Turbulence, symmetry, and the role of organism shape in perception: Fundamental Laws of Biology (3.3.1)
Abstract
The goal of the proposed work is to describe the effect of symmetry-breaking morphology on how organisms perceive the world while suspended in a turbulent flow. The three components of the research are laboratory measurements, a stochastic model, and the exploration of how perception depends on organism shape and symmetry. Laboratory measurements will use unique and powerful techniques that PI Variano developed and used previously for measuring axisymmetric objects in turbulence. Custom- fabricated transparent particles will be constructed in a wide variety of fundamental and biologically-inspired shapes. Particle motion will be measured along Lagrangian trajectories, revealing the distribution of particle rotation and the scales at which particles filter the surrounding flow. The method is robust and quick, so that a large number of different shapes can be investigated in a short amount of time, revealing how different features affect the passive motion of particles in turbulence. A stochastic model will be created that incorporates the laboratory results and leverages recent advances in modeling the turbulent velocity gradient tensor. The model will predict the motion of particles as a function of size and shape. The shape-space will contain key features that may confer selective advantage on organisms, including fins, tails, dorsal-ventral differentiation, and anterior-posterior differentiation. The stochastic model will be used to test the following hypothesis: bilateral symmetry represents a maximum in Òperceptive stability.Ó Perceptive stability is the degree to which an organismÕs sensory system is able to engage with a single environmental cue. This hypothesis is formulated to apply to all environments, and the proposed work will test it in the specific context of turbulent flows. In such a context, the hypothesis is that bilateral symmetry minimizes fast rotations, compared to cases of spherical symmetry, radial symmetry, and complete asymmetry. The proposed work will address for the first time the biomechanical impact of organism shape on life in turbulent environments. These results will provide insight into the evolutionary history of animal life; the split between bilateral and radial organisms is one of the fundamental steps in early evolution, and is a possible reason for the Cambrian explosion of biodiversity. The results can also contribute to Òtrait-basedÓ ecology, in which trophic interactions are described in terms of how organisms experience the environment. Overall, the hypothesis to be considered herein is a potential fundamental law of biology, of basic interest to the field. The results could also be used practically to accelerate the field of vehicle design, by providing guidance on vehicle shape and location of sensors. The schedule of the work is as follows. Year 1 will include 10 months of continuous data collection, with 2 weeks spent on each of 20 particle shapes. Year 1 will also include analytic and numerical construction of the model. Year 2 will be focused on specifying the modelÕs free parameters using the laboratory data. During year 2, a second campaign of data collection will focus closely on 8 additional particle shapes, measured for 5-6 weeks each (11 months total). Year 3 will continue the second data collection campaign, with 4 more shapes measured for 5-6 weeks each (6 months total). The main focus of year 3 will be to use the numerical model to evaluate the hypothesis. Throughout all three years, results will be shared with the community; extra effort will be made during years 2 and 3, to integrate the results in the biological literature so that these new biomechanical results can support the existing genomic methodology.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 04, 2018
- Source ID
- W911NF1610284
Entities
People
- Evan Variano
Organizations
- Army Contracting Command
- United States Army
- University of California, Berkeley