Towards a Comprehensive Dynamics of Evolution-
Exploring the Interplay of
Selection, Neutrality, Accident, and Function
Organized by
Jim Crutchfield, Santa Fe Institute
and
Peter Schuster, University of Vienna
Sponsored by
The Santa Fe Institute
Synopsis Evolution is currently
addressed at very different levels from paleontology to molecular
biology and even computer science. Common phenomena and common problems
relate the different areas across this wide range. Examples include
stepwise rather than gradual time courses of evolutionary adaptation,
the role of selectively neutral variants in optimization, the
destabilization of evolutionary memory as a function of parameters
(error thresholds), the emergence of dynamical behaviors induced by
finite populations, and the lack of a theory for genotype-phenotype
relations and for emergent functionality. New paradigms and
metaphors---e.g. self-organization, complex adaptive systems, phase
transitions, and stochastic dynamical systems---may help to achieve
progress and, hopefully, a new level of integration in analyzing
such problems.
The workshop will bring together researchers from different
disciplines as well as individuals of conflicting views on open problems
in order to stimulate and provoke multifocused discussions. It is
hoped that a synthesis of conflicting views---such as those of
selectionists, neutralists, and structuralists or those of
macroevolutionists and microevolutionists---will shed new light on
our understanding of evolutionary dynamics. A primary goal is to
help articulate a comprehensive dynamical theory that incorporates on
an equal footing structural constraints, variational attainability,
nonlinear population dynamics, neutrality, function, modularity, and
other constituent aspects of the evolutionary process.
The work portion of the workshop will critically review the
current, sometimes unformalized, proposals and recent theoretical
progress. It will then assess what extensions and new concepts will be
needed to address a number of concrete, but open problems, such as the
following.
- What are the limits of the metaphor of adaptive landscapes in
evolution? When can one employ the geographic metaphor of "landscapes"
rather than the full nonlinear population dynamics?
- How do dynamical natural kinds arise in evolution and how robust
are they to historical contingency?
- What are the roles of energetic and entropic barriers in
evolutionary adaptation? Are episodic evolutionary events common at
all scales?
- Are some classes of self-organization phenomena central to the
evolutionary process? Which kinds of evidence need to be assembled to
better test theories of self-organization?
- How do the developmental dynamics of self-organization guide and
constrain the nonlinear population dynamics of selection and genetic
variation?
- What classes of phenotypic degeneracy lead to neutral genetic
variation? What is the role of neutrality in macroevolution? Is there
a typology of neutral nets and innovation channels?
- Generalized error thresholds: What are the trade-offs and scaling
relationships between genome complexity, rate of genetic variation, and
population size, for example?
- In settings with complicated genotype-to-phenotype mappings, How
can we find the macroscopic coordinates relevant to adaptation
and search during a given evolutionary epoch?
- How do the global state space structures induced by nonlinear
population dynamics interact with the coarse-graining and
stochasticity arising from finite populations?
One useful product of this exercise would be the creation of a number
of tractable theoretical models, designed to capture the interplay of
evolution's underlying features---selection, neutrality, fixation,
accident, genotype-phenotype complexity, and phenotypic function.
Another would be an assessment of which questions are tractable
and timely. It is also hoped that the models and questions would
suggest new experiments and new methods of data collection and
analysis.
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