Integration of approaches in David Wake's model-taxon research platform for evolutionary morphology

The diving reflex and asphyxia: working across species in physiological ecology

Beginning in the mid-1930s the comparative physiologists Laurence Irving and Per Fredrik (Pete) Scholander pioneered the study of diving mammals, particularly harbor seals. Although resting on earlier work dating back to the late nineteenth century, their research was distinctive in several ways. In contrast to medically oriented physiology, the approaches of Irving and Scholander were strongly influenced by natural history, zoology, ecology, and evolutionary biology. Diving mammals, they argued, shared the cardiopulmonary physiology of terrestrial mammals, but evolution had modified these basic adaptive processes in extreme ways. In particular, seals' remarkable ability to hold breath, lower metabolism, produce energy anaerobically, and resist asphyxiation, provided a sharp contrast with terrestrial mammals, including humans. This diving physiology was an extreme elaboration of a general regulatory mechanism that allowed seals and other diving mammals to remain active underwater for extended periods. The decrease in heart rate referred to as bradycardia or the "diving reflex" was highly developed in diving mammals, but also found in less developed form in many other organisms faced by asphyxia. It therefore served as a kind of "master switch" for lowering metabolism in diving, hibernation, parturition, drowning, and other physiological responses involving lack of oxygen. Studying bradycardia unified a wide diversity of physiological phenomena, while also providing a context for contrasting the physiological responses of various species, including humans. Conducted in the laboratory and the field, this research served as a bridge between a comparative physiological ecology focused on non-human species and a human-centered general physiology.

Integration in biology: Philosophical perspectives on the dynamics of interdisciplinarity

This introduction to the special section on integration in biology provides an overview of the different contributions. In addition to motivating the philosophical significance of analyzing integration and interdisciplinary research, I lay out common themes and novel insights found among the special section contributions, and indicate how they exhibit current trends in the philosophical study of integration. One upshot of the contributed papers is that there are different aspects to and kinds of integration, so that rather than attempting to offer a universal construal of what integrations is, philosophers have to analyze in concrete cases in what respects particular aspects of scientific theorizing and/or practice are 'integrative' and how this instance of integration works and was achieved.

Dimensions of integration in interdisciplinary explanations of the origin of evolutionary novelty

Many philosophers of biology have embraced a version of pluralism in response to the failure of theory reduction but overlook how concepts, methods, and explanatory resources are in fact coordinated, such as in interdisciplinary research where the aim is to integrate different strands into an articulated whole. This is observable for the origin of evolutionary novelty-a complex problem that requires a synthesis of intellectual resources from different fields to arrive at robust answers to multiple allied questions. It is an apt locus for exploring new dimensions of explanatory integration because it necessitates coordination among historical and experimental disciplines (e.g., geology and molecular biology). These coordination issues are widespread for the origin of novel morphologies observed in the Cambrian Explosion. Despite an explicit commitment to an integrated, interdisciplinary explanation, some potential disciplinary contributors are excluded. Notable among these exclusions is the physics of ontogeny. We argue that two different dimensions of integration-data and standards-have been insufficiently distinguished. This distinction accounts for why physics-based explanatory contributions to the origin of novelty have been resisted: they do not integrate certain types of data and differ in how they conceptualize the standard of uniformitarianism in historical, causal explanations. Our analysis of these different dimensions of integration contributes to the development of more adequate and integrated explanatory frameworks.

When integration fails: Prokaryote phylogeny and the tree of life

Much is being written these days about integration, its desirability and even its necessity when complex research problems are to be addressed. Seldom, however, do we hear much about the failure of such efforts. Because integration is an ongoing activity rather than a final achievement, and because today's literature about integration consists mostly of manifesto statements rather than precise descriptions, an examination of unsuccessful integration could be illuminating to understand better how it works. This paper will examine the case of prokaryote phylogeny and its apparent failure to achieve integration within broader tree-of-life accounts of evolutionary history (often called 'universal phylogeny'). Despite the fact that integrated databases exist of molecules pertinent to the phylogenetic reconstruction of all lineages of life, and even though the same methods can be used to construct phylogenies wherever the organisms fall on the tree of life, prokaryote phylogeny remains at best only partly integrated within tree-of-life efforts. I will examine why integration does not occur, compare it with integrative practices in animal and other eukaryote phylogeny, and reflect on whether there might be different expectations of what integration should achieve. Finally, I will draw some general conclusions about integration and its function as a 'meta-heuristic' in the normative commitments guiding scientific practice.

Articulating Babel: An approach to cultural evolution

After an initial discussion of the character of interdisciplinary linkages between complex disciplines, I consider an area with confluences of many diverse disciplines-the study of cultural evolution. This must embrace not only the traditional biological sciences, but also the multiple often warring disciplines of the human sciences. This interdisciplinary articulation is in its early stages compared, e.g., to that of evolutionary biology or evolutionary developmental biology, and I try to lay out major axes along which its articulation should plausibly occur, given the relevant causal processes acting at different levels. One cannot have an adequate account of cultural evolution without recognizing a central role for cognitive and social development (since culture is cumulatively acquired by individuals through the life-cycle) and the social and cultural organizations and institutions and artifactual tools and infrastructure that support and structure these developmental processes. These induce a population structure that mediates the transmission, expression, and elaboration of culture, and in particular the different ways in which they scaffold learning and the development and articulation of complex skills. I consider how these elements should articulate the disciplines that tend to focus separately on them. Intentions and the market are not explicitly included in this account, and I consider ways in which these perspectives might enter.

Integration of specialties: An institutional and organizational view

By what mechanisms of organizational and institutional change do different specialties succeed in accommodating and working with one another? How do these mechanisms function over time to support and retard the emergence and stability of new knowledge? This paper considers two such mechanisms, metawork (work that determines the organization of work) and common knowledge (knowledge that participants know is known by all participants). These mechanisms integrate specialties by making the activities of multiple specialties dependent upon one another, and by segmenting the common effort from the parent specialties. Integration of specialties can lead to the development of new specialties. Integration is facilitated and impeded by the anchoring of specialties in the system of institutions that participate in research. Host organizations, degree programs, sponsors, associations, regulators, and other organizations provide resources and impose demands that shape research. Some of these impacts are obvious and direct; others are indirect and more subtle. The research specialties form a network (not a hierarchy) in which connections constantly form and reform, and in which the influence of different anchoring institutions are constantly waxing and waning. The complexity of connections and their pattern of change are especially obvious in the life sciences, which are an especially good place to study problems of integration.

Systems biology and the integration of mechanistic explanation and mathematical explanation

The paper discusses how systems biology is working toward complex accounts that integrate explanation in terms of mechanisms and explanation by mathematical models-which some philosophers have viewed as rival models of explanation. Systems biology is an integrative approach, and it strongly relies on mathematical modeling. Philosophical accounts of mechanisms capture integrative in the sense of multilevel and multifield explanations, yet accounts of mechanistic explanation (as the analysis of a whole in terms of its structural parts and their qualitative interactions) have failed to address how a mathematical model could contribute to such explanations. I discuss how mathematical equations can be explanatorily relevant. Several cases from systems biology are discussed to illustrate the interplay between mechanistic research and mathematical modeling, and I point to questions about qualitative phenomena (rather than the explanation of quantitative details), where quantitative models are still indispensable to the explanation. Systems biology shows that a broader philosophical conception of mechanisms is needed, which takes into account functional-dynamical aspects, interaction in complex networks with feedback loops, system-wide functional properties such as distributed functionality and robustness, and a mechanism's ability to respond to perturbations (beyond its actual operation). I offer general conclusions for philosophical accounts of explanation.