Asha Kannan

Asha Kannan

Biography

Asha Kannan is a rising senior at Middlebury College, studying Biology and Earth &Climate Sciences. Asha’s interest in science stems from a love of plants, cultivated while working at a community garden in her hometown of Palo Alto, California, and while studying abroad in Copenhagen, Denmark. As an undergraduate researcher in the Dukes Lab at Carnegie Science, Asha studied how vegetation influences microclimates and is now working on her senior thesis at Middlebury to understand the role of mosses in carbon cycling in drylands. She is currently in the Perron group at MIT, investigating how landscape evolution drives speciation in aquatic organisms. Asha is interested in pursuing a PhD at the intersection of climate evolution, geomorphology, and global change biology. At Middlebury, Asha is aboard member of the Sunday Night Environmental Group and a captain of theWomen’s Water Polo Team. Outside of school, she enjoys knitting and traveling

Abstract

River Basin Reorganization as a Driver of Aquatic Organism Speciation

Landscape change has a large influence on the evolutionary trajectory of biological communities. River network reorganization has the potential to induce speciation in aquatic communities by creating barriers to isolate previously connected populations, resulting in a lack of gene flow among organisms. Speciation will also occur randomly through stochastic mutations, regardless of landscape changes. While tectonism was previously thought to be the main creator of these barriers, recent biological observations have indicated that biodiversity hotspots—places where speciation outpaces extinction—can occur in both tectonically active and inactive regions. This project compares the biodiversity of aquatic metapopulations, groups of populations of the same ancestral species, in a dynamic landscape relative to a static base level landscape by mapping their phylogenies. These groups were modeled using a coupled landscape evolution and neutral community model, which tracks speciations and extinctions as the landscape changes. The resulting phylogenetic trees highlight the increased rate of speciation associated with forcings in
the dynamic landscape, such as fault migration. This coupled model can be adapted to any aquatic organisms in rivers, providing insight into relating ecosystem dynamics, species richness, and the evolutionary history of aquatic taxa to evolving landscapes.