Simon A. Levin
(Princeton University)

Mathématiques de la planète Terre 2013 / Mathematics of Planet Earth 2013

"Collective phenomena, collective motion, and collective action in ecological systems"

Fundamental questions in basic and applied ecology alike involve complex adaptive systems, in which localized interactions among individual agents give rise to emergent patterns that feed back to affect individual behavior.   In such systems, a central challenge is to scale from the “microscopic” to the “macroscopic, ” in order to understand the emergence of collective phenomena, the potential for critical transitions, and the ecological and evolutionary conflicts between levels of organization.  This lecture will explore some specific examples, from universality in bacterial pattern formation to collective motion and collective decision-making in animal groups.  It also will  suggest that studies of emergence, scaling and critical transitions in physical systems can inform the analysis of similar phenomena in ecological systems, while raising new challenges for theory.

DATE: Mercredi 17 juillet 2013, 16h00 / Wednesday, July 17, 2013, 4:00 pm


LIEU: Centre de recherches mathématiques
Pavillon André-Aisenstadt
Université de Montréal
Salle / Room 6214





Conférence dans le cadre de l'atelier "Biodiversité dans un monde en mouvement"
Lecture at the Workshop on Biodiversity in a Changing World

DATE: Mardi 23 juillet 2013, 14h00 / Tuesday, July 23, 2013, 2:00 pm

"Evolutionary perspectives on discounting, public goods and collective behavior"

Ecological and economic systems are alike in that individual agents compete for limited resources, evolve their behaviors in response to interactions with others, and form exploitative as well as cooperative interactions as a result.  In these complex adaptive systems, macroscopic properties like the flow patterns of resources like nutrients and capital emerge from large numbers of microscopic interactions, and feed back to affect individual behaviors.  Contagion can lead to critical transitions from one basin of attraction to another, as for example with eutrophication, desertification, pest outbreaks, and market collapses.  In both sorts of systems, evolution of one type or another leads to the differentiation of roles and the emergence of system organization, but with no guarantee of robustness.  It is crucial to understand how evolutionary forces have shaped individual behaviors in the face of uncertainty.  In this talk, I will explore the common features of these systems, especially as they involve the evolution of intragenerational and intergenerational resource allocation and the evolution of cooperation in dealing with public goods, common pool resources and collective movement. I will describe examples from bacteria and slime molds to vertebrate groups to insurance arrangements in human societies.

LIEU: Centre de recherches mathématiques
Pavillon André-Aisenstadt
Université de Montréal
Salle / Room 6214




Conférence s'adressant à un large auditoire
Suitable for a general audience

DATE : Jeudi 25 juillet 2013, 16h30 / Thursday, July 25, 2013, 4:30 pm

"The challenge of sustainability and the promise of mathematics"

The continual increase in the human population, magnified by increasing per capita demands on Earth's limited resources, raises the urgent mandate of understanding the degree to which these patterns are sustainable. The scientific challenges posed by this simply stated goal are enormous; mathematics provides a common language and a way to cross disciplines and cross scales. What measures of human welfare should be at the core of definitions of sustainability, and how do we discount the future and deal with problems of intragenerational and inter-generational equity? How do environmental and socioeconomic systems become organized as complex adaptive systems, and what are the implications for dealing with public goods at scales from the local to the global? How does the increasing interconnectedness of natural and human systems affect us, and what are the implications for management? What is the role of social norms, and how do we achieve cooperation at the global level? Mathematical tools help in understanding the collective dynamics of systems from bacterial biofilms to bird flocks and fish schools to ecosystems and the biosphere, and the emergent features that support life on the planet. They also provide ways to resolve the game-theoretic challenges of achieving cooperation among individuals and among nations in providing for our common future.

LIEU: Centre de recherches mathématiques
Pavillon André-Aisenstadt
Université de Montréal
Salle / Room 1360

Une réception suivra la conférence au Salon Maurice-L'abbé, Pavillon André-Aisenstadt (Salle 6245).
A reception will follow at the Salon Maurice-L'abbé, Pavillon André-Aisenstadt (Room 6245).