San Jose State University SJSU ScholarWorks Faculty Publications, Biological Sciences Biological Sciences May 2008 Life on the Edge: Morphological and Behavioral Adaptations for Survival on Wave-swept Shores Luke P. Miller Stanford University, [email protected] Follow this and additional works at: https://scholarworks.sjsu.edu/biol_pub Part of the Biology Commons Recommended Citation Luke P. Miller. "Life on the Edge: Morphological and Behavioral Adaptations for Survival on Wave-swept Shores" Faculty Publications, Biological Sciences (2008). This Dissertation is brought to you for free and open access by the Biological Sciences at SJSU ScholarWorks. It has been accepted for inclusion in Faculty Publications, Biological Sciences by an authorized administrator of SJSU ScholarWorks. For more information, please contact [email protected]. LIFE ON THE EDGE: MORPHOLOGICAL AND BEHAVIORAL ADAPTATIONS FOR SURVIVAL ON WAVE-SWEPT SHORES A DISSERTATION SUBMITTED TO THE DEPARTMENT OF BIOLOGY AND THE COMMITTEE ON GRADUATE STUDIES OF STANFORD UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Luke Paul Miller May 2008 © Copyright by Luke Paul Miller 2008 All Rights Reserved ii I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. ____________________________________ Mark W. Denny (Principal Adviser) I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. ____________________________________ George N. Somero I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. ____________________________________ Fiorenza Micheli I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. ___________________________________ Judith L. Connor Approved for the University Committee on Graduate Studies iii iv Abstract Wave-swept rocky shores serve as a home to a great diversity of organisms and are some of the most biologically productive habitats on earth. This burgeoning community exists in spite of the fact that the zone between the high and low tide marks can be one of the most physically harsh environments on earth. Large forces imposed by breaking waves and wide swings in temperature require the organisms living on rocky shores to adapt to a constantly changing environment or risk extirpation by physical forces. I have explored a number of hypothesized adaptations for survival on rocky shores and discuss how the results influence the evolutionary and ecological processes shaping shoreline communities. I developed a biophysical model to predict body temperatures for high shore littorine snails in order to address the role of evolved morphological and behavioral traits for controlling body temperature during extreme temperature exposures. The results demonstrate that while the behaviors of these snails allow them to reduce body temperatures by several degrees, the hypothesized roles of shell shape and color contribute relatively little to controlling body temperature. A similar biophysical model for predicting organismal body temperature was combined with a physiological study to examine the role of temperature stress in setting the distributional limits of an important mid-intertidal limpet, Lottia gigantea. With a temperature exposure protocol based on realistic field conditions, I measured sub-lethal and lethal temperature limits for this species, and found that the vertical distribution of L. gigantea may be set directly by high temperatures within certain microhabitats on the shore. The final section describes the role of behavior in barnacles in compensating for limits in the phenotypic plasticity of their feeding appendages. By directly monitoring the feeding activity of barnacles under breaking waves, I show that fast reaction times allow barnacles to avoid damaging water flows while still exploiting much of the available time for feeding. The studies in this thesis provide a number of new insights into the role of the abiotic environment in the evolution and ecology of organisms living on wave-swept rocky shores. v vi Acknowledgements While there is only one author’s name on the front of this dissertation, the document and the studies described within would not have come to be without the assistance of a large number of people. I am indebted to many people for their scientific, technical, philosophical, and emotional support through the course of my studies. What follows are my all-too-brief acknowledgements for everyone’s help. Primacy of place must of course go to my thesis advisor, Mark Denny. Perusing the acknowledgement sections of theses from Mark’s previous students, terms such as “endless knowledge”, “boundless enthusiasm”, “diplomacy”, “patience”, and “the right answers” keep coming up, for good reason. Mark was always willing to provide as much or as little guidance as each person desired, and could always be counted on for a fruitful discussion of any new idea, no matter how outlandish it might have seemed at first. His office door was always open, and he was amazingly adept at dropping whatever project was at hand and immediately coming up to speed on your current topic to lend any bit of advice or knowledge he had. Mark provided me with a constant stream of new ideas and new ways to visualize the bigger picture, and his influence is evident throughout this dissertation. Perhaps Mark’s greatest strength was his ability to attract a lab full of dynamic and motivated people. I had the chance to overlap with a number of wonderful Denny Lab members during my time here. In my early days as a lab technician, Ben, Loretta, and Elizabeth introduced me to the diversity of experiences waiting to be had in the lab. Joanna Nelson put up with me as an office mate with constant good cheer and the ability to look past the constantly growing pile of “work” on the desks, shelves, drawers, walls and floor of our office. After Joanna, it wasn’t until Kevin Miklasz arrived to start graduate school that someone else deigned to share an office with me. I benefitted from the help and advice of a number of laboratory technicians in my time: Lisa Walling, Tad Finkler, Anton Staaf, and Katie Mach. Katie went on to join the lab as a graduate student as well, and has been the source of many discussions over the vii years about science, society, politics and food. I thank Luke John Hoot Hunt, a.k.a. Luke 1, for his many insightful conversations, his helpful programming, and his numerous cockamamie ideas. Patrick and Rebecca Martone have been my closest compatriots through the graduate school journey. We spent a year in Palo Alto, commiserating and reminding each other that it would all get better when we moved down to Pacific Grove to start the real work of the PhD. Patrick was a great help with suggestions while writing, preparing presentations, and trudging through statistical methods. Rebecca served as a sounding board for all manner of topics on science and life, and she supplied me with just enough Spanish vocabulary to keep me out of trouble in Baja. The later years of my research were helped immeasurably by Michael Boller, who lent help and equipment whenever he could. Mike was another inveterate tinkerer, and we built a number of successful and occasionally not-so-successful pieces of equipment that provided hours of entertainment and a bit of data as well. Together we managed to leave a number of permanent marks on the landscape at Hopkins Marine Station. Rounding out the long list of lab-mates, I have to acknowledge Michael “Moose” O’Donnell and Chris Harley. Moose was there from the beginning of my stay in the Denny lab, and was more responsible for my occasional delinquency than anyone else. My method of experimentation has always tended towards the idea that there was only one way to find out if a plan was going to work, and that was to stop worrying and just try it. Moose shared the same sensibility, and together we made the most of the laboratory environment. Chris Harley showed up during those critical early years of my degree, and served as a superb role model for a young scientist. Chris mixed an infectious sense of humor with a vast knowledge of ecology, and provided a great deal of wisdom on how to go about doing science. These were the people that made research the enjoyable endeavor that I always hoped it would be. I owe a debt of gratitude to the other members of my committee as well. Fiorenza Micheli, Judith Connor, and George Somero all lent advice and encouragement. George in particular opened up his lab to a naïve biomechanics student and provided viii the tools and guidance to delve into the world of physiology. The members of his lab, including Jon Sanders, Tyler Evans, Cheryl Logan, Brent Lockwood, along with Melissa Pespeni, Maria-Inês Seabra, Yunwei Dong, and Lars Tomanek were all extremely helpful in troubleshooting techniques and explaining the intricacies of bench work. The rest of the faculty at Hopkins was helpful and supportive over the years as well. I owe particular thanks to Stuart Thompson for giving over a portion of his coffee maker space to the equipment I used for the data collection in the fourth chapter of this dissertation. Jim Watanabe provided a substantial amount of statistical help, and served as a great teacher for several courses I took or assisted with at Hopkins. The staff at Hopkins Marine Station was a great help throughout my studies.