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biology seminar

"Overwintering in the Arctic: Animal Strategies for Surviving the Long, Cold, and Dark"

SelfieDr. Brian Barnes

Bio:
Dr. Barnes is currently a Professor of Zoophysiology with the Institute of Arctic Biology at the University of Alaska in Fairbanks. He's also the Director of Alaska INBRE, an NIH capacity building program in biomedical research and also the Science co-Director at Toolik Field Station. He participated in summer workshops involving biological rhythms at Hopkins Marine Station. He has a  PhD in Zoology from the University of Washington where Jim Kenagy was his advisor. Dr. Barnes received his Post-doc in Psychology and Zoology with Irv Zucker and Paul Licht as advisors. He began as Assistant Professor at the University of Alaska in 1986.

Abstract:
In Alaska, winters begin early, last seemingly forever, are very cold, snowy and dark, as well as extremely beautiful, quiet, and serene. This talk will review the physiological and behavioral strategies available to animals for surviving and coping with arctic winters, including cryobiology in insects, freeze tolerance in frogs, and hibernation in ground squirrels and bears. Using data logging and advanced telemetry, the locations, behavior, sleep, circadian rhythms, cardiovascular patterns, and thermoregulation of animals were recorded as they overwinter under natural conditions.

Cucujus beetle larvae may not freeze at temperatures below -80C, wood frogs freeze almost solid and survive; arctic ground squirrels lose track of time, become torpid while colder than ice but warm to sleep, even as black bears continuously doze, only occasionally snore, and their hearts beat in a syncopated rhythm. Little is known about the genetic and molecular basis of hibernation, but discovering its mechanisms could lead to novel clinical therapies and escape strategies in humans.

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Date:
Location:
THM 116

"Highlights from 57 Years of Studying the Ecology, Biogeography and Evolution of Seed Dormancy and Germination"

SelfieDr. Carol Baskin 

Abstract:
What controls the timing of seed germination in nature? This question is of much interest because the timing of seed dormancy-break and germination are an important part of the adaptation of a species to its habitat. Thus, we want to know what environmental conditions are required for seed dormancy-break and germination in various kinds of habitats from the tropics to the arctic, i.e. germination ecology.

My first germination experiments were conducted in 1966 when I was a graduate student at Vanderbilt University; I am still expanding my knowledge about seeds of wild plants. My original work/interests have expanded from germination ecology to the world biogeography of nondormancy and of the five classes/kinds of dormancy and to the evolutionary relationships of nondormancy and the classes of dormancy.

I have studied ca. 400 species from Kentucky/Tennessee, as well as species from Hawaii, Tiawan and Sweden. With collaborators, I have been involved in seed germination studies in Argentina, Australia, Brazil, China, India, Iran and Japan. The world biogeography of seed dormancy was part of a book entitled “Seeds: ecology, biogeography, and evolution of dormancy and germination, C.C. Baskin and J.M. Baskin, 1998 (1st ed.) 2014 (2nd ed.), Elsevier/Academic Press,” which contained a complication of data on the world biogeography of seed dormancy for ca. 3,000 (1st ed.) and 13, 600 (2nd ed.) species. This data set provides an overview of seed dormancy of trees, shrubs and herbs in all the major vegetation zones on earth, and it has now been used by various collaborators to help investigate other aspects of seed biology, including the evolution of seed dormancy (i.e. dormancy transition states).  

I am a plant ecologist, and as such I seek information about the fossils and palaeohistory of seeds, embryo morphology, dormancy-breaking and germination requirements of seeds of species in all the major vegetation zones on earth and evolutionary relationships of nondormancy and the five classes of dormancy. Recently, I have been exploring how palaeohistory, biogeography and phylogeny have influenced seed dormancy-breaking and germination requirements in highly species-rich families such as the Asteraceae (ca. 30,000 species, sunflower family), Myrtaceae (ca. 6,000, Eucalyptus family) and Rubiaceae (ca. 13, 460 species, coffee family).

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Date:
Location:
THM 116

"Botanical research at Eastern Kentucky University: Fantastic ferns, conservation and beyond"

SelfieDr. Sally Chambers

Abstract:

Kentucky is a botanically diverse state home to over 2,000 native plants and more than 400 taxa that are of conservation concern. Kentucky’s native plants are phylogenetically diverse, and a subset of taxa reflect Kentucky’s geologic history as tropical relicts. This is especially true for the ferns in Kentucky, as many species occupy sandstone rock shelters which buffer extreme climatic conditions much like cave ecosystems. These microclimatic pockets create unique distribution patterns for the ferns that occupy this niche space, and even further partition the fern life cycle such that some crevices host only gametophytes while others host both gametophyte and sporophyte generations. This talk will focus on decades of work conducted in these unique rock shelter environments and the spatial differentiation of fern generations (gametophyte/sporophyte) in Kentucky, the Appalachians and beyond. Ecological research focusing on topics such as local adaptation, physiological tolerance limits, and population differentiation will be discussed. The remainder of the talk will highlight the botanical resources housed at Eastern Kentucky University and the utility of these natural history collections to scientists worldwide.



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Date:
Location:
THM 116

"The Evolution of Cell Types in the Cerebral Cortex"

SelfieDr. Maria Antonietta Tosches | Tosches Lab

Abstract:

The cerebral cortex is arguably the brain area that underwent the most profound transformations in vertebrate brain evolution. The expansion of the cerebral cortex in mammals was accompanied by an explosion of neuronal diversity. To discover general principles underlying the evolution of neuron types and circuits, we study the simple cerebral cortices of non-mammalian vertebrates. Our recent work has focused on the Spanish newt Pleurodeles waltl, a species with a key phylogenetic position in the vertebrate tree. We are investigating the neuroanatomy, cell type composition, and function of the Pleurodeles brain using a combination of modern neuroscience tools.

Our work on amphibians and reptiles indicates that the cerebral cortex of ancestral tetrapods was layered, with two main classes of neurons with distinct laminar positions, molecular identities, and long-range projections. In salamanders, these two layers are generated sequentially from multipotent progenitors in an outside-in sequence. We propose that in mammals new types of pyramidal neurons evolved from these two ancestral classes by diversification, through the emergence of novel gene regulatory interactions during neuronal differentiation.

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Date:
Location:
THM 116

CANCELLED | "Dissecting Ciliopathies: From Molecular Mechanism to Potential Treatments"

SelfieDr. Samantha Brugmann | Brugmann Lab

Bio:

Dr. Samantha Brugmann is a developmental biologist studying craniofacial development and disease. Her longterm goal is to help children with craniofacial anomalies by generating tissue amenable for surgical repair. To achieve this goal, her lab specifically focuses on the role the primary cilium during craniofacial development and the craniofacial anomalies that arise when the cilium do not function properly. Projects in her lab utilize avian, murine and humaninduced pluripotent stem cells to gain a better understanding of the molecular mechanisms associated with craniofacial anomalies. In addition to using existing animal models to understand human craniofacial disorders, her lab also sequences patients and generates cell-based models to uncover novel genetic causes for craniofacial ciliopathies.



Abstract:

The Brugmann Lab focuses on the understanding molecular and cellular processes important for craniofacial development and the onset of craniofacial anomalies (CFAs). CFAs represent approximately one third of all birth-defects. For the past decade, my research program has centered on treating these conditions by garnering a fundamental understanding of craniofacial development and pathological mechanisms associated with CFAs. We have specifically focused on a class of CFAs called ciliopathies, which are caused by disruptions to a cellular organelle called the primary cilium. Ciliopathies represent a fast-growing group of disorders, that can affect up to 1 in 800 people. My lab was the first to report that the craniofacial complex is the primary organ system affected in 30% of all ciliopathies, and thus coined the term craniofacial ciliopathies. My lab uses murine, avian and human model systems to understand molecular mechanisms associated with ciliopathies. Furthermore, we use these model systems to identify potential therapeutic avenues to treat this class of diseases. 

Date:
Location:
THM 116

"Planarian Stem Cells: A Model for Limitless Regeneration and Renewal"

SelfieDr. Carrie Adler | Adler Lab

Bio:

Carrie is currently an Assistant Professor in the Department of Molecular Medicine at Cornell University, where she started her lab in 2015. She attended college at Wesleyan University and afterwards worked as a technician with Bruce Mayer at Harvard Medical School, studying signal transduction pathways. For graduate school, Carrie enrolled in the Tetrad program at UCSF, joining Cori Bargmann's lab to study neural development in C. elegans. As a postdoc, Carrie trained with Alejandro Sánchez Alvarado at the University of Utah and the Stowers Institute for Medical Research.

Abstract:

Throughout our lives, we are constantly exposed to insults, including injuries, disease, and environmental toxins. Frequently referred to as a ‘fountain of youth’ given their potential for rejuvenation, stem cells have the capacity to restore damaged tissue. In most model organisms, regenerative capacity is limited and stem cells are scarce, which has made it difficult to pinpoint the mechanisms regulating their behavior. In addition, stem cell exhaustion occurs as we age, diminishing our ability to repair damaged tissues. Finally, while we have made significant progress in recapitulating organ growth in vitro, how might these tissues be used in humans to restore physiological function?

My research program has probed these questions in an emerging model organism, planarian flatworms. These animals have long been regarded as champion regenerators because they can rapidly replace any tissue that’s been damaged or lost, including the nervous system. The basis of this unlimited renewal lies in an abundant population of stem cells. My lab’s primary goals are to understand how these cells sense and respond to injury, and how they maintain genome integrity through repeated cell divisions that occur during regeneration.

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Date:
Location:
THM 116

Thomas Hunt Morgan Annual Lecture 2023: "African Integrative Genomics: Implications for Health and Disease"

Selfie Dr. Sarah Tishkoff | Tishkoff Lab

 

Sarah Tishkoff is the David and Lyn Silfen University Professor in Genetics and Biology at the University of Pennsylvania, holding appointments in the School of Medicine and the School of Arts and Sciences. She is also Director of the Penn Center for Global Genomics and Health Equity.

Dr. Tishkoff studies genomic and phenotypic variation in ethnically diverse Africans. Her research combines field work, laboratory research, and computational methods to examine African population history and how genetic variation can affect a wide range of traits – for example, why humans have different susceptibility to disease, how they metabolize drugs, and how they adapt through evolution.

Dr. Tishkoff is a member of the National Academy of Sciences and a recipient of an NIH Pioneer Award, a David and Lucile Packard Career Award, a Burroughs/Wellcome Fund Career Award, an ASHG Curt Stern award, and a Penn Integrates Knowledge (PIK) endowed chair. She is a member of the Scientific Advisory Panel for the Packard Fellowships for Science and Engineering and the Board of Global Health at the National Academy of Sciences and is on the editorial boards at PLOS GeneticsGenome Research; G3 (Genes, Genomes, and Genetics);Cell.

Her research is supported by grants from the National Institutes of Health, the National Science Foundation, the Chan Zuckerberg Institute, and the American Diabetes Association.

Abstract:

Africa is the ancestral homeland of all modern human populations within the past 300,000 years.  It is also a region of tremendous cultural, linguistic, climatic, phenotypic and genetic diversity.   Despite the important role that African populations have played in human history, they remain one of the most underrepresented groups in human genomics studies. A comprehensive knowledge of patterns of variation in African genomes is critical for a deeper understanding of human evolutionary history and the identification of functionally important genetic variation that plays a role in both normal variation and disease risk.  Here I will describe our studies of genomic variation in ethnically and geographically diverse Africans in order to reconstruct human evolutionary history and identify candidate genes that play a role in adaptation to infectious disease, diet, high altitude, stature, and skin color. I will highlight recent research integrating data from a genome wide association study of skin pigmentation in Africans and scans of natural selection from whole genome sequencing. Combining high-throughput reporter assays, Hi-C, CRISPR-based editing, and melanin content assays, we identified novel regulatory variants that impact melanin levels in vitro and modulate human skin color variation. Additionally, we identified a novel gene regulating pigmentation by impacting genes involved in oxidative phosphorylation and melanogenesis. These results provide insights into the mechanisms underlying human skin color diversity and adaptive evolution.

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Invite

Date:
Location:
THM 116

"The Promise and Practice of Inclusive Education"

SelfieDr. Bryan Dewsbury | Dewsbury Lab

Bio:

Bryan Dewsbury is an Associate Professor of Biology at Florida International University where he also is an Associate Director of the STEM Transformation Institute. He received is Bachelors degree in Biology from Morehouse College in Atlanta, GA, and his Masters and PhD in Biology from Florida International University in Miami, FL. He is the Principal Investigator of the Science Education And Society (SEAS) program, where his team conducts research on the social context of education. He is a Fellow of the John N. Gardner Institute and a Director at RIOS (Racially-Just Inclusive Open Science) institute. He conducts faculty development and support for institutions interested in transforming their educational practices pertaining to creating inclusive environments and, in this regard, has worked with over 100 institutions across North America, United Kingdom and West Africa. He is a co-author of the book 'Norton's Guide to Equity-Minded Teaching', available for free as an E-book. He is the founder of the National Science Foundation (NSF) funded Deep Teaching Residency, a national workshop aimed at supporting faculty in transforming their classroom to more meaningfully incorporate inclusive practices. He is the creator of the MOOC called 'Inclusive Teaching' sponsored by HHMI Biointeractive which will be released on August 15th. Bryan is originally from the Republic of Trinidad and Tobago and proudly still calls the twin island republic home.

Abstract:

Education holds the promise of preparing students to be engaged, thriving participants in a socially just democracy. For that ideal to occur, the structure and experience of the classroom must reflect both its constituents and consider the socially just imaginaries in which we would all like to inhabit. Using examples from the civil rights era's interrogation of our society, we will explore how an introductory biology course can help fulfill higher

education's civic mission.



Check out his book here!

Check out his HHMI/Inclusive Teaching trailer here!



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Date:
Location:
THM 116

"Mountains as Biodiversity Hotspots through Time: Integrating Fossils with Tectonics and Climate"

SelfieDr. 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.

 

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Date:
Location:
THM 116

“Behavioral Syndromes: Evolutionary Constraints and Adaptive Explanations”

SelfieNed 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.

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PmacCricket

Date:
Location:
THM 116
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