Evolutionary Developmental Biology

Special commendation from the Hans-und-Lea-Grundig Prize by the Rosa-Luxemburg-Foundation 2015 -- I -- Do have pictures an impact on future? Yes, say theories of embodiment by making perceptual foundations in place of representational arrangements responsible for it. -- I -- Wirken sich Bildern auf die Zukunft aus? Ja sagen Verkörperungstheorien und machen dafür weniger Repräsentationsmodelle als Wahrnehmungsweisen verantwortlich.

This paper proposes an abstract mathematical frame for describing some features of biological time. The key point is that usual physical (linear) representation of time is insufficient, in our view, for the understanding key phenomena of life, such as rhythms, both physical (circadian, seasonal …) and properly biological (heart beating, respiration, metabolic …). In particular, the role of biological rhythms do not seem to have any counterpart in mathematical formalization of physical clocks, which are based on frequencies along the usual (...) (possibly thermodynamical, thus oriented) time. We then suggest a functional representation of biological time by a 2-dimensional manifold as a mathematical frame for accommodating autonomous biological rhythms. The “visual” representation of rhythms so obtained, in particular heart beatings, will provide, by a few examples, hints towards possible applications of our approach to the understanding of interspecific differences or intraspecific pathologies. The 3- dimensional embedding space, needed for purely mathematical reasons, allows to introduce a suitable extra-dimension for “representation time”, with a cognitive significance. (shrink)

A summarizing English version on “Theory of Innovation and the Evolution of General Human Capabilities, such as Cognition-based Empathy” is included in the download. Den biologisch modernen Menschentyp charakterisieren sehr allgemeine Fähigkeiten, wie begriffliche Sprache, strategisches Denken und kognitionsgestützte Empathie. Neurobiologisch kann Empathiefähigkeit als eine Verbindung von Repräsentationen von Mitmenschen mit dem je eigenen Gefühlszentren im Gehirn angesehen werden. In Grundzügen ist sie vor vielleicht 100 000 Jahren als Folge von Mutationen der Erbsubstanz DNA entstanden. Für solche genetische Innovationen spielten (...) wohl nicht nur lokale Veränderungen des Genoms eine Rolle, sondern auch seltene größere Umordnungen, besonders neue Zufallskombinationen von Regelbereichen in der DNA. Dies könnte in seltenen Einzelfällen eine Art Weichenstellung für eine neue Richtung der Evolution bewirken, die dann in vielen kleinen Schritten ausgeprägt wurde. Interessant ist die Analogie solcher biologischer mit technischer Innovation: Auch in ihr, Beispiel Dampfschiff, spielt die (seltene) Neukombination von Grundfähigkeiten eine Initialrolle für die Ausbreitung einer Innovation. (shrink)

The aim of this paper lies in characterizing the explanations and models used in the field of evolutionary developmental biology throughout its history. While manipulative experiments in controlled conditions have been useful to set the bases of the discipline and are still routinely performed, this approach supposes a tension between the reliability and the representativity of the conclusions. Given the recent changes in the understanding of evolutionary phenomena, different authors currently emphasize the need of avoiding excessive simplifications in experimental approaches, (...) incorporating the complexity of the analyzed systems as a relevant trait in the study of biological diversity. On the other hand, the fragile and contingent nature of evolutionary processes and the impossibility of intervening some of these phenomena underscore the importance of non-manipulative models that allow the elucidation of how-possibly mechanisms. We argue that a pluralism characterized by the integration of different kinds of explanations, models and metaphors used in evo-devo allows to exploit their respective advantages, favours interdisciplinarity and can contribute to form a representative description of evolutionary processes without relinquishing the local and detailed study of actual mechanisms. (shrink)

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

In identifying intrinsic molecular chance and extrinsic adaptive pressures as the only causally relevant factors in the process of evolution, the theoretical perspective of the Modern Synthesis had a major impact on the perceived tenability of an ontology of dispositional properties. However, since the late 1970s, an increasing number of evolutionary biologists have challenged the descriptive and explanatory adequacy of this “chance alone, extrinsic only” understanding of evolutionary change. Because morphological studies of homology, convergence, and teratology have revealed a space (...) of possible forms and phylogenetic trajectories that is considerably more restricted than expected, evo-devo has focused on the causal contribution of intrinsic developmental processes to the course of evolution. Evo-devo’s investigation into the developmental structure of the modality of morphology – including both the possibility and impossibility of organismal form – has led to the utilisation of a number of dispositional concepts that emphasise the tendency of the evolutionary process to change along certain routes. In this sense, and in contrast to the perspective of the Modern Synthesis, evo-devo can be described as a “science of dispositions.” This chapter discusses the recent philosophical literature on dispositional properties in evo-devo, exploring debates about both the metaphysical and epistemological aspects of the central dispositional concepts utilised in contemporary evo-devo and addressing the epistemological question of how dispositional properties challenge existing explanatory models in evolutionary biology. (shrink)

In evolutionary biology, niche construction is sometimes described as a genuine evolutionary process whereby organisms, through their activities and regulatory mechanisms, modify their environment such as to steer their own evolutionary trajectory, and that of other species. There is ongoing debate, however, on the extent to which niche construction ought to be considered a bona fide evolutionary force, on a par with natural selection. Recent formulations of the variational free-energy principle as applied to the life sciences describe the properties of (...) living systems, and their selection in evolution, in terms of variational inference. We argue that niche construction can be described using a variational approach. We propose new arguments to support the niche construction perspective, and to extend the variational approach to niche construction to current perspectives in various scientific fields. (shrink)

The present volume is the fourth issue of the Almanac series entitled ‘Evolu-tion’. Thus, one can maintain that our Almanac, which has actually turned into a Yearbook, has succeeded (see below). The title of the present volume is ‘From Big Bang to Nanorobots’. In this way we demonstrate that all phases of megaevolution and Big History are cov-ered in the articles of the present Yearbook. Several articles also present fore-casts about possible future developments. The main objective of our Yearbook as (...) well as of the previous issues (see Grinin, Korotayev, Carneiro, and Spier 2011a, Grinin, Korotayev, and Rodrigue 2011a, Grinin and Korotayev 2013a) is the creation of a unified inter-disciplinary field of research in which scientists specializing in different disci-plines could work within a framework of unified or similar paradigms, using common terminology and searching for common rules, tendencies and regularities. At the same time for the formation of such an integrated field one should use all available opportunities: theories, laws and methods. In the present volume, a number of such approaches including those which will be described below are used. (shrink)

In the first part of this article we survey general similarities and differences between biological and social macroevolution. In the second (and main) part, we consider a concrete mathematical model capable of describing important features of both biological and social macroevolution. In mathematical models of historical macrodynamics, a hyperbolic pattern of world population growth arises from non-linear, second-order positive feedback between demographic growth and technological development. Based on diverse paleontological data and an analogy with macrosociological models, we suggest that the (...) hyperbolic character of biodiversity growth can be similarly accounted for by non-linear, second-order positive feedback between diversity growth and the complexity of community structure. We discuss how such positive feedback mechanisms can be modelled mathematically. (shrink)

The present article attempts at combining Big History potential with the potential of Evolutionary Studies in order to achieve the following goals: 1) to apply the historical narrative principle to the description of the star-galaxy era of the cosmic phase of Big History; 2) to analyze both the cosmic history and similarities and differences between evolutionary laws, principles, and mechanisms at various levels and phases of Big History. As far as I know, nobody has approached this task in a systemic (...) way yet. It appears especially important to demonstrate that many evolutionary principles, patterns, regularities, and rules, which we tend to find relevant only for higher levels and main lines of evolution, can be also applied to cosmic evolution. Moreover, almost everything that we know about evolution may be detected in the cosmic history, whereas many of the evolutionary characteristics are already manifested here in a rather clear and salient way. Of course, many of the characteristics are manifested in initial or nonsystematic forms but some features, on the contrary, appear to be more distinct just in the cosmic phase. And at the same time when many characteristics and features which are typical of biological and social evolution unexpectedly reveal their roots or protoforms at earlier phases, one becomes aware that the universal character of evolution is real and it can be detected in a number of manifestations. One should also bear in mind that the origin of galaxies, stars, and other celestial objects is the lengthiest evolutionary process among all evolutionary processes in the Universe. Such an approach opens new perspectives for our understanding of evolution and Big History, of their driving forces, vectors, and trends, it also creates a consolidated field for the multidisciplinary re-search. (shrink)

The allure of perennial questions in biology: temporary excitement or substantive advance? Content Type Journal Article Pages 1-4 DOI 10.1007/s11016-011-9533-5 Authors Alan C. Love, Department of Philosophy, Minnesota Center for Philosophy of Science, University of Minnesota, 831 Heller Hall, 271 19th Ave. S, Minneapolis, MN 55455-0310, USA Journal Metascience Online ISSN 1467-9981 Print ISSN 0815-0796.

To explain the evolutionary emergence of uniquely human skills and motivations for cooperation, Tomasello et al. (2012, in Current Anthropology 53(6):673–92) proposed the interdependence hypothesis. The key adaptive context in this account was the obligate collaborative foraging of early human adults. Hawkes (2014, in Human Nature 25(1):28–48), following Hrdy (Mothers and Others, Harvard University Press, 2009), provided an alternative account for the emergence of uniquely human cooperative skills in which the key was early human infants’ attempts to solicit care and (...) attention from adults in a cooperative breeding context. Here we attempt to reconcile these two accounts. Our composite account accepts Hrdy’s and Hawkes’s contention that the extremely early emergence of human infants’ cooperative skills suggests an important role for cooperative breeding as adaptive context, perhaps in early Homo. But our account also insists that human cooperation goes well beyond these nascent skills to include such things as the communicative and cultural conventions, norms, and institutions created by later Homo and early modern humans to deal with adult problems of social coordination. As part of this account we hypothesize how each of the main stages of human ontogeny (infancy, childhood, adolescence) was transformed during evolution both by infants’ cooperative skills “migrating up” in age and by adults’ cooperative skills “migrating down” in age. (shrink)

Griffiths and Stotz’s Genetics and Philosophy: An Introduction offers a very good overview of scientific and philosophical issues raised by present-day genetics. Examining, in particular, the questions of how a “gene” should be defined and what a gene does from a causal point of view, the authors explore the different domains of the life sciences in which genetics has come to play a decisive role, from Mendelian genetics to molecular genetics, behavioural genetics, and evolution. In this review, I highlight what (...) I consider as the two main theses of the book, namely: genes are better conceived as tools; genes become causes only in a context. I situate these two theses in the wider perspective of developmental systems theory. This leads me to emphasize that Griffiths and Stotz reflect very well an on going process in genetics, which I call the “epigenetization” of genetics, i.e., the growing interest in the complex processes by which gene activation is regulated. I then make a factual objection, which is that Griffiths and Stotz have almost entirely neglected the perspective of ecological developmental biology, and more precisely recent work on developmental symbioses, and I suggest that this omission is unfortunate in so far as an examination of developmental symbioses would have considerably strengthened Griffiths and Stotz’s own conclusions. (shrink)

Darwin´s Erkenntnis über die Abstammung der Arten durch Mutation und Selektion sind in aller Munde, dass aber darüber im Detail noch viel Unklarheit herrscht, ist weniger bekannt. Es sind Fortschritte der Entwicklungsbiologie, die erst seit wenigen Jahren uns molekulare Erklärungsmuster an die Hand geben, mit denen die Entstehung neuer Arten besser verständlich wird. Es handelt sich um die Aufklärung der Wirkungsweise von Genen und ihren molekularen Produkten, die während der embryonalen Entwicklung von Tier und Mensch dafür sorgen, daß der Organismus (...) sich normal entwickelt. Treten Veränderungen (Mutationen) in einem dieser Mastergene auf, so wird dies zur Missbildung oder gar zum Absterben des betreffenden Embryos führen. Aber in seltenen Fällen kann so auch eine neue Tierart begründet werden. Gerade im Darwin-Jahr werden die Lehrbücher zur Evolutionsbiologie um ein wesentliches Kapitel erweitert. Es ist mit EvoDevo überschrieben und will damit ausdrücken, daß Evolutionary Theory ohne Developmental Biology keinen Sinn macht. Die bisherigen Lücken im Verständnis des Evolutionsgeschehens und die neue Sicht von EvoDevo wird im Folgenden dargestellt werden. (shrink)

Bei der Suche nach dem rätselhaften Ursprung des Phänomens „Leben“ wird hier zunächst die zelluläre Ebene betrachtet. Im Grundaufbau zeigen alle Zellen viel Konstantes, aber gleichzeitig stellt jede Zelle ein einmaliges Individuum dar. Leben von Zellen gibt es nur als gegenseitiges Wechselspiel mit ihrer jeweiligen Umwelt. Das Genom (die Gesamtheit aller Gene) bleibt ab der Befruchtung in jeder Zelle eines Individuums konstant. Aber auch die Verwirklichung der Gene braucht eine „molekulare Umwelt“, besonders die vom Muttertier vorbereitete Umwelt im Zytoplasma des (...) Eies. Individualität eines Organismus (z.B. des Menschen) wird also nicht allein vom Genom festgelegt, sondern ist durch Entwicklungsprozesse bedingt (braucht Zeit!). „Leben“ kann (muß?) somit begriffen werden als ein wechselseitiges Kontinuum, welches alle Individuen, alle Spezies und alle Generationen miteinander und ihren Umwelten verbindet. Wie phylogenetisch betrachtet die allererste Zelle aus abiotischen Umständen entstehen konnte, wird hier nicht behandelt. Das Gesagte legt allerdings nahe, dass es nicht Gene waren, die sich eine belebte Welt erschufen, sondern bestimmte (Um-)Welten „erschufen“ sich Gene, die „lebenstauglich“ waren. (shrink)

Seit der Aufklärung versucht der Mensch, Gott abzuschaffen. Dabei fällt der Zufälligkeit, und damit auch der Ziellosigkeit in der darwinistischen Sicht der Evolution besonderes Gewicht zu. Diese weithin akzeptierten Dogmen stehen diametral gegen jahrtausendealte Vorstellungen, die letztlich in allen Kulturen und Religionen hervorgebracht wurden, daß die Natur eine Schöpfung Gottes sei, in der der Mensch das höchste, Gott-ebenbildliche Wesen sei. Nach Erkenntnissen der klassischen Genetik schienen Gene an die Stelle von Gott getreten zu sein: sie haben absolute Gewalt und beherrschen (...) die belebte Natur. Sie haben je einen eindeutigen Befehl, sind unbeugsam und gerecht, wie Gott im AT. Das Produkt Mensch ist nur einer ihrer zahllosen Spielbälle, existiert vorübergehend, ein Zigeuner in einer verlassenen Ecke des Kosmos (Monod, 1992). Diese neodarwinistische Sicht, die nicht zuletzt zum Niedergang der Kirchen bei uns beiträgt, wird von neuen Erkenntnissen der Entwicklungsbiologie (EvoDevo) infrage gestellt. (shrink)

Nach neodarwinistischem Verständnis der Evolution entstehen neue Organismen letztlich durch rein zufällige Mutationsprozesse auf genetischer Ebene. Ihre Überlebenschancen werden dann durch die jeweilig herrschende Umwelt begünstigt oder unterdrückt. Die Evolution ist demnach nur vom reinen Zufall geleitet. Neuere Einsichten aus Entwicklungsbiologie (EvoDevo) und Epigenetik haben unsere Sicht der Evolutionsabläufe jedoch deutlich erweitert. Dabei kommt der Umwelt eine lenkende Rolle zu, der reine Zufall verliert an Bedeutung. Damit lässt sich naturwissenschaftliches Verständnis wieder besser mit herkömmlichen Schöpfungsbildern versöhnen.

Die Frage nach der Vererbung von Eigenschaften bei Lebewesen beschäftigt den Menschen seit alters her: das ist Genetik. Auch lange schon beschäftigen sich Biologen mit der Frage, wie sich die vielen Tierarten im Laufe einer langen Stammesgeschichte herausbilden konnten: das ist Evolution. Wie wird Konstantes über Generationen bewahrt und Diverses/Neues eingeführt? Die überragenden Erfolge der Genetik haben uns im Glauben eingelullt, wir hätten diese Prozesse vollständig verstanden. Mit dem Aufkommen der so genannten Epigenetik kommen Grundlagen sowohl der Individual-, wie auch (...) der Stammesentwicklung jedoch wieder ins Schwanken. In diesem Artikel will ich einen kleinen Einblick in das Feld der Epigenetik und ihre gesellschaftliche Relevanz geben. (shrink)

Never was dogmatic reductionism helpful in conceiving the phenomenon of life. The post-genomic era has made it clear that genes alone cannot explain the functioning of whole organisms. Already each cell represents a unique, non-recurring individual. Recent progress in developmental biology has conveyed new perspectives both on the makings of individual organisms (ontogeny), as on evolutionary change (Evo-Devo). The genome (the entirety of all genes) of an animal remains constant from fertilization onwards in each cell. The realization of genes requires (...) molecular environments, in particular pertinent to the cytoplasm of the unfertilized egg. Individuality of an organism therefore is not only determined by its genome, but is shaped through developmental processes (it needs time!). Organisms can only exist through mutual interplays with their respective (molecular and cellular) environments at all levels of organization. Thus, life can be conceived of as endless networks of communication, e.g. as a mutual continuum, connecting all individuals, all species and all generations within their given environments. Evolutionarily, nature does not select fitting genes, but rather viable traits. The presented concepts render it unlikely that it was genes that founded our living world, but rather that distinct environments shaped “genes” (of whatever chemical nature) which proved to be “life-suitable”. (shrink)

Though the realm of biology has long been under the philosophical rule of the mechanistic magisterium, recent years have seen a surprisingly steady rise in the usurping prowess of process ontology. According to its proponents, theoretical advances in the contemporary science of evo-devo have afforded that ontology a particularly powerful claim to the throne: in that increasingly empirically confirmed discipline, emergently autonomous, higher-order entities are the reigning explanantia. If we are to accept the election of evo-devo as our best conceptualisation (...) of the biological realm with metaphysical rigour, must we depose our mechanistic ontology for failing to properly “carve at the joints” of organisms? In this paper, I challenge the legitimacy of that claim: not only can the theoretical benefits offered by a process ontology be had without it, they cannot be sufficiently grounded without the metaphysical underpinning of the very mechanisms which processes purport to replace. The biological realm, I argue, remains one best understood as under the governance of mechanistic principles. (shrink)

Stable evolutionary strategy of Homo sapiens (SESH) is built in accordance with the modular and hierarchical principle and consists of the same type of self-replicating elements, i.e. is a system of systems. On the top level of the organization of SESH is the superposition of genetic, social, cultural and techno-rationalistic complexes. The components of this triad differ in the mechanism of cycles of generation - replication - transmission - fixing/elimination of adoptively relevant information. This mechanism is implemented either in accordance (...) with the Darwin-Weismann modus, or according to the Lamarck modus, the difference between them is clear from the title. The integral attribute of the system of systems including ESSH is the production of evolutionary risks. The sources of evolutionary risk for stable adaptive strategy of Homo sapiens are the imbalance of (1) the intra-genomic co-evolution (intragenomic conflicts); (2) the gene-cultural co- evolution; (3) the inter-cultural co-evolution; (4) techno-humanitarian balance; (5) inter- technological conflicts (technological traps). At least phenomenologically the components of the evolutionary risk are reversible, but in the aggregate they are in potentio irreversible destructive ones for bio-social, and cultural self-identity of Homo sapiens. When the actual evolution is the subject of a rationalist control and/or manipulation, the magnitude of the 4th and 5th components of the evolutionary risk reaches the level of existential significance. (shrink)

• Aggregates of previously isolated cells of Hydra are capable, under suitable solvant conditions, of regeneration forming complete animals. In a first stage, ecto- and endodermal cells sort out, producing the bilayered hollow structure characteristic of Hydra tissue; thereafter, heads are formed (even if the original cell preparation contained no head cells), eventually leading to the separation of normal animals with head, body column and foot. Hydra appears to be the highest type of organism that allows for regeneration of the (...) entire structure from random cell aggregates. The system is particularly useful for studying cell interactions, tissue polarity, pattern formation, and cell differentiation. (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)

The introductory personal remarks refer to my motivations for choosing research projects, and for moving from physics to molecular biology and then to development, with Hydra as a model system. Historically, Trembley’s discovery of Hydra regeneration in 1744 was the begin¬ning of developmental biology as we understand it, with passionate debates about preformation versus de novo generation, mechanisms versus organisms. In fact, seemingly conflicting bottom-up and top-down concepts are both required in combination to understand development. In modern terms, this means (...) analysing the molecules involved, as well as searching for physical principles underlying development within systems of molecules, cells and tissues. During the last decade, molecular biology has provided surprising and impressive evidence that the same types of mol¬ecules and molecular systems are involved in pattern formation in a wide range of organisms, including coelenterates like Hydra, and thus appear to have been “invented” early in evolution. Likewise, the features of certain systems, especially those of developmental regulation, are found in many different organisms. This includes the generation of spatial structures by the interplay of self-enhancing activation and “lateral” inhibitory effects of wider range, which is a main topic of my essay. Hydra regeneration is a particularly clear model for the formation of defined patterns within initially near-uniform tissues. In conclusion, this essay emphasizes the analysis of development in terms of physical laws, including the application of mathematics, and insists that Hydra was, and will continue to be, a rewarding model for understanding general features of embryogenesis and regeneration. -/- -/- . (shrink)

Evolutionary theory is undergoing an intense period of discussion and reevaluation. This, contrary to the misleading claims of creationists and other pseudoscientists, is no harbinger of a crisis but rather the opposite: the field is expanding dramatically in terms of both empirical discoveries and new ideas. In this essay I briefly trace the conceptual history of evolutionary theory from Darwinism to neo-Darwinism, and from the Modern Synthesis to what I refer to as the Extended Synthesis, a more inclusive conceptual framework (...) containing among others evo–devo, an expanded theory of heredity, elements of complexity theory, ideas about evolvability, and a reevaluation of levels of selection. I argue that evolutionary biology has never seen a paradigm shift, in the philosophical sense of the term, except when it moved from natural theology to empirical science in the middle of the 19th century. The Extended Synthesis, accordingly, is an expansion of the Modern Synthesis of the 1930s and 1940s, and one that—like its predecessor—will probably take decades to complete. (shrink)

In men and women sexual arousal culminates in orgasm, with female orgasm solely from sexual intercourse often regarded as a unique feature of human sexuality. However, orgasm from sexual intercourse occurs more reliably in men than in women, likely reflecting the different types of physical stimulation men and women require for orgasm. In men, orgasms are under strong selective pressure as orgasms are coupled with ejaculation and thus contribute to male reproductive success. By contrast, women's orgasms in intercourse are highly (...) variable and are under little selective pressure as they are not a reproductive necessity. The proximal mechanisms producing variability in women's orgasms are little understood. In 1924 Marie Bonaparte proposed that a shorter distance between a woman's clitoris and her urethral meatus (CUMD) increased her likelihood of experiencing orgasm in intercourse. She based this on her published data that were never statistically analyzed. In 1940 Landis and colleagues published similar data suggesting the same relationship, but these data too were never fully analyzed. We analyzed raw data from these two studies and found that both demonstrate a strong inverse relationship between CUMD and orgasm during intercourse. Unresolved is whether this increased likelihood of orgasm with shorter CUMD reflects increased penile–clitoral contact during sexual intercourse or increased penile stimulation of internal aspects of the clitoris. CUMD likely reflects prenatal androgen exposure, with higher androgen levels producing larger distances. Thus these results suggest that women exposed to lower levels of prenatal androgens are more likely to experience orgasm during sexual intercourse. . (shrink)

In recent years, the concept of evolvability has been gaining in prominence both within evolutionary developmental biology (evo-devo) and the broader field of evolutionary biology. Despite this, there remains considerable disagreement about what evolvability is. This article offers a solution to this problem. I argue that, in focusing too closely on the role played by evolvability as an explanandum in evo-devo, existing philosophical attempts to clarify the evolvability concept have been overly narrow. Within evolutionary biology more broadly, evolvability offers a (...) robust explanation for the evolutionary trajectories of populations. Evolvability is an abstract, robust, dispositional property of populations, which captures the joint causal influence of their internal features on the outcomes of evolution (as opposed to the causal influence of selection, which is often characterized as external). When considering the nature of the physical basis of this disposition, it becomes clear that the many existing definitions of evolvability at play within evo-devo should be understood as capturing only aspects of a much broader phenomenon. 1 Introduction2 The Problem of Evolvability3 The Theoretical Role of Evolvability in Evolutionary Biology3.1 The explanatory targets of evolutionary biology3.2 Selection-based explanations3.3 Lineage explanations3.4 Evolvability-based explanations3.5 What properties must evolvability have?4 What Evolvability Really Is4.1 Making sense of ft4.2 Making sense of x and b5 What of the Limbs? The Power of E6 Conclusion. (shrink)

Commentary on research on butterflies' eyespots as a model in evolutionary developmental biology.

Evolutionary developmental biology (Evo-Devo) is a new and rapidly developing field of biology which focuses on questions in the intersection of evolution and development and has been seen by many as a potential synthesis of these two fields. This synthesis is the topic of the books reviewed here. Integrating Evolution and Development (edited by Roger Sansom and Robert Brandon), is a collection of papers on conceptual issues in Evo-Devo, while From Embryology to Evo-Devo (edited by Manfred Laubichler and Jane Maienschein) (...) is a history of the problem of the relations between ontogeny and phylogeny. (shrink)

Traditional accounts of the role of learning in evolution have concentrated upon its capacity as a source of fitness to individuals. In this paper I use a case study from invasive species biology—the role of conditioned taste aversion in mitigating the impact of cane toads on the native species of Northern Australia—to highlight a role for learning beyond this—as a source of evolvability to populations. This has two benefits. First, it highlights an otherwise under-appreciated role for learning in evolution that (...) does not rely on social learning as an inheritance channel nor “special” evolutionary processes such as genetic accommodation (both of which many are skeptical about). Second, and more significantly, it makes clear important and interesting parallels between learning and exploratory behaviour in development. These parallels motivate the applicability of results from existing research into learning and learning evolution to our understanding of the evolution of evolvability more generally. (shrink)

On a book concerned with taking developmental biology seriously within the context of evolutionary theory.

Philosophy can shed light on mathematical modeling and the juxtaposition of modeling and empirical data. This paper explores three philosophical traditions of the structure of scientific theory—Syntactic, Semantic, and Pragmatic—to show that each illuminates mathematical modeling. The Pragmatic View identifies four critical functions of mathematical modeling: (1) unification of both models and data, (2) model fitting to data, (3) mechanism identification accounting for observation, and (4) prediction of future observations. Such facets are explored using a recent exchange between two groups (...) of mathematical modelers in plant biology. Scientific debate can arise from different modeling philosophies. (shrink)

One important aspect of biological explanation is detailed causal modeling of particular phenomena in limited experimental background conditions. Recognising this allows a new avenue for intertheoretic reduction to be seen. Reductions in biology are possible, when one fully recognises that a sufficient condition for a reduction in biology is a molecular model of 1) only the demonstrated causal parameters of a biological model and 2) only within a replicable experimental background. These intertheoretic identifications –which are ubiquitous in biology and form (...) the basis of ruthless reductions (Bickle 2003)- are criticised as merely “local” (Sullivan 2009) or “fragmentary” (Schaffner 2006). However, in an instructive case, a biological model is preserved in molecular terms, and a complex biological phenomenon has been successfully reduced. In doing this the molecular model remains valid in a broader range of background conditions and meaningfully unites disparate biological phenomena. (shrink)

This article began as a review of a conference, organized by Gerhard Schlosser, entitled “Modularity in Development and Evolution.” The conference was held at, and sponsored by, the Hanse Wissenschaftskolleg in Delmenhorst, Germany in May, 2000. The article subsequently metamorphosed into a literature and concept review as well as an analysis of the differences in current perspectives on modularity. Consequently, I refer to general aspects of the conference but do not review particular presentations. I divide modules into three kinds: structural, (...) developmental, and physiological. Every module fulfills none, one, or multiple functional roles. Two further orthogonal distinctions are important in this context: module-kinds versus module-variants-of-a-kind and reproducer versus nonreproducer modules. I review criteria for individuation of modules and mechanisms for the phylogenetic origin of modularity. I discuss conceptual and methodological differences between developmental and evolutionary biologists, in particular the difference between integration and competition perspectives on individualization and modular behavior. The variety in views regarding modularity presents challenges that require resolution in order to attain a comprehensive, rather than a piecemeal and fragmentary, evolutionary developmental biology. (shrink)

Abstract: Under traditional Jewish Law (halacha), assessment of human reproductive cloning (HRC) has been formulated along four lines of inquiry, which I discussed in Part I of this paper. Therein I also analyze five relevant doctrines of Talmudic Law, concluding that under with a risk-benefit analysis HRC fails to fulfill the obligation ‘to be fruitful and multiply’ and should be strictly prohibited. Here, I review of the topic from an exigetical Biblical and Kabbalistic perspective, beginning with exploring comments of the (...) Ramban (Nachmanides) which suggest Kabbalistic insights very much in keeping with current biology. In this Part II of the paper, I expand and annotate statements of the Ramban on the interrelationship of the reproductive faculties of an organism and its soul by examining the development of the spiritual states of plant, animal and human and noting the commensurate evolution with its reproductive facilities. Speculating that the reproductive mechanism of each species is indelibly related to its soul-state, I suggest that interfering with human sexual reproduction by HRC has the same effect the Ramban argues is the result of Kilayim (interbreeding), i.e., wrecking havoc with the Universe. In Part III, I postulate a biologic explanation for warnings found in the Golemic Literature and suggest that these allude to the importance of maintaining human genetic diversity through sexual reproduction. The conclusions I reached after evaluating the propriety of HRC under a Kabbalistic/metaphysical index comports with those I reached using a traditional legal /halachic inquiry in Part I. Thus, both systems arrive at the conclusion that HRC is in violation of the divine and natural order and constitute a distinct biological threat to the survival of the human species, a conclusions in accord with current scientific thinking. (shrink)

Biosemiotics and Semiotics have similarities and differences. Both deal with signal and meaning. One difference is that Biosemiotics covers a domain (life) that is less complex that the one addressed by Semiotics (human). We believe that this difference can be used to have Biosemiotics bringing added value to Semiotics. This belief is based on the fact that a theory of meaning is easier to build up for living elements than for humans, and that the results obtained for life can make (...) available some tools for a higher level of complexity. Semiotic has been encountering some difficulties to deliver a scientific theory of meaning that can be efficient at the level of human mind. The obstacles come from our ignorance on the nature of human. As it is true that we do not understand the nature of human mind on a scientific basis. On the other hand, the nature and properties of life are better understood. And we can propose a modelization for a generation of meaningful information in the field of elementary life. Once such a modelization is established, it is possible to look at extending it to the domain of human life. Such an approach on a theory of meaning (begininig in Biosemiotics and aiming at Semiotics), is what we present in this paper. Taking an elementary living element as reference, we introduce the bases of a systemic theory of meaning. Using a simple living system submitted to a constraint, we define a meaningful information, a meaning generator system and some elements related to meaningful information transmission. We then try to identify the hypothesis that need to be taken into account so the results obtained for living elements can be extended to human. (shrink)