A number of recent biologists have used multi-level selection theory to help explain the major transitions in evolution. I argue that in doing so, they have shifted from a ‘synchronic’ to a ‘diachronic’ formulation of the levels of selection question. The implications of this shift in perspective are explored, in relation to an ambiguity in the meaning of multi-level selection. Though the ambiguity is well-known, it has never before been discussed in the context of the major transitions.

rom Flesh Gordon to Alex in Wonderland , title parodies have been a stock-in-trade of low comedy. We may not anticipate a tactical similarity between the mayhem of Mad magazine's movie reviews and the titles of major scientific works, yet two important nineteenth-century critiques of Darwin parodied his most famous phrases in their headings.

For a number of years, the debate in evolutionary biology over the ’levels of selection’ has attracted intense interest from philosophers of science. The main question concerns the level of the biological hierarchy at which natural selection occurs. Does selection act on organisms, genes, groups, colonies, demes, species, or some combination of these? According to traditional Darwinian theory the answer is the organism -- it is the differential survival and reproduction of individual organisms that drives the evolutionary process. But there (...) are alternative views too, including pluralist views which say that the choice between different levels of selection is often a matter of perspective, not empirical fact. (shrink)

The fitness of any evolutionary unit can be understood in terms of its two basic components: fecundity (reproduction) and viability (survival). Trade-offs between these fitness components drive the evolution of life-history traits in extant multicellular organisms. We argue that these trade-offs gain special significance during the transition from unicellular to multicellular life. In particular, the evolution of germ–soma specialization and the emergence of individuality at the cell group (or organism) level are also consequences of trade-offs between the two basic fitness (...) components, or so we argue using a multilevel selection approach. During the origin of multicellularity, we study how the group trade-offs between viability and fecundity are initially determined by the cell level trade-offs, but as the transition proceeds, the fitness trade-offs at the group level depart from those at the cell level. We predict that these trade-offs begin with concave curvature in single-celled organisms but become increasingly convex as group size increases in multicellular organisms. We argue that the increasingly convex curvature of the trade-off function is driven by the cost of reproduction which increases as group size increases. We consider aspects of the biology of the volvocine green algae – which contain both unicellular and multicellular members – to illustrate the principles and conclusions discussed. (shrink)

This book reviews some of life’s history. It suggests that one crucial feature of John Maynard Smith and Eörs Szathmáry’s The Major Transitions in Evolution is that it has a dynamic approach. In The Major Transitions in Evolution, Maynard Smith and Szathmáry bought a much more dynamic model to debates about the history of life. This book also shows that in the decade and more that has followed, the legacy of Maynard Smith and Szathmáry has been developed in important ways.

Division of labor and its associated phenomena have been viewed as prime examples of group-level adaptations. However, the adaptations are the result of the process of evolution by natural selection and thus require that groups of insects once existed and competed for reproduction, some of which had a heritable division of labor while others did not. We present models, based on those of Kauffman (1984) that demonstrate how division of labor may occur spontaneously among groups of mutually tolerant individuals. We (...) propose that division of labor itself is not a product of natural selection but instead is a "typical" outcome of self organization. (shrink)

The paper provides a new characterization of the concepts of necessity and contingency as they should be used in the historical context. The idea is that contingency (necessity) increases in direct (reverse) proportion to sensitivity to initial conditions. The merits of this suggestion are that it avoids the conflation of causality and necessity (or contingency and chance), that it enables the bracketing of the problem of free will while maintaining the concept of human action making a difference, that it sanctions (...) tendencies without recourse to teleology, and that it recasts the controversy between historicists and anti‐historicists in less dogmatic language. (shrink)

This paper presents a modified random network model to illustrate how groups can form in the absence of evolutionary forces, assuming groups are collections of entities at any level of organization. This model is inspired by the Zero Force Evolutionary Law, which states that there is always a tendency for diversity and complexity to increase in any evolutionary system containing variation and heredity. That is, in the absence of evolutionary forces, the expectation is a continual increase in diversity and complexity (...) at any level of biological hierarchy. I show that, when modeled, this expectation of increasing variation results not only in the formation of groups, but also in a higher probability of group formation than is found in a model that is purely random. (shrink)