Prof. James Griesemer will be giving a talk on “Life cycle models and origins-of-life scenarios: A reproducer perspective”.
Date and Venue: 20th October 2011, at 11:00, Seminar room – Dept of Logic and Philosophy of Science.
Abstract: A key feature of cellular living systems is organization of life trajectories into cycles. A now common view of the minimal organization of living systems — “chemoton” organization (Gánti 1971, 2003) — characterizes living systems in terms of three autocatalytic subsystems: a metabolic subsystem, a template hereditary subsystem, and a membrane boundary subsystem. Szathmáry and colleagues (e.g. Fernando et al. 2005, Fernando and Szathmáry 2009) investigate a variety of “infra-biological” systems that have some but not all components of chemoton organization. One or more of these may have emerged in possible chemical evolutionary routes to a biological protocell (Griesemer and Szathmáry 2010). In this talk, I consider the aim of such work to characterize the space of possible living systems in terms of the reproducer perspective on units of heredity, development and evolution (e.g. Griesemer 2000). I argue that it is important to recognize the role of theoretical perspectives in guiding the ways scientists track phenomena of interest. Different tracking perspectives lead to different evaluations of models and evidence. In origins of life research, replicator-, metabolism-, and boundary-first perspectives involve commitments about what sorts of chemical and molecular variation are worth tracking through life cycles to discover potential units of evolution. These commitments in turn govern choices of resolution in models of life cycles that guide and constrain judgments about important properties of proto-biological systems, such as whether they involve limited vs unlimited heredity or holistic vs modular replication. I offer some reflections on a recent argument by Vasas, Szathmáry and Santos (2010) that certain kinds of systems with “compositional” rather than “alphabetic” hereditary subsystems (e.g. GARD, Lancet and colleagues) cannot sustain fitter types by selection to illustrate the value of the reproducer perspective.