Kin selection is the key to altruism

Kin selection theory, also known as inclusive fitness theory, has been the subject of much debate and misunderstanding. Nevertheless, the idea that relatedness among individuals can drive the evolution of altruism has emerged as a central paradigm in evolutionary biology. Or has it? In two recent articles, E.O. Wilson argues that kin selection should no longer be considered the main explanation for the evolution of altruism in insect societies. Here, we discuss what these articles say about kin selection and how it relates to the theory. We conclude that kin selection remains the key explanation for the evolution of altruism in eusocial insects.     

The fitness value of information

Communication and information are central concepts in evolutionary biology. In fact, it is hard to find an area of biology where these concepts are not used. However, quantifying the information transferred in biological interactions has been difficult. How much information is transferred when the first spring rainfall hits a dormant seed, or when a chick begs for food from its parent? One measure that is commonly used in such cases is fitness value: by how much, on average, an individual's fitness would increase if it behaved optimally with the new information, compared to its average fitness without the information. Another measure, often used to describe neural responses to sensory stimuli, is the mutual information – a measure of reduction in uncertainty, as introduced by Shannon in communication theory. However, mutual information has generally not been considered to be an appropriate measure for describing developmental or behavioral responses at the organismal level, because it is blind to function; it does not distinguish between relevant and irrelevant information. In this paper we show that there is in fact a surprisingly tight connection between these two measures in the important context of evolution in an uncertain environment. In this case, a useful measure of fitness benefit is the increase in the long‐term growth rate, or the fold increase in number of surviving lineages. We show that in many cases the fitness value of a developmental cue, when measured this way, is exactly equal to the reduction in uncertainty about the environment, as described by the mutual information.     

Constant relative age and size at sex change for sequentially hermaphroditic fish

A general problem in evolutionary biology is that quantitative tests of theory usually require a detailed knowledge of the underlying trade-offs, which can be very hard to measure. Consequently, tests of theory are often constrained to be qualitative and not quantitative. A solution to this problem can arise when life histories are viewed in a dimensionless way. Recently, dimensionless theory has been developed to predict the size and age at which individuals should change sex. This theory predicts that the size at sex change/maximum size (L50/L(max)), and the age at sex change/age at first breeding (tau/alpha) should both be invariant. We found support for these two predictions across 52 species of fish. Fish change sex when they are 80% of their maximum body size, and 2.5 times their age at maturity. This invariant result holds despite a 60 and 25 fold difference across species in maximum size and age at sex change. These results suggest that, despite ignoring many biological complexities, relatively simple evolutionary theory is able to explain quantitatively at what point sex change occurs across fish species. Furthermore, our results suggest some very broad generalities in how male fitness varies with size and age across fish species with different mating systems.     

A bird's-eye view on the modern genetics workflow and its potential applicability to the locust problem

Genetics is an immense science and the current developments in its methods and techniques as well as the fast emerging tools make it one of the most powerful biological sciences. Indeed, from taxonomy and ecology to physiology and molecular biology, every biological science makes use of genetics techniques and methods at one time or another. In fact, development in genetics is such that it is now possible to characterize and analyze the expression of the whole set of genes of virtually every living organism, even if it is a non-model one. Locusts are notorious for the damage they cause to the ecosystems and economies of the areas affected by their recurrent population outbreaks. To prevent and deal with these outbreaks, we now count on both biological as well as chemical agents that are proving to be successful in reducing the damage that otherwise locust population outbreaks might cause. However, a better, efficient and environmentally friendly solution is still a hoped-for target. In my opinion, the ideal future pesticide should be both environmentally friendly, risk free and species-specific. To reach the knowledge needed for the development of such species-specific anti-locust agent, deep and accurate knowledge of the locusts’ genetics and molecular biology is a must. Since genes and their expression levels lie at the bottom of every biological phenomenon, any species-specific solution to the locust problem requires a good knowledge of these organisms’ genes as well as the quantitative and spatio-temporal dynamics of their expression. To reach such knowledge, collaborative work is needed as well as a clear workflow that, given the fast development in the genetics tools, is not always clear to all research groups. For this reason, here I describe a genetics workflow that should allow taking advantage of the most recent genetics tools and techniques to answer question relating to locust biology. My hope is that the adoption of this and other work strategies by different research groups, especially when the work is a collaborative one, would provide precious information on the biology and the biological phenomena that these economically important organisms exhibit.     

Why mental disorders are just mental dysfunctions (and nothing more): some Darwinian arguments

Mental disorders are often thought to be harmful dysfunctions. Jerome Wakefield has argued that such dysfunctions should be understood as failures of naturally selected functions. This suggests, implicitly, that evolutionary biology and other Darwinian disciplines hold important information for anyone working on answering the philosophical question, 'what is a mental disorder?'. In this article, the author argues that Darwinian theory is not only relevant to the understanding of the disrupted functions, but it also sheds light on the disruption itself, as well as on the harm that attends the disruption. The arguments advanced here are partially based on the view that a core feature of Darwinism is that it stresses the environmental relativity of functions and dysfunctions. These arguments show a very close empirical connection between social judgments (values) and dysfunctions (psychopathology), which is of interest for psychiatric theory. Philosophically, they lead to the conclusion that the concept of mental disorder is identical to the concept of mental dysfunction. Consequently, it is both misleading and redundant to conceptualize mental disorders as 'harmful dysfunctions', and not simply as 'mental dysfunctions'.     

Population biology of parasites: current status and prospects

The present state of parasite population biology is reviewed with special reference to parasites of fish. Mathematical models have provided a coherent body of theory which is supported by many laboratory investigations. There is nevertheless some disagreement between predictions based on this theory and data obtained from investigations of natural parasite populations. It is suggested that this is partly due to the oversimplifications and limitations of the models, and partly to the unsystematic approach of many field investigations and the resulting shortage of data of the right sort. In freshwater habitats disagreement may also be due to the rapid and extensive changes that are taking place in the habitats themselves as a direct consequence of human activities. Future developments should involve models becoming more realistic, and field investigations being conducted in a more systematic and analytical manner in order to obtain quantitative measurements of the essential population parameters.     

Chemical Ecology and Biomolecular Evolution

The belief in the Darwinian theory of evolution appeared to be shaken when one tried to interpret statements of molecular biology in it. As a consequence there arose a theory of non-Darwinian neutral evolution. The supporters of this theory believe that under natural conditions no factors exist which can distinguish and select organisms on their internal (molecular) structure. In the opinion of these neutralists natural selection cannot in principle control the molecular constitution of organisms. Contrary to the viewpoint of the critics of neutralism it is impossible to admit that nucleic acids, proteins and other biomolecules can evolve without the participation of natural selection. This controversy in contemporary theoretical biology can be solved by integrating the conceptions of molecular ecology with Darwinian theory. Molecular ecology acknowledges the interactions of organisms by means of chemical substances synthesized by them. Such chemical ecological factors play a leading part in the selective stages of biomolecular evolution. These diverse chemical ecological interrelations take place intensively when living beings interact with parasitic microbes.     

The philosophy of modelling or does the philosophy of biology have any use?

Biologists in search of answers to real-world issues such as the ecological consequences of global warming, the design of species'' conservation plans, understanding landscape dynamics and understanding gene expression make decisions constantly that are based on a ‘philosophical’ stance as to how to create and test explanations of an observed phenomenon. For better or for worse, some kind of philosophy is an integral part of the doing of biology. Given this, it is more important than ever to undertake a practical assessment of what philosophy does mean and should mean to biologists. Here, I address three questions: should biologists pay any attention to ‘philosophy’; should biologists pay any attention to ‘philosophy of biology’; and should biologists pay any attention to the philosophy of biology literature on modelling? I describe why the last question is easily answered affirmatively, with the proviso that the practical benefits to be gained by biologists from this literature will be directly proportional to the extent to which biologists understand ‘philosophy’ to be a part of biology, not apart from biology.     

Integrating evolutionary and molecular genetics of aging

Aging or senescence is an age-dependent decline in physiological function, demographically manifest as decreased survival and fecundity with increasing age. Since aging is disadvantageous it should not evolve by natural selection. So why do organisms age and die? In the 1940s and 1950s evolutionary geneticists resolved this paradox by positing that aging evolves because selection is inefficient at maintaining function late in life. By the 1980s and 1990s this evolutionary theory of aging had received firm empirical support, but little was known about the mechanisms of aging. Around the same time biologists began to apply the tools of molecular genetics to aging and successfully identified mutations that affect longevity. Today, the molecular genetics of aging is a burgeoning field, but progress in evolutionary genetics of aging has largely stalled. Here we argue that some of the most exciting and unresolved questions about aging require an integration of molecular and evolutionary approaches. Is aging a universal process? Why do species age at different rates? Are the mechanisms of aging conserved or lineage-specific? Are longevity genes identified in the laboratory under selection in natural populations? What is the genetic basis of plasticity in aging in response to environmental cues and is this plasticity adaptive? What are the mechanisms underlying trade-offs between early fitness traits and life span? To answer these questions evolutionary biologists must adopt the tools of molecular biology, while molecular biologists must put their experiments into an evolutionary framework. The time is ripe for a synthesis of molecular biogerontology and the evolutionary biology of aging.     

Reverend Paley's naturalist revival

This paper analyzes the remarkable popularity of William Paley's argument from design among contemporary naturalists in biology and the philosophy of science. In philosophy of science Elliott Sober has argued that creationism should be excluded from the schools not because it is not science but because it is 'less likely' than evolution according to fairly standard confirmation theory. Creationism is said to have been a plausible scientific option as presented by Paley but no longer to be acceptable according to the same standards that once approved it. In biology C. G. Williams and Richard Dawkins have seen in Paley a proto-adaptationist. This paper shows that the historical assumptions of Sober's arguments are wrong and that the philosophical arguments themselves take alternatives to science to be alternatives in science and conflate the null hypothesis, chance, with a competing explanatory hypothesis. It is also shown that the similarity of Paley's adaptationism to that of contemporary biology is not what it is made out to be.     

A general theory for the evolutionary dynamics of virulence

Most theory on the evolution of virulence is based on a game-theoretic approach. One potential shortcoming of this approach is that it does not allow the prediction of the evolutionary dynamics of virulence. Such dynamics are of interest for several reasons: for experimental tests of theory, for the development of useful virulence management protocols, and for understanding virulence evolution in situations where the epidemiological dynamics never reach equilibrium and/or when evolutionary change occurs on a timescale comparable to that of the epidemiological dynamics. Here we present a general theory similar to that of quantitative genetics in evolutionary biology that allows for the easy construction of models that include both within-host mutation as well as superinfection and that is capable of predicting both the short- and long-term evolution of virulence. We illustrate the generality and intuitive appeal of the theory through a series of examples showing how it can lead to transparent interpretations of the selective forces governing virulence evolution. It also leads to novel predictions that are not possible using the game-theoretic approach. The general theory can be used to model the evolution of other pathogen traits as well.     

Radiofrequency and extremely low-frequency electromagnetic field effects on the blood-brain barrier

During the last century, mankind has introduced electricity and during the very last decades, the microwaves of the modern communication society have spread a totally new entity--the radiofrequency fields--around the world. How does this affect biology on Earth? The mammalian brain is protected by the blood-brain barrier, which prevents harmful substances from reaching the brain tissue. There is evidence that exposure to electromagnetic fields at non thermal levels disrupts this barrier. In this review, the scientific findings in this field are presented. The result is a complex picture, where some studies show effects on the blood-brain barrier, whereas others do not. Possible mechanisms for the interactions between electromagnetic fields and the living organisms are discussed. Demonstrated effects on the blood-brain barrier, as well as a series of other effects upon biology, have caused societal anxiety. Continued research is needed to come to an understanding of how these possible effects can be neutralized, or at least reduced. Furthermore, it should be kept in mind that proven effects on biology also should have positive potentials, e.g., for medical use.     

From computational quantum chemistry to computational biology: experiments and computations are (full) partners

Computations are being integrated into biological research at an increasingly fast pace. This has not only changed the way in which biological information is managed; it has also changed the way in which experiments are planned in order to obtain information from nature. Can experiments and computations be full partners? Computational chemistry has expanded over the years, proceeding from computations of a hydrogen molecule toward the challenging goal of systems biology, which attempts to handle the entire living cell. Applying theories from ab initio quantum mechanics to simplified models, the virtual worlds explored by computations provide replicas of real-world phenomena. At the same time, the virtual worlds can affect our perception of the real world. Computational biology targets a world of complex organization, for which a unified theory is unlikely to exist. A computational biology model, even if it has a clear physical or chemical basis, may not reduce to physics and chemistry. At the molecular level, computational biology and experimental biology have already been partners, mutually benefiting from each other. For the perception to become reality, computation and experiment should be united as full partners in biological research.     

Understanding Quantitative Genetics in the Systems Biology Era

Biology is now entering the new era of systems biology and exerting a growing influence on the future development of various disciplines within life sciences. In early classical and molecular periods of Biology, the theoretical frames of classical and molecular quantitative genetics have been systematically established, respectively. With the new advent of systems biology, there is occurring a paradigm shift in the field of quantitative genetics. Where and how the quantitative genetics would develop after having undergone its classical and molecular periods? This is a difficult question to answer exactly. In this perspective article, the major effort was made to discuss the possible development of quantitative genetics in the systems biology era, and for which there is a high potentiality to develop towards "systems quantitative genetics". In our opinion, the systems quantitative genetics can be defined as a new discipline to address the generalized genetic laws of bioalleles controlling the heritable phenotypes of complex traits following a new dynamic network model. Other issues from quantitative genetic perspective relating to the genetical genomics, the updates of network model, and the future research prospects were also discussed.     

Embryology and evolution 1920-1960: worlds apart?

During the early part of the 20th century most embryologists were skeptical about the significance of Mendelian genetics to embryological development. A few embryologists began to study the developmental effects of Mendelian genes around 1940. Such work was a necessary step on the path to modern developmental biology. It occurred during the time when the Evolutionary Synthesis was integrating Mendelian and population genetics into a unified evolutionary theory. Why did the first embryological geneticists begin their study at that particular time? One possible explanation is that developmental genetics was a potential avenue of alliance between embryology and evolutionary biology, two fields that had been separated since the 1890s. To assess this possible motive it is necessary to explore the methodological contrasts that obtained between embryology and both Mendelian-chromosomal genetics and neo-Darwinian evolutionary theory. Some of these contrasts persist to the present day.     

Do organisms have an ontological status?

The category "organism" has an ambiguous status: is it scientific or is it philosophical? Or, if one looks at it from within the relatively recent field or sub-field of philosophy of biology, is it a central, or at least legitimate category therein, or should it be dispensed with? In any case, it has long served as a kind of scientific bolstering for a philosophical train of argument which seeks to refute the mechanistic or reductionist trend, which has been perceived as dominant since the 17th century, whether in the case of Stahlian animism, Leibnizian monadology, the neo-vitalism of Hans Driesch, or, lastly, of the "phenomenology of organic life" in the 20th century, with authors such as Kurt Goldstein, Maurice Merleau-Ponty, and Georges Canguilhem. In this paper I try to reconstruct some of the main interpretive stages or layers of the concept of organism in order to evaluate it critically. How might organism be a useful concept if one rules out the excesses of organismic biology and metaphysics? Varieties of instrumentalism and what I call the projective concept of organism are appealing, but perhaps ultimately unsatisfying.     

Organisms as natural purposes: the contemporary evolutionary perspective

Kant's conception of organisms as natural purposes raises a challenge to the adequacy of mechanistic explanation in biology. Certain features of organisms appear to be inexplicable by appeal to mechanical law alone. Some biological phenomena, it seems, can only be accounted for teleologically. Contemporary evolutionary biology has by and large ignored this challenge. It is widely held that Darwin's theory of natural selection gives us an adequate, wholly mechanical account of the nature of organisms. In contemporary biology, the category of the organism plays virtually no explanatory role. Contemporary evolutionary biology is a science of sub-organismal entities-replicators. I argue that recent advances in developmental biology demonstrate the inadequacy of sub-organismal mechanism. The category of the organism, construed as a 'natural purpose' should play an ineliminable role in explaining ontogenetic development and adaptive evolution. According to Kant the natural purposiveness of organisms cannot be demonstrated to be an objective principle in nature, nor can purposiveness figure in genuine explain. I attempt to argue, by appeal to recent work on self-organization, that the purposiveness of organisms is a natural phenomenon, and, by appeal to the apparatus of invariance explanation, that biological purposiveness provides genuine, ineliminable biological explanations.     

Feedback dynamics and cell function: Why systems biology is called Systems Biology

A new paradigm, like Systems Biology, should challenge the way research has been conducted previously. This Opinion article aims to present Systems Biology, not as the application of engineering principles to biology but as a merger of systems- and control theory with molecular- and cell biology. In our view, the central dogma of Systems Biology is that it is system dynamics that gives rise to the functioning and function of cells. The concepts of feedback regulation and control of pathways and the coordination of cell function are emphasized as an important area of Systems Biology research. The hurdles and risks for this area are discussed from the perspective of dynamic pathway modelling. Most of all, the aim of this article is to promote mathematical modelling and simulation as a part of molecular- and cell biology. Systems Biology is a success if it is widely accepted that there is nothing more practical than a good theory.