals that Waddington readily associated the (...) notion of epigenetics with the developmental process, in the contemporary uses of the notion this developmental connotation seems to have disappeared. The advent and success of molecular biology have probably contributed to focusing biologists’ attention on the “genetic” or the “non-genetic” over the “developmental”. In the present paper, I first examine the links that exist, in Waddington’s work, between the classical notion of epigenesis in embryology and those of epigenetics that Waddington proposed to connect, and even synthesize, data both from embryology and genetics. Second, I show that Waddington’s own view of epigenetics has changed over time and I analyze how these changes appear through his many representations of the relationships between genetic signals and developmental processes. (shrink)

Recent philosophical analyses of the epistemic dimension of images in the sciences show a certain trend in acknowledging potential roles of these images beyond their merely decorative or pedagogical functions. We argue, however, that this new debate has yet paid little attention to a special type of pictures, we call ‘visual metaphor’, and its versatile heuristic potential in organizing data, supporting communication, and guiding research, modeling, and theory formation. Based on a case study of Conrad Hal Waddington’s epigenetic landscape images (...) in biology, we develop a descriptive framework applicable to heuristic roles of various visual metaphors in the sciences. (shrink)

A central reason that undergirds the significance of evo-devo is the claim that development was left out of the Modern synthesis. This claim turns out to be quite complicated, both in terms of whether development was genuinely excluded and how to understand the different kinds of embryological research that might have contributed. The present paper reevaluates this central claim by focusing on the practice of model organism choice. Through a survey of examples utilized in the literature of the Modern synthesis, (...) I identify a previously overlooked feature: exclusion of research on marine invertebrates. Understanding the import of this pattern requires interpreting it in terms of two epistemic values operating in biological research: theoretical generality and explanatory completeness. In tandem, these values clarify and enhance the significance of this exclusion. The absence of marine invertebrates implied both a lack of generality in the resulting theory and a lack of completeness with respect to particular evolutionary problems, such as evolvability and the origin of novelty. These problems were salient to embryological researchers aware of the variation and diversity of larval forms in marine invertebrates. In closing, I apply this analysis to model organism choice in evo-devo and discuss its relevance for an extended evolutionary synthesis. (shrink)

Recent philosophical analyses of the epistemic dimension of images in the sciences show a certain trend in acknowledging potential roles of these images beyond their merely decorative or pedagogical functions. We argue, however, that this new debate has yet paid little attention to a special type of pictures, we call ‘visual metaphor’, and its versatile heuristic potential in organizing data, supporting communication, and guiding research, modeling, and theory formation. Based on a case study of Conrad Hal Waddington’s epigenetic landscape images (...) in biology, we develop a descriptive framework applicable to heuristic roles of various visual metaphors in the sciences. (shrink)

In the 1930s, two concepts excited the European biological community: the organizer phenomenon and organicism. This essay examines the history of and connection between these two phenomena in order to address the conventional ‘rise-and-fall’ narrative that historians have assigned to each. Scholars promoted the ‘rise-and-fall’ narrative in connection with a broader account of the devitalizing of biology through the twentieth century. I argue that while limited evidence exists for the ‘fall of the organizer concept’ by the 1950s, the organicism that (...) often motivated the organizer work had no concomitant fall – even during the mid-century heyday of molecular biology. My argument is based on an examination of shifting social networks of life scientists from the 1920s to the 1970s, many of whom attended or corresponded with members of the Cambridge Theoretical Biology Club (1932–1938). I conclude that the status and cohesion of these social networks at the micro scale was at least as important as macro-scale conceptual factors in determining the relative persuasiveness of organicist philosophy. (shrink)

Evolutionary systems biology (ESB) aims to integrate methods from systems biology and evolutionary biology to go beyond the current limitations in both fields. This article clarifies some conceptual difficulties of this integration project, and shows how they can be overcome. The main challenge we consider involves the integration of evolutionary biology with developmental dynamics, illustrated with two examples. First, we examine historical tensions between efforts to define general evolutionary principles and articulation of detailed mechanistic explanations of specific traits. Next, these (...) tensions are further clarified by considering a recent case from another field focused on developmental dynamics: stem cell biology. In the stem cell case, incompatible explanatory aims block integration. Experimental approaches aim at mechanistic explanation while dynamical system models offer explanation in terms of general principles. We then discuss an ESB case in which integration succeeds: search for general attractors using a dynamical systems framework synergizes with the experimental search for detailed mechanisms. Contrasts between the positive and negative cases suggest general lessons for achieving an integrated understanding of developmental and evolutionary dynamics. The key integrative move is to acknowledge two complementary aims, both relevant to explanation: identifying the space of possible dynamic states and trajectories, and mechanistic understanding of causal interactions underlying a specific phenomenon of interest. These two aims can support one another in a joint project characterizing dynamic aspects of evolving lineages. This more inclusive project can lead to insights that cannot be reached by either approach in isolation. (shrink)

Evo-Devo exhibits a plurality of scientific “cultures” of practice and theory. When are the cultures acting—individually or collectively—in ways that actually move research forward, empirically, theoretically, and ethically? When do they become imperialistic, in the sense of excluding and subordinating other cultures? This chapter identifies six cultures – three /styles/ (mathematical modeling, mechanism, and history) and three /paradigms/ (adaptationism, structuralism, and cladism). The key assumptions standing behind, under, or within each of these cultures are explored. Characterizing the internal structure of (...) the cultures is necessary for understanding how they collaborate or compete, and how they are fragmented or integrated, in the rich interdisciplinary /trading zone/ (Galison 1997) of Evo-Devo. Evo-Devo is an important example of how science can progress through a radical plurality of perspectives and cultures. (shrink)

From the 1930s through the 1970s, C. H. Waddington attempted to reunite genetics, embryology, and evolution. One of the means to effect this synthesis was his model of the epigenetic landscape. This image originally recast genetic data in terms of embryological diagrams and was used to show the identity of genes and inducers and to suggest the similarities between embryological and genetic approaches to development. Later, the image became more complex and integrated gene activity and mutations. These revised epigenetic landscapes (...) presented an image of how mutations could alter developmental pathways to yield larger phenotypic changes. These diagrams became less important as the operon became used to model differential gene regulation. (shrink)

This is the story of a textbook that students of developmental biology have used for 45 years. “An Introduction to Embryology” was released soon after a role for genes in the control of development became finally recognized but not yet well documented. Thus this book manifested the transition from embryology to developmental biology. The story of its author, Boris Balinsky, who against all odds survived to write this book, is remarkable on its own. He started his scientific career in the (...) USSR, but due to 20th century social and political upheavals, ended it in South Africa. This article will shed light on the life of Boris Balinsky, a scientist and writer and will explore the origins of his book. BioEssays 27:970–977, 2005. © 2005 Wiley Periodicals, Inc. (shrink)

In recent years, a number of philosophers have argued against a biological understanding of the innate in favor of a narrowly psychological notion. On the other hand, Ariew ((1996). Innateness and canalization. Philosophy of Science, 63, S19-S27. (1999). Innateness is canalization: in defense of a developmental account of innateness. In V. Hardcastle (Ed.), Where biology meets psychology: Philosophical essays (pp. 117-138). Cambridge, MA: MIT.) has developed a novel substantial account of innateness based on developmental biology: canalization. The governing thought of (...) this paper is that the notion of the innate, as it re-emerged with the work of Chomsky, is a general notion that applies equally to all biological traits. On this basis, the paper recommends canalization as a promising candidate account of the notion of the innate. (shrink)

The increasing application of network models to interpret biological systems raises a number of important methodological and epistemological questions. What novel insights can network analysis provide in biology? Are network approaches an extension of or in conflict with mechanistic research strategies? When and how can network and mechanistic approaches interact in productive ways? In this paper we address these questions by focusing on how biological networks are represented and analyzed in a diverse class of case studies. Our examples span from (...) the investigation of organizational properties of biological networks using tools from graph theory to the application of dynamical systems theory to understand the behavior of complex biological systems. We show how network approaches support and extend traditional mechanistic strategies but also offer novel strategies for dealing with biological complexity. (shrink)