Online research in philosophy

During the last two decades the role of quantitative genetics in evolutionary theory has expanded considerably. Quantitative genetic-based models addressing long term phenotypic evolution, evolution in multiple environments (phenotypic plasticity) and evolution of ontogenies (developmental trajectories) have been proposed. Yet, the mathematical foundations of quantitative genetics were laid with a very different set of problems in mind (mostly the prediction of short term responses to artificial selection), and at a time in which any details of the genetic machinery were virtually (...) unknown. In this paper we discuss what a model is in population biology, and what kind of model we need in order to address the complexities of phenotypic evolution. We review the assumptions of quantitative genetics and its most recent accomplishments, together with the limitations that such assumptions impose on the modelling of some aspects of phenotypic evolution. We also discuss three alternative appr oaches to the theoretical description of evolutionary trajectories (nonlinear dynamics, complexity theory and optimization theory), and their respective advantages and limitations. We conclude by calling for a new theoretical synthesis, including quantitative genetics and not necessarily limited to the other approaches here discussed. (shrink)

A response to Via about the existence (or not) and role of plasticity genes in evolution.

A discussion of plasticity genes and the genetic architecture of gene-environment interactions.

In addition to considerable debate in the recent evolutionary literature about the limits of the Modern Synthesis of the 1930s and 1940s, there has also been theoretical and empirical interest in a variety of new and not so new concepts such as phenotypic plasticity, genetic assimilation and phenotypic accommodation. Here we consider examples of the arguments and counter- arguments that have shaped this discussion. We suggest that much of the controversy hinges on several misunderstandings, including unwarranted fears of a general (...) attempt at overthrowing the Modern Synthesis paradigm, and some fundamental conceptual confusion about the proper roles of phenotypic plasticity and natural selection within evolutionary theory. (shrink)

An exploration of the nexus between ecology, evolutionary biology and molecular biology, via the concept of phenotypic plasticity.

The concept of Developmental Norm of Reaction is explored as a nexus between allometry, ontogeny, and phenotypic plasticity.

Phenotypic Evolution explicitly recognizes organisms as complex genetic-epigenetic systems developing in response to changing internal and external environments. As a key to a better understanding of how phenotypes evolve, the authors have developed a framework that centers on the concept of the Developmental Reaction Norm. This encompasses their views: (1) that organisms are better considered as integrated units than as disconnected parts (allometry and phenotypic integration); (2) that an understanding of ontogeny is vital for evaluating evolution of adult forms (ontogenetic (...) trajectories, epigenetics, and constraints); and (3) that environmental heterogeneity is ubiquitous and must be acknowledged for its pervasive role in phenotypic expression. (shrink)

In the fall of 1990 I had just began my doc- toral studies at the University of Connecticut. Freshly arrived from Italy, I came to the United States to work with Carl Schlichting on something to do with phenotypic plastic- ity. I spent most of that semester discussing with other graduate students what I thought was a momentous paper by Mary Jane West- Eberhard (1989) in the Annual Review of Ecol- ogy and Systematics. That paper, entitled Phe- notypic (...) Plasticity and the Origins of Diversity, was a (quite lengthy) forerunner of the (also quite bulky) book I am reviewing now. Like the paper, this volume has the potential to be momentous in the development of our ideas on phenotypic evolution. (shrink)

There have been rumblings for some time to the effect that the neo-darwinian synthesis of the early twentieth century is incomplete and due for a major revision. In the past decade, several authors have written books to articu- late this feeling and to begin the move towards a second synthesis. David Rollo, in his book Phenotypes (Kluwer, 1994), was among the first to attempt to bring the focus back to the problems posed by phenotypic evolution. In Phenotypic Evolution (Sinauer, 1998), (...) Carl Schlichting and I framed the debate in terms of the integration of development, environ- ment and genetics by articulating the concept of “developmental reaction norms”. (shrink)