A Leap of Faith, Part 1

I did my graduate work at the University of North Carolina, Chapel Hill, in what was then called the Department of Zoology. I had several important and formative experiences during those years: clear advice from my advisor, Nelson Hairston (1917-2008), about the value of well-designed experiments in ecology; an eye-opening course on the integration of ecological and evolutionary perspectives, taught by Janis Antonovics (then at Duke University, just a few miles from UNC); an abysmal failure in my own attempt at an experiment with praying mantises; an enlightening collaboration with a fellow grad student, Phil Service; and a dissertation project on the effects of forest clearcutting and competition on beetles in the mountains of southwestern North Carolina.

Although that dissertation project was reasonably successful, I realized it was not a good fit to my skills and interests. Many of my fellow students were excellent naturalists with a love for the organisms they studied. While I enjoy being outdoors, I’m not a naturalist. Instead, I’m intrigued by the conceptual questions that biologists ask about the living world. And as my graduate work moved forward, I realized that questions about evolution, including especially the mechanisms and dynamics of evolution, interested me most. However, the beetles I was studying were not well-suited to those questions. So how could I pursue my interests?

While we were finishing our doctoral projects, Phil and I spent a lot of time discussing potential systems for studying evolution. As he moved on in his career, Phil chose to study evolution using fruit flies, a long-standing model system for studying genetics. I recalled an undergrad course I had taken, where we learned about elegant experiments done with microbes, including one by Salvador Luria and Max Delbrück that showed mutations happen at random, not in response to selection.

Meanwhile, the graduate students and faculty at UNC had a seminar in which we discussed recent papers in the field of ecology. One week we read a terrific paper by Lin Chao, Bruce Levin, and Frank Stewart titled “A complex community in a simple habitat: an experimental study with bacteria and phage.” I forget who chose that paper for our seminar, but I owe that person a debt of gratitude. 

Phages are viruses that infect bacteria, and the paper provided an elegant demonstration of the interplay of ecological and evolutionary processes on a time scale of a few weeks. It documented the coevolution of E. coli and a virus, called T7, that can infect and kill the bacteria. The authors showed that the bacteria evolved resistance, then the virus evolved the ability to infect the resistant cells, and finally the bacteria evolved resistance to the viruses with the extended host range. Moreover, they showed that virus-sensitive and virus-resistant host genotypes coexisted because the sensitive types were better competitors for the limiting resources in the environment. That paper and others by Bruce Levin cemented my interest in using microbes to study evolution in action.

In March of 1981, about a year before I defended my dissertation, I wrote Bruce to ask if he would consider me for a postdoctoral position in his lab. I admitted I had no experience working with microbes, but I proposed an experiment. His team’s work showed that bacteria that evolved resistance to phage were outcompeted by their sensitive progenitors when those viruses were not present. I wondered whether the tradeoff was an unavoidable metabolic cost, or whether bacteria could evolve compensatory changes that reduced the cost of resistance. My proposed experiment suggested a way to look for such compensatory changes.

Bruce invited me to visit his lab and give a talk at the University of Massachusetts, Amherst, that spring. I remember him greeting me when I got off a bus at the town square and being surprised by just how young he looked. Although he was 40 years old and a full professor, Bruce could easily have passed for an undergrad. More importantly, I recall our intense discussions over the next two days with Bruce at a chalkboard, writing equations that described the growth of various interacting microbes, and using terms that I barely understood.

Despite my limited experience and knowledge of microbiology, Bruce offered me a postdoctoral position in his lab. I was thrilled, but also worried about doing research in a new field where I lacked experience and knowledge. Nonetheless, I took that leap of faith. And I’m so glad I did.

[Nelson Hairston after his retirement from UNC (left) and Bruce Levin in the mid-1980s (right).]

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!!

You gotta know when to hold ‘em

I was honored and humbled to speak at the Doctoral Hooding Ceremony last weekend at the University of North Carolina at Chapel Hill. I received my Ph.D. there in 1982. It was great to be back in Chapel Hill, seeing some old friends and making many new ones.

There was also one of those interesting small-world connections: UNC Chancellor Carol Folt is an ecologist. I first met Carol when she was an assistant professor at Dartmouth and I was commuting from Amherst, where I was a postdoc, to Dartmouth, to teach evolution as a sabbatical replacement for one semester. Carol is such a positive person, always smiling, and an energetic chancellor.

Anyhow, I had never given a talk like this before, so it was a challenge to prepare. Here’s what I had to say to new doctorates; maybe some of you will find it useful as well.

~~~ ~~~ ~~~

Let me begin by congratulating all of the new PhDs and recipients of other doctoral degrees. Each of you climbed a mountain that no one before you had ever climbed. That’s what made it a doctorate — your original research leading to new knowledge.

My remarks today are about constancy versus change, and about luck versus skill. They turn out to be core themes in the research I do, and they also have a lot to do with life, including the decisions we make in our professional careers.

Speaking of constancy, some things hardly seem to change. I got my degree here in 1982. And who won the NCAA men’s basketball title that year? Yep, it was the Tar Heels, just like this year.

Of course, there have also been a lot of changes since I was a student. Music, for example. When we went to the bar, we had these awesome communal listening devices, called jukeboxes. You didn’t even need headphones to hear the music.

Kool & the Gang’s “Celebration” was hot then — and it’s still a great song if you’ve got a party tonight! Cross-over country music was big, too.

Kenny Rogers had a hit called “The Gambler”, about advice from an old poker player. You’ve probably heard it. It goes like this:

“You got to know when to hold ‘em, Know when to fold ‘em, Know when to walk away, Know when to run.”

Of course, the song is about life, using poker as a metaphor. Just as in our careers and lives, poker requires making decisions in the face of uncertainty.

I had a lot of very good luck at Carolina. I went to a party where I happened to meet Madeleine, a graduate student in the School of Public Health, who is now my wife.

However, I also faced some difficulties, and while I managed to get through them, they led me to change the direction of my research.

I came to UNC to study ecology, which focuses on species and their interactions in nature. I got interested in biology when I took a non-majors course as an undergraduate at Oberlin College, and I saw the sweep of discoveries from molecular biology to vertebrate evolution.

As I contemplated graduate school, I focused on ecology because it was filled with interesting and unanswered questions that, to my naïve self back then, seemed like they wouldn’t be too hard to study.

Many ecologists are superb naturalists, including Nelson Hairston, my advisor here at Carolina, who loved the salamanders he studied, and who knew their biology inside and out.

Or Charles Darwin, who was fond of beetles. On a collecting trip, he already had two beetles he wanted, one in each hand, when he came upon a third that he also wanted to keep. He was so in love with his beetles that he popped one into his mouth to free up a hand. Well, it turns out that the one he put in his mouth was a bombardier beetle. To escape predators, they combine and squirt out two chemicals in an explosive exothermic reaction. Needless to say, Darwin lost all three of those beetles.*

As a kid, I loved being outdoors, hiking and playing sports. But I wasn’t a naturalist; I didn’t know very much about any particular group of animals or plants. At least partly because of that lack of familiarity with organisms in the wild, my first efforts at doing ecological research were failures.

Let me give one example, because it’s kind of funny — at least in hindsight. I tried to do a field experiment using praying mantises. I reared batches of them in the lab from egg cases, and then released them on small plots with two treatments. I had painstakingly cleared the vegetation around each plot by hand to keep the mantises where I put them. Well, the next time I went to see how they were doing, I couldn’t find a single one! Maybe some birds were watching me when I released the mantises, wondering: “What is this crazy guy doing?” before gobbling them up. I have no idea what happened, but that experiment was a total bust.

With hindsight, I was lucky that this project failed right away. The treatment effect I was looking for would probably not have given a significant outcome, even if the mantises had stayed put. So even failures can sometimes be valuable, by keeping us from wasting time—and by forcing us to change direction.

Maybe some of you had failed projects, too, before you found your bearings. It’s a normal part of science and scholarship, though it’s upsetting when it happens.

I had another project that also failed. But this second failure led me to the study system that became my dissertation, which was about the effects of forest cutting and competition on a certain group of insects, called ground beetles.

I loved being outdoors in the mountains of western North Carolina, although the frequent rainstorms often flooded the traps that I used to catch the beetles, drenching both the beetles and me. But this project, at last, was successful, leading to my dissertation and some papers.

But I also had doubts that this line of research was a good fit for my interests and skills. Maybe some of you are at similar points in your career.

I’m sure some of you have found work that you hope to continue for the rest of your life. If so, that’s terrific and more power to you.

Others of you might be pondering or even planning a change—using your degree and experience, but setting off in a new direction. Maybe not right away, but perhaps keeping an eye out for some opportunity that better fits your own skills and interests.

In my case, an exciting opportunity dawned in a graduate reading group, when we read a paper about the coevolution of bacteria and viruses that attack bacteria. Even though I had no experience in microbiology, I wrote the head of that lab with an idea for a project related to the paper, and—lucky for me—he hired me as a postdoc.

Before I started my new position, I was worried about working in an area where, once again, I had no experience. Well, I soon discovered that I enjoyed the work. I wasn’t good at it right away, but I liked the rhythm of a microbiology lab. Unlike praying mantises, the bacteria stayed put in their flasks. Unlike the beetles in the mountains, there weren’t any rainstorms in the lab. And sometimes you could see the results of an experiment the very next day.

Down the road, there were more hurdles. In my first year of looking for a faculty position, I applied for dozens of jobs. I got one interview and no offers. Meanwhile, the grant that funded my research wasn’t renewed, and I had a growing family to support. I even thought about leaving science — and I would have if Lady Luck hadn’t come through for me yet again.

The grant was renewed on the second try, and in my second year on the job market I got two offers. So I headed out to Irvine, California, where I started a project that continues to this day.

The project is an evolution experiment. In fact, the experiment was set up to address the same themes as my talk today—luck and skill, constancy and change—although in a scientific context, rather than a personal one.

In evolution, genetic mutations are random events, while the process that Darwin discovered—adaptation by natural selection, sometimes called “survival of the fittest”—multiplies the best competitors across the generations. I wanted to see how luck and skill—that is, mutation and selection—would play out if we could watch evolution over and over and over.

So I set up 12 populations of E. coli bacteria, all started from the same genetic stock, and I put them in identical flasks, with identical food, the same temperature, etc.

I wanted to know: Would they all change and adapt in the same way, showing the power of natural selection to shape life? Or would each population evolve along a different path, highlighting the importance of random mutation?

One thing that makes bacteria great for this experiment is that we can freeze samples and then later revive them as living cells. In essence, our freezers are time-travel machines for the bacteria, allowing us to directly compare and even compete bacteria that lived at different times.

You’ve all heard about our close relatives, the Neanderthals, who went extinct about 40,000 years ago. Some of you might know that their DNA has been recovered from fossils, allowing their genomes to be analyzed. It’s even been discovered that most of us have stretches of Neanderthal DNA in our own genomes.

But despite these amazing advances, we don’t really know what the Neanderthals were like and how similar they would be to us, if they were raised in our world. How well would they play chess, or music, or basketball? What topics would they choose for their dissertations? What would they talk about if they were at this podium?

Back to the experiment with bacteria: We’ve seen many parallel changes in the bacteria across the 12 replicate populations, showing that natural selection can sometimes make evolution predictable, despite the randomness of mutation. But we’ve also seen differences emerge, including in one lineage a surprising new ability to grow on a resource that other E. coli cannot use. And using new technologies that didn’t exist when the experiment was started, we’ve sequenced hundreds of genomes to find the mutations in samples from across the generations and populations, allowing us to test the repeatability of evolution at the level of the DNA itself.

I sometimes call it “the experiment that keeps on giving.” I originally intended the experiment to run for 2,000 generations, which would take about a year. Well, today it’s been running for almost 30 years, and the bacteria have been evolving for 67,000 generations.

This experiment keeps on giving because the bacteria keep evolving in interesting and sometimes unexpected ways, and because students bring new questions and ideas to the project. My hope is that it will continue long after I’m gone.

While the experiment gets a lot of nice press and compliments these days, there have been some obstacles along the way, as there always are in life and science.

When the first paper was submitted, one reviewer was very negative and even hostile. That reviewer wrote: “I feel like a professor giving a poor grade to a good student” — ouch! — without any suggestions for how to improve it. In fact, the reviewer even wrote: “This paper has merit and no errors, but I do not like it.” Well, I wasn’t going to fold — I liked the cards in this hand. So I wrote a rebuttal, and the paper was accepted. In fact, it went on to receive the journal’s award for best paper of the year.

A second obstacle was one of my own making. I came across another experimental system that I found fascinating, and still do — artificial life in the form of computer programs that can replicate themselves and evolve. At the time, I thought maybe the long-term experiment with bacteria had run its course. Well, unlike in poker, when you face important decisions in your research and career, you can ask other people for advice. It’s a good thing, because I was able to have my cake and eat it, too. Everyone told me: “Don’t end the experiment with bacteria. It’s too valuable.” So my lab has kept it going and it has continued to be a scientific gold mine.

Along the way, some creationists have criticized our work. Some don’t believe our results, while others believe us but say: “See, they’re still only bacteria” — as though any scientist would expect to see worms or monkeys or whatever emerge from this experiment.

There can be many reasons for misunderstandings between scientists and the public: problems of education, politics, and communication. The third problem — communication — is one that we can strive to overcome by explaining our work not only to our close colleagues, but also to the general public.

A couple of years ago I had a wonderful opportunity to communicate science to a broad public audience. I was asked by the producer of “Through the Wormhole with Morgan Freeman” to do a segment about our research on bacteria for that show.

One of the scenes had me playing poker with a few of my students. It shows how the effect of a random event—a particular card in a game of poker—depends on the context in which it occurs. The same is true in evolution. A particular mutation that might be advantageous in one species could be detrimental or even lethal in another.

Let’s have a look**:

“When there was a Queen and a King of Hearts on the table and you have the 10 and Ace of Hearts in your hand, you are set up to potentially make a Royal Flush, the most powerful hand in poker. All you need is for the final card to be the Jack of Hearts.”

I’ve been lucky in life. I was born to parents who nurtured me. I was born in a nation dedicated to life, liberty, and the pursuit of happiness. And like those of you receiving your degrees today, I was fortunate to get a superb education here at Carolina.

The French scientist Louis Pasteur — who in the 1800s disproved spontaneous generation, invented what we now call pasteurization, and developed the first rabies vaccine — said: “chance favors the prepared mind.”

Thanks to your Carolina education, and the hard work that brought you here today, you have a prepared mind. You will encounter many uncertainties, probably some obstacles, and hopefully some terrific opportunities as the cards of life are dealt to you.

Play them well: Know when to hold them, know when to fold them. And sometimes you won’t really know what to do, so you’ll just have to give it your best shot.

Thank you, and congratulations again to all of you receiving your doctoral degrees today.

~~~ ~~~ ~~~

*This story is told in the autobiographical chapter of The Life and Letters of Charles Darwin, edited by his son Francis Darwin. I should have checked the source instead of relying on my memory, as Darwin says he lost only two of the three beetles.  The details of the bombardier beetle’s chemical defense system were worked out in the 1960s by Thomas Eisner and others.

**Thanks to Tony Lund, who produced the television show, for also making the short clip that I showed in my talk. You can see a longer clip here.

 

Thirty Years

No, the LTEE did not suddenly jump forward by almost 3 years. That milestone will be reached on February 24, 2018.

Next Friday is the end of the semester at MSU and, for me, it will mark 30 years that I’ve been on the faculty: six at UC-Irvine, and 24 here at MSU. (I also taught for one semester at Dartmouth as a sabbatical replacement, while I was doing a postdoc at UMass.)

Holy cow: 30 years. Where did all that time go?

Well, a lot of it was spent advising, supervising, and mentoring graduate students. And those have been some of the most interesting, enjoyable, and rewarding professional experiences that I can imagine.

In fact, this afternoon Caroline Turner defended her dissertation – congratulations Dr. Turner! Her dissertation is titled “Experimental evolution and ecological consequences: new niches and changing stoichiometry.” It contains four fascinating and meaty chapters, two on the interplay between evolutionary and ecological processes in the LTEE population that evolved the ability to grow on citrate, and two on evolved changes in the elemental stoichiometry of bacterial cells over experimental time scales.

Caroline is the 20th student to complete her Ph.D. with me serving as the advisor or co-advisor. Here they all are, with links to their professional pages or related sites.

1. Felisa Smith, Ph.D. in 1991 from UC-Irvine.
2. John Mittler, Ph.D. in 1992 from UC-Irvine.
3. Mike Travisano, Ph.D. in 1993 from MSU.
4. Paul Turner, Ph.D. in 1995 from MSU.
5. Greg Velicer, Ph.D. in 1997 from MSU.
6. Brendan Bohannan, Ph.D. in 1997 from MSU.
7. Phil Gerrish, Ph.D. in 1998 from MSU.
8. Farida Vasi, Ph.D. in 2000 from MSU.
9. Vaughn Cooper, Ph.D. in 2000 from MSU.
10. Danny Rozen, Ph.D. in 2000 from MSU.
11. Kristina Hillesland, Ph.D. in 2004 from MSU.
12. Elizabeth Ostrowski, Ph.D. in 2005 from MSU.
13. Bob Woods, Ph.D. in 2005 from MSU.
14. Dule Misevic, Ph.D. in 2006 from MSU.
15. Gabe Yedid, Ph.D. in 2007 from MSU.
16. Sean Sleight, Ph.D. in 2007 from MSU.
17. Zack Blount, Ph.D. in 2011 from MSU.
18. Justin Meyer, Ph.D. in 2012 from MSU.
19. Luis Zaman, Ph.D. in 2014 from MSU. (Charles Ofria was the primary advisor.)
20. Caroline Turner, Ph.D. in 2015 from MSU.

There are also 8 doctoral students at various stages currently in my group at MSU including Brian Wade (Ph.D. candidate), Mike Wiser (Ph.D. candidate), Rohan Maddamsetti (Ph.D. candidate), Alita Burmeister (Ph.D. candidate), Elizabeth Baird, Jay Bundy, Nkrumah Grant, and Kyle Card.

My own advisor – the late, great Nelson Hairston, Sr. – said that he expected his graduate students to shed sweat and maybe even occasional tears, but not blood. I would imagine the same has been true for my students.

Thirty years, holy cow. Time flies when you’re working hard and having fun!

Added November 4, 2015:  And now #21 in my 31st year, as  Mike Wiser successfully defended his dissertation today!

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.