Seminar #64: A Model of Biological Individuation and Its Origins
We are starting up the Life and Mind seminars this term by reading and discussing a paper by Nathaniel Virgo which is based on his PhD thesis.
The meeting will take place next Friday, May 7, at 4pm in Bramber House BH-256.
If you would like a copy of the paper, please contact Nathaniel directly. The title and abstract are as follows:
A Model of Biological Individuation and Its Origins
This paper is concerned with the phenomenon of individuation, the splitting up of living matter into individual cells, organisms and colonies. When an external energy gradient is applied, some non-living physical systems exhibit an analogous phenomenon. We argue that studying the process of individuation in dissipative structures can give us useful insights into the nature of living systems. Our simulation results suggest that feedbacks analogous to those found in ecosystems can help form and maintain the conditions under which individuals occur.
Our simulations use a type of chemical model known as a reaction-diffusion system, which can form patterns in which there are blurred but spatially distinct “spots” of an autocatalytic substance, separated by regions in which no autocatalyst is present. These spots maintain their individuality through a balance between ongoing processes. In this respect they are similar to living organisms, especially when seen from the perspective of the theory of autopoiesis.
Living organisms exist within ecosystems, in which the supply of energy and nutrients is restricted, limiting their populations. We show that applying the same conditions to reaction-diffusion systems makes the formation of individuated patterns more likely: the system’s parameters become “tuned” to the values where individuation occurs.
We demonstrate that this phenomenon can produce individuals in reaction-diffusion systems with a more complex structure than a single spot, and we argue that it is likely to occur in non-equilibrium physical systems of many kinds rather than just reaction-diffusion systems. We speculate about the role that this kind of ecosystem-level negative feedback might have played in the origin of biological individuation.
All welcome! (Please contact Nathaniel for a copy of this paper so that we can discuss it during the seminar).