Natural selection. III. Selection versus transmission and the levels of selection

George Williams defined an evolutionary unit as hereditary information for which the selection bias between competing units dominates the informational decay caused by imperfect transmission. In this article, I extend Williams' approach to show that the ratio of selection bias to transmission bias provides a unifying framework for diverse biological problems. Specific examples include Haldane and Lande's mutation-selection balance, Eigen's error threshold and quasispecies, Van Valen's clade selection, Price's multilevel formulation of group selection, Szathmary and Demeter's evolutionary origin of primitive cells, Levin and Bull's short-sighted evolution of HIV virulence, Frank's timescale analysis of microbial metabolism, and Maynard Smith and Szathmary's major transitions in evolution. The insights from these diverse applications lead to a deeper understanding of kin selection, group selection, multilevel evolutionary analysis, and the philosophical problems of evolutionary units and individuality

Promotion of Cooperation by Selective Group Extinction

Multilevel selection is an important organizing principle that crucially underlies evolutionary processes from the emergence of cells to eusociality and the economics of nations. Previous studies on multilevel selection assumed that the effective higher-level selection emerges from lower-level reproduction. This leads to selection among groups, although only individuals reproduce. We introduce selective group extinction, where groups die with a probability inversely proportional to their group fitness. When accounting for this the critical benefit-to-cost ratio is substantially lowered. Because in game theory and evolutionary dynamics the degree of cooperation crucially depends on this ratio above which cooperation emerges previous studies may have substantially underestimated the establishment and maintenance of cooperation.Comment: Accepted for publication in New Journal of Physic

Making the most of clade selection

Clade selection is unpopular with philosophers who otherwise accept multilevel selection theory. Clades cannot reproduce, and reproduction is widely thought necessary for evolution by natural selection, especially of complex adaptations. Using microbial evolutionary processes as heuristics, I argue contrariwise, that (1) clade growth (proliferation of contained species) substitutes for clade reproduction in the evolution of complex adaptation, (2) clade-level properties favoring persistence – species richness, dispersal, divergence, and possibly intraclade cooperation – are not collapsible into species-level traits, (3) such properties can be maintained by selection on clades, and (4) clade selection extends the explanatory power of the theory of evolution

Nonresponse in the Belgian fertility and family survey.

Combining response data from the Belgian Fertility and Family Survey with individual level and municipality level data from the 1991 Census for both nonrespondents and respondents, multilevel logistic regression models for contact and cooperation propensity are estimated. The covariates introduced are a selection of indirect features out of the researcher control only. Contrary to previous research, Socio Economic Status is found to be positively related to cooperation. Another unexpected result is the absence of any considerable impact of ecological correlates such as urbanicity.Cooperation; Data; Design; Fertility and family survey; Logistic regression; Mixture experiment; Model; Models; Multilevel analysis; Nonrespons; Optimal; Optimal design; Process variables; Processes; Qualitative variables; Selection; Split-plot experiment; Variables;

Multilevel selection models using gllamm

Models for handling sample selection or informative missingness have been developed for both cross sectional and longitudinal or panel data. For cross sectional data, Heckman (1979) suggested a joint model for the response and sample selection processes where the disturbances of the processes are correlated. For longitudinal data, Hausman and Wise (1979) and Diggle and Kenward (1994) developed a model in which the continuous response (observed or unobserved), and possibly the lagged response, is a predictor of attrition or dropout. The Heckman model can be estimated using the heckman command in Stata and the Diggle-Kenward model is available in the Oswald package running in S-PLUS. Both models can also be estimated using gllamm with the advantage that the following three generalisations are possible. First, the models can be extended to multilevel settings where there may be unobserved heterogeneity between the clusters at the different levels in both the substantive and selection processes and where selection may operate at several levels. Second, the Heckman model can be modified for non-normal response processes. Third, both the Heckman and Diggle-Kenward models can be extended to situations where the substantive response is a latent variable measured by a number of indicators. I will show how the standard Heckman and Diggle-Kenward models are estimated in gllamm and give a examples of all three types of generalisation of these standard models. The research was carried out jointly with Anders Skrondal and Andrew Pickles.

An international multilevel competition policy system

This paper develops a proposal for an international multilevel competition policy system, which draws on the insights of the analysis of multilevel systems of institutions. In doing so, it targets to contribute to bridge a gap in the current world economic order, i.e. the supranational governance of private international restrictions to market competition. Such a governance can effectively be designed against the background of a combination of the well-known nondiscrimination principle and a lead jurisdiction model. Put very briefly, competition policy on the global level restricts itself to the selection and appointment of appropriate lead jurisdictions for concrete cross-border antitrust cases, while the substantive treatment remains within the competence of the existing national and regional-supranational antitrust regimes. --international competition policy,multilevel systems,international governance,economics of federalism,international economic order,international antitrust

How to Measure Group Selection in Real-world Populations

Multilevel selection and the evolution of cooperation are fundamental to the formation of higher-level organisation and the evolution of biocomplexity, but such notions are controversial and poorly understood in natural populations. The theoretic principles of group selection are well developed in idealised models where a population is neatly divided into multiple semi-isolated sub-populations. But since such models can be explained by individual selection given the localised frequency-dependent effects involved, some argue that the group selection concepts offered are, even in the idealised case, redundant and that in natural conditions where groups are not well-defined that a group selection framework is entirely inapplicable. This does not necessarily mean, however, that a natural population is not subject to some interesting localised frequency-dependent effects – but how could we formally quantify this under realistic conditions? Here we focus on the presence of a Simpson’s Paradox where, although the local proportion of cooperators decreases at all locations, the global proportion of cooperators increases. We illustrate this principle in a simple individual-based model of bacterial biofilm growth and discuss various complicating factors in moving from theory to practice of measuring group selection

Fitting aerodynamic forces in the Laplace domain: An application of a nonlinear nongradient technique to multilevel constrained optimization

A technique which employs both linear and nonlinear methods in a multilevel optimization structure to best approximate generalized unsteady aerodynamic forces for arbitrary motion is described. Optimum selection of free parameters is made in a rational function approximation of the aerodynamic forces in the Laplace domain such that a best fit is obtained, in a least squares sense, to tabular data for purely oscillatory motion. The multilevel structure and the corresponding formulation of the objective models are presented which separate the reduction of the fit error into linear and nonlinear problems, thus enabling the use of linear methods where practical. Certain equality and inequality constraints that may be imposed are identified; a brief description of the nongradient, nonlinear optimizer which is used is given; and results which illustrate application of the method are presented