Evolutionary Biology, Miscellaneous

One of the aims of the encyclical "Laudato Si’" is to help us “marvel at the manifold connections existing among creatures”, to show how we are also involved, and to motivate us thereby to care for our common home. Are there new dimensions of beauty available to us today because of recent advances in biology? In this paper I seek to answer this question by first recalling the basic criteria for beauty, as expressed by Aristotle and Aquinas, and then evaluating (...) their applicability as regards three ways in which some prominent twentieth century philosophers of biology have sought to overcome the limitations of reductionism. The overall argument refers especially to the works of Jakob von Uexküll and Georges Canguilhem. The results indicate that harmony, proportion, and integrity in the natural order should be more evident than ever before, especially as regards the way the organism and its environment codetermine each other. This insight allows a deeper appreciation of the message of "Laudato Si’". (shrink)

Is it possible to know anything about life we have not yet encountered? We know of only one example of life: our own. Given this, many scientists are inclined to doubt that any principles of Earth’s biology will generalize to other worlds in which life might exist. Let’s call this the “N = 1 problem.” By comparison, we expect the principles of geometry, mechanics, and chemistry would generalize. Interestingly, each of these has predictable consequences when applied to biology. The surface-to-volume (...) property of geometry, for example, limits the size of unassisted cells in a given medium. This effect is real, precise, universal, and predictive. Furthermore, there are basic problems all life must solve if it is to persist, such as resistance to radiation, faithful inheritance, and energy regulation. If these universal problems have a limited set of possible solutions, some common outcomes must consistently emerge. In this chapter, I discuss the N = 1 problem, its implications, and my response (Mariscal 2014). I hold that our current knowledge of biology can justify believing certain generalizations as holding for life anywhere. Life on Earth may be our only example of life, but this is only a reason to be cautious in our approach to life in the universe, not a reason to give up altogether. In my account, a candidate biological generalization is assessed by the assumptions it makes. A claim is accepted only if its justification includes principles of evolution, but no contingent facts of life on Earth. (shrink)

Eco/logical R/evolution, is the story of mankind, told with words of a great and wonderful subjective odyssey, the never-ending quest; for objective truths and collective Eudaimonia. The author raises the issues; of political weakness and widespread confusion, about logical analytical errors, of which we find many of in Old Marxist Ideology. As a conscious effort, is thus made, to expel the mental subjugation of Platonic Idealism, away from the clenches Aristotelian Realism, and its bastard offspring; Old Historical Materialism. The book (...) identifies, in the works of Darwin and Marx, a wide range of worrying philosophical incompatibilities, such that are clearly found; in their respective theories and research methodologies. -/- We hereby propose; that a New Marxist Philosophy of Science, stands a probable chance; at unifying the Natural and Social Sciences. As the convergence of truths is manifest, thus, it is mapped out in detail by the author, out of necessity. It invokes, a Marxist Metaphysical Identity, for the sole purpose off; presenting a teleological framework, for New Marxist Theory. -/- NOTE: Reader must look up each word in a dictionary, which they see on both sides of the "/" when found in the middle of a word. (shrink)

At the interface of developmental biology and evolutionary biology, the very criteria of scientific knowledge are up for grabs. A central issue is the status of evolutionary genetics models, which some argue cannot coherently be used with complex gene regulatory network (GRN) models to explain the same evolutionary phenomena. Despite those claims, many researchers use evolutionary genetics models jointly with GRN models to study evolutionary phenomena. This dissertation compares two recent research projects in which researchers jointly use the two kinds (...) of models. I use methods from the empirical social sciences, such as digital corpus analysis, content analysis, and structured case analysis. I infer three primary conclusions about projects of the kind studied. First, they employ an implicit concept of gene that enables the joint use of both kinds of models. Second, they pursue more epistemic aims besides mechanistic explanation of phenomena. Third, they don’t work to create and export broad synthesized theories. Rather, they focus on phenomena too complex to be understood by a common general theory, they distinguish parts of the phenomena, and they apply models from different theories to the different parts. For such projects, seemingly incompatible models are synthesized largely through mediated representations of complex phenomena. (shrink)

Christians who are theistic evolutionists and Christians who are proponents of intelligent design very frequently criticize one another on the basis that the other’s position is theologically suspect. Ironically, both camps have accused the other of being deistic and thus sub-Christian in their understanding of God’s relation to creation. In this paper, I consider the merit of these charges. I conclude that, although each position has both deistic and nondeistic forms, theistic evolution in its treatment of life’s history is typically (...) deistic, whereas intelligent design typically is not. (shrink)

Review of: Robert J. Richards and Michael Ruse: Debating Darwin. University of Chicago Press, Chicago. 2016. ISBN: 9780226384429, 320 pages, price: $30.00 (hardcover).

In the received view of the history of the Modern Evolutionary Synthesis, paleontology was given a prominent role in evolutionary biology thanks to the significant influence of paleontologist George Gaylord Simpson on both the institutional and conceptual development of the Synthesis. Simpson's 1944 Tempo and Mode in Evolution is considered a classic of Synthesis-era biology, and Simpson often remarked on the influence of other major Synthesis figures – such as Ernst Mayr and Theodosius Dobzhansky – on his developing thought. Why, (...) then, did paleontologists of the 1970s and 1980s – Stephen Jay Gould, Niles Eldredge, David M. Raup, Steven Stanley, and others – so frequently complain that paleontology remained marginalized within evolutionary biology? This essay considers three linked questions: first, were paleontologists genuinely welcomed into the Synthetic project during its initial stages? Second, was the initial promise of the role for paleontology realized during the decades between 1950 and 1980, when the Synthesis supposedly "hardened" to an "orthodoxy"? And third, did the period of organized dissent and opposition to this orthodoxy by paleontologists during the 1970s and 1980s bring about a long-delayed completion to the Modern Synthesis, or rather does it highlight the wider failure of any such unified Darwinian evolutionary consensus? (shrink)

n this text, we revisit part of the analysis of anti-entropy in Bailly and Longo (2009} and develop further theoretical reflections. In particular, we analyze how randomness, an essential component of biological variability, is associated to the growth of biological organization, both in ontogenesis and in evolution. This approach, in particular, focuses on the role of global entropy production and provides a tool for a mathematical understanding of some fundamental observations by Gould on the increasing phenotypic complexity along evolution. Lastly, (...) we analyze the situation in terms of theoretical symmetries, in order to further specify the biological meaning of anti-entropy as well as its strong link with randomness. (shrink)

Organogenesis and metamorphosis require the intricate orchestration of multiple types of cellular interactions and signaling pathways. Glutamate (Glu) is an excitatory extracellular signaling molecule in the nervous system, while Ca2+ is a major intracellular signaling molecule. The first Glu receptors to be cloned are Ca2+‐permeable receptors in mammalian brains. Although recent studies have focused on Glu signaling in synaptic mechanisms of the mammalian central nervous system, it is unclear how this signaling functions in development. Our recent article demonstrated that Ca2+‐permeable (...) AMPA‐type Glu receptors (GluAs) are essential for formation of a photosensitive organ, development of some neurons, and metamorphosis, including tail absorption and body axis rotation, in ascidian embryos. Based on findings in these embryos and mammalian brains, we formed several hypotheses regarding the evolution of GluAs, the non‐synaptic function of Glu, the origin of GluA‐positive neurons, and the neuronal network that controls metamorphosis in ascidians. (shrink)

Despite remarkable empirical and methodological advances, our theoretical understanding of the evolutionary processes that made us human remains fragmented and contentious. Here, we make the radical proposition that the cultural communities within which Homo emerged may be understood as a novel exotic form of organism. The argument begins from a deep congruence between robust features of Pan community life cycles and protocell models of the origins of life. We argue that if a cultural tradition, meeting certain requirements, arises in the (...) context of such a “social protocell,” the outcome will be an evolutionary transition in individuality whereby traditions and hominins coalesce into a macroscopic bio-socio-technical system, with an organismal organization that is culturally inherited through irreversible fission events on the community level. We refer to the resulting hypothetical evolutionary individual as a “sociont.” The social protocell provides a preadapted source of alignment of fitness interests that addresses a number of open questions about the origins of shared adaptive cultural organization, and the derived genetic adaptations that support them. Also, social cooperation between hominins is no longer in exclusive focus since cooperation among traditions becomes salient in this model. This provides novel avenues for explanation. We go on to hypothesize that the fate of the hominin in such a setting would be mutualistic coadaptation into a part-whole relation with the sociont, and we propose that the unusual suite of derived features in Homo is consistent with this hypothesis. (shrink)

Efforts from diverse disciplines, including evolutionary studies and biomechanical experiments, have yielded new insights into the genetic, signaling, and mechanical control of tooth formation and functions. Evidence from fossils and non‐model organisms has revealed that a common set of genes underlie tooth‐forming potential of epithelia, and changes in signaling environments subsequently result in specialized dentitions, maintenance of dental stem cells, and other phenotypic adaptations. In addition to chemical signaling, tissue forces generated through epithelial contraction, differential growth, and skeletal constraints act (...) in parallel to shape the tooth throughout development. Here recent advances in understanding dental development from these studies are reviewed and important gaps that can be filled through continued application of evolutionary and biomechanical approaches are discussed. (shrink)

All organisms live in close association with microbes. However, not all such associations are meaningful in an evolutionary context. Current debate concerns whether hosts and microbes are best described as communities of individuals or as holobionts (selective units of hosts plus their microbes). Recent reports that assortative mating of hosts by diet can be mediated by commensal gut microbes have attracted interest as a potential route to host reproductive isolation (RI). Here, the authors discuss logical problems with this line of (...) argument. The authors briefly review how microbes can affect host mating preferences and evaluate recent findings from fruitflies. Endosymbionts can potentially influence host RI given stable and recurrent co‐association of hosts and microbes over evolutionary time. However, observations of co‐occurrence of microbes and hosts are ripe for misinterpretation and such associations will rarely represent a meaningful holobiont. A framework in which hosts and their microbes are independent evolutionary units provides the only satisfactory explanation for the observed range of effects and associations. (shrink)

The aim of this article is to identify the strongest evolutionary debunking argument against moral realism and to assess on which empirical assumptions it relies. In the recent metaethical literature, several authors have de-emphasized the evolutionary component of EDAs against moral realism: presumably, the success or failure of these arguments is largely orthogonal to empirical issues. I argue that this claim is mistaken. First, I point out that Sharon Street’s and Michael Ruse’s EDAs both involve substantive claims about the evolution (...) of our moral judgments. Next, I argue that combining their respective evolutionary claims can help debunkers to make the best empirical case against moral realism. Some realists have argued that the very attempt to explain the contents of our endorsed moral judgments in evolutionary terms is misguided, and have sought to escape EDAs by denying their evolutionary premise. But realists who pursue this reply can still be challenged on empirical grounds: debunkers may argue that the best, scientifically informed historical explanations of our moral endorsements do not involve an appeal to mind-independent truths. I conclude, therefore, that the empirical considerations relevant for the strongest empirically driven argument against moral realism go beyond the strictly evolutionary realm; debunkers are best advised to draw upon other sources of genealogical knowledge as well. (shrink)

Many have expected that understanding the evolution of norms should, in some way, bear on our first-order normative outlook: How norms evolve should shape which norms we accept. But recent philosophy has not done much to shore up this expectation. Most existing discussions of evolution and norms either jump headlong into the is/ought gap or else target meta-ethical issues, such as the objectivity of norms. My aim in this paper is to sketch a different way in which evolutionary considerations can (...) feed into normative thinking—focusing on stability. I will discuss two forms of argument that utilize information about social stability drawn from evolutionary models, and employs it to assess claims in political philosophy. One such argument treats stability as feature of social states that may be taken into account alongside other features. The other uses stability as a constraint on the realization of social ideals, via a version of the ought-implies-can maxim. These forms of argument are not new; indeed they have a history going back at least to early modern philosophy. But their marriage with evolutionary information is relatively recent, has a significantly novel character, and has received little attention in recent moral and political philosophy. (shrink)

I respond to Vladas Griskevicius and Douglas T. Kendrick (G&K) and Gad Saad's (S) defenses of the view that Consumer Studies would benefit from the appeal to evolution in all work aimed at understanding consumer behavior. I argue that G&K and S's reliance on one theoretical perspective, that of evolutionary psychology, limits their options. Further, I point out some specific problems with the theoretical perspective of evolutionary psychology. Finally, I introduce some alternative evolutionary approaches to studying human behavior that could (...) profitably be adopted in consumer research. -/- . (shrink)

As multilevel selection theory has gained greater acceptance over the past quarter-century, scientists and scholars have shown an increased interest in the theory's historical antecedents. Despite this interest, however, the early twentieth century remains largely unexplored. It is generally assumed that biologists thought "naively" about evolutionary dynamics during this era, and that their attempts to explain biological phenomena often lacked sophistication. Now that several recent works have called attention to the complex relationship between biological individuality and the levels of selection, (...) we believe it will prove instructive to revisit these early-twentieth-century biologists and reassess their criteria for biological individuality. Doing so reveals that they constructed a multilevel explanation of evolution that anticipated modern interpretations in several important ways. Though it is certainly true that most of these early biologists failed to recognize natural selection's pervasive agency, it is no less true that one of them, termite expert Alfred Emerson, artfully united the multilevel theory of "emergent evolution" with natural selection in a way that differs but little from the theory of multilevel selection that many scientists and scholars now promote. After reviewing the historical record, we place these early-twentieth-century biologists in their proper historical context, and we compare their interpretation of evolution with modern interpretations. (shrink)

The endangered species Tokudaia osimensis has the unique chromosome constitution of 2n = 25, with an XO/XO sex chromosome configuration (2n = 25; XO). There is urgency to preserve this species and to elucidate the regulator(s) that can discriminate the males and females arising from the indistinguishable sex chromosome constitution. However, it is not realistic to examine this rare animal species by sacrificing individuals. Recently, true naïve induced pluripotent stem cells were successfully generated from a female T. osimensis, and the (...) sexual plasticity of its germ cells was elucidated. This achievement constitutes the basis of an attractive research area, including embryonic fate determination, sex determination, and factor(s) that can replace the Y chromosome. In this essay, concrete strategies to conserve rare animal species and to reveal their specific characteristics using other compatible and abundant animals are proposed. -/- . (shrink)

Welch :263–279, 2017) has recently proposed two possible explanations for why the field of evolutionary biology is plagued by a steady stream of claims that it needs urgent reform. It is either seriously deficient and incapable of incorporating ideas that are new, relevant and plausible or it is not seriously deficient at all but is prone to attracting discontent and to the championing of ideas that are not very relevant, plausible and/or not really new. He argues for the second explanation. (...) This paper presents a twofold critique of his analysis: firstly, the main calls for reform do not concern the field of evolutionary biology in general but rather, or more specifically, the modern evolutionary synthesis. Secondly, and most importantly, these calls are not only inspired by the factors, enumerated by Welch, but are also, and even primarily, motivated by four problematic characteristics of the modern synthesis. This point is illustrated through a short analysis of the latest reform challenge to the modern synthesis, the so-called extended evolutionary synthesis. We conclude with the suggestion that the modern synthesis should be amended, rather than replaced. (shrink)

Linear depictions of the evolutionary process are ubiquitous in popular culture, but linear evolutionary imagery is strongly rejected by scientists who argue that evolution branches. This point is frequently illustrated by saying that we didn't evolve from monkeys, but that we are related to them as collateral relatives. Yet, we did evolve from monkeys, but our monkey ancestors are extinct, not extant. Influential voices, such as the late Stephen Jay Gould, have misled audiences for decades by falsely portraying the linear (...) and branching aspects of evolution to be in conflict, and by failing to distinguish between the legitimate linearity of evolutionary descent, and the branching relationships among collateral relatives that result when lineages of ancestors diverge. The purpose of this article is to correct the widespread misplaced rejection of linear evolutionary imagery, and to re-emphasize the basic truth that the evolutionary process is fundamentally linear. (shrink)

No single author presented Darwin with a more difficult question about his priority in discovering natural selection than the British comparative anatomist and paleontologist Richard Owen. Owen was arguably the most influential biologist in Great Britain in Darwin’s time. Darwin wanted his approbation for what he believed to be his own theory of natural selection. Unfortunately for Darwin, when Owen first commented in publication about Darwin’s theory of descent he was openly hostile. Darwin was taken off-guard. In private meetings and (...) correspondence prior to 1860 Owen had been nothing but polite and friendly, even helping Darwin in cataloguing and analyzing Darwin’s zoological specimens from the Beagle voyage. Every early indication predicted a life-long friendship and collaboration. But that was not to be. Owen followed his slashing review with a mounting campaign in the 1860s to denounce and discredit both Darwin and his small but ascendant circle of friends and supporters. But that was not enough for Owen. Starting in 1866, perhaps by now realizing Darwin had landed the big fish, Owen launched a new campaign, to claim the discovery of “Darwin’s theory” for himself. Darwin naturally fought back, mainly in the “Historical Sketch” that he prefaced to Origin starting in 1861. But when we peel back the layers of personal animus and escalating vituperation we discover in fact their quarrel was generated more by mutual misunderstanding than scientific disagreement. The battle ended only when Darwin finally penetrated to the crux of the matter and put an end to the rivalry in 1872, in the final version of the Sketch. (shrink)

I argue that Goethe’s scientific writings carry in them the seeds of the theory of evolution. Goethe’s works on plant morphology reflects the conflicting ideas of his era on the discreteness and on the stability of species. Goethe’s theory of plant morphology provides a link between the discontinuous view of nature, as exemplified in works of the Swedish botanist Carl Linnaeus (1707-1778), and the continuous view of nature, as exemplified in the work of the English naturalist Charles Darwin (1809-1882).

In recent years, there has been growing awareness among evolutionary ethicists that systems of cooperation based upon “weak” reciprocity mechanisms lack scalability, and are therefore inadequate to explain human ultrasociality. This has produced a shift toward models that strengthen the cooperative mechanism, by adding various forms of commitment or punishment. Unfortunately, the most prominent versions of this hypothesis wind up positing a discredited mechanism as the basis of human ultrasociality, viz. a “greenbeard.” This paper begins by explaining what a greenbeard (...) is, and why evolutionary theorists are doubtful that such a mechanism could play a significant role in explaining human prosociality. It goes on to analyze several recent philosophical works in evolutionary ethics, in order to show how the suggestion that morality acts as a commitment device tacitly relies upon a greenbeard mechanism to explain human cooperation. It concludes by showing how some early scientific models in the “evolution of cooperation” literature, which introduced punishment as a device to enhance cooperation, also tacitly relied upon a greenbeard mechanism. (shrink)

It is of philosophical and epistemological interest to examine how Darwin conceived the process of division of labour within Natural History. Darwin observed the advantages brought by division of labour to the human economy, and considered that the principle of divergence within nature, which is, according to him, one of the two ‘keystones’ of his theory, gave comparable advantages. This led him to re-examine Milne-Edwards’ view on the notion of division of physiological labour, and to introduce this with modifications into (...) his naturalist writings. After a short review of the Darwinian historiography dealing with this issue, I first show the conceptual confusion into which Darwin plunges, when using a so-called economic argument to defend his thesis of the maximization of beings in a given territory due to division of labour. Following this I propose several hypotheses to explain these shifts, recurring in Darwin’s texts, from one conception and from one application to another, of the division of labour. (shrink)

In this brief commentary I compare and contrast two different views of evolution: one of limited (convergent) evolution and mathematical predictability, and one of unbounded diversity and no entailing laws. Clearly these opposing views cannot both be true at the same time. Their disagreement seems to rest on different underlying assumptions, and the challenge is to see if they can be reconciled.

Exaptations are adaptations that have undergone a major change in function. By recruiting genes from sources originally unrelated to vision, exaptation has allowed for sudden and critical photosensory innovations, such as lenses, photopigments, and photoreceptors. Here we review new or neglected findings, with an emphasis on unicellular eukaryotes (protists), to illustrate how exaptation has shaped photoreception across the tree of life. Protist phylogeny attests to multiple origins of photoreception, as well as the extreme creativity of evolution. By appropriating genes and (...) even entire organelles from foreign organisms via lateral gene transfer and endosymbiosis, protists have cobbled photoreceptors and eyespots from a diverse set of ingredients. While refinement through natural selection is paramount, exaptation helps illustrate how novelties arise in the first place, and is now shedding light on the origins of photoreception itself. -/- . (shrink)

Historians tend to speak of the problem of the origin of species or the species question, as if it were a monolithic problem. In reality, the phrase refers to a, historically, surprisingly fluid and pluriform scientific issue. It has, in the course of the past five centuries, been used in no less than ten different ways or contexts. A clear taxonomy of these separate problems is useful or relevant in two ways. It certainly helps to disentangle confusions that have inevitably (...) emerged in the literature in its absence. It may, secondly, also help us to gain a more thorough understanding, or sharper view, of the history of evolutionary thought. A consequent problem-centric look at that history through the lens of various origin of species problems certainly yields intriguing results, including and particularly for our understanding of the genesis of the Wallace–Darwin theory of evolution through natural selection. (shrink)

This paper gives a detailed narrative of a controversial empirical research in postwar population genetics, the analysis of the cytological polymorphisms of an Australian grasshopper, Moraba scurra. This research intertwined key technical developments in three research areas during the 1950s and 1960s: it involved Dobzhansky’s empirical research program on cytological polymorphisms, the mathematical theory of natural selection in two-locus systems, and the building of reliable estimates of natural selection in the wild. In the mid-1950s the cytologist Michael White discovered an (...) interesting case of epistasis in populations of Moraba scurra. These observations received a wide diffusion when theoretical population geneticist Richard Lewontin represented White’s data on adaptive topographies. These topographies connected the information on the genetic structure of these grasshopper populations with the formal framework of theoretical population genetics. As such, they appeared at the time as the most successful application of two-locus models of natural selection to an empirical study system. However, this connection generated paradoxical results: in the landscapes, all grasshopper populations were located on a ridge while they were expected to reach a peak. This puzzling result fueled years of research and triggered a controversy attracting contributors from Australia, the United States and the United Kingdom. While the original problem seemed, at first, purely empirical, the subsequent controversy affected the main mathematical tools used in the study of two-gene systems under natural selection. Adaptive topographies and their underlying mathematical structure, Wright’s mean fitness equations, were submitted to close scrutiny. Suspicion eventually shifted to the statistical machinery used in data analysis, reflecting the crucial role of statistical inference in applied population genetics. In the 1950s and 1960s, population geneticists were not simply in search for new generalizations about the evolutionary process and for new evidence about genetic variation: struggling against statistical artifacts, they were searching for reliable tests and descriptors to analyze their data. (shrink)

In this paper I seek to show how cultural niche construction theory offers the potential to extend the human evolutionary story beyond the Pleistocene, through the Neolithic, towards the kind of very large-scale societies in which we live today. The study of the human past has been compartmentalised, each compartment using different analytical vocabularies, so that their accounts are written in mutually incompatible languages. In recent years social, cognitive and cultural evolutionary theories, building on a growing body of archaeological evidence, (...) have made substantial sense of the social and cultural evolution of the genus Homo. However, specialists in this field of studies have found it difficult to extend their kind of analysis into the Holocene human world. Within southwest Asia the three or four millennia of the Neolithic period at the beginning of the Holocene represents a pivotal point, which saw the transformation of human society in the emergence of the first large-scale, permanent communities, the domestication of plants and animals, and the establishment of effective farming economies. Following the Neolithic, the pace of human social, economic and cultural evolution continued to increase. By 5000 years ago, in parts of southwest Asia and northeast Africa there were very large-scale urban societies, and the first large-scale states. An extension of cultural niche construction theory enables us to extend the evolutionary narrative of the Pleistocene into the Holocene, opening the way to developing a single, long-term, evolutionary account of human history. (shrink)

The handicap principle stipulates that signal reliability can be maintained if signals are costly to produce. Yet empirical biologists are typically unable to directly measure evolutionary costs, and instead appeal to expenditure as a sensible proxy. However the link between expenditure and cost is not always as straightforward as proponents of HP assume. We consider signaling interactions where whether the expenditure associated with signaling is converted into an evolutionary cost is in some sense dependent on the behavior of the intended (...) recipient of the signal. We illustrate this with a few empirical examples and demonstrate that on this alternative expenditure to cost mapping the traditional predictions of HP no longer hold. Instead of full information transfer, a partially informative communication system like those uncovered by Wagner :163–181, 2013) and Zollman et al. is possible. (shrink)

Comparative mapping and sequencing show that turnover of sex determining genes and chromosomes, and sex chromosome rearrangements, accompany speciation in many vertebrates. Here I review the evidence and propose that the evolution of therian mammals was precipitated by evolution of the male‐determining SRY gene, defining a novel XY sex chromosome pair, and interposing a reproductive barrier with the ancestral population of synapsid reptiles 190 million years ago (MYA). Divergence was reinforced by multiple translocations in monotreme sex chromosomes, the first of (...) which supplied a novel sex determining gene. A sex chromosome‐autosome fusion may have separated eutherians (placental mammals) from marsupials 160 MYA. Another burst of sex chromosome change and speciation is occurring in rodents, precipitated by the degradation of the Y. And although primates have a more stable Y chromosome, it may be just a matter of time before the same fate overtakes our own lineage. (shrink)

The conference explored an extraordinary diversity of aging strategies in organisms ranging from short‐lived species to “immortal” animals and plants. Research on the biological processes of aging is at the brink of a revolution with respect to our understanding of its underlying mechanisms as well as our ability to prevent and cure a wide variety of age‐related pathologies.

Mitochondria exist in large numbers per cell. Therefore, the strength of natural selection on individual mtDNAs for their contribution to cellular fitness is weak whereas the strength of selection in favor of mtDNAs that increase their own replication without regard for cellular functions is strong. This problem has been solved for most mitochondrial genes by their transfer to the nucleus but a few critical genes remain encoded by mtDNA. Organisms manage the evolution of mtDNA to prevent mutational decay of essential (...) services mitochondria provide to their hosts. Bottlenecks of mitochondrial numbers in female germlines increase the homogeneity of mtDNAs within cells and allow intraorganismal selection to eliminate cells with low quality mitochondria. Mechanisms of intracellular “quality control” allow direct selection on the competence of individual mtDNAs. These processes maintain the integrity of mtDNAs within the germline but are inadequate to indefinitely maintain mitochondrial function in somatic cells. (shrink)

Life-history evolution is a complex process. Life-history theory covers the fundamental level of the process, the evolution of life-history traits. Life-history traits interact; those coevolving as a response to the same selection pressure form life-history tactics. Top level of the hierarchy, life-history strategy, is formed by genetically interconnected tactics. Our aim is to expand the traditional view to life-history evolutionby considering what boundary conditions a successful life-history strategy has to fulfil. We claim that the most fundamental condition successful strategies have (...) to meet is to minimize the risk of evolutionary failure. Here the risk of failure refers to failure in transferring practitioners of the strategy to the next time point, either through survival, or by reproduction. We make an attempt to classify types of risks as they lead to evolutionary failure, and discuss how risk minimization ideas may be approached empirically. We conclude that understanding how traits evolve may not cover all aspects of how strategies evolve. We emphasize that bookkeeping ofthe actual causes of failure might help in developing life-history theory that uses causes of selection to predict responses to selection. (shrink)

It is unreasonable to assume that our pre-scientific emotion vocabulary embodies all and only those distinctions required for a scientific psychology of emotion. The psychoevolutionary approach to emotion yields an alternative classification of certain emotion phenomena. The new categories are based on a set of evolved adaptive responses, or affect-programs, which are found in all cultures. The triggering of these responses involves a modular system of stimulus appraisal, whose evoluations may conflict with those of higher-level cognitive processes. Whilst the structure (...) of the adaptive responses is innate, the contents of the system which triggers them are largely learnt. The circuits subserving the adaptive responses are probably located in the limbic system. This theory of emotion is directly applicable only to a small sub-domain of the traditional realm of emotion. It can be used, however, to explain the grouping of various other phenomena under the heading of emotion, and to explain various characteristic failings of the pre-scientific conception of emotion. (shrink)

This paper examines the very disparate positions that various actors have taken towards the argument of subversion from within in a set of related debates on group selection, altruism and the handicap principle. Using this set of debates as a case study, this paper argues that different applications of epistemic values were one of the factors behind the disagreements between John Maynard Smith and Amotz Zahavi over a number of important evolutionary issues. The paper also argues that these different applications (...) were connected to important epistemological differences related in part to their disciplinary background. Apart from conflicting evolutionary views concerning the theoretical feasibility of the handicap effect, these antagonists both differed in the confidence they ascribed to mathematical modeling and over the hereditary basis for altruistic behavior. (shrink)

The paper links discussions of two topics: biological individuality and the simplest forms of mentality. I discuss several attempts to locate the boundary between metabolic activity and ‘minimal cognition.’ I then look at differences between the kinds of individuality present in unicellular life, multicellular life in general, and animals of several kinds. Nervous systems, which are clearly relevant to cognition and subjectivity, also play an important role in the form of individuality seen in animals. The last part of the paper (...) links these biological transitions to the evolutionary history of subjective experience. (shrink)

Turtles are among the most intriguing amniotes but their communication and signaling have rarely been studied. Traditionally, they have been seen as basically just silent armored ‘walking stones’ with complex physiology but no altruism, maternal care, or aesthetic perception. Recently, however, we have witnessed a radical change in the perception of turtle behavioral and cognitive skills. In our study, we start by reviewing some recent findings pertaining to various highly developed behavioral and cognitive patterns with special emphasis on turtles. Then (...) we focus on freshwater turtles and use data about their sexual behavior and size sexual dimorphism to test whether conspicuous coloration of the head is in these animals related to sexual processes. We found that absence of aggressive mating behavior is statistically associated with the presence of conspicuous coloration on turtles’ heads. It also seems that while species with female-biased SSD are characterised by conspicuously colored head ornaments, in species with male-biased SSD conspicuous coloration is absent. Unlike large females, males thus seem to be under pressure to develop conspicuous coloration and engage in non-aggressive behavior using signaling to succeed in courtship. And finally, we discuss possible roles of head color patterns in turtle communication during mating. (shrink)

Man is a biosocial entity, so, in the study of his adaptive peculiarities two directions, that is, biologic and social, can be determined. Within the biological framework it is possible to combine evolutionary, genetic, medical-biological and ecological investigations. Recently, the problem of man’s adaptation to profound changes taking place in the environment, under the impact of man’s activity, becomes of growing importance. The second direction of the man adaptation research may be called social or socio-cultural. In the course of social (...) adaptation man acts as an adaptively-adapting entity, inasmuch as, unlike animals, he does not only adapt himself to the environment, but also transforms it in course of his activity, sometimes creating a new environment. The complex study of human being makes necessary a synthesis of natural-scientific and socialhumanitariansides of the man’s adaptation problem. The analysis of the above mentioned directions, of social and biological man’s adaptations research, enables us tocome to the conclusion that no one direction, taking separately, can resolve the problem of man’s adaptation, which has a complicated pattern with many aspects. The man’s adaptation problem emerged within the framework of biology, and during a long time it was of evolutionary-biological character. However, in the course of the development of science it has become an interdisciplinary issue. It may be conceived profoundly and with all aspects only by means of an interdisciplinary synthetic analysis. (shrink)

Here is one way that philosophers and biologists sometimes speak of Darwin’s explanatory innovation: ‘Eyes, organs of echolocation, camouflage and the like are all wonderful instances of contrivance, of complex adaptation, of good design. Paley and the other natural theologians sought to explain this good design by appeal to an intelligent designer. Darwin, on the other hand, offers us a superior explanation for the appearance of this same property: Darwin shows us that we can explain good design through the action (...) of selection. Indeed, selection is the only process that can explain good design in nature. And that is why evolutionary biologists can continue to use a version of the argument from design called the argument from biological design: when we see an instance of good design in nature, we should infer not the guiding hand of God, but the hand of selection at work.’ -/- . (shrink)

That endogenous retrovirus (ERV) is present within the placenta of humans and other mammals has been known for the past 25 years, but the significance of this observation is still not fully understood. Much molecular biological data have emerged in recent years to support the earlier electron microscopic data on the presence of placental ERV. The evidence for ERV in animal and human placental tissue is presented, then integrated with data on the the presence of ERV in a range of (...) other tissues, in particular teratocarcinoma cells. Placental invasiveness and maternal immunosuppression are then discussed in relation to metalloproteinase secretion, the immunosuppressive potential of retroviruses, and placental growth factors, while the evidence for a functional link between placental proto‐oncogenes and trophoblast malignancy is reviewed. Finally, placental development, structure, and life span are discussed within an evolutionary context. The hypothesis that one or more ancient trophoblastic ERVs could have played a role in the evolution and divergence of all placental mammals is evaluated. BioEssays 20:307‐316, 1998. © 1998 John Wiley & Sons, Inc. (shrink)