Winter 2020 Seminar Series
Friday 21 February 2020 11:10 AM - Noon Fisher Hall 33 - 285
California fire regimes and modern fire departure: understanding geographic differences in fire trends and ecosystem management
Hugh Safford PhD, Regional Ecologist, US Forest Service, Pacific Southwest Region and Adjunct Professor, Department of Environmental Science and Policy, University of California-Davis
California recently experienced its most extreme fire years ever and the trends are for more of the same. Although public and political perception is that the issues are similar across the State – and although climate warming is certainly affecting forest disturbances across the board – the rash of large, severe wildfires has different causal roots in different parts of California. Two distinctly different historic fire regimes characterize lowland and montane areas where these fires are wreaking havoc. Lowland fires mostly occur in chaparral and related shrubland types, where fuels are typically dense, surface and canopy fuels are in contact, postfire fuel recovery is rapid, plant diversity is strongly connected to severe fire, and late summer and fall conditions are extremely dry and often hot; in such ecosystems, fires have always been severe and often large, but today the frequency of such events is rising rapidly with human ignitions. Montane fires mostly occur in yellow pine and mixed conifer ecosystems, where canopy fuels are typically disconnected from the surface, fuels are more spatially discontinuous, plant diversity is maximized in low and moderate severity fires, and summer and fall conditions are more moderate; fires in these ecosystems were historically high frequency and low severity but fire suppression has greatly increased fuel loading and continuity, leading to conditions that promote large, severe fires. In both ecosystems – but primarily in the lowlands – expansion of flammable suburban housing into the wildlands has led to a great increase in the number of homes and lives lost. Management responses to these developing conditions can be effective, but in lowland shrubland ecosystems they tend to run counter to conservation and ecological restoration goals. In montane forests on the other hand, management actions are much more easily aligned with conservation and restoration.
Friday 14 February 2020 11:10 AM - Noon Fisher Hall 33 - 285
Ecological physiology of plant eating lizards: shifts in gut structure, function, and microbes
Beck Wehrle PhD, Department of Ecology and Evolutionary Biology, UC Irvine
Plant eating is relatively rare in lizards, yet has independently evolved many times. How do physiology, morphology, behavior, and ecology integrate to accommodate this dietary strategy? Do lizards that have rapidly evolved morphological changes in conjunction with a recent diet shift show physiological adaptations to their new plant diet? How do highly derived herbivorous lizards get the tools to digest plant fiber? I present my work on gut form and function of lizards and their microbiomes as they relate to dietary shifts and specialization.
Friday 7 February 2020 11:10 AM - Noon Fisher Hall 33 - 285
Targeting cancer metastasis
Hasini Jayatilaka PhD, Medical Affairs Group at Syneos Health
Hasini Jayatilaka received her PhD from Johns Hopkins University in Chemical and Biomolecular engineering where she discovered a novel synergistic signaling pathway between interleukin 6 and 8 that is responsible for regulating metastasis. Inhibition of this pathway decreases the metastatic burden of cancer cells. Testing in pre-clinical models has demonstrated that inhibition of this synergistic cell density-dependent-signaling mechanism significantly reduces effective metastasis to the lungs, liver, and lymph nodes without accelerating tumor growth. The results of Hasini's study established a novel method of solely targeting metastasis which is responsible for 90% of cancer related deaths and laid the foundation for the development of combination therapies that effectively target tumor growth and metastasis, and the establishment of bi-specific antibodies to target the synergistic signaling mechanism. Hasini was named a Forbes 30 under 30 in Science in 2018 for her contributions to cancer metastasis.
Dr. Jayatilaka is currently a consultant in the scientific and Medical Affairs Group at Syneos Health where she works with mid-size, and large pharmaceutical organizations to develop product-specific medical affairs strategy.
Prior to Syneos Health, Dr. Jayatilaka was a post-doctoral scientist at Stanford University and studied mechanisms of relapse and metastasis using novel technologies such as mass cytometry (CyTOF) and Multiplexed lon Beam Imaging (MIBI) to conduct multipara meter protein analysis. Considering that current cancer treatments ultimately fail owing to metastasis and relapse, her work uncovered new insights that will help in the development of immunotherapies by providing future avenues for therapeutic design.
Friday 31 January 2020 11:10 AM - Noon Fisher Hall 33 - 285
"pH"ingerprinting coastal oceans: connecting climate change, natural variability, and biological feedbacks
Nyssa Silberger PhD, Assistant Professor, Biology Department, California State University, Northridge
Most of the world's population lives within 100 km of a coastline and depend on coastal marine ecosystems for sustenance, shoreline protection, and economic resources. Because our shorelines are threatened from numerous local and global human impacts, it is essential to understand how they will change in the future. Coastal ecosystems persist in a highly dynamic environment, especially with respect to pH. This high variability of pH is driven by complex physical and biological processes that complicate climate change predictions. Using coral reefs and rocky intertidal ecosystems as examples, I discuss several case studies that highlight how pH, in combination with other anthropogenic stressors, affect ecosystem functioning. Specifically, I focus on how ecosystem function is affected by natural pH variability across multiple spatial scales, biological feedbacks between pH and ecosystem metabolism, and how a local stressor (nutrient enrichment) affects biologically-driven pH dynamics. Understanding the natural variability of coastal ecosystems and how organisms both drive and respond to changes in pH is necessary to project how ecosystem functioning will change in the future.
Friday 24 January 2020 11:10 AM - Noon Fisher Hall 33 - 285
Getting chased up the mountain: mitonuclear interactions may drive adaptation to high elevation
Elizabeth Dahlhoff PhD, Professor, Department of Biology, Santa Clara University
"Climate change is altering landscapes across the globe and organisms must adapt to these new conditions or face extinction. Coordination between nuclear and mitochondrial genomes is critical to this process, yet consequences of mitonuclear interactions have rarely been investigated in populations where individuals with divergent mitochondrial and nuclear genomes naturally interbreed. I will discuss effects of mitonuclear genetic variation in populations of the leaf beetle Chrysomela aeneicollis living at high elevation (2400-3600 m) in California's Sierra Nevada. We found that fecundity, larval development rate, running speed and male mating frequency are higher for beetles with geographically 'matched' mitonuclear genotypes than 'mismatched' ones. The magnitude of these effects are typically greater for southern than northern mitochondrial haplotypes, and is altered by heat treatment and measurement elevation. These findings suggest that mitonuclear incompatibility reduces performance and reproductive success in nature, effects that could be exacerbated in stressful, rapidly changing environments."
Friday 17 January 2020 11:10 AM - Noon Fisher Hall 33 - 285
Shark skin travel time: using dermal denticle assemblages to reconstruct historical shark communities on coral reefs
Erin Dillon PhD, Candidate, Ecology, Evolution, and Marine Biology, UC Santa Barbara
How abundant were sharks on coral reefs before humans? Many coastal shark populations have declined steeply over the last several decades, but longer records of change are unavailable. This hinders our ability to determine baseline shark abundance, understand natural variation in shark communities over time and space, and interpret sharks' functional roles on coral reefs in natural and human-impacted systems. In this talk, Erin will explore the use of dermal denticles, the small tooth-like scales that cover the bodies of sharks and rays, as a new tool for reconstructing historical shark communities on coral reefs.
Erin earned her B.S. in Biology with Honors in Marine Biology from Stanford University. She then worked as a fellow at the Smithsonian Tropical Research Institute in Panama for two years before starting graduate school. Currently, Erin is a fourth-year PhD candidate at UC Santa Barbara working with Dr. Douglas McCauley.
Friday 10 January 2020 11:10 AM - Noon Fisher Hall 33 - 285
Our constant frenemy Escherichia coli: an old bacterium learning new tricks
Alejandra Yep, PhD, Assistant Professor, Biological Sciences, Cal Poly State University
Escherichia coli is the most thoroughly studied bacterium on Earth and we know everything there is to know about it… or do we? The truth is, Escherichia coli can still surprise you! From a key player in your healthy microbiome to deadly foodborne outbreaks to stubborn urinary tract infections, Escherichia coli seemingly can do it all. In my lab at the Biological Sciences Department at Cal Poly, we study several aspects of this extremely diverse species, including survival in the environment, pathogenicity in the urinary tract, and mechanisms of acquisition of antibiotic resistance.