Gaylord Donnelley Postdoctoral Associates

Advait Jukar

Advait Jukar, Ph.D.

Research description: Advait will be studying the impacts of human hunting and climate change on the megafaunal extinction in India. He will use tools including faunal analyses, stable isotopes, bone surface modification, and geochronology to understand the anthropogenic and environmental context of this extinction. The recent extinction of large terrestrial vertebrates has been the focus of paleontological, archeological, and ecological research for decades, but the causes are poorly understood in some of the most biodiverse regions of the world, like the Indian Subcontinent. India unlike large parts of the world, retains several species of large mammals such as rhinos and elephants. Advait’s goal is to understand why so many large species have survived in this region.

Fellowship dates: July 2020 – June 2022

James Lichtenstein

James Lichtenstein, Ph.D.

Research description: James has spent the last six years investigating the causes and consequences of individual behavioral variation. At YIBS he will study how ecosystems drive the evolution of diversity in predator behavior and how the evolution of behavioral diversity affects ecosystems. Species-diverse ecosystems are predicted to constrain the evolution of trait diversity within predator species, and this trait diversity increases how many prey they kill, thereby increasing plant growth. James will test this using experimental evolution to create predatory insect populations with low or high levels of diversity in the behaviors they use to hunt prey. These predators will then be deployed in meadows to test how their behavioral traits affect ecosystem structure. Teasing apart these intricate eco-evolutionary dynamics could help explain how ecosystems function, potentially allowing us to use artificial evolution to shape ecosystems.

Fellowship dates: September 2020 - August 2022

Thomas Boag

Thomas Boag, Ph.D.

Research description: Thomas’s research focuses on understanding how climate impacts trends in biodiversity both in the modern ocean and the geologic past. He uses a combination of tools in his research including stratigraphy, paleontology, and organismal ecophysiology to answer questions such as how changes in the redox structure and temperature of Earth’s oceans influenced early animal evolution. In addition, his work has focused on understanding how warming oceans in the coming centuries will impact the range size of species and latitudinal diversity patterns. At Yale, Thomas will be focused on understanding how climate change will impact the physiology of seafloor sediment-dwelling animals that are found throughout the global ocean. These animals play a critical role in mediating several key marine biogeochemical cycles, including the coupled carbon-phosphorous-oxygen cycle, the sulfur cycle, and organic carbon burial.

Fellowship dates: November 2020 - September 2022

Natasha Picciani, Ph.D.

Research description: Natasha is an evolutionary biologist interested in understanding how organismal diversity evolves and the mechanisms that can constrain or facilitate complex evolutionary outcomes across species. At Yale she will focus on understanding the mechanisms that drive the evolution of complex life cycles using the polyp and jellyfish life stages of cnidarians. The goal of her work is to better understand the relationship between jellyfish reduction and polyp specialization and investigate whether disruption of cell differentiation can serve as a developmental mechanism underlying the loss of complexity. The loss of complexity in one phase of a life cycle is often associated with an increase in another phase of the life cycle. Overall, her work investigates the dynamics of evolutionary constraints, how these shape changes in organismal complexity, and the developmental basis of those changes.

Fellowship dates: December 2020 – November 2022


Erynn Johnson

Erynn Johnson, Ph.D.

Research description: Erynn uses interdisciplinary approaches and biomechanical experimentation to understand how predation pressures shaped the evolution of mollusk shells over deep time. She utilizes mathematical modeling, 3D printing, and computer-automated design to test the form and function of modern, extinct, and theoretical morphologies. These tests are used to isolate and analyze how different aspects of mollusk shell morphology contribute to shell strength. Studying key intervals of ecological change in the fossil record allows us to understand how predators have influenced their prey over long periods of time, providing potential insights to the long-term impacts of human activities on marine ecosystems.

Fellowship dates: July 2021 – June 2023


Maya Stokes, Ph.D.

Research description: Maya works at the intersection of Life and Earth sciences to understand how changes to Earth’s surface over geologic timescales influence the distribution and evolution of life. Maya uses computational models as well as geologic and genomic datasets to integrate disparate disciplines. Her graduate training was in geomorphology with a focus on “river capture”, an abrupt change in flow direction when one river segment forges a new connection with a channel in another basin. Geomorphic processes, like river capture, are hypothesized to influence the evolution of aquatic organisms, yet testing such hypotheses requires the integration of geologic and genomic data. At Yale, she will be investigating how river incision has shaped the landscape of the Appalachian Mountains as well as the evolution of the aquatic taxa in the region. She is broadly interested in understanding the ways in which tectonic, climatic and geomorphic processes influence the evolution of life.

Fellowship dates: August 2021 – July 2023

Catherine Hernandez

Catherine Hernandez, Ph.D.

Research description: Catherine Hernandez is generally interested in how environmental change will alter microbial interactions. Just like in macroorganisms, microorganismal physiology and fitness are impacted by abiotic factors, and their ecology and evolution will be shaped by global change. At Yale, Catherine will be particularly focused on how temperature impacts the interactions between environmental bacteria and the bacteriophage (phage) viruses that infect them. Catherine will be using observational and experimental evolution approaches to study geographic patterns of thermal responses, the relationship between viral host range and thermal performance, and how virus populations adapt to changing temperatures. These results will provide insight into how temperature can alter microbial community composition, trait evolution, and the structure of microbial networks. Given the important role of phages in structuring microbial communities, this work has implications for predictions of climate change impacts on microbially-mediated ecosystem processes like nutrient cycling.

Fellowship dates: September 2021 – August 2023

Karen Chen

Karen Chen, Ph.D.

Research description: Karen Chen is a quantitative geographer studying how urban land cover and form change over time and their impacts on human well-being. Working with Prof. Karen Seto, she will use the synergy of deep learning, remote sensing, and Geographic Information Systems to characterize the 3-D built environment and urbanization in the Global South.

Fellowship dates: September 2021 – August 2023