The concept of hierarchical organization is commonplace in science. Subatomic particles compose atoms, which compose molecules; cells compose tissues, which compose organs, which compose organisms; etc. Hierarchical organization is particularly prominent in ecology, a field of research explicitly arranged around levels of ecological organization. The concept of levels of organization is also central to a variety of debates in philosophy of science. Yet many difficulties plague the concept of discrete hierarchical levels. In this paper, we show how these difficulties undermine (...) various implications ascribed to hierarchical organization, and we suggest the concept of scale as a promising alternative to levels. Investigating causal processes at different scales offers a way to retain a notion of quasi-levels that avoids the difficulties inherent in the classic concept of hierarchical levels of organization. Throughout, our focus is on ecology, but the results generalize to other invocations of hierarchy in science and philosophy of science. (shrink)

Complexity science has proliferated across academic domains in recent years. A question arises as to whether any useful sense of ‘generalized complexity ’ can be abstracted from the various versions of complexity to be found in the literature, and whether it could prove fruitful in a scientific sense. Most attempts at defining complexity center around two kinds of notions: Structural, and temporal or dynamic. Neither of these is able to provide a foundation for the intuitive or generalized notion when taken (...) separately; structure is often a derivative notion, dependent on prior notions of complexity, and dynamic notions such as entropy are often indefinable. The philosophical notion of process may throw light on the tensions and contradictions within complexity. Robustness, for instance, a key quality of complexity, is quite naturally understood within a process-theoretical framework. Understanding complexity as process also helps one align complexity science with holistically oriented predecessors such as General System Theory, while allowing for the reductionist perspective of complexity. These results, however, have the further implication that it may be futile to search for general laws of complexity, or to hope that investigations of complex objects in one domain may throw light on complexity in unrelated domains. (shrink)

One of the first questions that paleontologists ask when they identify a large-scale trend in the fossil record (e.g., size increase, complexity increase) is whether it is passive or driven. In this article, I explore two questions about driven trends: (1) what is the underlying cause or source of the directional bias? and (2) has the strength of the directional bias changed over time? I identify two underdetermination problems that prevent scientists from giving complete answers to these two questions.

Sewall Wright introduced the metaphor of evolution on “adaptive landscapes” in a pair of papers published in 1931 and 1932. The metaphor has been one of the most influential in modern evolutionary biology, although recent theoretical advancements show that it is deeply flawed and may have actually created research questions that are not, in fact, fecund. In this paper I examine in detail what Wright actually said in the 1932 paper, as well as what he thought of the matter at (...) the very end of his career, in 1988. While the metaphor is flawed, some of the problems which Wright was attempting to address are still with us today, and are in the process of being reformulated as part of a forthcoming Extended Evolutionary Synthesis. (shrink)

Natural selection explains how living forms are fitted to theirconditions of life. Darwin argued that selection also explains what hecalled the gradual advancement of the organisation, i.e.evolutionary progress. Present-day selectionists disagree. In theirview, it is happenstance that sustains conditions favorable to progress,and therefore happenstance, not selection, that explains progress. Iargue that the disagreement here turns not on whether there exists aselection-based condition bias – a belief now attributed to Darwin – but on whether there needs to be such a bias (...) for selection to count as explaining progress. In Darwin''s own view, selection explained progressso far as more complex organisms have the selective advantage whenselection operates unimpeded. I show that these two explanations ofevolutionary progress, selection and happenstance, answer for theirobjectivity to different standards, and for their truth or falsehood todifferent features of the world. (shrink)

One problem faced in discussions of the evolution of intelligence is the need to get a precise fix on what is to be explained. Terms like "intelligence," "cognition" and "mind" do not have simple and agreed-upon meanings, and the differences between conceptions of intelligence have consequences for evolutionary explanation. I hope the papers in this volume will enable us to make progress on this problem. The present contribution is mostly focused on these basic and foundational issues, although the last section (...) of the paper will look at some specific models and programs of empirical work. (shrink)

Los conceptos de evolución y cambio evolutivo son a la vez laxos y polisémicos: se aplican a fenómenos muy diferentes y no siempre se definen con precisión. La aplicación extendida del paradigma neo-darwinista clásico, además, suele imponer un esquema adaptacionista al análisis de los hechos evolutivos, en el cual las funciones juegan un papel lógicamente anterior a los rasgos y sus formas. En este artículo proponemos, como etapa previa a la formulación de hipótesis sobre las causas del cambio, un modelo (...) de espacio forma-función que pueda responder a preguntas como cuándo se da un cambio en los rasgos de una arquitectura biológica y de qué tipo son estos cambios. Un modelo de este tipo nos permite ver claramente cuándo se da un cambio en la forma o en la función y qué alcance evolutivo tiene. (shrink)

Cancer is typically spoken of as a “complex” disease. But, in what sense are cancers “complex”? Is there one sense, or several? What implications does this complexity have – both for how we study, and how we intervene upon cancers? The aim of this paper is first, to clarify the variety of senses in which cancer is spoken of as "complex" in the scientific literature, and second, to discover what explanatory and predictive roles such features play.

The impressive variation amongst biological individuals generates many complexities in addressing the simple-sounding question what is a biological individual? A distinction between evolutionary and physiological individuals is useful in thinking about biological individuals, as is attention to the kinds of groups, such as superorganisms and species, that have sometimes been thought of as biological individuals. More fully understanding the conceptual space that biological individuals occupy also involves considering a range of other concepts, such as life, reproduction, and agency. There has (...) been a focus in some recent discussions by both philosophers and biologists on how evolutionary individuals are created and regulated, as well as continuing work on the evolution of individuality. (shrink)

Analytical categories of scientific cultures have typically been used both exclusively and universally. For instance, when styles of scientific research are employed in attempts to understand and narrate science, styles alone are usually employed. This article is a thought experiment in interweaving categories. What would happen if rather than employ a single category, we instead investigated several categories simultaneously? What would we learn about the practices and theories, the agents and materials, and the political-technological impact of science if we analyzed (...) and applied styles, paradigms, and models simultaneously? I address these questions in general and for a specific case study: a brief history of systematics. (shrink)

Philosophers and psychologists make many different, seemingly incompatible parsimony claims in support of competing models of cognition in nonhuman animals. This variety of parsimony claims is problematic. Firstly, it is difficult to justify each specific variety. This problem is especially salient for Morgan's Canon, perhaps the most important variety of parsimony claimed. Secondly, there is no systematic way of adjudicating between particular claims when they conflict. I argue for a view of parsimony in comparative psychology that solves these problems, based (...) on Sober's view that parsimony claims are claims that one model is more plausible given background theory. (shrink)

Geologists, Paleontologists and other historical scientists are frequently concerned with narrative explanations targeting single cases. I show that two distinct explanatory strategies are employed in narratives, simple and complex. A simple narrative has minimal causal detail and is embedded in a regularity, whereas a complex narrative is more detailed and not embedded. The distinction is illustrated through two case studies: the ‘snowball earth’ explanation of Neoproterozoic glaciation and recent attempts to explain gigantism in Sauropods. This distinction is revelatory of historical (...) science. I argue that at least sometimes which strategy is appropriate is not a pragmatic issue, but turns on the nature of the target. Moreover, the distinction reveals a counterintuitive pattern of progress in some historical explanation: shifting from simple to complex. Sometimes, historical scientists rightly abandon simple, unified explanations in favour of disunified, complex narratives. Finally I compare narrative and mechanistic explanation, arguing that mechanistic approaches are inappropriate for complex narrative explanations. (shrink)

The common opinion has been that evolution results in the continuing development of more complex forms of life, generally understood as more complex organisms. The arguments supporting that opinion have recently come under scrutiny and been found wanting. Nevertheless, the appearance of increasing complexity remains. So, is there some sense in which evolution does grow complexity? Artificial life simulations have consistently failed to reproduce even the appearance of increasing complexity, which poses a challenge. Simulations, as much as scientific theories, are (...) obligated at least to save the appearances! We suggest a relation between these two problems, understanding biological complexity growth and the failure to model even its appearances. We present a different understanding of that complexity which evolution grows, one that genuinely runs counter to entropy and has thus far eluded proper analysis in information-theoretic terms. This complexity is reflected best in the increase in niches within the biosystem as a whole. Past and current artificial life simulations lack the resources with which to grow niches and so to reproduce evolution’s complexity. We propose a more suitable simulation design integrating environments and organisms, allowing old niches to change and new ones to emerge. (shrink)

(1997). Cartesian cut, Heisenberg cut, and the concept of complexity. World Futures: Vol. 49, The Quest for a Unified Theory of Information, pp. 333-355.

The functional complexity, or the number of functions, of organisms hasfigured prominently in certain theoretical and empirical work inevolutionary biology. Large-scale trends in functional complexity andcorrelations between functional complexity and other variables, such assize, have been proposed. However, the notion of number of functions hasalso been operationally intractable, in that no method has been developedfor counting functions in an organism in a systematic and reliable way.Thus, studies have had to rely on the largely unsupported assumption thatnumber of functions can be (...) measured indirectly, by using number ofmorphological, physiological, and behavioral parts as a proxy. Here, amodel is developed that supports this assumption. Specifically, the modelpredicts that few parts will have many functions overlapping in them, andtherefore the variance in number of functions per part will be low. If so,then number of parts is expected to be well correlated with number offunctions, and we can use part counts as proxies for function counts incomparative studies of organisms, even when part counts are low. Alsodiscussed briefly is a strategy for identifying certain kinds of parts inorganisms in a systematic way. (shrink)

The cybernetic definition of a living individual proposed previously (Korzeniewski, 2001) is very abstract and therefore describes the essence of life in a very formal and general way. In the present article this definition is reformulated in order to determine clearly the relation between life in general and a living individual in particular, and it is further explained and defended. Next, the cybernetic definition of a living individual is confronted with the real world. It is demonstrated that numerous restrictions imposed (...) on the cybernetic definition of life by physical reality imply a number of particular properties of life that characterize present life on Earth, namely: (1) a living individual must be a dissipative structure (and therefore a low-entropy thermodynamic system out of the state of equilibrium); (2) spontaneously-originated life must be based on organic compounds; (3) evolutionarily stable self-dependent, free-living individuals must have some minimal level of complexity of structure and function; (4) a living individual must have a record of identity separated from an executive machinery; (5) the identity of living individuals must mutate and may evolve; (6) living individuals may collect and accumulate information in subsequent generations over very long periods of time; (7) the degree of complexity of a living individual reflects the degree of complexity of its environment (ecological niche) and (8) living individuals are capable of supple adaptation to varying environmental conditions. Thus, the cybernetic definition of a living individual, when confronted with the real physical world, generates most of the general properties of the present life on Earth. (shrink)

This paper is a defense of "explanatory pluralism" (i.e., the view that some events can be correctly explained in two distinct ways). To defend pluralism, I identify two distinct (but compatible) styles of explanation in paleobiology. The first approach ("actual sequence explanation") traces out the particular forces that affect each species. The second approach treats the trend as "passive" or "random" diffusion away from a boundary in morphological space. I argue that while these strategies are distinct, some trends are correctly (...) explained in both ways. Further, since neither strategy can be reduced or eliminated from paleobiology, we should accept that both strategies can provide correct explanations for a single trend. (shrink)

Argues that truth, moral right, political right, and aesthetic value may be understood as arising out of a naturalist account of humanity, if naturalism is rightly conceived.

A short review of complexity research from the perspective of history and philosophy of biology is presented. Complexity and its emergence has scientific and metaphysical meanings. From its beginning, biology was a science of complex systems, but with the advent of electronic computing and the possibility of simulating mathematical models of complicated systems, new intuitions of complexity emerged, together with attempts to devise quantitative measures of complexity. But can we quantify the complex?

Hull's recent work in evolutionary epistemology is marred by a deep tension. While he maintains that conceptual and biological evolution are both driven by selection processes, he also claims that only the former is globally progressive. In this paper I formulate this tension and present four possible responses (including Hull's). I argue that Hull's position rests on the assumption that there is a goal which is sufficiently general to describe most scientific activity yet precise enough to guide research. Working from (...) within Hull's framework, I argue that a non-progressionist stance is both preferable and more consistent with Hull's basic commitments. (shrink)

El proyecto del ‘Darwinismo Formal’ de Alan Grafen propone una formulación matemática de la teoría de Darwin que pretende demostrar que la selección natural moldea los rasgos fenotípicos a través de la maximización de la eficacia. El proyecto de Grafen reposa sobre tres premisas: la selección natural es la única fuerza que moldea los fenotipos; la eficacia es la única medida de le evolución; y el diseño biológico surge como resultado de un proceso de optimización selectiva. En este trabajo argumentamos (...) que estas tres premisas limitan la aplicabilidad del modelo a los hechos evolutivos más simples. Esto se debe a que Grafen implícitamente presupone un concepto de eficacia que es a la vez causa y efecto de las novedades fenotípicas; lo que, por un lado, vacía la teoría de Darwin de poder explicativo y, por el otro, lleva a ignorar la potencial contribución de fuerzas evolutivas no selectivas en la configuración de la complejidad biológica. Para superar estos escollos del proyecto de del Darwinismo Formal - que son además comunes a todos los modelos formales adaptacionistas - proponemos sustituir el concepto causal de eficacia por el de robustez, definiendo así el diseño biológico como forma y función en lugar de como maximización de la eficacia. (shrink)

The model of major transitions in evolution devised by Maynard Smith and Szathmáry has exerted tremendous influence over evolutionary theorists. Although MTE has been criticized for inconsistently combining different types of event, its ongoing appeal lies in depicting hierarchical increases in complexity by means of evolutionary transitions in individuality. In this paper, we consider the implications of major evolutionary events overlooked by MTE and its ETI-oriented successors, specifically the biological oxygenation of Earth, and the acquisitions of mitochondria and plastids. By (...) reflecting on these missed events, we reveal a central philosophical disagreement over the explanatory goals of major transitions theory that has yet to be made explicit in the literature. We go on to argue that this philosophical disagreement is only reinforced by Szathmáry’s recent revisions of MTE in the form of MTE 2.0. This finding motivates us to propose an alternative explanatory strategy: specifically, an interactionist metabolic perspective on major transitions. A metabolic framework not only avoids many of the criticisms that beset classic and revised MTE models, but also accommodates missing events and provides crucial explanatory components for standard major transitions. Although we do not provide a full-blown alternative theory and do not claim to achieve unity, we explain why foregrounding metabolism is crucial for any attempt to capture the major turning points in evolution, and why it does not lead to unmanageable pluralism. (shrink)

This paper reviews Rosenberg’s and McShea’s textbook in philosophy of biology, entitled Philosophy of Biology. A Contemporary Introduction. I insist on the excellent quality of this textbook, then I turn to more critical comments, which deal mainly with what philosophy of biology is, and what it should be.

This paper is interested in the relationship between evolutionary thinking and moral behavior and commitments, ethics. There is a traditional way of forging or conceiving of the relationship. This is traditional evolutionary ethics, known as Social Darwinism. Many think that this position is morally pernicious, a redescription of the worst aspects of modern, laissez-faire capitalism in fancy biological language. It is argued that, in fact, there is much more to be said for Social Darwinism than many think. In respects, it (...) could be and was an enlightened position to take; but it flounders on the matter of justification. Universally, the appeal is to progress—evolution is progressive and, hence, morally we should aid its success. I argue, however, that this progressive nature of evolution is far from obvious and, hence, traditional social Darwinism fails. There is another way to do things. This is to argue that the search for justification is mistaken. Ethics just is. It is an adaptation for humans living socially and has exactly the same status as other adaptations, like hands and teeth and genitalia. As such, ethics is something with no standing beyond what it is. However, if we all thought that this was so, we would stop being moral. So part of the experience of ethics is that it is more than it is. We think that it has an objective referent. In short, ethics is an illusion put in place by our genes to make us good social cooperators. (shrink)

Evolution in its contemporary meaning in biology typically refers to the changes in the proportions of biological types in a population over time (see the entry on the concept of evolution to 1872 for earlier meanings). As evolution is too large of a topic to address thoroughly in one entry, the primary goal of this entry is to serve as a broad overview of contemporary issues in evolution with links to other entries where more in-depth discussion can be found. The (...) entry begins with a brief survey of definitions of evolution, followed by a discussion of the different modes of evolution and related philosophical issues, and ends with a summary of other topics in the philosophy of evolution focusing particularly on topics covered in this encyclopedia. (shrink)

Darwin’s claim that Natural Selection, through optimization of fitness, explains complex biological design has not yet been properly formalized. Alan Grafen’s Formal Darwinism Project aims at providing such a formalization and at demonstrating that fitness maximization is coherent with results from Population Genetics, usually interpreted as denying it. We suggest that Grafen’s proposal suffers from some limitations linked to its concept of design as optimized fitness. In order to overcome these limitations, we propose a classification of evolutionary facts based on (...) a bi-dimensional complexity space, which adds robustness to fitness as measure of the quality of a design. In this space, each point represents an organismic architecture, and movement between two points would be an evolutionary fact. Natural Selection explains movement along the fitness axis, while non-selective mechanisms explain movement on the robustness axis. Moreover, we propose a thermodynamic metaphor to draw parallelisms between notions of fitness and entropy, robustness and energy, and movement in this space and reversible and irreversible cycles. We argue that this metaphor illustrates different evolutionary processes usually overlooked by proposals of formalization of Darwinian theory, such Grafen’s Formal Darwinism Project. (shrink)

This chapter contains sections titled: Highlights of Past Literature Current Work Future Work.

The conventional wisdom declares that evolution is not goal directed, that teleological considerations play no part in our understanding of evolutionary trends. Here I argue that, to the contrary, under a current view of teleology, field theory, most evolutionary trends would have to be considered goal directed to some degree. Further, this view is consistent with a modern scientific outlook, and more particularly with evolutionary theory today. Field theory argues that goal directedness is produced by higher-level fields that direct entities (...) contained within them to behave persistently and plastically, that is, returning them to a goal-directed trajectory following perturbations (persistence) and directing them to a goal-directed trajectory from a large range of alternative starting points (plasticity). The behavior of a bacterium climbing a chemical food gradient is persistent and plastic, with guidance provided by the external “food field,” the chemical gradient. Likewise, an evolutionary trend that is produced by natural selection is a lineage behaving persistently and plastically under the direction of its local ecology, an “ecological field.” Trends directed by selection-generated boundaries, thermodynamic gradients, and certain internal constraints, would also count as goal directed. In other words, most of the causes of evolutionary trends that have been proposed imply goal directedness. However, under field theory, not all trends are goal directed. Examples are discussed. Importantly, nothing in this view suggests that evolution is guided by intentionality, at least none at the level of animal intentionality. Finally, possible implications for our thinking about evolutionary directionality in the history of life are discussed. (shrink)

1.1 - Background - page 17 1.2 - The Style of Approach - page 18 1.3 - Motivation - page 19 1.4 - Style of Presentation - page 20 1.5 - Outline of the Thesis - page 21..

A sign is something that refers to something else. Signs, whether of natural or cultural origin, act by provoking a receptive system, human or nonhuman, to form an interpretant (a movement or a brain activity) that somehow relates the system to this "something else." Semiotics sees meaning as connected to the formation of interpretants. In a biosemiotic understanding living systems are basically engaged in semiotic interactions, that is, interpretative processes, and organic evolution exhibits an inherent tendency toward an increase in (...) semiotic freedom. Mammals generally are equipped with more semiotic freedom than are their reptilian ancestor species, and fishes are more semiotically sophisticated than are invertebrates. The evolutionary trend toward the production of life forms with an increasing interpretative capacity or semiotic freedom implies that the production of meaning has become an essential survival parameter in later stages of evolution. (shrink)

There are at least two senses in which human beings can be called “naturally artificial”: being adapted for creation of and participation in niche constructed environments, and being adapted for creation of and participation in such environments despite an exceptional indeterminacy in the details of the niche constructed environments themselves. The former puts human beings in a common category with many niche-constructing organisms while the latter is arguably distinctive of our species. I explain how this can be so by developing (...) an account of supporting concepts of complexity, contingency, and content-openness, and show how to defend the position against a common style of objection by a single comparative case study: hermit crabs and their shells versus humans and their movable dwellings. Finally, I consider evidence that such a feature is indeed species-typical and evolved in human populations. (shrink)

Recently, Barbara Renzi argued that Kuhn's account of scientific change is undermined by mismatches in the analogy that Kuhn supposedly draws between scientific change and biological evolution. We argue that Renzi's criticism is inadequate to Kuhn's account of scientific change, as Kuhn does not draw any precise analogy between the mechanisms of scientific change and biological evolution nor aims to argue that the mechanisms of scientific change and biological evolution are similar in any important respects. Therefore, pointing to mismatches between (...) the central concepts that feature in the descriptions of the two phenomena simply misses the point of Kuhn's analogy. *Received January 2010; revised January 2010. †To contact the authors, please write to: Thomas A. C. Reydon, Leibniz Universität Hannover, Im Moore 21, D‐30167 Hannover, Germany; e‐mail: [email protected]‐hannover.de. (shrink)

Modern biology is ambivalent about the notion of evolutionary progress. Although most evolutionists imply in their writings that they still understand large-scale macroevolution as a somewhat progressive process, the use of the term “progress” is increasingly criticized and avoided. The paper shows that this ambivalence has a long history and results mainly from three problems: (1) The term “progress” carries historical, theoretical and social implications which are not congruent with modern knowledge of the course of evolution; (2) An incongruence exists (...) between the notion of progress and Darwin’s theory of selection; (3) It is still not possible to give more than a rudimentary definition of the general patterns that were generated during the macroevolution of organisms. The paper consists of two parts: the first is a historical overview of the roots of the term “progress” in evolutionary biology, the second discusses epistemological, ontological and empirical problems. It is stated that the term has so far served as a metaphor for general patterns generated amongst organisms during evolution. It is proposed that a reformulation is needed to eliminate historically imported implications and that it is necessary to develop a concept for an appropriate empirical description of macroevolutionary patterns. This is the third way between, on the one hand, using the term indiscriminately and, on the other hand, ignoring the general patterns that evolution has produced. (shrink)

The consensus among cultural evolutionists seems to be that human cultural evolution is cumulative, which is commonly understood in the specific sense that cultural traits, especially technological traits, increase in complexity over generations. Here we argue that there is insufficient credible evidence in favor of or against this technological complexity thesis. For one thing, the few datasets that are available hardly constitute a representative sample. For another, they substantiate very specific, and usually different versions of the complexity thesis or, even (...) worse, do not point to complexity increases. We highlight the problems our findings raise for current work in cultural-evolutionary theory, and present various suggestions for future research. (shrink)

This paper offers a novel view of unity in neuroscience. I set out by discussing problems with the classical account of unity-by-reduction, due to Oppenheim and Putnam. That view relies on a strong notion of levels, which has substantial problems. A more recent alternative, the mechanistic “mosaic” view due to Craver, does not have such problems. But I argue that the mosaic ideal of unity is too minimal, and we should, if possible, aspire for more. Relying on a number of (...) recent works in theoretical neuroscience—network motifs, canonical neural computations and design-principles—I then present my alternative: a “flat” view of unity, i.e. one that is not based on levels. Instead, it treats unity as attained via the identification of recurrent explanatory patterns, under which a range of neuroscientific phenomena are subsumed. I develop this view by recourse to a causal conception of explanation, and distinguish it from Kitcher’s view of explanatory unification and related ideas. Such a view of unity is suitably ambitious, I suggest, and has empirical plausibility. It is fit to serve as an appropriate working hypothesis for 21st century neuroscience. (shrink)

The distinction between idiographic science, which aims to reconstruct sequences of particular events, and nomothetic science, which aims to discover laws and regularities, is crucial for understanding the paleobiological revolution of the 1970s and 1980s. Stephen Jay Gould at times seemed conflicted about whether to say (a) that idiographic science is fine as it is or (b) that paleontology would have more credibility if it were more nomothetic. Ironically, one of the lasting results of the paleobiological revolution was a new (...) way of doing historical science that defies categorization as idiographic or nomothetic. Yet the tension between (a) and (b) persists in some recent work in the philosophy of science, with Carol Cleland defending a version of (a) and Dan McShea and Robert Brandon defending a version of (b). In placing Cleland's work into conversation with that of McShea and Brandon, this paper defends a third (c) synthetic approach that emphasizes the blending of idiographic and nomothetic work. (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)

Radboud Universiteit Nijmegen, 06 september 2010.