Chemical Engineering Seminar

Abstract: Single-celled marine organisms, whether solitary or colonial, offer a valuable window into major evolutionary transitions, including the rise of eukaryotes and the shift to multicellularity. Here, we investigate the role of flow physics in these important transitions using ciliates, a clade of single-celled eukaryotes that either swim or attach and generate feeding currents to capture prey. Combining mechanistic models with biological data, we show that nutrient transport drives functional design of single-celled ciliates, wherein cells optimize their feeding efficiency by designating a specific portion of the cell surface as a ‘mouth' and varying their cilia coverage by life strategy -- motile or sessile. In colonial living, an important step towards multicellularity, we demonstrate that hydrodynamic coupling between proximate cells results in faster feeding flows compared to solitary living, and accrued feeding benefits are asymmetric: all individuals benefit from acting together, but those with weaker solitary feeding currents gain more from partnering than those with stronger currents. These results highlight a unifying theme of "evolutionary fluid dynamics," uncovering how flow physics shapes the selective forces driving early cellular adaptations and the emergence of multicellular organization.

Bio: Eva Kanso is a professor and the Z.H. Kaprielian Fellow in the department of Aerospace and Mechanical Engineering of the Viterbi School of Engineering at the University of Southern California (USC), with courtesy appointment in the department of Physics and Astronomy of the USC Dornsife College of Letters, Arts and Sciences. Prior to joining USC in 2005, Kanso held a two-year postdoctoral position in Computing and Mathematical Sciences at Caltech. She received a Ph.D. degree in 2003 and an M.S. degree in 1999 in Mechanical Engineering, as well as an M.A. degree in 2002 in Mathematics, all from the University of California at Berkeley. She obtained her Bachelor of Engineering degree from the American University of Beirut with distinction. Kanso held a rotating position as a program director at the National Science Foundation (2021-2023). She held visiting positions at Princeton University (2025-2026), the Institut de Recherche sur les Phénomènes Hors Equilibre, IRPHE, Marseille (2024), the Ecole Supérieure de Physique et de Chimie Industrielles, ESPCI, Paris (2021), the Courant Institute of Mathematical Sciences, New York (2016-2017), the Flatiron Institute at the Simons Foundation, New York (2016-2017), and the Laboratoire LadHyX at the Ecole Polytechnique, Palaiseau (2015). Her research interests concern fundamental problems in the biophysics of cellular and subcellular processes and the physics of animal behavior, both at the individual and collective levels. A central theme in her work is the role of the mechanical environment, specifically the fluid medium and fluid-structure interactions, in shaping and driving biological functions.