Reconciling “stress” and “health” in physical anthropology: What can bioarchaeologists learn from the other subdisciplines?

The concepts of “stress” and “health” are foundational in physical anthropology as guidelines for interpreting human behavior and biocultural adaptation in the past and present. Though related, stress and health are not coterminous, and while the term “health” encompasses some aspects of “stress,” health refers to a more holistic condition beyond just physiological disruption, and is of considerable significance in contributing to anthropologists' understanding of humanity's lived experiences. Bioarchaeological interpretations of human health generally are made from datasets consisting of skeletal markers of stress, markers that result from (chronic) physiological disruption (e.g., porotic hyperostosis; linear enamel hypoplasia). Non-specific indicators of stress may measure episodes of stress and indicate that infection, disease, or nutritional deficiencies were present in a population, but in assessing these markers, bioarchaeologists are not measuring “health” in the same way as are human biologists, medical anthropologists, or primatologists. Rather than continue to diverge on separate (albeit parallel) trajectories, bioarchaeologists are advised to pursue interlinkages with other subfields within physical anthropology toward bridging “stress” and “health.” The papers in this special symposium set include bioarchaeologists, human biologists, molecular anthropologists, and primatologists whose research develops this link between the concepts of “stress” and “health,” encouraging new avenues for bioarchaeologists to consider and reconsider health in past human populations. Am J Phys Anthropol 155:181–185, 2014. © 2014 Wiley Periodicals, Inc.     

Whose Turn? Chromosome Research and the Study of the Human Genome

A common account sees the human genome sequencing project of the 1990s as a “natural outgrowth” of the deciphering of the double helical structure of DNA in the 1950s. The essay aims to complicate this neat narrative by putting the spotlight on the field of human chromosome research that flourished at the same time as molecular biology. It suggests that we need to consider both endeavors – the human cytogeneticists who collected samples and looked down the microscope and the molecular biologists who probed the molecular mechanisms of gene function – to understand the rise of the human genome sequencing project and the current genomic practices. In particular, it proposes that what has often been described as the “molecularization” of cytogenetics could equally well be viewed as the turn of molecular biologists to human and medical genetics – a field long occupied by cytogeneticists. These considerations also have implications for the archives that are constructed for future historians and policy makers.     

Causal mechanisms of evolution and the capacity for niche construction

Ernst Mayr proposed a distinction between “proximate”, mechanistic, and “ultimate”, evolutionary, causes of biological phenomena. This dichotomy has influenced the thinking of many biologists, but it is increasingly perceived as impeding modern studies of evolutionary processes, including study of “niche construction” in which organisms alter their environments in ways supportive of their evolutionary success. Some still find value for this dichotomy in its separation of answers to “how?” versus “why?”questions about evolution. But “why is A?” questions about evolution necessarily take the form “how does A occur?”, so this separation is illusory. Moreover, the dichotomy distorts our view of evolutionary causality, in that, contra Mayr, the action of natural selection, driven by genotype-phenotype-environment interactions which constitute adaptations, is no less “proximate” than the biological mechanisms which are altered by naturally selected genetic variants. Mayr’s dichotomy thus needs replacement by more realistic, mechanistic views of evolution. From a mechanistic viewpoint, there is a continuum of adaptations from those evolving as responses to unchanging environmental pressures to those evolving as the capacity for niche construction, and intermediate stages of this can be identified. Some biologists postulate an association of “phenotypic plasticity” (phenotype-environment covariation with genotype held constant) with capacity for niche construction. Both “plasticity” and niche construction comprise wide ranges of adaptive mechanisms, often fully heritable and resulting from case-specific evolution. Association of “plasticity” with niche construction is most likely to arise in systems wherein capacity for complex learning and behavioral flexibility have already evolved.     

Invasive species denialism: a reply to Ricciardi and Ryan

This paper offers a defense against ad hominem aspersions cast in this journal by Ricciardi and Ryan (Biol Invasions 20(3):549–553, 2018) who allege that several articles I wrote represent “invasive species denialism” and “science denialism.” I summarize the arguments found in those articles. They are (1) science cannot define ecological “harm” and thus cannot measure its risk; (2) invasion biologists rely on tautologies, i.e., definitions of concepts like “biodiversity” and “ecosystem intactness,” that exclude exotic species; (3) no empirical evidence shows that introduced plants have been significant causes of extinction; (4) biologists cannot tell by observing a species whether it is native or a naturalized alien; and (5) debates over the meanings and measurements of key concepts in invasion biology have passed the point of diminishing returns. These arguments may be wrong but none is “similar to the denialism that has affected climate science and medical science” as Ricciardi and Ryan aver.     

A phylogenetic analysis of dispersal norms,descent and subsistence in Sino-Tibetans

Sex-biased dispersal has long been of interest to anthropologists and biologists, as it can structure populations and determine patterns of kinship, relatedness and cooperation. In most contemporary human societies, females usually disperse at marriage. In a minority of human societies, male dispersal, bisexual philopatry, or both sexes dispersing is practiced. Previous studies suggest that emergence of either agriculture, cattle pastoralism, or patriliny is associated with female-biased dispersal in certain language families. The ancestral patterns of sex-specific dispersal and its ecological correlates in Sino-Tibetans remain uncertain. Here we use comparative phylogenetic methods to infer the evolutionary history of sex-specific dispersal in Sino-Tibetan groups, and tested for coevolution between subsistence (agriculture and cattle-keeping), descent and sex-specific dispersal. We use a variety of ethnographic and historical sources to identify dispersal strategies across Sino-Tibetan phylogenetic trees (n = 97). We found that 1) earliest Sino-Tibetan groups were likely patrilocal; 2) agriculture likely co-evolved with only female dispersal patterns, but the result is sensitive to alternative coding strategy; 3) there is no evidence that domestic cattle co-evolved with dispersal patterns of either gender; and 4) kinship descent likely co-evolved with female dispersal, but not with male dispersal. Moreover, change from state of “patrilineal” to “non-patrilineal” triggered change in female dispersal patterns, from “female non-stay” to “female stay”. Our results suggest that change in descent drove change in female-specific dispersal pattern in Sino-Tibetans. Our findings illustrated how subsistence or descent can play different roles in shaping sex-biased dispersal patterns.     

What is a species? Essences and generation

Arguments against essentialism in biology rely strongly on a claim that modern biology abandoned Aristotle’s notion of a species as a class of necessary and sufficient properties. However, neither his theory of essentialism, nor his logical definition of species and genus (eidos and genos) play much of a role in biological research and taxonomy, including his own. The objections to natural kinds thinking by early twentieth century biologists wrestling with the new genetics overlooked the fact that species have typical developmental cycles and most have a large shared genetic component. These are the “what-it-is-to-be” members of that species. An intrinsic biological essentialism does not commit us to Aristotelian notions, nor even modern notions, of essence. There is a long-standing definition of “species” and its precursor notions that goes back to the Greeks, and which Darwin and pretty well all biologists since him share, that I call the Generative Conception of Species. It relies on there being a shared generative power that makes progeny resemble parents. The “what-it-is-to-be” a member of that species is that developmental type, mistakes in development notwithstanding. Moreover, such “essences” have always been understood to include deviations from the type. Finally, I shall examine some implications of the collapse of the narrative about essences in biology.     

When is a cladist not a cladist?

The term “cladist” has distinct meanings in distinct contexts. Communication between philosophers, historians, and biologists has been hindered by different understandings of the term in various contexts. In this paper I trace historical and conceptual connections between several broadly distinct senses of the term “cladist”. I propose seven specific definitions that capture distinct contemporary uses. This serves to disambiguate some cases where the meaning is unclear, and will help resolve apparent disagreements that in fact result from conflicting understandings of the term.     

Mort ou persistance du darwinisme ? Regard d’un épistémologue

The article examines why evolutionary biologists have been haunted by the question whether they are “Darwinian” or “non-Darwinian” ever since Darwin's Origin of species. Modern criticisms addressed to Darwinism are classified into two categories: those concerning Darwin's hypothesis of “descent with modification” and those addressed to the hypothesis of natural selection. In both cases, although the particular models that Darwin proposed for these two hypotheses have been significantly revised and expanded, Darwin's general framework has constrained and canalized evolutionary research, in the sense that it has settled an array of possible theoretical choices. Gould's changing attitudes regarding Darwinism is taken as a striking illustration of this interpretation.     

Is there a special conservation biology?

Conservation biology is special to the extent that it fills useful roles in the scientific and conservation fields that are not being filled by practitioners of other disciplines. The emergence of the “new conservation biology” in the late 1970's and its blossoming in the 1980's and 1990's reflect, to a large degree, a failure of traditional academic ecology and the natural resource disciplines to address modern conservation problems adequately. Yet, to be successful conservation biology, as an interdisciplinary field, must build on the strengths of other disciplines both basic and applied. The new conservation biology grew out of concern over extinction of species, although the field has expanded to include issues about management of several levels of biological organization. I examine four controversial questions of importance to conservation biologists today: 1) are there any robust principles of conservation biology? 2) Is advocacy an appropriate activity of conservation biologists? 3) Are we educating conservation biologists properly? 4) Is conservation biology distinct from other biological and resource management disciplines? I answer three of these questions with a tentative “yes” and one (3) with a regretful “in most cases, no.” I see a need for broader Training for students of conservation biology, more emphasis on collecting basic field data, compelling applications of conservation biology to real problems, increased influence on policy, and expansion of the international scope of the discipline. If all these occur, conservation biology will by truly special.     

Can an Engineer Fix an Immune System?–Rethinking theoretical biology

In an instant classic paper (Lazebnik, in Cancer Cell 2(3); 2002: 179–182) biologist Yuri Lazebnik deplores the poor effectiveness of the approach adopted by biologists to understand and “fix” biological systems. Lazebnik suggests that to remedy this state of things biologist should take inspiration from the approach used by engineers to design, understand, and troubleshoot technological systems. In the present paper I substantiate Lazebnik’s analysis by concretely showing how to apply the engineering approach to biological problems. I use an actual example of electronic circuit troubleshooting to ground the thesis that, in engineering, the crucial phases of any non-trivial troubleshooting process are aimed at generating a mechanistic explanation of the functioning of the system, which makes extensive recourse to problem-driven qualitative reasoning possibly based on cognitive artifacts applied to systems that are known to have been designed for function. To show how to translate these findings into biological practice I consider a concrete example of biological model building and “troubleshooting”, aimed at the identification of a “fix” for the human immune system in presence of progressing cancer, autoimmune disease, and transplant rejection. The result is a novel immune system model—the danger model with regulatory cells— and new, original hypotheses concerning the development, prophylaxis, and therapy of these unwanted biological processes. Based on the manifest efficacy of the proposed approach, I suggest a refocusing of the activity of theoretical biologists along the engineering-inspired lines illustrated in the paper.     

Logical fallacies and invasion biology

Leading invasion biologists sometimes dismiss critics and criticisms of their field by invoking “the straw man” fallacy. Critics of invasion biology are also labelled as a small group of “naysayers” or “contrarians”, who are sometimes engaging in “science denialism”. Such unfortunate labels can be seen as a way to possibly suppress legitimate debates and dismiss or minimize reasonable concerns about some aspects of invasion biology, including the uncertainties about the geographic origins and complex environmental impacts of species, and the control programs against species perceived as “invasive”. In assessing the quality of the debate in this area, we examine the validity of the use of various strategies, including the “straw man” concept, and explore a range of potential logical fallacies present in some recent prominent discussions about invasion biology and so-called “invasive” species. The goal is to add some clarity to the concepts involved, point out some problematic issues, and improve the quality of the debates as the discussions move forward.     

Biodiversity,biological uncertainty,and setting conservation priorities

In a world of massive extinctions where not all taxa can be saved, how ought biologists to decide their preservation priorities? When biologists make recommendations regarding conservation, should their analyses be based on scientific criteria, on public or lay criteria, on economic or some other criteria? As a first step in answering this question, we examine the issue of whether biologists ought to try to save the endangered Florida panther, a well known “glamour” taxon. To evaluate the merits of panther preservation, we examine three important arguments of biologists who are skeptical about the desirability of panther preservation. These arguments are (1) that conservation dollars ought to be spent in more efficient ways than panther preservation; (2) that biologists and conservationists ought to work to preserve species before subspecies; and (3) that biologists and conservationists ought to work to save habitats before species or subspecies. We conclude that, although all three arguments are persuasive, none of them provides convincing grounds for foregoing panther preservation in favor of other, more scientifically significant conservation efforts. Our conclusion is based, in part, on the argument that biologists ought to employ ethical, as well as scientific, rationality in setting conservation priorities and that ethical rationality may provide persuasive grounds for preserving taxa that often are not viewed by biologists as of great importance.     

Epigenetics: localizing biology through co-laboration

This paper reports on a co-laborative laboratory ethnography in a molecular biology laboratory conducting research on environmental epigenetics. It focuses on a single study concerned with the material implications of social differentiation. The analysis briefly raises biopolitical concerns. Its main concern lies with an understanding of the human body as local in its working infrastructure or “inner laboratory”, an understanding that emerges from the co-laborative inquiry between biologists and anthropologist. This co-laborative mode of inquiry raises productive tensions within biology as to the universal or local nature of human nature and within anthropology as to the status of human biology within social theory. The paper cannot resolve this tension. Rather it explores it as an epistemic object in the context of interdisciplinarity, ontography and co-laboration. In concluding, it specifies co-laboration as temporary, non-teleological joint epistemic work aimed at producing new kinds of reflexivity.     

Invasive species: reality or myth?

In view of the recent debate on the future of invasion biology, we argue that species could be regarded as invasive only when after adaptation in non-native habitats they reach yet another fitness maximum. We suggest that invasion biologists need to unambiguously clarify what constitutes being “invasive” to refute those who call for an end to invasion biology.     

T.H. Huxley's Criticism of German Cell Theory: An Epigenetic and Physiological Interpretation of Cell Structure

In 1853, the young Thomas Henry Huxley published a long review of German cell theory in which he roundly criticized the basic tenets of the Schleiden-Schwann model of the cell. Although historians of cytology have dismissed Huxley’s criticism as based on an erroneous interpretation of cell physiology, the review is better understood as a contribution to embryology. “The Cell-theory” presents Huxley’s “epigenetic” interpretation of histological organization emerging from changes in the protoplasm to replace the “preformationist” cell theory of Schleiden and Schwann (as modified by Albert vonKölliker), which posited the nucleus as the seat of organic vitality. Huxley’s views influenced a number of British biologists, who continued to oppose German cell theory well into the twentieth century. Yet Huxley was pivotal in introducing the new German program of “scientific zoology” to Britain in the early 1850s,championing its empiricist methodology as a means to enact broad disciplinary and institutional reforms in British natural history.     

A pragmatic approach to the possibility of de-extinction

A number of influential biologists are currently pursuing efforts to restore previously extinct species. But for decades, philosophers of biology have regarded “de-extinction” as conceptually incoherent. Once a species is gone, it is gone forever. We argue that a range of metaphysical, biological, and ethical grounds for opposing de-extinction are at best inconclusive and that a pragmatic stance that allows for its possibility is more appealing.     

Inclusive fitness is an indispensable approximation for understanding organismal design

For some decades most biologists interested in design have agreed that natural selection leads to organisms acting as if they are maximizing a quantity known as “inclusive fitness.” This maximization principle has been criticized on the (uncontested) grounds that other quantities, such as offspring number, predict gene frequency changes accurately in a wider range of mathematical models. Here, we adopt a resolution offered by Birch, who accepts the technical difficulties of establishing inclusive fitness maximization in a fully general model, while concluding that inclusive fitness is still useful as an organizing framework. We set out in more detail why inclusive fitness is such a practical and powerful framework, and provide verbal and conceptual arguments for why social biology would be more or less impossible without it. We aim to help mathematicians understand why social biologists are content to use inclusive fitness despite its theoretical weaknesses. Here, we also offer biologists practical advice for avoiding potential pitfalls.     

Transgressive Hybrids as Hopeful Monsters

The origin of novelty is a critical subject for evolutionary biologists. Early geneticists speculated about the sudden appearance of new species via special macromutations, epitomized by Goldschmidt’s infamous “hopeful monster”. Although these ideas were easily dismissed by the insights of the Modern Synthesis, a lingering fascination with the possibility of sudden, dramatic change has persisted. Recent work on hybridization and gene exchange suggests an underappreciated mechanism for the sudden appearance of evolutionary novelty that is entirely consistent with the principles of modern population genetics. Genetic recombination in hybrids can produce transgressive phenotypes, “monstrous” phenotypes beyond the range of parental populations. Transgressive phenotypes can be products of epistatic interactions or additive effects of multiple recombined loci. We compare several epistatic and additive models of transgressive segregation in hybrids and find that they are special cases of a general, classic quantitative genetic model. The Dobzhansky-Muller model predicts “hopeless” monsters, sterile and inviable transgressive phenotypes. The Bateson model predicts “hopeful” monsters with fitness greater than either parental population. The complementation model predicts both. Transgressive segregation after hybridization can rapidly produce novel phenotypes by recombining multiple loci simultaneously. Admixed populations will also produce many similar recombinant phenotypes at the same time, increasing the probability that recombinant “hopeful monsters” will establish true-breeding evolutionary lineages. Recombination is not the only (or even most common) process generating evolutionary novelty, but might be the most credible mechanism for sudden appearance of new forms.     

Differentiation,ageing, and terminal differentiation: A semantic analysis

The largely unsolved problems in the theoretical analysis of differentiation and ageing involve a substantial component of linguistic (semantic) difficulties. Some of these are simple traps of ambiguity, resulting from metaphorical or analogical employment of established terms—for example, “terminal differentiation” (loss of division potential in vitro) as a borrowing from “differentiation” as used by developmental biologists, or “commitment” by analogy with “determination”. Some difficulties represent a failure to adopt (at least provisionally) an operational (empirical) view—for example, failure to ask what is the nature of the evidence for the view that a fertilized ovum is totipotential, or to scrutinize the evidence for the view that cells “terminally differentiated” in vitro in a conventional medium are in fact moribund under all conditions, or to examine more closely the view that the differentiated state and the cycling state are mutually exclusive.With respect to the problem of ageing, we review some of the critical experiments on ”terminal differentiation” or “clonal senescence”. We then proceed to consider some of the models that have been proposed, including a molecular model proposed by the author which appears to overcome some of the objections to other models. Some of the models exemplify the results of what are ultimately semantic vices.The problems with which these remarks began should indeed yield to the immense and novel resources of molecular biology. But the development of complete analyses demands not only good luck and delicate technique but also critical semantic clarity and severity. Given the best tools, we shall solve major theoretical problems only if we understand quite fully what problem it is that we are trying to solve—and the history of science illustrates that this is not as elementary a matter as it sounds. For the working scientist semantics (and indeed all philosophy of science) is not an indulgence or a frill, but a basic technical resource.     

De-extinction and the conception of species

Developments in genetic engineering may soon allow biologists to clone organisms from extinct species. The process, dubbed “de-extinction,” has been publicized as a means to bring extinct species back to life. For theorists and philosophers of biology, the process also suggests a thought experiment for the ongoing “species problem”: given a species concept, would a clone be classified in the extinct species? Previous analyses have answered this question in the context of specific de-extinction technologies or particular species concepts. The thought experiment is given more comprehensive treatment here. Given the products of three de-extinction technologies, twenty-two species concepts are “tested” to see which are consistent with the idea that species may be resurrected. The ensuing discussion considers whether or not de-extinction is a conceptually coherent research program and, if so, whether or not its development may contribute to a resolution of the species problem. Ultimately, theorists must face a choice: they may revise their commitments to species concepts (if those concepts are inconsistent with de-extinction) or they may recognize de-extinction as a means to make progress in the species problem.