|DATE||SPEAKER / HOST||SEMINAR TOPIC|
|Oct. 29 BIOSCI 1102 10:30-11:30||Speaker: Dr. Alex Little, Department of Ecology, Evolution & Marine Biology, University of California, Santa Barbara
||The Price of Change: mechanisms and costs of adaptive plasticity
Many animals are able to remodel their physiology within their lifetimes to compensate for changing environments (adaptive plasticity). The advantages of plasticity have been well-described, but understanding associated trade-offs has proven difficult. One reason is that the proximate mechanisms that regulate plastic responses are largely unknown, and so we can only speculate whether they carry inherent costs. However, an integrative approach is helping me to identify these proximate pathways, and thereby make and test predictions about the contextual costs of plasticity. For example, what are the costs of plasticity in the presence of multiple stressors? What are the costs of plasticity particularly when that plasticity goes unused (i.e. in a stable environment)? Here I will discuss my work identifying the regulatory signaling pathways that underlie plastic responses in a zebrafish (Danio rerio) model. This work mainly focuses on a family of proteins that act both as hormone receptor and transcriptional regulator: the nuclear receptors. Using my expertise in transgenic techniques, high throughput drug screening, and interaction proteomics, I am developing transgenic models that will help model the ecological costs of plasticity in complex environments. Next, I will discuss my work identifying inherent (or maintenance) costs of plasticity using a saltwater marsh anemone (Nematostella vectensis). Here, my findings reveal that reduced metabolic rates represent a performance cost of developmental plasticity, whereas increased thermal sensitivity represents a performance cost of reversible acclimation. These early findings represent only a subset of the trade-offs I am currently quantifying in this system. To my knowledge, such trade-offs have not been empirically validated in any animal model. Together, my work combines emerging biomedical tools with more traditional measures of physiology to explore the mechanisms and costs of plastic responses in a changing world.
|Nov. 5 BIOSCI 1102 10:30-11:30||Speaker: Dr. Alex Zimmer, Department of Biological Sciences, University of Alberta
||Shaping physiological phenotypes: The influence of genomic, developmental, and environmental inputs on salt and water balance in freshwater fishes
Ecological and evolutionary success of animals depends on the expression of phenotypes that are compatible with their environment. In order to understand how specific physiological phenotypes arise, and the degree of plasticity or flexibility of these phenotypes, it is critical that we integrate the study of physiology across different levels of biological organisation. In my research, I have used ionoregulatory systems (salt and water balance) of freshwater fishes as a model to demonstrate how the genome and environment interact to influence phenotypes and how these interactions change over life history to shape physiological systems. In particular, I have studied how fishes sustain Na+ absorption, a process critical to maintaining internal ion and water balance, over development and in response to a range of environmental conditions (ionic strength, pH, contaminant exposure). In this presentation, I will discuss the molecular mechanisms of Na+ absorption by rainbow trout, how they change over development, and the implications that this has in understanding how fish at different stages of life history respond to changes in environmental conditions. I will also discuss the use of CRISPR/Cas9 gene editing as a tool to knock out genes that regulate Na+ absorption in zebrafish and explore how the resulting reduction in genetic complexity influences the expression and plasticity of phenotypes. This research highlights the importance of integrating molecular, organismal, and environmental physiology to understand how fishes occupy different environmental niches and how they respond to environmental change.
|Nov. 12 BIOSCI 1102 10:30-11:30||Speaker: Dr. Erin McCallum, Swedish University of Agricultural Sciences
||From mechanisms to populations: Assessing the ecological consequences of emerging pollutants for aquatic organisms
Human use of synthetic chemical compounds, such as pharmaceuticals and personal care products, is on the rise in developed countries. Many of these chemicals are discharged into freshwater ecosystems via, for example, municipal wastewater effluents. While the concentrations in surface waters are often unlikely to cause direct mortality, there is rising concern about how chronic exposure to sub-lethal amounts of these pollutants may directly or indirectly affect animal fitness. I will discuss a series of experiments I conducted addressing how pharmaceuticals and municipal wastewater effluents impact wild fish across scales of biological organization, from physiology to behaviour to changes in fish community composition. I will compare my results from controlled laboratory studies with findings from in situ field exposures and from studies using animal tracking technologies. Our current understanding of how chemical contaminants affect aquatic organisms is largely based on individual-level responses. Yet, understanding and mitigating the impacts of anthropogenic pollution requires knowledge of how pollutants affect animals in their natural social environment and habitats. I will therefore highlight how my research program is closing these knowledge gaps by focusing on complex inter- and intra-specific interactions (e.g., predator-prey, social dominance) in realistic environments.
Nov. 19 Humphrey Aud. 10:30-11:30
|Speaker: Dr. Tim Healy, Scripps Institute of Oceanography, UC San Diego
||Mechanisms underlying physiological adaptation: linking genotype to phenotype
Fitness-related physiological traits play key roles in both the adaptive responses of organisms to environmental change, and the formation of reproductive barriers between locally adapted populations. Therefore, identifying the mechanistic basis for variation in these traits is a critical aspect of understanding local adaptation and early-stage reproductive isolation. My research addresses this need by integrating comparative physiology, genetics and genomics to provide novel insights into the mechanisms that underlie intraspecific variation in tolerance limits, metabolic rate and oxidative phosphorylation. In this talk, I demonstrate these approaches using my graduate work on adaptive responses to anthropogenic climate change in the Atlantic killifish (Fundulus heteroclitus), and my postdoctoral work on hybrid breakdown, mitochondrial performance and mitonuclear compatibility in Californian tiger copepods (Tigriopus californicus). Taken together, these studies reveal the immense complexity and polygenic nature of the physiological and genetic mechanisms that underlie population divergence and local adaptation, and illustrate the power of my integrative approach for studying the evolution of physiological systems. My research not only highlights the pivotal role that physiological traits play in adaptive processes, but also addresses a fundamental goal of modern biology: mechanistically linking genotype to phenotype.
BIOSCI 1103 3:30-4:30
|Speaker: Dr. Joe Schwarcz, McGill Office for Science and Society
Host: Biology Graduate Student Association
|Hey! There are Cockroaches in my Chocolate Ice Cream!
No, there really are no cockroaches in chocolate ice cream. But one of my radio listeners did jump to this conclusion after misinterpreting what had been said about a certain food colourant. Being on one end of a microphone and in front of television cameras for over twenty years has afforded some fascinating insight into the public’s perception of science. It has also provided an opportunity to separate sense from nonsense in areas ranging from nutrition and medications to cosmetics and pesticides. This highly visual and entertaining presentation examines some serious as well as some frivolous experiences in dealing with the public and emphasizes the importance of fostering critical thinking.
|Host: Capstone Speaker||TBA|
|Apr 9 (tentative)||
Speaker: Dr. Laura Harrington, Department of Entomology, Cornell University
Host: Al Downe Lecture and Adam Chippindale
BIOSCI 1103 2:30-3:30
|Speaker: Dr. Graham Scott, Department of Biology, McMaster University
Host: Yuxiang Wang
|Living the High Life: Integrative Functional Mechanisms of High-Altitude Adaptation
High-altitude environments provide fertile ground for investigating the mechanisms and evolution of physiological systems underlying animal performance. The cold and oxygen-depleted (‘hypoxic’) environment at high altitudes requires that endothermic animals sustain high rates of O2 consumption for thermogenesis and locomotion while facing a diminished O2 supply. My research examines the ways in which high-altitude natives overcome these challenges. I will present our work on the respiratory, cardiovascular, and mitochondrial mechanisms of high-altitude adaptation in deer mice (Peromyscus maniculatus). In doing so, I will discuss the mechanisms underlying the evolution of complex performance traits and the evolution of phenotypic plasticity.
BIOSCI 1103 10:30-11:30
|Speaker: Dr. Margaret Eng, Toxicology Centre, University of Saskatchewan
||Integrating Laboratory and Field Approaches in Wildlife Toxicology
We live in a contaminated world, with approximately 23,000 chemicals registered for use in Canada, in addition to numerous contaminants that are unintentionally released in industrial processes. There are many challenges to deciphering the effects of these contaminants on wildlife populations. Laboratory assessments often lack ecological relevance, and conversely the majority of field assessments are correlative in nature. I use a combination of laboratory and field approaches and integrate methods from multiple disciplines (molecular biology, physiology, neurobiology, behaviour) to make causal linkages between contaminant exposure and effects in birds. I will present two case studies from this research. The first demonstrates the use of predictive genotyping, field manipulations, and molecular diagnostics to verify that 2 wild bird species (European starlings and gray catbirds), like the domestic chicken, are highly sensitive to dioxin-like compounds – results that can directly inform risk assessment without extensive toxicity testing on wild birds. In the second example, I used a combination of captive behavioral trials, controlled exposures in the field, and automated telemetry to demonstrate that field-realistic concentrations of a neonicotinoid insecticide cause appetite suppression, body mass loss and migratory delays in migrating white-crowned sparrows. These results link neonicotinoid exposure to population-level consequences, as the timing of migration is critical and delays are known to affect survival and reproduction. This research highlights how we can increase our capacity to answer fundamental and applied questions in animal biology and ecotoxicology by Integrating methods across levels of biological organization, and merging field studies with captive studies and laboratory analysis in novel ways.