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Irreversible Processes in Ecological Evolution/Population genetics of low-probability transitions

From Complex Time

January 30, 2019
2:30 pm - 3:30 pm


Stephen Proulx (UCSB)


I will discuss several examples from population genetics and adaptive dynamics where the probability for a transition between “equilibrium” states is very low. These situations can occur when stochastic environmental conditions create scenarios with alternate stable states that can only be invaded by mutations of large effect, for instance in scenarios with overlapping generations and lottery competition. In a similar vein, when mutations of small effect cause intermediate phenotypes with low fitness, transitions can be rare. Another type of transition involves feedback between the environment and the distribution of population phenotypes, for example in terms of the evolution of mating preferences in combination with the evolution of ecological specialization. Yet another scenario occurs when multiple independent mutations are required to cross an “adaptive valley”. This has parallels in ecological theory, for example with the invasion of novel habitats (e.g. zoonotic diseases). I will encourage discussion of how these different concepts and modes of analysis may be extended to situations with eco-evo feedbacks.

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Post-meeting Reflection

Stephen Proulx (UCSB) Link to the source page

My two questions:

1) How can we incorporate analyses of non-equilibrium dynamics *and* be able to make general theory?

2) How often do ecological feedbacks results in bi-stable evolutionary states?

Following up on my first question about non-equilibrium dynamics: We had a discussion of how to analyzed and communicate these kinds of results in publications. It seems that there is a missing set of tools to be able to categorize and communicate these kinds of results.

Pamela Martinez:

One of the ideas here was that frequency dependent selection could lead to coexistence, but also that this coexistence was complicated by environmental variability. The model fitting approach involved modeling both process and observation error, and some of the results were consistent with relatively constant total levels of infection even while reported cases could still vary.

Robert Marsland:

Some of what I was particularly interested in from this talk was liking the May type stability analysis to some sets of more mechanistic models. It was really interested in the possibility that the transition between communities that allowed as many species as niche to coexist and as the noise level goes up then the system transitions to maintaining only half the species.

Reference Material

I uploaded a paper by Alan Hastings and others on transient phenomena in ecology, published in Science as a review article.

I uploaded my paper on the stochastic lottery model that shows transitions between two different population states "What can Invasion Analyses Tell us about Evolution under Stochasticity in Finite Populations?". This paper develops an adaptive dynamics model for evolution of phenotype under a fecundity-survivorship trade off.

I posted a paper "Indirect genetic effects clarify how traits can evolve even when fitness does not" that relates to some of the discussion about interactions between individuals and the regulating factors that cause feedbacks and may themselves be evolving populations.

Title Author name Source name Year Citation count From Scopus. Refreshed every 5 days. Page views Related file
Transient phenomena in ecology Alan Hastings, Karen C. Abbott, Kim Cuddington, Tessa Francis, Gabriel Gellner, Ying Cheng Lai, Andrew Morozov, Sergei Petrovskii, Katherine Scranton, Mary Lou Zeeman Science 2018 128 2
Indirect genetic effects clarify how traits can evolve even when fitness does not 1930 0 4
What can Invasion Analyses Tell us about Evolution under Stochasticity in Finite Populations ? Selection 2001 0 0