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| Wednesday, January 3 — Session 2: Animal Locomotion and Behavior - Ecology |
| 3:40-4:20 pm |
Iain Couzin
University of Oxford
Collective Animal Behaviour
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| 4:20-4:40 pm |
Silas Alben
Harvard University
Email: alben@deas.harvard.edu
authors: Silas Alben, Michael Shelley, Peter Madden, George Lauder
Fin ray design and use in fish swimming
Fish fins have evolved over millions of years in a convergent fashion, leading to a highly-intricate fin-ray structure that is found in half of all fish species. This fin ray presumably arose for reasons of efficient hydrodynamic interaction. I will present a linear elasticity model of the fin ray, based on the physical picture of the ray which has emerged from past experiments. By comparing the model with recent experiments performed in the Lauder Lab in Harvard's Biology department, we find that the model helps to understand some of the fundamental properties of fin rays. I will also present some recent results from a fully-coupled fin-fluid model, which combines a model for flexible bodies in a fluid flow with the dynamics of vortex sheets. |
| 4:40-5 pm |
Timothy Halpin-Healy
Physics Department, Barnard College, Columbia University
Email: healy@phys.columbia.edu
The Dynamics of Conformity & Dissent
Nature is ripe with dynamical aggregation phenomena, in which an initially homogeneous collection of weakly interacting particles fragment, disperse, \& coalesce. Condensation and droplet formation is, of course, a well-known example in physics, galaxy formation and clustering another. The formation of swarms, schools, herds, or even the flocking of birds provide compelling zoological illustrations. Rich stochastic behavior, as well as phase transition phenomena, are evident in different evolutionary minority (e.g., El Farol Bar), public goods, and other societal selection games, such as the Seceder Model,* which introduces a novel dynamical frustration via the competing tendencies to be distinct, yet part of the group. The Seceder Model reveals that an iterative microscopic rule favoring dissent, yet permitting conformity, cannot only lead to self-segregation \& the genesis of distinct groups, but also yields an abundant diversity of cluster-forming dynamics. In this talk, we will discuss population fragmentation, ideological symmetry-breaking and nonlinear group dynamics characteristic of this intriguing model. Phys. Rev. Lett. 90 258103* \& 238701, 91 028701. |
| 5-5:20 pm |
Linda Moniz
Trinity University, Washington
Email: MonizL@trinitydc.edu
author: Linda Moniz, Trinity University, James D. Nichols, US Geological Survey, Patuxent Wildlife Research Center, Jonathan M. Nichols , Naval Research Laboratory
Mapping the Information Landscape: Peaks and Valleys for Ecological Monitoring
We investigate previously unreported phenomena that have significant impact on the design of surveillance monitoring programs for ecological systems. Ecological monitoring practitioners have long recongnized that different species are differentially informative of a systems' dynamics, as codified in the well-know concept of indicator or keystone species. Using a novel combination of techniques from nonlinear dynamics, we described marked variation among spatial sites in information content, with respect to dynamics in the entire region. Using examples from both a predator-prey system and verified water-level data from a NOS/NOAA montoring program, we present evidence that these phenomena are widespread and design of surveillance monitoring programs should reflect knowledge of their existence. |
| 5:20-6 pm |
Anette (Peko) Hosoi
Massachustts Institute of Technology
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