August 2020 - oeb_non-oeb_graduate_students@lists.fas.harvard.edu

[Oeb_non-oeb_graduate_students] [Oeb-all] REMINDER: Please take the OEB Climate Survey!

by Kramer, Elena M.

Dear OEB Community, You still have three weeks left to respond to the OEB Climate Survey, but please do it now! So far, about 20% of our community has responded, which is a great start, but we want a solid majority of members to respond and we can’t achieve that without your help. Please let us know if you have any difficulties with the link. Cheers, Elena Begin forwarded message: From: "Amorim, Jose M." <jamorim(a)fas.harvard.edu<mailto:jamorim@fas.harvard.edu>> Subject: Please take the OEB Climate Survey! Date: August 13, 2020 at 7:45:43 PM EDT To: "Kramer, Elena M." <ekramer(a)oeb.harvard.edu<mailto:ekramer@oeb.harvard.edu>> Dear Members of the OEB Community, As you may know, the University has made a commitment to transform Harvard into a place where all the members of its increasingly diverse community know and feel that they truly belong. This effort was begun by President Drew Faust, was examined and reported on by the Presidential Task Force on Inclusion and Belonging, and action is being taken now under President Larry Bacow. If you haven’t already done so, I encourage you to take a look at the task force’s website and particularly the “call to action,” which outlines the simple, daily ways in which we can all help with this effort. https://inclusionandbelongingtaskforce.harvard.edu/call-action Locally, at OEB we are deeply committed to strengthening our community as a welcoming place in which each and every member enjoys an equal and unimpeded opportunity to thrive. Our offices, labs, and classrooms should be places where we can all do our best work, in an environment that encourages tolerance, collegiality, and respect. In order to reach the highest level of academic excellence, we must also excel in inclusive excellence. Our first step towards the goal of realizing inclusive excellence is to learn what we are doing well and where we need improvement. This is where we need your help. Below you will find a link to a survey of students, faculty, staff and administrators regarding the climate in the OEB Department. Participation in this assessment is voluntary. The survey is completely anonymous. Survey data will analyzed by Harvard College Institutional Research - an independent party. The survey will be open through Friday, September 11. Results will be presented at a department-wide Community Town Hall Forum on Diversity, Inclusion, and Belonging (details to be announced). If you have any questions, concerns, or comments regarding any of these matters, please do not hesitate to reach out to Elena Kramer (ekramer(a)oeb.harvard.edu<mailto:ekramer@oeb.harvard.edu>) or Sarine der Kaloustian (sarine_derkaloustian(a)fas.harvard.edu<mailto:sarine_derkaloustian@fas.harvard.edu>). We thank you greatly in advance for your valuable input and honesty, and look forward to working with you on this very important effort. Please follow the survey link: https://harvard.az1.qualtrics.com/jfe/form/SV_1AffCnq3GIT9vMN Best regards, Elena Elena M. Kramer, Ph.D. (she, hers) Bussey Professor of Organismic and Evolutionary Biology Chair, Dept. of Organismic and Evolutionary Biology Interim Director, Harvard University Herbaria Harvard University 16 Divinity Ave Biolabs 1119A Cambridge MA 02138 Office (617)496-3460 (do not leave message) Lab (617)384-7820 ekramer(a)oeb.harvard.edu<mailto:ekramer@oeb.harvard.edu> ******************************************* Elena M. Kramer, Ph.D. (she, hers) Bussey Professor of Organismic and Evolutionary Biology Chair, Dept. of Organismic and Evolutionary Biology Interim Director, Harvard University Herbaria Harvard University 16 Divinity Ave Biolabs 1119A Cambridge MA 02138 Office (617)-496-3460 (do not leave message) Lab (617)384-7820 ekramer(a)oeb.harvard.edu<mailto:ekramer@oeb.harvard.edu> _______________________________________________ Oeb-all mailing list Oeb-all(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb-all _______________________________________________ Oeb_affiliation mailing list Oeb_affiliation(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb_affiliation

3 years, 9 months

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[Oeb_non-oeb_graduate_students] [Oeb-all] Dissertation Defense - Kari Taylor-Burt - Tomorrow, Wednesday, August 19

by Carmosino, Lydia

Dear All, Please join us for Kari Taylor-Burt's dissertation defense tomorrow - Wednesday, August 19, at 11:00 AM. Kari will provide a public talk, followed by a private defense with her committee, via Zoom. Zoom Details: https://harvard.zoom.us/j/97136996576?pwd=NTJ5RzJsblZWRjE0cUZGUzZML1kwdz09 Meeting ID-971 3699 6576 Password-783674 Title: How to waddle with a paddle: a study of duck hindlimb anatomy, kinematics, and muscle function across behaviors and species Committee: Andrew Biewener (Advisor), George Lauder, Stephanie Pierce, Thomas Roberts (Brown U.) Abstract: The most impressive animal movements often arise from animals that have specialized their anatomy, muscle function, and kinematics (the way they move) for a specific behavior or environment. However, specialization may come at a cost, as most animals require their structures and muscles to perform multiple behaviors. Despite the specialization of their hindlimb (pelvic limb) for swimming, ducks are able to use their hindlimbs to move on land and to takeoff, in addition to swimming at the surface and diving. How are they able to use the same structures (the hindlimb, pelvis, and foot) and muscles that drive them to perform so many behaviors? What structures and traits are associated with their specialization for aquatic locomotion, and are there tradeoffs in locomotor ability that come with this specialization? In my dissertation, I begin to explore the answers to these questions by studying the kinematics (Ch. 1, 3), muscle function (Ch. 1, 2), and anatomy of ducks (Ch. 3) across behaviors and across the duck phylogeny. In Chapter 1, I examined kinematics and function of a bi-articular hindlimb muscle, the lateral gastrocnemius (LG), during aquatic and terrestrial takeoffs in mallard ducks. Unlike many waterbirds, mallards are capable of vertical takeoffs from both land and water, regimes where force production and demands on the animal differ. Mallards change their kinematics and LG function with takeoff medium. Importantly, the knee moves in the opposite direction, extending during terrestrial takeoff to launch the body into the air but flexing during aquatic takeoff to contribute to caudal motion of the foot. The LG powers both ankle extension and knee flexion, so it undergoes larger excursions and higher shortening velocities during aquatic takeoffs than terrestrial, making tuning of the muscle's force-length and force-velocity properties across takeoff media challenging. The function of the mallard LG was explored in greater depth in Chapter 2 by focusing on how it operates during cyclical behaviors like walking and swimming. Post-activation potentiation (PAP) is a less well-studied physiological property of muscle that represents an increase in force and rate of force development in muscle after recent activation. PAP could therefore impact LG function during behaviors that require repeated muscle activation. Using an in situ muscle preparation, I controlled mallard LG cycle frequency, length change, and activation parameters to mimic surface swimming. As hypothesized, PAP affected LG function, resulting in a gradual increase in muscle force, rate of force development, and work production over several cycles despite no change in activation. The degree of PAP depended on cycle frequency. This work was novel because our knowledge of mallard LG function during cyclical behaviors in vivo allowed me to make a strong connection between these behaviors and PAP of the muscle observed in situ. Ducks exhibit a wide range of swimming abilities, including highly terrestrial species, ducks that swim well but only at the surface, foot-propelled divers, and wing-and-foot-propelled divers. In Chapter 3, I explored how anatomy and movement relate to specialization for swimming in ducks. Some hindlimb structures differed among behavioral groups, including the proportional length of the femur and tarsometatarsus, the shape of the femur and tibiotarsus, and the lateral cnemial crest size. However, only the increased size of the cnemial crest is consistent with the anatomical features seen in other avian swimming specialists and is thought to contribute to increased knee stabilization (by increasing the moment arm of knee extensors) and to powering distal limb movement (by increasing attachment surface for the digital flexors). I examined how kinematics varied among surface swimmers (mallards), foot-propelled divers (scaup), and wing-propelled divers (eiders) during walking, surface swimming, and diving. All three species increased speed by increasing stride length for all behaviors. Cycle frequency was increased with speed only during walking, remaining constant during surface swimming and diving. Eiders increased stride length with diving speed more rapidly than the others, perhaps enabled by their simultaneous use of wings and feet. During walking, eiders used higher cycle frequencies and both eiders and scaup exhibited higher body angles, perhaps an indication of lower terrestrial stability than the surface swimming mallards. ___________________________________________________ Lydia Carmosino Senior Academic Programs Administrator Department of Organismic and Evolutionary Biology Harvard University * 26 Oxford Street * Cambridge, MA 02138 lydia_carmosino(a)harvard.edu<mailto:lydia_carmosino@harvard.edu> _______________________________________________ Oeb-all mailing list Oeb-all(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb-all _______________________________________________ Oeb_affiliation mailing list Oeb_affiliation(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb_affiliation

3 years, 10 months

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[Oeb_non-oeb_graduate_students] [Oeb-all] Dissertation Defense - Zachary Morris - Tomorrow, Tuesday, August 18

by Carmosino, Lydia

Dear All, Please join us for Zachary Morris's dissertation defense tomorrow - Tuesday, August 18, at 9:00 AM. Zachary will provide a public talk, followed by a private defense with his committee, via Zoom. Zoom Details: https://harvard.zoom.us/j/92546896907?pwd=M0V4N2hVTk5DMHRhZmx5KzR2OTZtUT09 Meeting ID-925 4689 6907 Password-783674 Title: Developmental and evolutionary origins of the crocodylian snout and amniote face Committee: Stephanie Pierce (advisor), Arkhat Abzhanov, James Hanken, Elena Kramer, Clifford Tabin Abstract: Crocodylians (alligators, crocodiles, and gharial) are instantly recognizable by their flattened skulls and tooth-filled jaws, an adaptation which aids in capturing prey in shallow water and along riverbanks. A popular perception is that crocodylians have remained unchanged ever since the time non-avian dinosaurs roamed the Earth and that all species are anatomically very similar. However, this group has a rich fossil record with impressive variation in skull anatomy and ecology, including terrestrial ancestors that superficially resemble later evolving dinosaurs, marine lineages with incredibly elongated snouts (region of the face in front of the eyes) and tail fins, and short, pug-faced herbivores with mammal-like molars. Within their general semi-aquatic habitat, living species also display substantial variation in snout shape and dietary ecology, including 'slender' forms with long snouts that specialize on fast swimming fish, 'moderate' forms like Alligator which have a generalized diet, and 'blunt' snouted forms which process more tough, shelled prey. Arguably, crocodylians and their extinct relatives display the greatest variation in the proportions of the snout of all amniotes (mammals, reptiles, and birds). These different snout forms are often used as examples of adaptation because similar shapes have convergently evolved many times in both living forms and their extinct relatives. Although the phylogenetic relationships, anatomy, biomechanics, and post-hatching growth of crocodylians have been previously studied, the developmental origins of the crocodylian skull remain poorly understood. In this dissertation, I explore the embryonic development of the crocodylian skull to assess mechanisms of snout shape evolution in living crocodylians, their stem-lineage, and amniotes more generally. In Chapter 1, I use micro-computed tomography and digital photography to assemble the first geometric morphometric (GMM) dataset of embryonic and post-hatching crocodylian skull shape, quantify species-specific developmental patterns, and reconstruct the evolution of skull development within Crocodylia. This analysis reveals that most species develop from a conserved embryonic shape (highlighting a developmental constraint) and that changes in the timing and rate of snout elongation and widening (i.e., heterochrony) were key mechanisms in the convergent evolution of similar snout shapes. In Chapter 2, I expand this GMM dataset to include extinct relatives of crocodylians, implement a new method to quantify organization and patterns of skull shape in stem-crocodylians, and assess the ecological and developmental mechanisms driving patterns of skull shape across more than 200 million years of crocodylian evolution. While skull shape disparity of the earliest stem-crocodylians was highly distinct, skull evolution within Crocodylomorpha followed modern crocodylian developmental 'lines of least resistance', suggesting crocodylian-like skull development likely evolved by the Jurassic. In Chapter 3, I review the processes involved in the developmental formation of the amniote face and present preliminary data on the role of cellular proliferation in crocodylian snout development, which suggests current models for skull development cannot explain the origins of amniote facial disparity. Although more data are needed to understand the molecular mechanisms underlying the origins of facial disparity among and within amniote clades, in this dissertation I am able to identify anatomical and cellular components of development that were critical for the origin of the crocodylian skull and are key mechanisms underlying convergence. ___________________________________________________ Lydia Carmosino Senior Academic Programs Administrator Department of Organismic and Evolutionary Biology Harvard University * 26 Oxford Street * Cambridge, MA 02138 lydia_carmosino(a)harvard.edu<mailto:lydia_carmosino@harvard.edu> _______________________________________________ Oeb-all mailing list Oeb-all(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb-all _______________________________________________ Oeb_affiliation mailing list Oeb_affiliation(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb_affiliation

3 years, 10 months

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[Oeb_non-oeb_graduate_students] [Oeb-all] Please check you inbox: OEB Climate Survey

by Kramer, Elena M.

Dear OEB Community, Last night you should have all received a very important message from Jose Amorim with the subject line Please take the OEB Climate Survey! This is the moment we’ve been working towards for two months so please take ~10 minutes to fill out the survey. We very much want to hear from ALL of you. The survey will be open for a month, and I will keep reminding you, but there is no time like the present! I assure you, the survey is completely anonymous. No one from OEB will ever see the raw data and all the analysis will be done by a different organization in FAS. If you have any questions about the survey or the analysis process, please feel free to reach out to Benita Wolff at benita_wolff(a)fas.harvard.edu<mailto:benita_wolff@fas.harvard.edu>. Have a good weekend. Cheers, Elena ******************************************* Elena M. Kramer, Ph.D. (she, hers) Bussey Professor of Organismic and Evolutionary Biology Chair, Dept. of Organismic and Evolutionary Biology Interim Director, Harvard University Herbaria Harvard University 16 Divinity Ave Biolabs 1119A Cambridge MA 02138 Office (617)496-3460 (do not leave message) Lab (617)384-7820 ekramer(a)oeb.harvard.edu<mailto:ekramer@oeb.harvard.edu> _______________________________________________ Oeb-all mailing list Oeb-all(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb-all _______________________________________________ Oeb_affiliation mailing list Oeb_affiliation(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb_affiliation

3 years, 10 months

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[Oeb_non-oeb_graduate_students] [Oeb-all] Important Updates

by Kramer, Elena M.

Hi Everyone, These updates when out to PIs and COVID safety officers but I want to make sure that everyone gets them. Please let me, Becky or Sarine know if you have any questions. Cheers, Elena UPDATES FOR THIS WEEK: * HUHS is delaying the implementation of mandatory weekly testing until the new system is in place, which we expect to be no later than the end of August. Dean Stubb's has advised Science Division colleagues to not schedule additional tests at this point, but rather to await the implementation of the next-gen system. Please see his FAS Divison of Science Update email from August 12th. Returning lab personnel that have not had their initial baseline screening should make an appointment through HUHS to complete the baseline requirement. * The Parking Office has announced new, significantly discounted parking options including $10 day passes and different monthly options starting at $35 per month. For more information, please see https://www.transportation.harvard.edu/covidparking. * Harvard created a new website for reentry to campus - refer this site to new or newly-returning group members: https://www.harvard.edu/coronavirus/planning-2020-21/steps-for-office-and-l… * All those who can successfully work remotely should continue to do so - As we work to maintain a low occupancy on campus, here is a reminder from the July 2020 return-to-campus work policy: "Harvard’s current policy is that, 'all those who can successfully work remotely should continue to do so.' This applies to all members of the Harvard community, including staff, faculty, students, and postdocs." ******************************************* Elena M. Kramer, Ph.D. (she, hers) Bussey Professor of Organismic and Evolutionary Biology Chair, Dept. of Organismic and Evolutionary Biology Interim Director, Harvard University Herbaria Harvard University 16 Divinity Ave Biolabs 1119A Cambridge MA 02138 Office (617)496-3460 (do not leave message) Lab (617)384-7820 ekramer(a)oeb.harvard.edu<mailto:ekramer@oeb.harvard.edu> _______________________________________________ Oeb-all mailing list Oeb-all(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb-all _______________________________________________ Oeb_affiliation mailing list Oeb_affiliation(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb_affiliation

3 years, 10 months

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[Oeb_non-oeb_graduate_students] [Oeb-all] How are you?

by Kramer, Elena M.

Dear OEB Community, No, really, I would like to know how you are doing. Let’s face it, this has been a rough five months for all of us and perhaps the hardest part is that it’s not over yet. Whether you want to label it anxiety, depression, frustration, “quarantine blues<https://www.npr.org/sections/health-shots/2020/05/10/849164258/too-much-alo…>”, or the “pandemic wall<https://www.nytimes.com/2020/08/05/opinion/coronavirus-mental-illness-depre…>”, we’re all struggling to some degree or another. We’re basically running a marathon that we didn’t sign up for, so what can you do? Actually, there are a lot of resources and, perhaps more importantly, a lot of skilled people who want to help you. First, I want to point you towards the Employee Assistance Program<https://hr.harvard.edu/employee-assistance-program>, which is operated by KGA Human Resources<https://my.kgalifeservices.com/?org_code=harvard>. If you haven’t checked out their website or given them a call, I strongly encourage you to do so. Their whole purpose is to help you navigate Harvard benefits and resources. If you can’t figure out whether Harvard has a program or service that can help you, they are the ones to talk to. You might be surprised at how many options there actually are. Another helpful resource is the Rosenthal Center for Wellness and Health Promotion<https://wellness.huhs.harvard.edu/virtual-resources>, which runs a wide away of programs, including a lot of yoga and meditation options, all of which are free to Harvard employees. For our graduate students, I would strongly encourage you to reach out to Danielle Farrell<https://gsas.harvard.edu/person/danielle-farrell>. Danielle’s role is to connect with students who may be experiencing academic or personal challenges to provide them support, help them navigate and connect to resources, and strategize and problem-solve. Please feel free to set-up an appointment at https://gsasstuserv.youcanbook.me/ or email her directly (farrell(a)fas.harvard.edu<mailto:farrell@fas.harvard.edu>). She can meet via Zoom or speak on the phone, whatever works best for you! If you have been missing your OEB colleagues, the good news is that Wendy Heywood has been very busy updating the department website<https://oeb.harvard.edu/news-events> and putting together a fantastic newsletter<https://oeb.harvard.edu/newsletter>. You will see that there are some great OEB seminars coming up this fall, and other social events will be starting as well, including Happy Hours. And remember, I have office hours on Wednesday afternoons at 4pm<https://harvard.zoom.us/j/94550500868?pwd=c0E0bVRveC9KRk1HZVFSRFVTYUtGdz09>, stop by anytime. Take care of yourselves! Cheers, Elena ******************************************* Elena M. Kramer, Ph.D. (she, hers) Bussey Professor of Organismic and Evolutionary Biology Chair, Dept. of Organismic and Evolutionary Biology Interim Director, Harvard University Herbaria Harvard University 16 Divinity Ave Biolabs 1119A Cambridge MA 02138 Office (617)496-3460 (do not leave message) Lab (617)384-7820 ekramer(a)oeb.harvard.edu<mailto:ekramer@oeb.harvard.edu> _______________________________________________ Oeb-all mailing list Oeb-all(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb-all _______________________________________________ Oeb_affiliation mailing list Oeb_affiliation(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb_affiliation

3 years, 10 months

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[Oeb_non-oeb_graduate_students] [Oeb-all] OEB 2019-2020 Newsletter is here!

by Heywood, Wendy

Dear OEB, The 2019-2020 OEB Newsletter is now available online. In this issue you will find news and events that have happened during the academic year and upcoming events for the 2020-2021 academic year. We hope you enjoy the issue! https://oeb.harvard.edu/newsletter Best wishes, -Wendy -- Wendy Heywood Communications and Events Coordinator Organismic and Evolutionary Biology Harvard University 26 Oxford Street, Cambridge, MA 02138 ph: 617-496-4639 f: 617-496-8308 e: wheywood(a)oeb.harvard.edu<mailto:wheywood@oeb.harvard.edu> [/Users/wheywood/Library/Containers/com.microsoft.Outlook/Data/Library/Caches/Signatures/signature_2041373930]Harvard_oeb | [/Users/wheywood/Library/Containers/com.microsoft.Outlook/Data/Library/Caches/Signatures/signature_2094839069] Harvardoeb Consider the environment. Please print this email only if necessary. [cid:image001.jpg@01D394FF.B8954D00] _______________________________________________ Oeb-all mailing list Oeb-all(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb-all _______________________________________________ Oeb_affiliation mailing list Oeb_affiliation(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb_affiliation

3 years, 10 months

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[Oeb_non-oeb_graduate_students] Ernst Mayr Library update

by Flynn FAS, Christian

A message from Mary Sears and Connie Rinaldo, Ernst Mayr Library: Dear MCZ and OEB, Harvard Library has approved a limited re-occupancy for the Ernst Mayr Library. Mary will be in Mondays, beginning August 10, from 10-2; Connie on Wednesdays 8-12. No users can come into the library but we will help however we can. Let us know what we can do for you. We are looking forward to being in the library! Connie and Mary

3 years, 10 months

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[Oeb_non-oeb_graduate_students] [Oeb-all] Dissertation Defense - Kari Taylor-Burt - Wednesday, August 19

by Carmosino, Lydia

Dear All, Please join us for Kari Taylor-Burt's dissertation defense on Wednesday, August 19, at 11:00 AM. Kari will provide a public talk, followed by a private defense with her committee, via Zoom. Zoom Details: https://harvard.zoom.us/j/97136996576?pwd=NTJ5RzJsblZWRjE0cUZGUzZML1kwdz09 Meeting ID-971 3699 6576 Password-783674 Title: How to waddle with a paddle: a study of duck hindlimb anatomy, kinematics, and muscle function across behaviors and species Committee: Andrew Biewener (Advisor), George Lauder, Stephanie Pierce, Thomas Roberts (Brown U.) Abstract: The most impressive animal movements often arise from animals that have specialized their anatomy, muscle function, and kinematics (the way they move) for a specific behavior or environment. However, specialization may come at a cost, as most animals require their structures and muscles to perform multiple behaviors. Despite the specialization of their hindlimb (pelvic limb) for swimming, ducks are able to use their hindlimbs to move on land and to takeoff, in addition to swimming at the surface and diving. How are they able to use the same structures (the hindlimb, pelvis, and foot) and muscles that drive them to perform so many behaviors? What structures and traits are associated with their specialization for aquatic locomotion, and are there tradeoffs in locomotor ability that come with this specialization? In my dissertation, I begin to explore the answers to these questions by studying the kinematics (Ch. 1, 3), muscle function (Ch. 1, 2), and anatomy of ducks (Ch. 3) across behaviors and across the duck phylogeny. In Chapter 1, I examined kinematics and function of a bi-articular hindlimb muscle, the lateral gastrocnemius (LG), during aquatic and terrestrial takeoffs in mallard ducks. Unlike many waterbirds, mallards are capable of vertical takeoffs from both land and water, regimes where force production and demands on the animal differ. Mallards change their kinematics and LG function with takeoff medium. Importantly, the knee moves in the opposite direction, extending during terrestrial takeoff to launch the body into the air but flexing during aquatic takeoff to contribute to caudal motion of the foot. The LG powers both ankle extension and knee flexion, so it undergoes larger excursions and higher shortening velocities during aquatic takeoffs than terrestrial, making tuning of the muscle's force-length and force-velocity properties across takeoff media challenging. The function of the mallard LG was explored in greater depth in Chapter 2 by focusing on how it operates during cyclical behaviors like walking and swimming. Post-activation potentiation (PAP) is a less well-studied physiological property of muscle that represents an increase in force and rate of force development in muscle after recent activation. PAP could therefore impact LG function during behaviors that require repeated muscle activation. Using an in situ muscle preparation, I controlled mallard LG cycle frequency, length change, and activation parameters to mimic surface swimming. As hypothesized, PAP affected LG function, resulting in a gradual increase in muscle force, rate of force development, and work production over several cycles despite no change in activation. The degree of PAP depended on cycle frequency. This work was novel because our knowledge of mallard LG function during cyclical behaviors in vivo allowed me to make a strong connection between these behaviors and PAP of the muscle observed in situ. Ducks exhibit a wide range of swimming abilities, including highly terrestrial species, ducks that swim well but only at the surface, foot-propelled divers, and wing-and-foot-propelled divers. In Chapter 3, I explored how anatomy and movement relate to specialization for swimming in ducks. Some hindlimb structures differed among behavioral groups, including the proportional length of the femur and tarsometatarsus, the shape of the femur and tibiotarsus, and the lateral cnemial crest size. However, only the increased size of the cnemial crest is consistent with the anatomical features seen in other avian swimming specialists and is thought to contribute to increased knee stabilization (by increasing the moment arm of knee extensors) and to powering distal limb movement (by increasing attachment surface for the digital flexors). I examined how kinematics varied among surface swimmers (mallards), foot-propelled divers (scaup), and wing-propelled divers (eiders) during walking, surface swimming, and diving. All three species increased speed by increasing stride length for all behaviors. Cycle frequency was increased with speed only during walking, remaining constant during surface swimming and diving. Eiders increased stride length with diving speed more rapidly than the others, perhaps enabled by their simultaneous use of wings and feet. During walking, eiders used higher cycle frequencies and both eiders and scaup exhibited higher body angles, perhaps an indication of lower terrestrial stability than the surface swimming mallards. ___________________________________________________ Lydia Carmosino Senior Academic Programs Administrator Department of Organismic and Evolutionary Biology Harvard University * 26 Oxford Street * Cambridge, MA 02138 lydia_carmosino(a)harvard.edu<mailto:lydia_carmosino@harvard.edu> _______________________________________________ Oeb-all mailing list Oeb-all(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb-all _______________________________________________ Oeb_affiliation mailing list Oeb_affiliation(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb_affiliation

3 years, 10 months

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[Oeb_non-oeb_graduate_students] [Oeb-all] Dissertation Defense - Zachary Morris - Tuesday, August 18

by Carmosino, Lydia

Dear All, Please join us for Zachary Morris's dissertation defense on Tuesday, August 18, at 9:00 AM. Zachary will provide a public talk, followed by a private defense with his committee, via Zoom. Zoom Details: https://harvard.zoom.us/j/92546896907?pwd=M0V4N2hVTk5DMHRhZmx5KzR2OTZtUT09 Title: Developmental and evolutionary origins of the crocodylian snout and amniote face Meeting ID-925 4689 6907 Password-783674 Committee: Stephanie Pierce (advisor), Arkhat Abzhanov, James Hanken, Elena Kramer, Clifford Tabin Abstract: Crocodylians (alligators, crocodiles, and gharial) are instantly recognizable by their flattened skulls and tooth-filled jaws, an adaptation which aids in capturing prey in shallow water and along riverbanks. A popular perception is that crocodylians have remained unchanged ever since the time non-avian dinosaurs roamed the Earth and that all species are anatomically very similar. However, this group has a rich fossil record with impressive variation in skull anatomy and ecology, including terrestrial ancestors that superficially resemble later evolving dinosaurs, marine lineages with incredibly elongated snouts (region of the face in front of the eyes) and tail fins, and short, pug-faced herbivores with mammal-like molars. Within their general semi-aquatic habitat, living species also display substantial variation in snout shape and dietary ecology, including 'slender' forms with long snouts that specialize on fast swimming fish, 'moderate' forms like Alligator which have a generalized diet, and 'blunt' snouted forms which process more tough, shelled prey. Arguably, crocodylians and their extinct relatives display the greatest variation in the proportions of the snout of all amniotes (mammals, reptiles, and birds). These different snout forms are often used as examples of adaptation because similar shapes have convergently evolved many times in both living forms and their extinct relatives. Although the phylogenetic relationships, anatomy, biomechanics, and post-hatching growth of crocodylians have been previously studied, the developmental origins of the crocodylian skull remain poorly understood. In this dissertation, I explore the embryonic development of the crocodylian skull to assess mechanisms of snout shape evolution in living crocodylians, their stem-lineage, and amniotes more generally. In Chapter 1, I use micro-computed tomography and digital photography to assemble the first geometric morphometric (GMM) dataset of embryonic and post-hatching crocodylian skull shape, quantify species-specific developmental patterns, and reconstruct the evolution of skull development within Crocodylia. This analysis reveals that most species develop from a conserved embryonic shape (highlighting a developmental constraint) and that changes in the timing and rate of snout elongation and widening (i.e., heterochrony) were key mechanisms in the convergent evolution of similar snout shapes. In Chapter 2, I expand this GMM dataset to include extinct relatives of crocodylians, implement a new method to quantify organization and patterns of skull shape in stem-crocodylians, and assess the ecological and developmental mechanisms driving patterns of skull shape across more than 200 million years of crocodylian evolution. While skull shape disparity of the earliest stem-crocodylians was highly distinct, skull evolution within Crocodylomorpha followed modern crocodylian developmental 'lines of least resistance', suggesting crocodylian-like skull development likely evolved by the Jurassic. In Chapter 3, I review the processes involved in the developmental formation of the amniote face and present preliminary data on the role of cellular proliferation in crocodylian snout development, which suggests current models for skull development cannot explain the origins of amniote facial disparity. Although more data are needed to understand the molecular mechanisms underlying the origins of facial disparity among and within amniote clades, in this dissertation I am able to identify anatomical and cellular components of development that were critical for the origin of the crocodylian skull and are key mechanisms underlying convergence. ___________________________________________________ Lydia Carmosino Senior Academic Programs Administrator Department of Organismic and Evolutionary Biology Harvard University * 26 Oxford Street * Cambridge, MA 02138 lydia_carmosino(a)harvard.edu<mailto:lydia_carmosino@harvard.edu> _______________________________________________ Oeb-all mailing list Oeb-all(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb-all _______________________________________________ Oeb_affiliation mailing list Oeb_affiliation(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/oeb_affiliation

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oeb_non-oeb_graduate_students August 2020