scholarly journals Emergent multilevel selection in a simple spatial model of the evolution of altruism

2021 ◽  
Author(s):  
Rutger Hermsen
Keyword(s):  
Group Dynamics ◽  
Social Evolution ◽  
Experimental Studies ◽  
Formal Theory ◽  
Multilevel Selection ◽  
Altruistic Behavior ◽  
Theory Of Evolution ◽  
Evolutionary Origins ◽  
Starting Point ◽  
The Commons

Theories on the evolutionary origins of altruistic behavior have a long history and have become a canonical part of the theory of evolution. Nevertheless, the mechanisms that allow altruism to appear and persist are still incompletely understood. The spatial structure of populations is known to be an important determinant. In both theoretical and experimental studies, much attention has been devoted to populations that are subdivided into discrete groups. Such studies typically imposed the structure and dynamics of the groups by hand. Here, we instead present a simple individual-based model in which organisms spontaneously self-organize into spatially separated colonies that themselves reproduce by binary fission and hence behave as Darwinian entities in their own right. Using software to automatically track the rise and fall of colonies, we are able to apply formal theory on multilevel selection and thus quantify the within- and among-group dynamics. This reveals that individual colonies inevitably succumb to defectors, resulting in within-colony "tragedies of the commons". Even so, altruism persists in the population because more altruistic colonies reproduce more frequently. The emergence of the colonies themselves depends crucially on the length scales of motility, altruism, and competition. This reconfirms the general relevance of these scales for social evolution, but also stresses that their impact can only be understood fully in the light of the emergent eco-evolutionary spatial patterns. The results also demonstrate that emergent spatial population patterns can function as a starting point for transitions of individuality.

Evolution, genetics, and systematics

2017 ◽  
Author(s):  
Francisco J. Ayala ◽  
Camilo J. Cela-Conde
Keyword(s):  
Population Genetics ◽  
Sexual Selection ◽  
Fossil Record ◽  
Life Sciences ◽  
Altruistic Behavior ◽  
Synthetic Theory ◽  
Theory Of Evolution ◽  
Evolution By Natural Selection ◽  
Current Paradigm ◽  
Epigenetic Processes

This chapter starts with the general principles of the theory of evolution by natural selection advanced by Darwin and the Mendelian theory of heredity. Next comes consideration of the “new-Darwinian synthesis” or “synthetic theory,” which integrates both precedents into what has become the current paradigm of the life sciences. Molecular evolution and population genetics follow, including epigenetic processes. Next, special models of selection are considered, such as sexual selection and the models that account for altruistic behavior. After the mechanisms of speciation, the main concepts of systematics are explored, which facilitate understanding of different traits. The chapter finally explores the fundamental concepts of taxonomy and the methods from phenetics to cladistics, that makes it possible to evaluate the diversity of organisms and the methods for dating the fossil record.

Imagining Technology and Environmental Law

2016 ◽  
Author(s):  
Elizabeth Fisher
Keyword(s):  
Potential Role ◽  
Environmental Law ◽  
Environmental Problems ◽  
Limited Resources ◽  
Sociotechnical Imaginaries ◽  
Law And Technology ◽  
Starting Point ◽  
Chemicals Regulation ◽  
The Commons

Understandings of environmental law and technology are often co-produced as part of distinctive sociotechnical imaginaries. This essay explores this phenomenon by showing how Hardin’s famous essay, the ‘Tragedy of the Commons’, is capable of being interpreted in two different ways, which provide divergent visions of the potential role of environmental law and technology in addressing environmental problems. The first, and more popular, interpretation characterizes law and technology as instruments for bringing about shifts in morality in light of limited resources. A different reading of Hardin’s essay portrays law and technology in more constitutive terms. Identifying these different characterizations provides a starting point for a richer and more nuanced debate about the interaction between environmental law and technology. This is illustrated by an example from chemicals regulation.

scholarly journals Staphylococcus aureuscoagulases are exploitable yet stable public goods in clinically relevant conditions

2018 ◽  
Vol 115 (50) ◽  
pp. E11771-E11779 ◽  
Author(s):  
Urvish Trivedi ◽  
Jonas S. Madsen ◽  
Jake Everett ◽  
Cody Fell ◽  
Jakob Russel ◽  
...  
Keyword(s):  
Public Goods ◽  
Social Evolution ◽  
Defense Mechanism ◽  
Critical Role ◽  
Local Population ◽  
Coagulation Cascade ◽  
The Public ◽  
Innate Defense ◽  
The Commons

Coagulation is an innate defense mechanism intended to limit blood loss and trap invading pathogens during infection. However,Staphylococcus aureushas the ability to hijack the coagulation cascade and generate clots via secretion of coagulases. Although manyS. aureushave this characteristic, some do not. The population dynamics regarding this defining trait have yet to be explored. We report here that coagulases are public goods that confer protection against antimicrobials and immune factors within a local population or community, thus promoting growth and virulence. By utilizing variants of a methicillin-resistantS. aureuswe infer that the secretion of coagulases is a cooperative trait, which is subject to exploitation by invading mutants that do not produce the public goods themselves. However, overexploitation, “tragedy of the commons,” does not occur at clinically relevant conditions. Our micrographs indicate this is due to spatial segregation and population viscosity. These findings emphasize the critical role of coagulases in a social evolution context and provide a possible explanation as to why the secretion of these public goods is maintained in mixedS. aureuscommunities.

scholarly journals Kin and group selection are both flawed but useful data analysis tools

2019 ◽  
Author(s):  
jeff smith ◽  
R. Fredrik Inglis
Keyword(s):  
Empirical Research ◽  
Social Evolution ◽  
Multilevel Selection ◽  
Selection Theory ◽  
Fitness Effects ◽  
Data Driven Approach ◽  
Biological Interpretation ◽  
Multilevel Selection Theory ◽  
Microbial Systems ◽  
Analytical Tools

AbstractFor understanding the evolution of social behavior in microbes, mathematical theory can aid empirical research but is often only used as a qualitative heuristic. How to properly formulate social evolution theory has also been contentious. Here we evaluate kin and multilevel selection theory as tools for analyzing microbial data. We reanalyze published datasets that share a common experimental design and evaluate these theories in terms of data visualization, statistical performance, biological interpretation, and quantitative comparison across systems. We find that the canonical formulations of both kin and multilevel selection are almost always poor analytical tools because they use statistical regressions that are poorly specified for the strong selection and nonadditive fitness effects common in microbial systems. Analyzing both individual and group fitness outcomes helps clarify the biology of selection. We also identify analytical practices in empirical research that suggest how theory might better handle the challenges of microbial data. A quantitative, data-driven approach thus shows how kin and multilevel selection theory both have substantial room for improvement as tools for understanding social evolution in all branches of life.

scholarly journals Group Dynamics and Student Participation in a Chinese Setting: Teacher and Observer Perspectives

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
John Harper ◽  
Hui-ju Chen
Keyword(s):  
Classroom Management ◽  
Group Dynamics ◽  
Student Participation ◽  
Chinese Students ◽  
Effective Teacher ◽  
Teacher Student ◽  
Starting Point ◽  
Language Classroom ◽  
Institutional Contexts ◽  
Management Techniques

This article addresses the frequently discussed notion of Chinese students’ supposed reticence and passivity in the English as a Foreign Language classroom. Using the concept of group dynamics as a starting point, it examines teachers’ classroom-management techniques in terms of promoting (or not promoting) active student participation. The study, using a grounded theory of research, analyzed classroom data obtained from class observations and from class filmings and supplemented these data with post-lesson interviews with the four involved teachers. Findings suggested that Chinese students were not necessarily reticent or passive but rather engaged actively when given a learning environment conducive to active engagement. The study pointed to three practical implications for classroom teachers: (1) promoting participation by working toward group cohesion, (2) promoting participation by providing effective teacher-student scaffolding and by providing opportunities for student-student scaffolding, (3) promoting participation by actively replacing textbook materials in order more effectively to offer students adequate support in terms of both language and affect. Acknowledging the fact that different institutional contexts may require different classroom-management techniques, the study calls for further testing of the present findings in other Chinese settings.

Social Evolution versus Sudden Change

2002 ◽  
Author(s):  
David Ehrenfeld
Keyword(s):  
Catholic Church ◽  
Social Evolution ◽  
Sudden Change ◽  
Science And Religion ◽  
Darwinian Evolution ◽  
Theory Of Evolution ◽  
Long Time ◽  
The Mind ◽  
Changes Over Time ◽  
Academy Of Sciences

In an address to the Pontifical Academy of Sciences, meeting at the Vatican on October 22, 1996, Pope John Paul II accepted the theory of evolution, thus bringing to an official end, for the Catholic Church, the most bitter and most persistent of all debates between science and religion. “New knowledge,” John Paul said, “has lead to the recognition of the theory of evolution as more than a hypothesis.” He qualified his statement somewhat by pointing out that there are many readings of evolution, “materialist, reductionist, and [his preference] spiritualist interpretations.” Still, we must not quibble; the Pope has endorsed slow evolutionary change, Darwinian evolution, as the likely way that nature modifies all living creatures, including all human beings. Fashioning us in the image of God, the Pope appears to believe, took a very, very long time. The dust has not yet settled on the great evolution war, nor will it settle soon. A few intelligent scientists are still not convinced that evolutionary theory explains the species richness of our planet and the amazing adaptations, such as eyes, wings, and social behavior, of its in-habitants. There also remain powerful religious orthodoxies that show no sign of giving up the fight for creationist theology. A second war about evolution is now being waged, an invisible, un-publicized struggle between a different set of protagonists; it is a war whose outcome will affect our lives and civilization more directly than the original controversy ever did. The new protagonists are not science and traditional religion; instead, they are the corporate apostles of the religion of progress versus those surviving groups and individuals committed to slow social evolution as a way of life. To understand this other struggle, it is necessary to look at evolution in a broad context that transcends biology. Not just a way of explaining how the camel got her hump or how the elephant got his trunk, the idea of evolution can also be applied to the writing of a play that “evolves” in the mind of the playwright or the “evolution” of treaties, banking systems, and anything else that changes over time in a non random direction.

scholarly journals Kin and multilevel selection in social evolution: a never-ending controversy?

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 776 ◽  
Author(s):  
Jos Kramer ◽  
Joël Meunier
Keyword(s):  
Kin Selection ◽  
Group Selection ◽  
Evolutionary Biology ◽  
Social Evolution ◽  
Selection Process ◽  
Structured Populations ◽  
Multilevel Selection ◽  
Current Debate ◽  
The Relationship ◽  
Shed Light

Kin selection and multilevel selection are two major frameworks in evolutionary biology that aim at explaining the evolution of social behaviors. However, the relationship between these two theories has been plagued by controversy for almost half a century and debates about their relevance and usefulness in explaining social evolution seem to rekindle at regular intervals. Here, we first provide a concise introduction into the kin selection and multilevel selection theories and shed light onto the roots of the controversy surrounding them. We then review two major aspects of the current debate: the presumed formal equivalency of the two theories and the question whether group selection can lead to group adaptation. We conclude by arguing that the two theories can offer complementary approaches to the study of social evolution: kin selection approaches usually focus on the identification of optimal phenotypes and thus on the endresult of a selection process, whereas multilevel selection approaches focus on the ongoing selection process itself. The two theories thus provide different perspectives that might be fruitfully combined to promote our understanding of the evolution in group-structured populations.

scholarly journals Prediction of Tip-Leakage Losses in Axial Turbines

1990 ◽  
Author(s):  
M. I. Yaras ◽  
S. A. Sjolander
Keyword(s):  
Experimental Studies ◽  
Prediction Methods ◽  
Tip Leakage ◽  
Starting Point ◽  
Turbine Cascades ◽  
Axial Turbines ◽  
Improved Model

Existing methods for predicting the tip-leakage losses in turbomachinery are based on a variety assumptions, many of which have not been fully verified experimentally. Recently, several detailed experimental studies in turbine cascades have helped to clarify the physics of the flow and provide data on the evolution of the losses. The paper examines the assumptions underlying the prediction methods in the light of these data. An improved model for the losses is developed, using one of the existing models as the starting point.

Acoustic Speckle: Theory and Experimental Analysis

1979 ◽  
Vol 1 (4) ◽  
pp. 303-324 ◽  
Author(s):  
John G. Abbott ◽  
F. L. Thurstone
Keyword(s):  
Experimental Study ◽  
Experimental Analysis ◽  
Phased Array ◽  
Imaging System ◽  
Experimental Studies ◽  
Laser Speckle ◽  
Speckle Reduction ◽  
Multiple Images ◽  
Starting Point ◽  
Speckle Patterns

A theoretical and experimental study of speckle, as applied to ultrasonic imaging, is presented. The concept of laser speckle is briefly reviewed and is used as a starting point to explain the origin of acoustic speckle. The primary differences between these two phenomena are discussed and are confirmed by experiment. An experimental study of speckle reduction by summation of multiple images is also presented. Several techniques for generating independent speckle patterns for use in image summation schemes are proposed. A phased array, dynamically focused sector imaging system was used in all of the experimental studies reported.

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