AAAS SESSION ON HOW SYMBIOSIS, HORIZONTAL GENE TRANSFER AND VIROLUTION CALL FOR AN EXTENDED SYNTHESIS
Organized by Nathalie Gontier and Moderated by Luís Correia
Saturday, February 16, 2013: 1:30 PM-4:30 PM
Room 308 (Hynes Convention Center)
Comparative (meta)genomics have made us realize that horizontal evolutionary phenomena have been vastly underestimated. The serial endosymbiogenetic theory has proven the symbiogenetic origin of mitochondria and plastids. Symbiosis studies further prove that symbiotic unions continue to be relevant to understand evolution. Symbiotic unions can become transmitted vertically, from parent to offspring, through means other than germ-line transmission. There currently also exists abundant evidence for horizontal or lateral gene transfer in microorganisms. And evidence is piling up that Lateral Gene Transfer also occurs abundantly in eukaryotic organisms. Gene sequencing techniques further prove that also viruses contribute to the evolution of life. They might have played a crucial role in the development of the genetic code, and viral genes are abundantly present in non-coding DNA regions that used to be designated as "Junk DNA". Such horizontal evolutionary phenomena pose major challenges to the Modern Synthesis that makes a clear distinction between ontogeny and phylogeny, emphasizes germ-line transmission, and that defines speciation as a splitting or "branching off" process. Horizontal evolutionary studies have consequences for how we define units of evolution, biological individuals, how we draw the tree of life, and how we conceptualize speciation.
SYMBIOSIS AS A DRIVING FORCE OF EVOLUTION
Vice-president of the International Symbiosis Society, Boston University
Symbiosis often results in the rapid acquisition of potentially favorable traits and can be seen as a primary source of novelty upon which natural selection can express. Indeed, individuals evolving into communities appears to dominate the biosphere. A new symbiosis definition that implies its evolutionary strength is proposed.
THE IMPORTANCE OF HORIZONTAL GENE TRANSFER IN THE EVOLUTION OF LIFE
Institut für Molekulare Evolution, Heinrich-Heine-Universität, Germany
In micro-organisms, lateral or horizontal gene transfer occurs through processes such as bacterial conjugation, transformation, and transduction. Such horizontal transfers are often not depicted in tree of life imagery. My talk will focus on how phylogenomic network models enable the modeling of lateral gene transfer in a variety of taxa.
HOW RESEARCH ON SYMBIOSIS SHOULD TRANSFORM OUR UNDERSTANDING OF ADAPTION
Département de philosophie, Université de Montréal
Symbiosis shows the limitations of any attempt to reduce the process of adaptation to within lineage change. Symbionts are in many respects modular traits that can be passed on vertically or horizontally in ways that clearly affect the evolutionary success of the communities they are involved in. Symbiosis, as a process of generating new cohesive biological units, shows the limitation of focusing the study of adaptation exclusively on continuous cohesive genetic units of same species organisms.
THE IMPORTANCE OF HORIZONTAL EVOLUTION FOR THE SOCIOCULTURAL SCIENCES
Applied Evolutionary Epistemology Lab, Centre for Philosophy of Science, University of Lisbon
Universal selectionism is used to designate a shared theoretical framework and shared methodological toolkit (a universal language) to comprehend and model vertical biological and sociocultural evolution. In similar vein, symbiogenesis can be universalized to designate a shared theoretical framework and methodological toolkit to comprehend and model horizontal sociocultural evolutionary processes that occur through processes of cultural diffusion, cultural contact, or language mixing.
MODELS OF MULTI-SPECIES EVOLUTION IN NATURAL AND ARTIFICIAL SOCIETIES
Laboratory of Agent Modeling, University of Lisbon
Computational models can provide an effective tool to model multi-species evolution: parasitic, mutualist, cooperative and symbiogenetic interactions. The talk will review several such models of co-evolution, and show how they can model both natural settings and artificial scenarios as well as how they can be used for solving engineering problems.
Organized by Nathalie Gontier and Emanuele Serrelli and Moderated by Emanuele Serrelli
Sunday, February 17, 2013: 8:30 AM-11:30 AM
Room 203 (Hynes Convention Center)
When Eldredge and Gould formulated punctuated equilibria theory, they put several macroevolutionary phenomena on the agenda that were not addressed by the early population geneticists and the founders of the Modern Synthesis. Their theory provides alternative scientific interpretations for the mode and tempo of evolution. Occurring gaps in the fossil record, or the lack of evidence for the existence of intermediate species, are understood as real. And some (living) fossils don't appear to undergo any significant evolutionary change for millions of years, which necessitates the study of stasis. Acknowledging that evolution can occur faster or slower than predicted by Neodarwinians has consequences for how we define species, and what the levels of evolution are. Macroevolutionary studies provide different species concepts, and argue that evolution can occur at levels higher than the pheno- or genotype. Today, multiple scholars investigate the causes of evolutionary stasis as well as punctuations, macroevolutionary trends, and how evolution occurs at different hierarchies. In recent years, evidence for macroevolution is also provided from within the field of molecular biology, and the pattern of punceq has been proven to be present in neontological and even sociocultural evolutionary phenomena. The session will examine how macroevolutionary studies call for an extension of the Modern Synthesis, and which methodologies and techniques enable the study of macroevolutionary events.
STEPHEN GOULD'S HIERARCHICAL ALTERNATIVE TO NEODARWINISM: A HISTORICAL PERSPECTIVE
University of North Carolina Wilmington
This paper will examine the historical significance of Stephen Jay Gould's hierarchical "expansion" of Darwinism, focusing on the development of these ideas during the late 1970s and early 1980s as part of a larger program to establish "paleobiology" as an autonomous subdiscipline of evolutionary biology. The talk will explore the success of Gould's program, and the extent to which paleobiology has become oriented around questions of macroevolutionary hierarchy as a result.
THE EVOLUTION OF EVOLUTION: CHANGING DYNAMICS IN MACROEVOLUTION
Douglas H. Erwin
Smithsonian Institution, Washington, DC
Most conceptions of macroevolution have involved a process that does not vary over time, with differences in the origination of new clades, or higher taxa controlled by ecology. Recent insights from evo-devo suggest a need to revisit this view and explore the non-uniformitarian aspects of macroevolution.
CONTINGENCY AND THE EXPLANATION OF MACROEVOLUTIONARY TRENDS
Department of Philosophy, Connecticut College
Once scientists identify a macroevolutionary trend, they typically ask whether it is passive and generated by a random walk, or driven and generated by a directional bias in the state space. My talk will explore the connection between the passive/driven distinction and questions about the contingency of evolutionary history. I will suggest that the historical processes that generate passive trends exhibit greater contingency, whereas those that generate driven trends exhibit less contingency.
COMPLEXITY AND LIMITS TO CHANGE
IceLab and Department for Ecology & Environmental Science, Umeå University, Sweden
Biological organisms are constantly under selection to improve the efficiency with which they function, and a common way to achieve this is via improved organization of its body, that is, complexity. This complexity, however, may make it harder for populations and species to adapt to a changing environment, and it might explain stasis. In my talk I ask whether this is the reason most species go extinct, and to what extent the same principle applies to human organizations.
PUNCTUATED EQUILIBRIA: A UNIVERSAL PATTERN IN LIFE AND CULTURE
Nathalie Gontier & Emanuele Serrelli
Applied Evolutionary Epistemology Lab, Centre for Philosophy of Science, University of Lisbon, Portugal
Punctuated equilibria theory describes a pattern of evolution: long periods of stasis are intermitted by short periods of rapid change. This pattern, first observed in the fossil record, appears to be universal. It has been detected in extant species on a molecular level, in the cultural dispersal of artifacts, and in the historical dispersal of certain language families. We will investigate which mechanisms underlie the pattern of punctuated equilibria in both biological and cultural evolution.
EXPANDING THE ROLE OF BIOGEOGRAPHY AND NICHE EVOLUTION IN MACROEVOLUTIONARY THEORY
Alycia L. Stigall
Ohio University, Athens, USA
Understanding the processes that control speciation is critical to any modern macroevolutionary synthesis. A variety of theoretical constructs have been proposed to explain various differential speciation patterns observed in the fossil record, such as higher rates of speciation among stenotopic vs. eurytopic species. Most of these explanations, however, rely on only one or two explanatory variables and may be overly simplistic. Developing a more complete understanding of speciation processes requires a broader synthesis of multiple explanatory factors including the role of external factors such as climatic and tectonic, impact of ecosystem-level processes, relative niche breadth, and relative stability of species’ niches during environmental change (biotic and abiotic). This paper explores the relationship between biogeography, ecological niches, and speciation in a series of case studies focusing on the Late Ordovician and Late Devonian shallow marine brachiopods and bivalves and Neogene horses of North America.
Copyright AppEEL 2012