This proposal will develop the theory of "flocking": the collective, coherent motion of large numbers of organisms or biomolecules. This ubiquitous biological phenomenon occurs for organisms (flocks of birds, schools of fish), cells (collections of swimming bacteria, migration of cancer cells in tumors) and subcellular molecules (long molecules such as microtubules and actin filaments involved in the operation and reproduction of cells). The project will apply ideas originally developed for fluid dynamics (air flow over airplane wings, weather forecasting, and plumbing) to flocks.
This project will extend that approach to investigating what holds flocks together at their boundaries; to study the effects of birth and death of organisms or molecules (which is very important for molecules inside living cells, which are constantly created and destroyed as they move), and to compare predictions of the theory with experiments on diverse biological systems. Among these are experiments on the mitotic spindle, a spindle-shaped structure of long, rigid molecules called microtubules that forms inside cells when they divide, and which acts to separate the chromosomes into the two daughter cells. This work will also address flocks of organisms (such as birds and fish) to study their shapes and how those shapes fluctuate as the flock moves.
This work is strongly interdisciplinary and will advance condensed-matter physics, molecular biophysics, cellular biology, fluid mechanics, organismal biology, and medicine (through a deeper understanding of processes that impact cancer cell migration and wound healing). The proposed work will integrate research and learning by involving students and postdoctoral fellows in the research, and through the development of new course materials at CU-Boulder and the University of Oregon.