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"Be Fruitful and Multiply: How Reproductive Capacity Evolves"

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Dr. Cassandra Extavour | Extavour Lab

Bio
Cassandra Extavour is a native of Toronto, where she attended the University of Toronto Schools and went on to obtain an Honors BSc at the University of Toronto with a specialist in Molecular Genetics and Molecular Biology, a Major in Mathematics and a Minor in Spanish. She obtained her PhD with Antonio Garcia Bellido at the Severo Ochoa Center for Molecular Biology at the Autonomous University of Madrid. She performed postdoctoral work first with Michalis Averof at the Institute for Molecular Biology and Biotechnology in Crete, Greece, and subsequently with Michael Akam at the University of Cambridge. At Cambridge she received a BBSRC Research Grant and became a Research Associate in the Department of Zoology. In 2007 she established her independent laboratory as an Assistant Professor in the Department of Organismic and Evolutionary Biology at Harvard University, where she was promoted to Associate Professor in 2011 and to Full Professor in 2014. In 2021 she became a Howard Hughes Medical Institute Investigator, and was named the Timken Professor of Organismic and Evolutionary Biology and of Molecular and Cellular Biology at Harvard. Click here to read more.

Abstract:
Reproduction is a crucial fitness parameter, essential for species survival and evolution. Despite its importance, there is massive variation in reproductive capacity across animals, even between very closely related species. Moreover, reproductive capacity can be modified by environmental and ecological factors. Our aim is to understand how genetic variation interacts with ecological variation to regulate distinct and reproductive capacities between species, to determine whether and how ecological variation contributes to the evolution of adaptive variation in reproductive capacity. Our approach takes advantage of the fact that in sexually reproducing animals, the number of offspring that an individual can produce is often predicted by the anatomy of the ovary or testis, the sites of gamete production. In female insects, ovaries are subdivided into egg-producing units called ovarioles, which are generated in species-specific numbers during development. Ovariole number, and correspondingly reproductive capacity, can vary by more than four orders of magnitude across insects. I will discuss our findings on the mechanisms of genetic and environmental control of ovariole number in closely and distantly related insect species, and their implications for the broader questions of the genetic and developmental basis of fitness-relevant evolutionary change.

Date:
Location:
THM 116

"Insights from a Quarter Century of Work on the Ecology of Behavioral Syndromes"

Selfie Dr. Andy Sih | Sih Lab

Andy Sih’s laboratory works on the evolution of ecologically important behaviors (predator-prey, mating, and social behaviors) life history traits, and how these influence population and community ecological patterns,  Most projects examine freshwater organisms e.g., fish amphibian larvae, crayfish, insects and other freshwater invertebrates.  Current applied ecological interests include studying effects of pesticides on predator-prey interactions, and behavioral mechanisms underlying species invasions.

 

 

 

 

FishLizardReproduction

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Date:
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Location:
JSB 161N

"Timekeeping in Latitudinal Avian Migrants: A Story from Buntings"

SelfieDr. Vinod Kumar | Kumar Lab

Abstract:

Cycles in biological systems are all-pervasive in nature. Birds, like any other species, express daily rhythms in activity/rest, hormone secretion, and several other rhythmic characteristics. Most bird species also show long-term cycles in feeding behavior, body fattening (in migrants), reproduction, molt, or migration. Both daily and seasonal behaviors are under the strict control of the endogenous clock mechanisms, but the role of the environment remains critical for optimal performance and ultimately survival. Synchrony with the environment is achieved through the interaction of clock components with external cues (e.g. photoperiod), and internal coordination among different rhythmic physiological correlates is achieved through neural and endocrine signaling. Thus, we are interested to learn about how birds achieve precision in timing their daily and seasonal activities in sync with the periodic environment. Our research effort mainly centers around the “Avian Circadian and Seasonal Systems: Study from Behavior to Molecules”. The working hypothesis has been that specialized cells localized in different tissues express genes involved in the clock circuitry, and different cell populations control the food intake, body fattening, reproductive axis, molt, and migration, in a way that each event can be timed and spaced with each other to optimize an ecological adaptation. 

Date:
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Location:
THM 116
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