ENHS Nature Trails January 2003 Article 1

This month's speaker: Bill Cesko

Stickleback Natural History and Evolution

We've had many personable speakers since I've been doing this newsletter, but I think this month's guest will be one of the most audience-connected we've had. Not only will we be fascinated with his research, but his enthusiasm will carry us right on into the lab. One can feel some of his energy just by reading his life experiences below as he reported them to me. Here's what Bill had to say:

I grew up in northern Pennsylvania and spent much of my childhood tromping through the woods and splashing in streams. The mountains, valleys and rivers in this corner of the globe make it a truly beautiful place. Some of my fondest memories are catching minnows and crayfish in the small stream near my parents' house. As I grew older, I began to spend much more time hiking and camping. Pennsylvania has an extensive system of hiking trails, and I spent many weekends backpacking along them with my two brothers and other friends. I always felt most comfortable in the woods, perhaps because both of my parents enjoyed spending time outdoors; my father especially liked to camp.

Although my father wasn't quite up to a long hike, he often joined my brothers and me for camping weekends. Also, like many families in the Northeast, we vacationed at beach houses on barrier islands from Virginia to New Jersey. Unlike many families, however, we spent much of our time not at the beach but in the tidal areas behind the islands! The amazing diversity in salt marshes left a lasting impression on me, and I believe it was the start of my love affair with aquatic ecosystems.

Two experiences in high school helped mature my interest in understanding the workings of aquatic ecosystems. First, I joined our high school marine science club, and we spent time each year at the Wallop's Island Marine Consortium in Virginia. The consortium is located near Assateaque and Chincoteague Islands, and is run as a research station by several universities. In addition, a program for high schoolers at the consortium exposes students to the wonders of natural world, with hopes of turning them on to careers in biology. To this end, The Consortium was very successful. Many of my fellow students have become professionals in the life sciences, and many say that their time at Wallop's Island played a role.

We spent most of our days in the field collecting specimens, from brackish streams by canoe or the open-ocean with trawling nets, and then in the evenings after dinner we would examine the specimens in the laboratory. It was the first time I realized how enjoyable working all day can be when you like what you're doing. The second high school influence that sealed my fate as a biologist was, surprisingly, our high school physics teacher, Kelly Landon. He was the first to show me what an elegant and beautiful language mathematics can be for understanding the natural world, biological as well as physical. The combination of these two experiences shaped my choice of undergraduate degrees and my future career path.

I received my undergraduate training in biology at the University of Pennsylvania, a program well known for great contributions to our understanding of biological communities and ecosystems. Researchers at Penn have been especially successful at describing and understanding the dynamics of biological systems using mathematical models. For my honors thesis I once again turned to an aquatic system, trying to understand the decline in numbers of the Diamondback Terrapin turtle (Malaclemys terrapin) in some regions of the Chesapeake Bay. I examined the hypothesis that incidental death of young turtles in crab pots could account for the decline, and found that young females disproportionately died in this manner. Including my data into population models, showed that indeed the removal of these young females could account for the decline in the population size. Terrapins, like many other turtles, live for up to 100-150 years, and contribute only a few offspring a year to their population. The death of young females therefore removes the most important contributor of offspring to future generations. Armed with these data and our mathematical models, we designed turtle excluder devices for crab pots and convinced the Maryland Department of Natural Resources to push for their use. This experience taught me that not only can math be an elegant way for understanding the natural world, it can also be a powerful tool for its conservation.

AND EVO-DEVO IS NOT THE NAME OF A ROCK BAND.

Toward the end of my undergraduate degree, I took a course on evolution from, and had many discussions with, Dr. Neil Shubin. Dr. Shubin is a pioneer in the field of the evolution of development (Evo-Devo), and my time with him sparked a great interest in evolution. For my doctorate work I studied the threespine stickleback, Gasterosteus aculeatus, with Dr. Susan Foster at Clark University in Massachusetts. Clark is one of the oldest graduate schools in the country, and many significant scientific contributions have occurred there, including, among others: the first rocket launch by Robert Goddard, the development of the birth control pill, and the first measurement of the speed of light, for which Albert Michelson was the first American to win the Nobel prize. At Clark, I concentrated my research on the roles of different evolutionary processes on the formation of new species. I used populations of stickleback in Alaska that were undergoing rapid divergence in many attributes leading to new species, and found that natural selection may play a much more important role in speciation than had recently been realized. Because it is important for us to understand not only why species go extinct, but what processes allow them to be formed in the first place, I was supported by a graduate fellowship from the Environmental Protection Agency, and grants from the National Science Foundation.

Towards the end of my graduate career, my interests in Evo-Devo sparked by Dr. Shubin came once again to the fore of my thinking. Specifically, I wanted to understand the developmental genetic basis of evolutionary change. In other words, what are the genes that underlay the amazing biodiversity within and across species?

I began exploring the current research being performed using different organisms in my specific area of interest. And in an amazing piece of luck, I learned of the desire of Drs. Chuck Kimmel and John Postlethwait at the University of Oregon to use the threespine stickleback to study the genetic basis of evolutionary change! As many of you know, researchers at the U of O were the first to use zebrafish, Danio rerio, to understand developmental genetics. I decided that Oregon was therefore an ideal place to start similar research on stickleback, and I signed on to their project. Over the past two years I have been helping to understand the genetic basis of change in one of the defining features of stickleback, their bony armor. Because one impetus of our work is finding genes important in bone formation, I have been supported by a fellowship from the National Institutes of Health, and we have just been awarded funding from the National Science Foundation. Much exciting research on stickleback will happen at the University of Oregon over the next several years!

AND WHAT WILL WE LEARN ABOUT YOUR RESEARCH AND PROGRESS FRIDAY NIGHT?

I will describe the amazing diversity in behavioral, morphological and life history traits that exists across different populations of stickleback around the world. I will go on to explain why within-species diversity provides an amazingly good system for understanding the processes by which biodiversity is created. I will review the large amount of work done by others on stickleback evolution as well as my own contribution to our understanding of how new species form. Lastly, I will finish the talk by describing our work here at the University of Oregon on trying to uncover the genetic basis of at least some of the amazing diversity of physical attributes of stickleback, and what our work might mean for understanding the genetic basis of evolutionary changes leading to biodiversity across species, families and kingdoms.

[ Back ]

Page last modified: 21 January 2003
Location: http://biology.uoregon.edu/enhs/archive/jan03/jan031.html
E-mail the WebSpinner: cpapke@gmail.com