Evolutionary developmental biology is a rapidly growing discipline whose ambition is to address questions that are of relevance to both evolutionary biology and developmental biology. This field has been increasingly progressing as a new and independent comparative science. However, we argue that evo-devo’s comparative approach is challenged by several metaphysical, methodological and socio-disciplinary issues related to the foundation of heuristic functions of model organisms and the possible criteria to be adopted for their selection. In addition, new tools have to be (...) developed to deal with newly chosen model organisms. Therefore, we present a modelling framework suitable to integrate data on individual variation into evo-devo studies on new model organisms and thus to compensate for current idealization practices deliberately suppressing variation. (shrink)

I identify a controversial hypothesis in evolutionary biology called the plasticity-first hypothesis. I argue that the plasticity-first hypothesis is underdetermined and that the most popular means of studying the plasticity-first hypothesis are insufficient to confirm or disconfirm it. I offer a strategy for overcoming this problem. Researchers need to develop a richer middle range theory of plasticity-first evolution that allows them to identify distinctive empirical traces of the hypothesis. They can then use those traces to discriminate between rival explanations of (...) evolutionary episodes. The best tools for developing such a middle range theory are experimental evolution and formal modelling. (shrink)

The concept of adaptation is employed in many fields such as biology, psychology, cognitive sciences, robotics, social sciences, even literacy and art,1 and its meaning varies quite evidently according to the particular research context in which it is applied. We expect to find a particularly rich catalogue of meanings within evolutionary biology, where adaptation has held a particularly central role since Darwin’s The Origin of Species (1859) throughout important epistemological shifts and scientific findings that enriched and diversified the concept. Accordingly, (...) a conceptual taxonomy of adaptation in evolutionary biology may help to disambiguate it. Interdisciplinary researches focused on adaptation would benefit from such a result. In the present work we recognize and define seven different meanings of adaptation: (1) individual fitness; (2) adaptation of a population; (3) adaptation as the process of natural selection; (4) adaptive traits; (5) molecular adaptation; (6) adaptation as structural tinkering; (7) plasticity. For convenience here, we refer to them as W-, P-, NS-, T-, M-, S- and PL-ADAPTATION. We present the seven meanings in some detail, hinting at their respective origins and conceptual developments in the history of evolutionary thought (references are offered for further deepening). However, it is important to point out that evolution researchers seldom if ever refer to a single meaning purified from the others. This applies also to the authors we cite as representatives of one of the seven meanings. In Discussion and Conclusion draw from our work some future perspectives for adaptation within evolutionary biology. (shrink)

Recent work on inheritance systems can be divided into inclusive conceptions, according to which genetic and non-genetic inheritance are both involved in the development and transmission of nearly all animal behavioral traits, and more demanding conceptions of what it takes for non-genetic resources involved in development to qualify as a distinct inheritance system. It might be thought that, if a more stringent conception is adopted, homologies could not subsist across two distinct inheritance systems. Indeed, it is commonly assumed that homology (...) relations cannot survive a shift between genetic and cultural inheritance systems, and substantial reliance has been placed on that assumption in debates over the phylogenetic origins of hominin behavioral traits, such as male-initiated intergroup aggression. However, in the homology literature it is widely accepted that a trait can be homologous—that is, inherited continuously in two different lineages from a single common ancestor—despite divergence in the mechanisms involved in the trait’s development in the two lineages. In this paper, we argue that even on an extremely stringent understanding of what it takes for developmental resources to form a separate inheritance system, homologies can nonetheless subsist across shifts between distinct inheritance systems. We argue that this result is a merit of this way of characterizing what it is to be an inheritance system, that it has implications for adjudicating between alternative accounts of homology, and that it offers an important cautionary lesson about how to reason with the homology concept, particularly in the context of cultural species. (shrink)

In this paper, I will conduct three interrelated analyses. First, I will develop an analysis of various concepts in the history of biology that used to refer to individual-level phenomena but were then reinterpreted by the Modern Synthesis in terms of populations. Second, I argue that a similar situation can be found in contemporary biological theory. While different approaches reflect on the causal role of developing organisms in evolution, proponents of the Modern Synthesis avoid any substantial change by reinterpreting and (...) explaining individual-level phenomena from a population perspective. Finally, I will approach this debate by advocating the statistical reading of natural selection, which holds that explanations by natural selection are statistical. I will argue that the above historical conceptual reinterpretations belong to a new explanatory strategy developed by the Modern Synthesis based on population thinking. The reinterpretation of concepts at the individual level is part of the explanatory framework of the Modern Synthesis and the empty role of development within this framework. Moreover, the statistical perspective adopted here allows for the integration of two explanatory models: population-statistical and individual-causal. Finally, I will argue that this pluralistic framework can help to define the explanatory scope of the different biological approaches in order to achieve a coherent integration of development into evolution without rejecting population thinking. (shrink)

In this paper, we propose the expression cognitive twists for cognitive mechanisms that result from the coevolution of genes and learning. Evidence is available that at least some cultural learning mechanisms, such as imitation and language, have evolved genetically under the pressure produced by culture, even though they are mostly acquired through domain-general learning during development. Although the existence of these mechanisms is consistent with evolutionary theory, their importance has not been sufficiently emphasized by mind-centered accounts of human cognitive evolution, (...) namely evolutionary psychology and cultural evolutionary psychology. We provide concrete examples of cognitive twists, such as vocal imitation. Genetic changes in action-perception matching circuits suggest that human imitation and perhaps language are cognitive twists, namely plastic, learnable, yet genetically evolved cognitive mechanisms. We conclude that cognitive twists depict plausible evolutionary scenarios for the evolution of cognition in Homo sapiens. (shrink)

On the basis of findings from developmental biology, some researchers have argued that evolutionary theory needs to be significantly updated. Advocates of such a “developmental update” have, among other things, suggested that we need to re-conceptualize units of selection, that we should expand our view of inheritance to include environmental as well as genetic and epigenetic factors, that we should think of organisms and their environment as involved in reciprocal causation, and that we should reevaluate the rates of evolutionary change. (...) However, many of these same conclusions could be reached on the basis of other evidence, namely from microbiology. In this paper, I ask why microbiological evidence has not had a similarly large influence on calls to update biological theory, and argue that there is no principled reason to focus on developmental as opposed to microbiological evidence in support of these revisions to evolutionary theory. I suggest that the focus on developmental biology is more likely attributable to historical accident. I will also discuss some possible room for overlap between developmental and microbiology, despite the historical separation of these two subdisciplines. (shrink)

Environmental heterogeneity is invoked as a key explanatory factor in the adaptive evolution of a surprisingly wide range of phenomena. This article aims to analyze this explanatory scheme of categorizing traits or properties as adaptations to environmental heterogeneity. First it is suggested that this scheme can be understood as a reaction to how heterogeneity adaptations were discounted or ignored in the modern synthesis. Then a positive account is proposed, distinguishing between two broad categories of adaptation to environmental heterogeneity: properties selected (...) for by well-defined patterns of environmental heterogeneity, and properties that help organisms exploit novel patterns of environmental heterogeneity. (shrink)

The emergence of individuality during the evolutionary transition from single cells to multicellularity poses a range of problems. A key issue is how variation in lower‐level individuals generates a corporate (collective) entity with Darwinian characteristics. Of central importance to this process is the evolution of a means of collective reproduction, however, the evolution of a means of collective reproduction is not a trivial issue, requiring careful consideration of mechanistic details. Calling upon observations from experiments, we draw attention to proto‐life cycles (...) that emerge via unconventional routes and that transition, in single steps, individuality to higher levels. One such life cycle arises from conflicts among levels of selection and invokes cheats as a primitive germ line: it lays the foundation for collective reproduction, the basis of a self‐policing system, the selective environment for the emergence of development, and hints at a plausible origin for a soma/germ line distinction. (shrink)

Whether evolutionary change can occur by genetic assimilation, or more generally by genetic accommodation, remains controversial. Here we examine some of the experimental evidence for both phenomena. Several experiments in Drosophila suggest that assimilation is possible, and a new paper1 shows that a color polyphenism in the tobacco hornworm, Manduca sexta, can evolve by genetic accommodation. We argue that genetic accommodation, including assimilation, is a plausible mechanism in evolution; however, more work is required to test how this mechanism acts and (...) how often it is involved in evolutionary change. BioEssays 28: 868–873, 2006. © 2006 Wiley periodicals, Inc. (shrink)

Although classical evolutionary theory, i.e., population genetics and the Modern Synthesis, was already implicitly ‘gene-centred’, the organism was, in practice, still generally regarded as the individual unit of which a population is composed. The gene-centred approach to evolution only reached a logical conclusion with the advent of the gene-selectionist or gene’s eye view in the 1960s and 1970s. Whereas classical evolutionary theory can only work with (genotypically represented) fitness differences between individual organisms, gene-selectionism is capable of working with fitness differences (...) among genes within the same organism and genome. Here, we explore the explanatory potential of ‘intra-organismic’ and ‘intra-genomic’ gene-selectionism, i.e., of a behavioural-ecological ‘gene’s eye view’ on genetic, genomic and organismal evolution. First, we give a general outline of the framework and how it complements the—to some extent—still ‘organism-centred’ approach of classical evolutionary theory. Secondly, we give a more in-depth assessment of its explanatory potential for biological evolution, i.e., for Darwin’s ‘common descent with modification’ or, more specifically, for ‘historical continuity or homology with modular evolutionary change’ as it has been studied by evolutionary developmental biology (evo-devo) during the last few decades. In contrast with classical evolutionary theory, evo-devo focuses on ‘within-organism’ developmental processes. Given the capacity of gene-selectionism to adopt an intra-organismal gene’s eye view, we outline the relevance of the latter model for evo-devo. Overall, we aim for the conceptual integration between the gene’s eye view on the one hand, and more organism-centred evolutionary models (both classical evolutionary theory and evo-devo) on the other. (shrink)

Arguments for an extended evolutionary synthesis often center on the concept of “reciprocal causation.” Proponents argue that reciprocal causation is superior to standard models of evolutionary causation for at least two reasons. First, it leads to better scientific models with more predictive power. Second, it more accurately represents the causal structure of the biological world. Simply put, proponents of an extended evolutionary synthesis argue that reciprocal causation is empirically and explanatorily apt relative to competing causal frameworks. In this paper, I (...) present quantitative survey data from faculty members in biology departments at universities across the United States to evaluate this claim. The survey data indicate that a majority of the participants do not agree (i.e., most either disagree or neither agree nor disagree) that the concept of reciprocal causation confers a larger advantage on research practices. However, a majority of the participants agree that the causal framework of the extended evolutionary synthesis more accurately represents the structure of the biological world. These results demonstrate that the explanatory merits of a conceptual framework and its practical utility can come apart in interesting and informative ways. (shrink)

Scientific disputes about how often different processes or patterns occur are relative frequency controversies. These controversies occur across the sciences. In some areas—especially biology—they are even the dominant mode of dispute. Yet they depart from the standard picture of what a scientific controversy is like. In fact, standard philosophical accounts of scientific controversies suggest that relative frequency controversies are irrational or lacking in epistemic value. This is because standard philosophical accounts of scientific controversies often assume that in order to be (...) rational, a scientific controversy must reach a resolution and be about a scientifically interesting question. Relative frequency controversies rarely reach a resolution, however, and some scientists and philosophers are skeptical that these controversies center on scientifically interesting questions. In this paper, I provide a novel account of the epistemic contribution that relative frequency controversies make to science. I show that these controversies are rational in the sense of furthering the epistemic aims of the scientific communities in which they occur. They do this despite rarely reaching a resolution, and independent of whether the controversies are about scientifically interesting questions. This means that assumptions and about what is required for a controversy to be rational are wrong. Controversies do not need to reach a resolution in order to be rational. And they do not need to be about anything scientifically interesting in order to make valuable epistemic contributions to science. (shrink)

Although classical evolutionary theory, i.e., population genetics and the Modern Synthesis, was already implicitly ‘gene-centred’, the organism was, in practice, still generally regarded as the individual unit of which a population is composed. The gene-centred approach to evolution only reached a logical conclusion with the advent of the gene-selectionist or gene’s eye view in the 1960s and 1970s. Whereas classical evolutionary theory can only work with fitness differences between individual organisms, gene-selectionism is capable of working with fitness differences among genes (...) within the same organism and genome. Here, we explore the explanatory potential of ‘intra-organismic’ and ‘intra-genomic’ gene-selectionism, i.e., of a behavioural-ecological ‘gene’s eye view’ on genetic, genomic and organismal evolution. First, we give a general outline of the framework and how it complements the—to some extent—still ‘organism-centred’ approach of classical evolutionary theory. Secondly, we give a more in-depth assessment of its explanatory potential for biological evolution, i.e., for Darwin’s ‘common descent with modification’ or, more specifically, for ‘historical continuity or homology with modular evolutionary change’ as it has been studied by evolutionary developmental biology during the last few decades. In contrast with classical evolutionary theory, evo-devo focuses on ‘within-organism’ developmental processes. Given the capacity of gene-selectionism to adopt an intra-organismal gene’s eye view, we outline the relevance of the latter model for evo-devo. Overall, we aim for the conceptual integration between the gene’s eye view on the one hand, and more organism-centred evolutionary models on the other. (shrink)

In this paper, I present an emerging explanatory framework about ageing and care. In particular, I focus on how, in contrast to most classical accounts of ageing, biomedicine today construes the ageing process as a modifiable trajectory. This framing turns ageing from a stage of inexorable decline into the focus of preventive strategies, harnessing the functional plasticity of the ageing organism. I illustrate this shift by focusing on studies of the demographic dynamics in human population, observations of ageing as an (...) intraspecifically heterogenous phenotype, and the experimental manipulation of longevity, in both model organisms and humans. I suggest that such an explanatory framework about ageing creates the epistemological conditions for the rise of a peculiar form of prevention that does not aim to address a specific condition. Rather it seeks to stall the age-related accumulation of molecular damage and functional deficits, boosting individual resilience against age-related decline. I call this preventive paradigm “ground-state prevention.” While new, ground-state prevention bears conceptual resemblance to forms of medical wisdom prominent in classic Galenic medicine, as well as in the Renaissance period. (shrink)

It is clear throughout Cognitive Gadgets Heyes believes the development of cognitive capacities results from the interaction of genes and experience. However, she opposes cognitive instincts theorists to her own view that uniquely human capacities are cognitive gadgets. Instinct theorists believe that cognitive capacities are substantially produced by selection, with the environment playing a triggering role. Heyes’s position is that humans have similar general learning capacities to those present across taxa, and that sophisticated human cognition is substantially created by our (...) socioculturally transmitted environment. It is a core strategy of Heyes to provide evidence of learning altering a cognitive capacity to conclude that a capacity is a cognitive gadget and not an instinct. We draw on recent work on the evolution of learning preparedness to examine the adequacy of this strategy. In particular, we analyse experimental evolution work showing how selection affects cognition within the laboratory. First, this work reveals that change due to learning can still be retained under genetic assimilation. This suggests that domain-specific adaptation can coexist with learning, moderate nativism, an option missed by the instinct versus gadget distinction. Second, we describe the conditions that select for increased preparedness in learning: certainty, reliability, and particular costs. We consider how these conditions can be used when conducting evolutionary reasoning about cognition, applying them to the important capacity for imitation. We find that the conditions lend theoretical support to moderate nativism about the capacity to imitate, which is supported by psychological evidence. (shrink)

Adaptation by means of natural selection depends on the ability of populations to maintain variation in heritable traits. According to the Modern Synthesis this variation is sustained by mutations and genetic drift. Epigenetics, evodevo, niche construction and cultural factors have more recently been shown to contribute to heritable variation, however, leading an increasing number of biologists to call for an extended view of speciation and evolution. An additional common feature across the animal kingdom is learning, defined as the ability to (...) change behavior according to novel experiences or skills. Learning constitutes an additional source for phenotypic variation, and change in behavior may induce long lasting shifts in fitness, and hence favor evolutionary novelties. Based on published studies, I demonstrate how learning about food, mate choice and habitats has contributed substantially to speciation in the canonical story of Darwin’s finches on the Galapagos Islands. Learning cannot be reduced to genetics, because it demands decisions, which requires a subject. Evolutionary novelties may hence emerge both from shifts in allelic frequencies and from shifts in learned, subject driven behavior. The existence of two principally different sources of variation also prevents the Modern Synthesis from self-referring explanations. (shrink)

Four sequential, sub-processes are identified as the fundamental steps in the processing of signals by big-brained animals. These are, Detection of the signal, its Representation in correlated sensory brain structure, the Interpretation of the signal in another part of the brain and the Expression of the receiver’s response. We label this four-step spatiotemporal process DRIE. We support the view that when the context within which such signals are produced and received is relatively constant, the DRIE process can be ultimately assimilated (...) into the genome, with the Interpretation sub-phase is markedly decreased in duration as speed and efficiency are maximized. With frequent repetition and learning, an analogous result can be attained epigenetically as exemplified in human word and text recognition, allowing tasks critical to primate social function to be accomplished with rapidity and accuracy. (shrink)

In this paper, I will conduct three interrelated analyses. First, I will develop an analysis of various concepts in the history of biology that used to refer to individual-level phenomena but were then reinterpreted by the Modern Synthesis in terms of populations. Second, a similar situation can be found in contemporary evolutionary theory. While different approaches reflect on the causal role of developing organisms in evolution, proponents of the Modern Synthesis refrain from any substantial change by reinterpreting and explaining individual-level (...) phenomena from a population perspective. Finally, I will approach these historical and contemporary debates by arguing for the statistical reading of natural selection, which holds that explanations by natural selection are statistical. My main conclusion is that the historical conceptual reinterpretations belong to a new explanatory strategy developed by the Modern Synthesis based on population thinking. Adopting the statistical point of view has three advantages for the issues discussed in this paper. First, understanding historical conceptual change as part of an explanatory shift fits with the emergence of population biology as a discipline that employs statistical methods. Second, concerning current debates in evolutionary biology, the statisticalist reading can validate the goal of both sides of the dispute. It ascribes an invaluable role to the population statistical explanation of the MS and also commends the study of developmental and organismal causes of adaptive evolution. Finally, the division of explanatory roles in evolutionary biology, embarrassed by statisticalism, can be related to the different interpretations that important biological concepts have undergone throughout history and contemporary biology, i.e., that the division of explanatory roles allows for a division of conceptual interpretations. (shrink)