Dr. Tara Smiley | Smiley Lab

Bio:

I am an evolutionary ecologist interested in how climate and landscape history shape the diversity, biogeography, and ecological structure of mammalian faunas across spatio-temporal scales. I test hypotheses about how changes in climate, tectonic activity, topographic complexity, and habitat heterogeneity impact communities and ecological processes at local scales and govern diversity at regional scales. To do so, I use the fossil record to investigate diversity patterns, macroevolutionary processes, and paleoecology, focusing on the history of small mammals during the Cenozoic. My work on the past is conducted in parallel with investigations of modern and historical small-mammal populations across broad climatic and environmental gradients today.

My research group integrates fieldwork, specimen-based research, and quantitative paleobiology. Primary tools of our research include stable isotope ecology and paleoenvironmental reconstruction, analysis of trait variation, diversification analysis, and coupling of geological and biological modeling approaches. We work in western North America and in the East African Rift, both tectonically active and dynamic landscapes with high species richness today and in the past. 



Abstract: 

Mountains across the globe are biodiversity hotspots for many different groups of plants and animals; however, the deep-time relationship between mountain building and biodiversity remains elusive and requires integration across disciplines in geosciences, paleontology, and biology. When and how did these hotspots form? What role do landscape and climate dynamics play in eco-evolutionary processes? Using modern and fossil records, as well as empirical and quantitative approaches, my research program investigates how the biodiversity of mammals has been influenced by tectonic and climate interactions that shape mountain landscapes and generate topographic and climatic gradients. In this presentation, I will focus on the diversification history and faunal structure of mammals in the Basin and Range Province of western North America across the Neogene, highlighting the role of tectonic extension and global warming during the Miocene Climate Optimum (17-14 million years ago) at multiple spatial scales. I will also share new research from coupled landscape-biotic evolution models to understand how tectonic uplift may both generate and preserve evidence of montane biodiversity hotspots in the fossil record.

Watch the seminar here!

Ned Dochtermann | Dochtermann Lab

Abstract:

While behavioral syndromes are frequently argued to represent an optimal outcome of correlated selection, they also have the potential to constrain evolutionary responses. Via intraspecific and interspecific comparisons we attempted to determine whether behavioral variation was distributed in a manner consistent with either (or both) of these explanations. We compared the distribution of genetic variation across four populations of field crickets (Gryllus integer) and for seven behavioral measures. The distribution and orientation of genetic variation was conserved across populations and divergence among populations was constrained to a shared direction in multivariate space. We then compared the distribution of behavioral variation across five species of crickets and identified a strong phylogenetic signal. Combined, these intra- and interspecific comparisons are consistent with behavioral syndromes acting as constraints on evolutionary outcomes. Finally, in a natural population of deer mice (Peromyscus maniculatus) we compared the orientation of behavioral variation with the direction of selection acting on the population. We found that the distribution of behavioral variation was inconsistent with our a priori predictions. These three independent results suggest that intuitive adaptive explanations may be insufficient to explain the ubiquity of behavioral syndromes.

Check out the seminar here!

Dr. Van Savage

Bio:

I am a Professor in the Ecology and Evolutionary Biology and Biomathematics departments. A major goal of my research is to quantify and understand the possible functions, forms, and interactions of biological systems that result in the extraordinary diversity in nature. I have studied a wide range of areas such as metabolic scaling, consumer-resource interactions, rates of evolution, effects of global warming on ecosystems, tumor growth, and sleep. Complementary to this, I aim to understand how much variation around optima or averages is considered healthy or adaptive versus diseased or disturbed states, which are essentially deviations from normal or sustainable functioning. As I attempt to make progress on these questions, I join together ecology, evolutionary theory, physiology, mathematical modeling, image-analysis software, informatics, and biomedical sciences. Many theories, including some of my work, focus on optimal or average properties, but more recently, I have been working to obtain the large amounts of data necessary to characterize variation in key properties. My new findings about the diversity and variation in form and function are revealing flaws in current models, and I am working to develop new theories that incorporate realistic amounts of natural variation.

Abstract:

The question of which factors contribute to ecosystem and food webs stability is one of the most fundamental and foundational in all of ecology. Here I present findings from a new numerical model that allows us to include or exclude different potential factors, and I interpret these results using a novel method that examines how stability and connectance change with consumer-resource size ratios. In this way we are able to compare our predictions and model with empirically grounded data and known trends. Consequently, we are also able to study how variation in size distributions within food webs overall impact the stability of food webs. These results are followed by a more analytical mathematical treatment of how eigenvalue distributions—directly related to system stability—change depending on the structure of the interaction matrix. As part of this, I review and revisit seminal work by Robert May and Stefano Allesina, and connect with and synthesize some lesser known theorems from linear algebra to illuminate and understand some of the results from our numerical model. Finally, I talk about how this work might be extended to consider the impacts of increasing or fluctuating temperatures due to climate change, and possible directions for enlarging and extending the

mathematical concept of stability to something closer to its ecological meaning.

Dr. Joseph L Graves, Jr.

Bio:

Dr. Joseph Graves, Jr. received his Ph.D. in Environmental, Evolutionary and Systematic Biology from Wayne State University in 1988. In 1994 he was elected a Fellow of the Council of the American Association for the Advancement of Science (AAAS.) In 2012, he was chosen as one of the “Sensational Sixty” commemorating 60 years of the NSF Graduate Research Fellowship Award.  In 2017, he was listed as an “Outstanding Graduates” in Biology at Oberlin College; and was an “Innovator of the Year” in US Black Engineer Magazine.

His research in the evolutionary genomics of adaptation shapes our understanding of biological aging and bacterial responses to nanomaterials. He is presently Associate Director/co-PI of the Precision Microbiome Engineering (PreMiEr) Engineering Research Center of Excellence (Gen-4 ERC) funded by the National Science Foundation (2022—2027). He has published five books: A Voice in the Wilderness: A Pioneering Biologist Explains How Evolution Can Help Us Solve Our Biggest Problems, (New York: Basic Books), 2022; with Alan Goodman, Racism, Not Race: Answers to Frequently Asked Questions, Columbia University Press, 2022. Racism, Not Race was named by Kirkus Reviews as “One of the Best Non-Fiction 2021” and to its “Best Books About Being Black in America 2021”; Principles and Applications of Antimicrobial Nanomaterials, (Amsterdam NE: Elsevier),  2021; The Emperor's New Clothes: Biological Theories of Race at the Millennium, Rutgers University Press, 2005 and The Race Myth: Why We Pretend Race Exists in America, Dutton Press, 2005.

He leads programs addressing underrepresentation of minorities in science. He has aided underserved youth in Greensboro via the YMCA chess program.  He has also served on the Racial Reconciliation and Justice Commission, and COVID Vaccination Task Fore of the Episcopal Diocese of North Carolina. He also served as the science advisor to the Chicago, New Brunswick, and Methodist of Ohio Theological Seminaries through the AAAS Dialogues of Science, Ethics, and Religion (DoSER) program.

Abstract: 

In A Voice in the Wilderness, I discuss the story of how I became the first African American evolutionary biologist.  It was a life of strife that followed me everywhere I went. I was beset by imposter syndrome, by depression, by racism, by negligence, and contempt.  And yet I persevered and became a prominent scholar in evolutionary biology.  I have helped to lead the fight against scientific racism, utilizing my science a tool to resist exploitation and change the demography of the scientific enterprise.



Check out his most recent article here!

Dr. Rafael Demarco | Demarco Lab

Bio:

I am a new Assistant Professor in the Department of Biology at the University of Louisville whose ultimate goal is to understand how changes in metabolism impact stem cell behavior during homeostasis, aging and stress conditions. I was trained as a geneticist during my Ph.D. with Dr. Erik Lundquist at the University of Kansas, where I learned to ask questions and interpret genetic data using model organisms. To pursue my objective of studying stem cells and their niches, I obtained my postdoctoral training and later position as a Research Specialist in the laboratory of Dr. Leanne Jones (first at the Salk Institute and then at the University of California, Los Angeles and San Francisco), a leading expert in the fields of stem cells and current director of the Bakar Aging Research Institute at UCSF. During my time working with Dr. Jones, I developed my own research interests focusing on how different aspects of metabolism impact the stem cell niche present in the Drosophila testis. Unexpectedly, I found that both stem cell populations present in the testis niche employ mechanisms to maintain proper lipid homeostasis in order to prevent stem cell loss. Disruptions in either mitochondrial fusion (in germline stem cells1) or autophagy (in cyst stem cells2) led to deficient lipid catabolism and ectopic accumulation of lipids in the stem cell niche, which promoted stem cell loss through differentiation. Hence, a model has emerged revealing a novel metabolic facet in the regulation of stem cell fate, which appears conserved across stem cell systems3. In my recently established laboratory, I am engaged in pursuing the mechanism(s) through which ectopic lipid accumulation can impact stem cell fate within the niche, which could shed light into the development of new strategies targeting stem cell-based regenerative therapies.

Abstract:

The capacity of stem cells to self-renew or differentiate has been attributed to distinct metabolic states. A genetic screen targeting regulators of mitochondrial dynamics revealed that mitochondrial fusion is required for male germline stem cell (GSC) maintenance in Drosophila melanogaster.  Depletion of Mitofusin (dMfn) or Optic atrophy 1 (Opa1) led to dysfunctional mitochondria, activation of Target of Rapamycin (TOR), and a dramatic accumulation of lipid droplets (LDs). Pharmacologic or genetic enhancement of lipid utilization by the mitochondria decreased LD accumulation, attenuated TOR activation and rescued GSC loss caused by inhibition of mitochondrial fusion. However, the mechanism(s) leading to GSC loss were unclear. TOR activation has been demonstrated to suppress JAK-STAT signaling by stabilizing the JAK-STAT inhibitor SOCS36E. As JAK-STAT signaling is critical for regulating stem cell self-renewal in the testis, we wanted to test the hypothesis that the increase in TOR activity in early germ cells would lead to SOCS36E stabilization, which in turn, could contribute to stem cell loss.  Indeed, we found that SOCS36E levels were higher in early germ cells upon depletion of dMfn or Opa1. Subsequently, we show that activation of the JAK-STAT pathway, but not BMP signaling, is sufficient to rescue loss of GSCs as a result of the block in mitochondrial fusion.  In addition, preliminary genetic and proximity-labeling data suggest that LD accumulation acts in parallel to TOR/SOCS36E to promote GSC loss. Our findings highlight a critical role for mitochondrial metabolism and lipid homeostasis in GSC maintenance, providing a framework for investigating the impact of metabolic diseases on stem cell function and tissue homeostasis.

Dr. Jessica Blois | Blois Lab

BIO:

Dr. Jessica Blois is an Associate Professor in the Department of Life and Environmental Sciences at UC Merced. Her research is particularly focused on examining the relative roles of environmental versus biotic drivers of biodiversity change, in merging data from different kinds of fossil proxies such as mammal bones and plant macrofossils, and in applying perspectives from the past to help conserve biodiversity. Her work combines field work aimed at broadening our samples of fossil and modern mammals, phylogeographic analyses to understand how genetic diversity is structured spatiotemporally, and paleobiogeographic modeling. Dr. Blois’ primary study system is North American mammals from the past 21,000 years, and she also has a strong focus on developing the paleo-informatic infrastructure to enable large-scale science.

Abstract:

Climates today are changing substantially and will continue to do so over the next hundred years and beyond. All of the different elements that comprise Earth’s biosphere—its biodiversity—depend on and respond to Earth’s climate in a variety of ways, and in turn, Earth’s biodiversity modulates the magnitude and trajectory of climate change. Species responses to highly novel climatic (and other anthropogenically-forced) conditions—which may fall outside the range of conditions experienced by species over their histories—will impact the adaptive capacity and evolutionary potential of species and shape future patterns of biodiversity. In this talk, I will present several recent projects illustrating how climate impacts biodiversity. I will focus on ecological processes that structure local populations and communities, and then move towards how we can scale up towards a broader understanding of how ecological processes structure biodiversity patterns across space and time.

Watch the seminar here!

Hugo Reyes-Centeno HEVA (Human Evolution & Virtual Anthropology Lab) EduceLab

Dr. Hugo Reyes-Centeno is an evolutionary anthropologist specializing on the emergence of modern human anatomy and behavior over the last million years. In addition, he conducts inter-disciplinary research on human biocultural diversity and the study of natural and cultural heritage worldwide. Prior to joining the University of Kentucky in 2020 as Assistant Professor of Anthropology, he served as Scientific Coordinator and co-founder of the Center for Advanced Studies “Words, Bones, Genes, Tools” at the University of Tübingen (Germany), where he also completed a dissertation in the Institute of Archaeological Science and the Senckenberg Centre for Human Evolution and Paleoenvironments. His research has appeared in Cell, PNAS, Journal of Human Evolution, and PLoS Genetics, among other venues. He has performed paleontological and archaeological fieldwork in France, Italy, Peru, the Philippines, and Spain. Currently, he serves as Co-PI of the NSF-funded EduceLab: Infrastructure for Next Generation Heritage Science.

Abstract: Despite consensus on the emergence of anatomically modern humans in Africa and their subsequent dispersal into the rest of the world, the mode and timing of these processes remain controversial topics. In addressing them, data on human anatomical and genomic variation have sometimes generated conflicting inferences. Therefore, approaches that consider both lines of evidence under a common theoretical framework are important for reconciling competing evolutionary models. In this talk, I highlight research that tests competing models of human dispersal out of Africa, which applies quantitative genetic and population genetic methods to anatomical and genomic data. I discuss the caveats of these conclusions, including the influence of admixture between modern humans and other hominins. Furthermore, I examine how these findings align with the known human fossil record and a growing inventory of ancient genomes from archaeological and paleontological contexts. Finally, I review how ongoing field and laboratory projects in Eastern Africa, Southeast Asia, and South America shed light on human evolution, adaptations, and dispersals.

 Erin Dolan

Abstract: A graduate student’s relationship with their research advisor is considered to be the single-most influential factor in the quality and outcomes of their graduate training experience. Indeed, effective mentorship by research advisors promotes the development and success of graduate mentees. Yet, mentoring relationships, like any prolonged relationship, can have negative elements. Little research has examined the problematic elements of graduate research mentoring, even though prior research on mentoring in workplace settings suggests that negative mentoring experiences are common. This seminar will present findings from research on the negative mentoring that graduate life science researchers experience, including how their experiences differ from negative mentoring experienced in workplace settings. The session will offer insights on how mentor behaviors may be experienced as harmful or unhelpful and on how mentees and mentors can identify, avoid, and mitigate the impacts of negative mentoring.

Evangeline Ballerini Ballerini Lab

Evangeline Ballerini is an Assistant Professor in Biological Sciences at California State University, Sacramento. Evangeline’s research examines the evolutionary genetics and developmental biology of traits influencing ecological interactions between plants and pollinators with a focus on the genus Aquilegia. Evangeline earned a BA from the Integrative Biology department at the University of California, Berkeley and a PhD from the Organismic and Evolutionary Biology department at Harvard University and conducted postdoctoral research at the University of Georgia and the University of California, Santa Barbara.

Abstract: The genus Aquilegia, commonly known as columbine, represents a classic example of adaptive radiation following the evolution of a key innovation - floral nectar spurs. Nectar spurs, tubular outgrowths of floral tissue that produce and store nectar, are hypothesized to promote speciation through pollinator specialization. Variation in spur morphology, along with other floral features such as color and orientation, allows flowers to adapt to different animal pollinators, contributing to reproductive isolation. I will present work focused on understanding the genetic basis of trait evolution in the genus Aquilegia at multiple evolutionary timescales. To shed light on how nectar spurs evolved in the Aquilegia ancestral lineage, I will highlight studies in which I used a combination of genomic and transcriptomic analyses to identify a key gene regulating nectar spur development. Focusing on more recent evolutionary history, I will discuss work in which I use similar techniques to explore the genetic basis of several floral traits distinguishing closely related Aquilegia species adapted to different animal pollinators and examine the population genetic processes influencing the evolution of these traits important for ecological speciation in the genus.

"Genomic approaches to the study of sexual selection and male pregnancy"

Texas A&M University

Faculty Hosts: Dr.Craig Sargent

Sponsored by Biology Ribble Endowment



*Refreshments served at 3:45pm