A Leap of Faith, Part 2

My wife, infant son, and I moved to Amherst the first weekend of April 1982. A beautiful snow fell on Sunday. Then, early on Monday morning, my new boss Bruce Levin cross-country skied by the old house we were renting, knocked on the door, and asked me when I’d be coming to the lab!

I had much to learn, of course. I remember learning how to use a pipettor from a technician in Bruce’s lab, and how exciting it was to estimate the number of cells in a flask (typically many millions or even billions). That estimation is done not by counting the cells directly, but instead involves precisely diluting small amounts through a series of test tubes, each tube containing a large, known volume of a sterile solution. At the end of the dilution series, one takes a tiny amount from the final tube and spreads it across an agar plate. The plate is then incubated for a day or so, during which time each of the few hundred cells that survived the dilutions grows into a separate colony. A colony is a clump of millions of cells that can be seen with the naked eye, unlike the individual cells that can be seen only by using a microscope. One counts the colonies on the plate and, using that number and the dilutions that one made, one can then back-calculate the density of cells in the original flask.

In my first effort at this most basic procedure, I did three replicates from the same flask. I was thrilled when I counted the colonies on the first two plates, and the numbers differed by only a few percent. The third plate, however, differed by perhaps a factor of two, which meant I had done something wrong—maybe I’d let an air bubble into the pipettor’s tip, displacing some of the liquid—and I realized the importance of attention to details.

A little later, while I was still learning the ropes, Bruce had me perform a more complicated experiment to measure the rate at which a certain virus, called T6, adsorbs to and infects E. coli cells. The experiment required a lot of repetitive dilutions and plating of samples that I had to process quickly and accurately. The basic idea is that free viruses should decline in number over time as more and more of them enter cells. (This decline continues only until the first viruses to infect cells have had enough time to produce the next generation of viruses, hence the need to process the samples quickly.) Alas, my experiment was a total failure. What was I doing wrong? I think Bruce had me repeat the experiment, with the same lousy outcome. Though he never said it, perhaps he would regret hiring me. After all, given my lack of experience, Bruce had also taken a leap of faith.

After my second failure, Bruce checked his notes about the particular strain that we were using. As it turned out, he had given me a strain of E. coli that was resistant to T6! Hence, there were no infections, and that explained my failed experiments. Later on, I was able to use the same protocol to measure the rate at which a different virus, T2, adsorbed to and infected E. coli.

Oh, and what about my experiment to look for evolutionary changes that compensated for the cost of bacterial resistance to infection by viruses? That’s what I had proposed in my letter to Bruce asking about a postdoc. I never got to that experiment while I was in Bruce’s lab. However, it provided the seed for a project that I eventually conducted as an early-career faculty member at the University of California, Irvine.

[Bacterial colonies growing on agar plates. Photo credit: Brian Baer, MSU.]

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Autumn at MSU

A lovely autumn morning in East Lansing.

Next week I’ ll get to discuss a couple of my all-time favorite papers – Chao and Levin on colicins, and Lieberman et al. on parallel evolution in an epidemiological setting – with graduate students in our Integrative Microbial Biology course.

That is all.  Happy Friday, and have a great weekend.

Coach Izzo and me

Chalk up another great year for the Michigan State men’s basketball team and coach Tom Izzo. The Spartans were co-champions of the Big10 and won the conference’s grueling tournament. And in the NCAA’s March Madness, they made it all the way to the Final Four, knocking out the top-seeded team in the process.

Being a fan of this team got me thinking: Coach and I have a lot in common. We’ve both been doing our jobs, mostly at MSU, for a long time. Coach Izzo came here as a part-time assistant in 1983, becoming head coach in 1995. I was on the faculty at UC-Irvine starting in 1985, before moving here in 1991.

But the real similarities are deeper and more important:

First and foremost, we’ve both been fortunate to be surrounded by talented and hard-working students who listen to our ideas, experiment with them, develop them in their own ways, and translate them into meaningful outcomes—winning big games and making new discoveries.

That’s not to say there aren’t frustrations along the way: games lost, grants and papers rejected, grinding practice on the court and repetition in the lab, and even occasional conflicts. But our students are usually resilient—they overcome those setbacks and frustrations, and they go on to productive lives as players and coaches, researchers and teachers, and other careers as well.

We also both had mentors who helped us start our own careers. In Coach Izzo’s case, one mentor was Jud Heathcote, the previous head coach who hired him as an assistant. My mentors included my doctoral advisor, Nelson Hairston, and my postdoctoral supervisor, Bruce Levin. Coach Izzo and I also had friends who helped shape our careers early on: Steve Mariucci, who went on to become an NFL coach; and Phil Service, who did important work on life-history evolution.

Coach Izzo and I also both benefitted, I think, from early successes—again, largely due to our students—that helped establish our reputations, allowing us to retain our jobs and thrive by recruiting more talented, hard-working students. For Tom Izzo, it was players like Mateen Cleaves, Charlie Bell, and Mo Peterson who took the Spartans to the Sweet 16 in his 3^rd year as head coach and to the Final Four the next year, and who won the 1999-2000 National Championship. For me, the early students included Judy Bouma, Felisa Smith, John Mittler, Mike Travisano, Paul Turner, and Farida Vasi, and postdocs Toai Nguyen and Valeria Souza.

Coach Izzo has also had assistant coaches and staff, who I imagine do a lot of the heavy lifting. While some might eventually become head coaches of their own teams, many others labor in relative obscurity. In a similar vein, I’ve had outstanding lab managers including Sue Simpson, Lynette Ekunwe, and—for over 20 years, before retiring last year—Neerja Hajela.

Coach Izzo and I have both had deep benches—students who helped the team succeed without being in the limelight themselves. For Coach Izzo, they include the walk-ons and others who see limited action in games, but who compete against the starters every day in practice, helping everyone become even better. I think of three undergraduates who joined my lab when it was just getting started in Irvine (all Vietnamese refugees, by the way) who asked if they could work in my lab. Trinh Nguyen, Quang Phan, and Loan Duong prepared media and performed experiments like some incredible three-brained, six-handed machine, setting a high standard for everyone who followed in their footsteps.

Coach Izzo and I are nearly the same age. Retirement might be easier, but neither of us is ready for that. It’s too much fun when you’ve got talent to encourage and guide like Cassius Winston, Joshua Langford, Nick Ward, Xavier Tillman, and Aaron Henry—and on my team Jay Bundy, Kyle Card, Nkrumah Grant, Minako Izutsu, and Devin Lake.

Of course, there’s more that Coach Izzo and I have in common—we were lucky to be born into circumstances that allowed us to pursue our dreams without the obstacles that many others face.

Last but not least, Coach Izzo and I have had supportive partners who’ve accepted our peculiar obsessions and the long hours and frequent travel that our work entails.

Go Green! Go Students!!

Ralph Evans

Ralph Evans was an exceptionally talented young scientist and wonderful human being. He joined Bruce Levin’s lab as a doctoral student while I was a postdoc in that lab. Bruce and I met Ralph at the joint meeting of the Genetics Society of America, the Society for the Study of Evolution, and the American Society of Naturalists, which was held in St. Louis in June of 1983. That was an historic conference for anyone who studies microbial evolution because several leaders in that nascent field—including Bruce, Dan Dykhuizen, Dan Hartl, and Barry Hall—arranged a session to discuss the future of the field. Among other things, that session led to the organization of the Gordon Research Conference on Microbial Population Biology; the first of those conferences was held in 1985 and chaired by Bruce.

Among the highlights of that 1983 conference was meeting Ralph Evans. Ralph was from Texas, and he had done his undergraduate studies at Rice University. He was in graduate school at the University of Minnesota working in ecology. But after Ralph heard about this new field, he was determined to join it. I can still recall chatting with Ralph after the discussion session about the exciting things one could do with microbes to understand ecology, evolution, and infectious disease. I forget the exact timing, but Ralph soon joined Bruce’s lab at the University of Massachusetts, Amherst (with the blessing of Peter Abrams, his advisor at Minnesota). Ralph and I talked about science pretty much every day from his arrival in the lab until I left to join the faculty at the University of California, Irvine, in the late summer of 1985.

Ralph and I not only shared scientific interests, but Ralph and his wife Barbara (Bard as he called her) became wonderful friends with my wife Madeleine and me. Ralph had a soft Texas drawl, a gentle sense of humor, and a kind and sweet demeanor. He took a special liking to our toddler son Daniel—I still remember all of us walking in a snowy field as Ralph pulled Daniel in a sled. We even shared a washing machine with Ralph and Bard—they owned the machine but had no place to put it, while we had the space and a great need for one!

Tragically, as Ralph was pursuing his doctoral research, he was struck with an aggressive and ultimately lethal brain cancer. He and Bard battled through it together. She joined him in the lab to help with his work, and we sent a then-new-fangled watch that had an alarm setting to help Ralph remember when to do the next step of his experiments. Ralph had a remission, and we all had high hopes when he set off to do a postdoc with Dan Dykhuizen at Stony Brook. Alas, the cancer returned. I gave a talk at Stony Brook and got to say goodbye to Ralph, but not really—for he was in the hospital and non-responsive.

In loving memory of Ralph, and in recognition of the areas of science that most interested him, Madeleine and I have established the Ralph Evans Award. To honor Ralph’s legacy, the award may be given to either a postdoctoral researcher or senior graduate student in the Department of Microbiology and Molecular Genetics here at MSU for important contributions to the understanding of microbial evolution and its underlying ecological and genetic processes.

Thank you, Ralph, for your friendship and inspiration.

[Bruce with three of his UMass graduate students—Lone, Judy, and Ralph—in the late 1980s.]

[Ralph (far left) at a party at Bruce’s home in Amherst in the summer of 1985.]

[Here Madeleine and I are with Zachary Blount, who received the inaugural Ralph Evans Award.]

[Group photo from the first GRC on Microbial Population Biology: Bruce is front and center, and Ralph is near the back, center-left with a big smile.]

Who Knows Where the Time Goes

Today is the 29^th birthday of the long-term evolution experiment (LTEE). As I wrote on Twitter: “May the cells live long & prosper, both in & out of the -80C freezers.” I hope they—and the rest of the world—will be evolving and improving long after I’m gone.

Anyhow, after my tweet, Luis Zaman asked for a picture of me on my own 29^th birthday. (I started the LTEE when I was 31.) Alas, I don’t have one. But I’ve found some pictures from around that time—including just before and after I moved to UC-Irvine to start my first faculty position, and over the next few years up to about the time I started the LTEE.

Summer, 1985: This photo is from Amherst, Massachusetts, where I did my postdoc with the amazing Bruce Levin, who hosted a goodbye party for us. From left to right: Ralph Evans, a brilliant graduate student and dear friend, who died tragically just a few years later of brain cancer. My beautiful wife, Madeleine. Our one-year-old daughter Shoshannah, being held by forever-young Bruce. Yours truly, holding our three-year-old son Daniel. And Miriam Levin, an art historian.

October, 1985: Shoshannah on my shoulders at the San Diego Zoo, a few months after we moved to Irvine.

March, 1986: First-year faculty member burning the midnight oil in our Las Lomas apartment at UCI. Working on a paper? Or getting ready to teach 700 students the next day? (Two sections of Ecology, a required course for Bio Sci majors, with an hour to recuperate in between. It was well worth it, though, because one of the students in one of the many quarters I taught that course was the great Mike Travisano.)

October, 1986: Moving up in the world, we bought a new house on Mendel Court in University Hills. My parents visited, and that’s my mother, Jean, a poet who loved science.

March, 1987: The great Lin Chao came for a visit. We grew pea plants on the trellis below the number 6—after all, it was 6 Mendel Court.

June, 1987: One of the fun events at UCI was Desert X (for extravaganza), hosted by Dick MacMillan, the chair of Ecology and Evolutionary Biology, on his property near Joshua Tree National Park. With Madeleine, who is “holding” our Number 3.

June, 1987: Working Xtra hard at Desert X with close friend and colleague Al Bennett.

September, 1987: With an already smiling one-month-old Natalie.

January, 1989: Time for some snuggles. Meanwhile, the LTEE is not quite a year old.

The title of this post is a song by Fairport Convention, with the hauntingly beautiful voice of the late, great Sandy Denny. You should listen to it.

Questions from Jeremy Fox about the LTEE, part 1

EDIT (23 June 2015): PLOS Biology has published a condensed version of this blog-conversation.

~~~~~

Over at the Dynamic Ecology blog, Jeremy Fox asked me some interesting questions about the history, philosophy, and science of the E. coli long-term evolution experiment. Perhaps mistakenly—in terms of time management, not my interest!—I agreed to try to answer them … though over what time frame, I’m not sure. Anyhow, here is Jeremy’s first question followed by my (very) short and (too) long answers.

~~~~~

• When you first started the LTEE, did you consider it to be a low risk or high risk experiment? Because I could see arguing both ways. In some ways, it’s low risk, because one can imagine lots of different possible outcomes, all of which would be interesting if they occurred. But in other ways, it’s high risk–I imagine that many of the interesting outcomes (including those that actually occurred!) would’ve seemed unlikely, if indeed they’d even occurred to you at all. Or did you not worry much about the range of possible outcomes because the experiment was basically a lottery ticket? “This’ll be cheap and not much work, let’s just do it and see what happens. Something really cool might happen, but if it turns out boring that’s ok because it wasn’t a big investment.”

~~~~~

The short answer: Life was good, and I wasn’t thinking about risk. Or as they say about investing: it’s better to be lucky than smart!

The long, non-linear* answer: I’d already had success with some shorter duration, more traditionally designed experiments (e.g., Lenski, 1988), and so it wasn’t a total shot in the dark—that is, I knew the LTEE would yield data. I also knew, though, that it was an unusually abstract, open-ended, and non-traditional experiment, and that it might not appeal to some people for those reasons. But I loved (and still do) the seemingly simple (but in reality complex) questions, issues, and hypotheses that motivated the LTEE.

I never thought of the LTEE project as a “lottery ticket”, but some follow-up work that grew out of it had that feel.** And, oddly enough, there was one lottery-ticket aspect of the research early on, although that reflected a lack of preparation rather than a well-conceived feature.***

Maybe I was overly confident, but I’d also say that I was pretty sure the outcomes—whatever they might be—would be “cool.” The questions were intriguing, and there hadn’t been many, if any, previous attempts to answer them quite so directly. Data would be forthcoming, and even if the results weren’t definitive, I felt there would be some interest in trying to interpret whatever data emerged.**** Plus, I knew enough about what would happen—based on the experiments I had already done—that I was confident that the data and analyses would be informative with respect to at least some of my questions. Also, the use of microbes to study evolution in action was still uncommon, so the novelty of the approach would ensure some interest among my colleagues—although let me emphasize that Lin Chao, Dan Dykhuizen, Barry Hall, and Bruce Levin, among others, had already demonstrated the power of using microbes for experimental studies of evolutionary questions.*****

I should also say, in case it’s not obvious, that I had no idea or intention that the experiment would continue for anywhere near as long as it has lasted—nor that it might, I now hope, be running long after I’m gone. I had previously performed some experiments that lasted several hundred generations, and as I saw the dynamics and thought about the math behind the dynamics, I realized that over those time scales I might be seeing the effects of only one or two beneficial mutations as they swept to fixation. That hardly seemed satisfactory for experiments to explore the structure of the fitness landscape. So I decided the experiment should run for 2,000 generations, over which time I expected there would be at least several fixations of beneficial mutations in each population (and I was right), and that would deserve calling it long-term. That would take a little less than a year, given the 100-fold dilution and 6.6 generations of re-growth each day.

Of course, propagating the lines for 2,000 generations was one thing—running the competitions to measure fitness, analyzing the data, writing the paper, responding to reviews, all that took longer. So while the experiment began in February 1988, the first paper (Lenski et al., 1991) was not submitted until August 1989, resubmitted September 1990, accepted that November, and finally published in December 1991. Meanwhile, the LTEE itself continued and the generations ticked by. The baseline work of keeping the populations going is not that onerous—yes, somebody has to attend to the transfers every day, but once a lab team reaches a moderate size, it’s not too hard to arrange. And I lived next to the campus in Irvine, so it wasn’t hard for me to come in on the weekends and holidays … and my wife still loves me, and my kids recognized my face ;>)

You also wondered whether some of the interesting possible and actual outcomes had occurred to me when I started. Definitely not! I had made a strategic decision to make the environment of the LTEE very simple in order to eliminate, or at least reduce, certain complications (especially frequency-dependent interactions and clonal interference). And while I think my planning kept these complications from getting out of hand, the tension between the simplicity of the experimental design and all the complications has definitely been part of its interest. That tension, along with time, the evolutionary potential of the bacteria, and the smart, talented, creative** and hard-working students and colleagues have made the LTEE what I call “the experiment that keeps on giving.”

Footnotes

*Hey, that’s what footnotes are for, right?

**I’ve thought that way about some follow-on work that uses the LTEE lines, but not about the project as a whole. Here are a couple of examples of “lottery tickets” that people suggested to me, and that won big. A former postdoc Paul Sniegowski, now on the faculty at Penn, wanted to know whether the actual mutation rate itself might be evolving in the LTEE populations. Bingo! Several lines evolved hypermutability and so, curiously enough, the first mutations we ever mapped affected the mutation rate itself (Sniegowski et al., 1997). Another example: Dominique Schneider is a molecular microbiologist in Grenoble, and we’ve collaborated for over 15 years. He thought we should look at whether DNA topology—the physical supercoiling inside the cell—might have changed in the LTEE lines. Well, I thought to myself, why would it change? But Dom’s lab will do all the work, so sure, why not look? And it turns out, sure enough, that DNA supercoiling changed repeatedly in the LTEE lines (Crozat et al., 2005), and it even led us to discover a gene not previously known to affect supercoiling (Crozat et al., 2010). There’s a lesson here, by the way—work with people who are smarter, who have different interests, and who have different skills than oneself.

***I actually started two versions of the LTEE—not one experiment with two proper treatments, but two separate experiments that differed in terms of both the starting strain and the environment. Unlike the successful LTEE, I hadn’t done any previous evolution experiments with the other ancestral strain and environment. Anyhow, I soon stopped the other version when the populations evolved a phenotype that made it very difficult to work with them. In brief, the populations evolved to make pinprick-sized colonies that were next-to-impossible to count in the assays we use to measure fitness. Who needed that headache! So, in a way, I guess I had two lottery tickets: I hadn’t done the relevant prior work for one of them, whereas the one that paid off was actually a pretty strategic gamble.

****I was at UC Irvine when I started the LTEE, and Michael Rose was one of my colleagues there. His work on the evolution of aging—postponed senescence—in fruit flies (e.g., Rose 1984) was an inspiration in terms of the importance and power of long experiments. We also spent a lot of time discussing fitness landscapes, the alternative perspectives of Sewall Wight and R. A. Fisher about the dynamics on those landscapes, and what experiments might tell us. Michael didn’t design, direct, or do the lab work for the first LTEE paper, but he helped me clarify my thinking and write the first paper on the LTEE (Lenski et al., 1991). Perhaps more importantly, his interest in the questions and issues made me realize that other smart people would also be interested.

*****I used to complain, mostly in jest, that “Evolutionary biologists say I’m asking the right questions, but studying the wrong organism, and microbiologists tell me I’m studying the right organism but asking the wrong questions.” I got that sort of response occasionally, but many people from both fields were very interested and encouraging. For example, I remember David Wake telling me, after one of my first talks about the LTEE, how much he liked both the questions and the approach.

References

Lenski, R. E. 1988. Experimental studies of pleiotropy and epistasis in Escherichia coli. II. Compensation for maladaptive pleiotropic effects associated with resistance to virus T4. Evolution 42: 433-440.

Lenski, R. E., M. R. Rose, S. C. Simpson, and S. C. Tadler. 1991. Long-term experimental evolution in Escherichia coli. I. Adaptation and divergence during 2,000 generations. American Naturalist 138:  1315-1341.

Sniegowski, P. D., P. J. Gerrish, and R. E. Lenski. 1997. Evolution of high mutation rates in experimental populations of Escherichia coli. Nature 387: 703-705.

Crozat, E., N. Philippe, R. E. Lenski, J. Geiselmann, and D. Schneider. 2005. Long-term experimental evolution in Escherichia coli. XII. DNA topology as a key target of selection. Genetics 169: 523-532.

Crozat, E., C. Winkworth, J. Gaffé, P. F. Hallin, M. A. Riley, R. E. Lenski, and D. Schneider. 2010. Parallel genetic and phenotypic evolution of DNA superhelicity in experimental populations of Escherichia coli. Molecular Biology and Evolution 27:2113-2128.

Rose, M. R. 1984. Laboratory evolution of postponed senescence in Drosophila melanogaster. Evolution 38: 1004-1010.

 

Lenski Interview with The Molecular Ecologist

John Stanton-Geddes asked me some great questions for a series on “People Behind the Science” at The Molecular Ecologist blog.  He gave me permission to repost the interview here.

1) Did you always think you’d become an evolutionary biologist?

No!  I always enjoyed being outdoors (sports and hiking), but I didn’t have any particular interest in biology.  However, my mother (who dropped out of college when she married, but then co-authored a sociology textbook with my father) was very interested in biology.  She would give me articles she had read and enjoyed from Natural History and elsewhere.

I went to Oberlin College, where I thought that I might major in government.  But I disliked my first government class.  I also took a team-taught biology class for non-majors.  All of the instructors spoke on topics about which they cared deeply, and I was hooked!  I took more biology courses, and I was especially drawn to ecology because there were so many ideas and questions.  At that time, I wrongly viewed evolutionary biology as a more descriptive, old-fashioned field with fewer questions that one might still address.  (By the way, several other evolutionary biologists were at Oberlin when I was there including Deborah Gordon, Joe Graves, Kurt Schwenk, and Ruth Shaw. Not bad for a small school!)

I went to graduate school at the University of North Carolina, where Nelson Hairston, Sr., was my advisor.  Nelson was interested in the interface of ecology and evolution, and that opened my eyes.  I was also influenced by Janis Antonovics, then at Duke University.  I took his Ecological Genetics course, and he served on my committee.  Janis had written a paper in which he argued that “The distinction between ‘ecological time’ and ‘evolutionary time’ is artificial and misleading.”  That really got me thinking.  I tried to develop a couple of field-based projects that would address evolutionary questions, but I didn’t know what I was doing and they failed.  In the end, my dissertation project was pure ecology.

By then, though, I knew I wanted to pursue evolutionary biology.  While we were finishing our doctoral projects, a fellow grad student Phil Service and I spent a lot of time discussing model systems for studying evolution.  For his postdoc, Phil chose to work with Drosophila.  I recalled an undergrad course in which we read about elegant experiments with microbes that addressed fundamental questions, such as one by Salvador Luria and Max Delbrück showing that mutations happen at random and not in response to selection.  Meanwhile, in a graduate seminar, we read a paper by Lin Chao and Bruce Levin on the coevolution of bacteria and viruses.  I wrote Bruce to ask if he might have an opening for a postdoc.  Lucky for me, Bruce knew Nelson and invited me for a visit.

2) You’ve described the theme of your research as “the tension between chance and necessity”. Can you comment on how chance and necessity have shaped your career?

The ancient Greek philosopher Democritus said, “Everything existing in the universe is the fruit of chance and necessity.”  In my long-term evolution experiment with E. coli, we can explore the tension between chance and necessity because we have replicate populations started with the same ancestor and evolving under identical conditions, and because we can replay evolution from different points along the way.  But it’s difficult, if not impossible, to tease apart the roles of chance and necessity with a sample size of one, which is the life that each of us has experienced, and without the ability to replay our own lives.  (On that last point, let me recommend Replay, a science-fiction novel by Ken Grimwood.)

I would say, though, that most people who have had some success in their adult lives also started out very lucky.  We were fortunate to be born at times and in places where we had food, familial love, education, and opportunity.

3) Reading your blog it’s clear that you are a student of the philosophy and history of science. Do you think we should include more history and philosophy in scientific training? Any advice on something we should all go out and read?

I do think that the history and philosophy of science deserve more emphasis in science and education than they usually receive.  But I didn’t have any formal education in those areas.  Instead, I became interested in these issues through teachers, mentors, colleagues, and my own explorations.

For something to read in this area, I suggest Darwin’s Century by Loren Eiseley.  (Originally published in 1958, it was republished in 2009 by Barnes & Noble.)  The book discusses the fascinating history of evolutionary thought in the decades before and after the publication of The Origin of Species.  I first read Darwin’s Century in a course at Oberlin taught by James Stewart.

4) If you were starting your career today, what would you study? 

If I were starting today, and at my present age, I might choose to study the history of science, especially evolutionary biology and its antecedents.

But if I were starting out young, as one usually does, I’d like things to unfold as they did.  It might be tempting to skip the rough patches, but dissatisfaction with my early research led me to make the switch to microbial evolution.  Would I have enjoyed this lab-based work as much, if I hadn’t discovered that I was not nearly as good at fieldwork as many of my peers?

5) How close have you come to giving up as a researcher and doing something completely different?

The job market was tough when I was a postdoc, and I had a growing family to support.  So after a slew of applications and rejections, and a period of uncertain funding, I started to think about other possibilities.  Luckily for me, things turned around before I had to make a switch.  (You can read more about it in my blog post, The Good Old Days.)

6) What’s the meaning of life?

I think that some understanding of evolution—at a basic level accessible to anyone with an open mind and a decent education—gives perspective about our place, both as individuals and as a species, in the grand sweep of time and space.  Recognizing the transience of my personal existence fills me with awe and respect for the continuity of life and ideas.  And belonging to a species that is profoundly altering the world that enabled the continuity of life reminds me of our responsibility for ensuring its future.