I retire today

September 30, 2015 • 4:01 am

Before people who like this site worry that I’m retiring from writing here, let me clarify. That is not what I mean by “retiring.”  Posting here will continue as usual, though there will be only two posts today. As of 4:30 p.m. Chicago time, I’m retiring in the conventional sense—from my job at the University of Chicago. As I sleep tonight in Poland, seven hours ahead of Chicago, I will be transformed from Professor to Professor Emeritus (or, on this site, to Professor Ceiling Cat, Emeritus).

This has been in the offing for two years, but I don’t often post here about personal issues, and wanted to delay this news until retirement was a fait accompli. And, as today’s Hili dialogue suggests, not that much will change for me, save that I will no longer do research with my own hands or teach students (emeritus faculty aren’t allowed to teach at Chicago). I get to keep my office, and will still work hard, but the nature of that work will change a bit.

Several years ago, I began to realize that my job as a scientist and academic was not as challenging as it had been for the previous 35 years. I had mastered the requisites of such a job: doing research, writing papers, mentoring and teaching students, getting grants, and so on.  The one challenge left was discovering new things about evolution, which was the really exciting thing about science. I’ve always said that there is nothing comparable to being the first person to see something that nobody’s seen before. Artists must derive some of the same satisfaction when creating new fictional worlds, or finding new ways to see the existing world, but it is only those who do science—and I mean “science” in the broad sense—who are privileged to find and verify new truths about our cosmos.

But finding truly new things—things that surprise and delight other scientists—is very rare, for science, like Steve Gould’s fossil record, is largely tedium punctuated by sudden change. And so, as I began to look for more sustaining challenges; I slowly ratcheted down my research, deciding that I’d retire after my one remaining student graduated. That decision was made two years ago, but the mechanics of retirement—and, in truth, my own ambivalence—have led to a slight delay. Today, though, is the day.

What am I going to do now? Well, I’m not going to take up golf, which I always found a bit silly. I won’t do any more “bench work”—research with my own hands—but I’m not going to abandon science. I will still write about it, both on this website and in venues like magazines and their e-sites, and I’m planning a popular book on speciation. Writing, for me, is the New Big Challenge, and one that can never be mastered. My aspiration is to write about science in beautiful and engaging words, and to find my own voice so that I’m not simply aping the popular science writers I admire so much. That is a challenge that will last a lifetime, for there is never an end to improving one’s writing.

And I do plan to travel more, visiting those places I’ve longed to see but haven’t had time: Antarctica, Australia, Southeast Asia, Bali, the wildlife refuges of Africa, Patagonia, and so on.

But let me look back now, for I feel the urge to close my academic career by summarizing it.

When I was applying for jobs, my advisor, Dick Lewontin, used to write in his recommendation letters something like this: “If Jerry has one fault, he’s too self-deprecating and tends to sell himself short.” He was right, for I never wanted to succumb to the arrogance of those who internalize the admiration they receive. But today I’ll try to be honest without being too self-deprecating.

So what have I accomplished? First, it’s been a good career. Scientifically, I’ve accomplished far more than I ever imagined. In truth, had I known as a graduate student the hurdles I’d have to surmount to become a professor at a great university and accomplish a goodly amount of widely cited research, I probably would have given up.  But I didn’t look at the whole track: I took things one hurdle at a time. Now I’m at the end of the race, and though can’t say I’ve won, I’m happy with my finish.

What am I proudest of? My research, of course, for the desire to find out things was what made me a scientist. The pivotal moment was when, as an undergraduate in genetics class, we were given two tubes of fruit flies, one with white eyes, the other with the normal reddish-brown eyes. We were assigned the job of finding out what mutation caused the eyes to lose pigment. When I crossed the flies from the two tubes, the offspring had normal-colored eyes, but when those “F1 progeny” were crossed among themselves, one got four colors in the offspring: normal, white, and two new colors: dark brown and bright orange. How could that be? I remember puzzling this out, and then the solution came to me in a flash while sitting on the bleachers in swimming class. The white-eyed flies must have two mutant genes, one that blocked the production of red pigment (producing brown eyes), and one blocking the brown pigment (orange eyes). When both mutations were present, no pigment was produced, ergo white eyes. I went back to the lab, tested that theory, and found not only that I was right, but that the two genes resided on the same chromosome (the second), though they were far apart. I gave them cumbersome names, but they were in fact the classic mutations cinnabar and brown.

The excitement of that moment, and the clean results I got when testing my hypothesis, is what made me an evolutionary geneticist. Since then, I’ve always tried to do experiments in which the result are clean: experiments in which there are two possible outcomes that are easily distinguishable. While the study of evolution is often messy, evolutionary genetics is neater, and both my students and I have concentrated on studies in which the results unequivocally favor one hypothesis rather than another. It all goes back to that moment in gym class.

I am proud of my work on speciation, and I will try not to be overly modest when claiming that I think I helped revive the study of how species form, at least in a genetic sense—a research area that had lain moribund for many years. There is now a cottage industry of work on speciation, much of it inspired by the work my students and I did at The University of Maryland (my first job) and then at The University of Chicago. The specific things we found, and what they meant, will of course be immersed in and then covered by the stream of science, and our names will be forgotten. But that is the fate of most of us, and it is enough for me to have shunted the evolutionary-biology stream towards one of its more important questions: why is nature divided up into lumps (species) instead of forming a complete organic continuum? And how do those lumps form? I was privileged to have made a few discoveries that helped answer these questions, and to have inspired others to make even more discoveries.

What I’m proudest of, I suppose, is the book I wrote with my ex-student Allen Orr, Speciation, published in 2004. It took each of us six years to write, was widely acclaimed and, more important, was influential. I still see that book as my true legacy, for it not only summed up where the field had gone, but also highlighted its important but unsolved questions, serving as a guide for future research.

I’m also very proud of my graduate students, which are one’s human legacy: the academic sons and daughters whose work will change the course of science long after I’m gone. I have had a very small output of students: only four, with one of them opting for a career in science writing. The other three are well-known academics, and I’m immensely proud that they’re all seen as “stars.” I can’t really claim credit for their accomplishments, as they were all self-starters, nor can I say that I had an eye for talent. All I can say is that I sat in the lab with them, engaged in nonstop conversation about science as we “pushed flies” together (counted and manipulated flies under the microscope with ermine-fur paintbrushes); and I think that conversation helped motivate and guide them.

And I’m proud that up to the very end I did my own research with my own hands. I don’t fault those senior scientists who tell others what to do and sit in their offices writing up the results of that guided research, but being a lab manager was never my forte. In fact, given that I loved to work at the bench, I didn’t have time to manage others, and this also constrained me to have only one student at a time. (I’ve also had only one postdoc, and I am proud of her accomplishments as a molecular evolutionary geneticist.)

On a more mundane level, I’m proud of having never gone without grant support for my entire career, something that’s a rarity in these days of tight funding. I had the same grant, renewed every three years, for over three decades: “The genetics of speciation.” I am immensely grateful to the National Institutes of Health for providing the largesse for all my research.

What could I have done better? To a determinist like me, regrets are unproductive (though perhaps useful to others), as I couldn’t have done other than what I did. But I wish I had been a better teacher, especially of undergraduates. Given that my true love was research, and that one is evaluated at a place like the University of Chicago largely on research rather than teaching, I probably put too little effort into teaching. I wish I had had interacted more with my undergraduate students, for at the University of Chicago they are a bright and curious bunch. My teaching ratings always came in about average, and I always wished they were higher. On the other hand, a lot of my research was done in collaboration with undergraduates who asked to work in my lab after taking my evolution course, and several of these have gone on to careers in either science or medicine.

The University of Chicago is a diverse and stimulating place: we have great professors and courses in every area of the liberal arts and sciences. I wish I had interacted more with my diverse colleagues over my career. The University is a bit Balkanized, though, so such opportunities are rare, and there’s precious little time. But I love the humanities, and wish I had sat in on courses in English, philosophy, history, and the sciences of physical anthropology, paleontology, and so on. Perhaps I’ll have more time to do that now. But at least I fulfilled the two vows I made as an aspiring academic: I would never leave college, and I would always have a job in which I could wear jeans to work.

Academics who retire are often asked what advice they have for younger folks. (I have in fact been asked that question repeatedly throughout my career.) And of course we all tend to advise people to do exactly what we did! For that is really all we can say: do the things that, we think, helped make us personally successful. And here I’ll mention two things, both of which characterized my own career. Perhaps these can influence the neuronal wiring of younger researchers and affect their own lives.

First, there is no substitute for hard work. Brains are not enough, and, in truth, I’ve never seen myself as particularly smart. But I have worked very hard—often seven days a week—and it is to that hard work that I attribute what success I’ve had. Good ideas are few—I’ve had about three in my life—but everyone has the capacity (though not perhaps the inclination) to work hard. To all grad students, then: if you’re not in the lab on weekends, you’re not doing it right. That is not to say that you shouldn’t have a life outside the lab, for of course that’s vital, but if you’re passionate about your work, you’ll want to do it outside conventional work hours. Science is not a nine-to-five job.

The second bit of advice was imparted by my mentor Dick Lewontin at his “pre-retirement” party at Harvard, when he stood up in front of the coelacanth—the “living fossil” fish preserved in a tank of formalin, which Dick pointed out as an appropriate backdrop. He ended his brief remarks by emphasizing the one thing he wanted the younger generation to absorb. It was this: if you’re a professor, DO NOT slap your name as an author on the papers of your students—at least not unless you did substantial work on the project. Such gratuitous co-authorship inflates your curriculum vitae in a less-than-honest way, and also diminishes the accomplishments of your students.

It is a truth universally acknowledged in academics (and named the “Matthew Effect” after the appropriate Biblical verse) that the “senior author” of a research paper—the head of the lab where the work was done—gets the lion’s share of credit for that work. The unfortunate result is that the graduate students and postdocs are left picking up the crumbs, seen as mere functionaries. That is not the way it should be. Senior authors have already attained their status and security, while junior authors are merely aspiring to such a position. To me, the only justification for putting your name on a student’s paper is that you either did a large portion of the work with your own hands or contributed substantially to the analysis. Simply handing a student an idea, providing the funding or materials for the research, or helping the student/postdoc write the paper isn’t sufficient to warrant authorship. Those are our duties as professors, while our privilege is to do the science and find out new things.

One anecdote about this. My first well-known paper showed that, as revealed by gel electrophoresis, some genes had many more alleles (gene forms) than previously thought—up to twenty or thirty forms segregating in a population. I wrote up a paper for the journal Genetics, and at the top put the names of two authors: myself and Dick Lewontin. At the end of the day, I timidly placed the paper on his desk for his comments and emendations.

The next morning I found the paper on my desk, covered with red scrawls (Dick’s handwriting was atrocious), but with Lewontin’s name crossed out. He told me, “Don’t ever do that again.” Lewontin was part of a lineage of academics who abjured credit-mongering. His own advisor, Theodosius Dobzhansky, often published research that derived from his own ideas, for which he did much of the physical labor of reading chromosome slides, and for which he wrote the entire paper—and yet his name wasn’t under the title. Often his technicians were the sole authors: Boris Spassky and Olga Pavlovsky. And Dobzhansky came from the very first modern genetics lab—that of Thomas Hunt Morgan—whose members (save, perhaps, H. J. Muller) didn’t care very much about who got the credit. I am proud to be part of that lineage and of trying to sustain its traditions.

I’m often told that without putting your name on every paper coming from your lab, you won’t advance professionally. That is not true. For 30 years I submitted grant proposals to the National Institutes of Health listing all the papers published during my previous funding period. Many of these papers did not have my name on them. And the NIH didn’t care a bit: they cared about how much good research had been done on their dime, not whether my name was on the papers; and they continued to fund me.

So to the professors: try to not grab credit that you really don’t deserve. It is your job to help students write papers and find good ideas; it is your job to guide their research and suggest how to analyze that research. But that does not justify your taking credit for their work. To the students: do not assume automatically that your professor’s name should go on your paper. Perhaps that’s the lab “tradition”, and you must hew to it lest you offend your boss. But even if you must succumb to this form of coercion, try not to do it yourself when you become the boss.

And with that advice I will end this post. I have had a good run, I regret nothing, at least scientifically, and I’ve been given the greatest privilege a scientist can have: to be the first to discover some previously unknown things about our universe.

Wednesday: Hili dialogue

September 30, 2015 • 4:00 am

As always, Hili is here to announce big changes in my life. This will be the first of only two posts today.

Hili: So you are really going to retire?
Jerry: Yes, I am.
Hili: And what are you going to do then?
Jerry: More or less the same thing.

P1030406a

In Polish:
Hili: Czy to prawda, że dziś przechodzisz na emeryturę?
Jerry: Tak, to prawda.
Hili: I co będziesz robił?
Jerry: Właściwie to samo.

Lawrence Krauss on Ben Carson (it’s not pretty)

September 29, 2015 • 2:00 pm

When I wrote my post on Sept. 24 dissecting Ben Carson’s ignorance of cosmology and evolution, I realized at the end that the people who would read here it already agreed with me, and that I had spent over two hours basically entertaining myself. Still, at least the problems with his creationist views of the cosmos and evolution were on the record somewhere.

Well, Lawrence Krauss has put them on the record in a much bigger venue, the New Yorker. If you want to see a small but loud fish blasted to bits in a barrel, read Krauss’s piece “Ben Carson’s scientific ignorance.” Krauss concentrates more on Carson’s physics arguments—including his mushbrained claims about entropy—than on evolution, but that’s okay, as I’ve done the evolution work.

Here’s one excerpt from Krauss’s takedown:

Last week, when he was confronted, during a speech at Cedarville University, about his failure to understand basic and fundamental scientific concepts, Carson responded, “I’m not going to denigrate you because of your faith, and you shouldn’t denigrate me for mine.” What Carson doesn’t seem to recognize is that there is a fundamental difference between facts and faith. An inability to separate religious beliefs from an assessment of physical reality runs counter to the very basis of our society—the separation of church and state.

Carson continues to insist, as do many religionists, that science, like religion, is simply a form of faith. I’ve picked the meat off that canard before, both in Slate and in Faith versus Fact, and we needn’t belabor it here. What’s funny about that argument is that it boils down to this claim by believers: “See! Science is just as bad as religion!” If they truly were equivalent, theology would have made as much progress in understanding God as science has in understanding the universe. But the score is zero for the former and a gazillion for the latter.

Krauss is probably preaching to the choir as much as I did, for in the end there are few creationists who read The New Yorker, and virtually no supporters of Carson, but it’s still good to get the scientific objections on the record. Krauss concludes, as do most rationalists, that having a man like Carson in the White House is unthinkable:

While many may debate whether his lack of public-service experience disqualifies him from serious consideration in this race, Carson’s ideas about religion, science, and public office, as revealed in the past week, suggest that there are far deeper reasons to be concerned about his candidacy for the highest office in the land.

But of course that goes for nearly every Republican candidate, for as far as I know there is no GOP candidate who openly endorses the truth of evolution.

The anurans of autumn

September 29, 2015 • 12:30 pm

by Greg Mayer

In a previous post here at WEIT, I’d reported on some toads and a painted turtle that I’d rescued from stair and window wells, and then released back into the wild last spring. I’d mentioned at the time that I periodically check these places, especially a deep (ca. 20 feet down) window well on the west side of the building my office is in, because it faces a pond and woods, and animals coming out of the woods regularly fall down into it. So at the beginning of the semester in early September, I took my vertebrate zoology class out during our first lab period, and we investigated the window well. There was a pretty good ‘crop’ this fall– eleven American toads (Bufo americanus), and 23 green frogs (Rana clamitans).

Bufo Kenosha 1
American toads just outside Greenquist Woods, Kenosha, Wisconsin, 17.ix.2015. There are clearly six of them, the same ones as in “Spot the toads“.

The toads fell into two size classes: medium (in picture above), about 55 mm snout-vent length, and small, about 40 mm. The green frogs were all about the same size– 35 mm. These latter were probably all a single age class, having metamorphosed from tadpoles earlier in the summer, and then hitting the building and falling in the window well as they began to disperse away from their natal pond. Bullfrogs (Rana catesbeiana) are also common in the pond, but we’ve never found them in the window well– they must have different dispersal behavior.

Chrsi Noto Bufo release
Chris Noto helps to release American toads in Greenquist Woods, 17.ix.2015.

Frogs and toads are collectively known as anurans— it means “not having a tail”– and adult frogs and toads do, of course, lack tails. The anurans we rescued from the window well had been there varying lengths of time, but most were in at least decent shape, though some were thin and dehydrated. We kept them in the lab for a couple of weeks, feeding them and rehydrating them. We then released them on two warm days just as autumn was about to begin. My colleague Chris Noto was teaching a lab on a floor looking out over the woods, and he saw me encumbered with toads as I attempted to take their pictures and carry them back out to the woods. He came down and helped with the pictures and the release (which were featured in two “Spot the __” posts, on frogs and toads).

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Small American toad, about to be released into Greenquist Woods, 17.ix.2015.

The green frogs were released a few days later.

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Green frogs anxiously await their transfer to the pond, 20.ix.2015.
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One last picture.
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Well, maybe just one more.
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And then it’s time to re-enter the pond.
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Green frogs queue up to enter Greenquist Pond, 20.ix.2015.

[JAC: a video of the release. I have to commend Greg for both taking the time to rescue these frogs and also calling them to our attention. Frogs are not only underappreciated animals, but are harbingers of human damage to the environment, climatic and otherwise. And I’ve always said that if frogs hadn’t evolved, we simply wouldn’t be able to imagine them!]

There are at least a dozen or more different sorts of anurans around the world that are worthy of their own vernacular name, but because only two sorts occur in England, we are stuck with calling them all either “frog” or “toad” in English. The American toad and the green frog do, however, correspond to the two sorts found in England (what are sometimes called the “true toads” and the “true frogs”, respectively).

Anurans are amphibians, and like most amphibians, have a complex life cycle. The word “amphibian” alludes to this– it means “both lives”, because a typical amphibian lives both on the land and in the water. Reptiles and their descendants (the amniotes, including birds and mammals), do not have this dual life cycle. One of the former candidates for the title of “first reptile” was the 270 million year old Seymouria, which has reptile-like features; but when it was found that its close relatives had aquatic larvae with gills, it was clear they were not reptiles, but rather led the “both lives” of an amphibian.

“Both lives” does not seem to adequately summarize the life of a typical amphibian, such as the American toad. They begin life as eggs in water, hatch out as tailed, gilled, tadpoles, that then swim about, eventually losing their tails and gills and sprouting legs to transform into toadlets, which then move onto land. After sexually maturing, they return to the pond each spring, to resume an amphibious existence, there to mate and reproduce. The adults then leave the pond for the summer to live wholly on land, while their eggs begin the complex cycling again. To paraphrase The Who, “Amphibians? They’re bleeding Quadrophibians.”

American students become more fragile, less emotionally resilient, and more traumatized

September 29, 2015 • 11:00 am

Psychology Today sometimes publishes some pretty wonky stuff, but this article, about the emotional resilience of American college students—or rather its decline—rings true from the kind of incidents (granted, anecdotes) documented on this site. Further, its author, Peter Gray, a psychologist at Boston University and expert in educational psychology, has impeccable credentials.

In his piece, “Declining student resilience: a serious problem for colleges,” Gray first documents the growing problem of the emotional fragility of students, and, at the end, suggests a cause.  As I said, I’m not aware of any concerted psychological studies of students’ emotional states, although Gray implies that there’s documentation about growing problems with student mental health. Nevertheless, it’s pretty clear that students seem increasingly more upset by things that challenge them, and are demanding accommodation, whether that accommodation involves getting higher grades or suppressing disturbing ideas. I’ve written a lot about “trigger warnings”, “safe spaces,” and student protests against what’s call “hate speech”: these are phenomena of the last decade or so, and anyone who’s been teaching for a long time recognizes that. But Gray documents it with more examples:

A year ago I received an invitation from the head of Counseling Services at a major university to join faculty and administrators for discussions about how to deal with the decline in resilienceamong students. At the first meeting, we learned that emergency calls to Counseling had more than doubled over the past five years. Students are increasingly seeking help for, and apparently having emotional crises over, problems of everyday life. Recent examples mentioned included a student who felt traumatized because her roommate had called her a “bitch” and two students who had sought counseling because they had seen a mouse in their off-campus apartment. The latter two also called the police, who kindly arrived and set a mousetrap for them.

Faculty at the meetings noted that students’ emotional fragility has become a serious problem when in comes to grading. Some said they had grown afraid to give low grades for poor performance, because of the subsequent emotional crises they would have to deal with in their offices. Many students, they said, now view a C, or sometimes even a B, as failure, and they interpret such “failure” as the end of the world. Faculty also noted an increased tendency for students to blame them (the faculty) for low grades—they weren’t explicit enough in telling the students just what the test would cover or just what would distinguish a good paper from a bad one. They described an increased tendency to see a poor grade as reason to complain rather than as reason to study more, or more effectively. Much of the discussions had to do with the amount of handholding faculty should do versus the degree to which the response should be something like, “Buck up, this is college.” Does the first response simply play into and perpetuate students’ neediness and unwillingness to take responsibility? Does the second response create the possibility of serious emotional breakdown, or, who knows, maybe even suicide?

The dilemma of the last two sentences is something I’ve faced. My first response, which of course is based on my own experience in college, is to tell the students to “tough it out.” But that’s uncharitable, for we receive these students with their emotionality already formed by what happened to them before college (see below). I suggest one solution below, but that’s only a quick fix to a problem that runs deeper.

That head of counseling mentioned by Gray reports that this trend appears to be nationwide, accompanied by a growing number of reports of mental health issues among students.  He added, “The lack of resilience is interfering with the academic mission of the University and is thwarting the emotional and personal development of students.” And that is indeed the case.

What is going on here, and what do we do about it? One solution, I think, is to train students not only in “sensitivity” to diverse viewpoints when they enter college, but also to train them in listening to differing opinions without taking offense. That, to me, seems an eminently viable tactic: let incoming students read, for instance, the University of Chicago’s “free expression” standards, and then let them discuss them. We must somehow teach students why universities should be places where all viewpoints should be aired, and that viewpoints that seem offensive or incorrect can be countered with other speech.

Here’s Geoff Stone, the law professor at the U of C and chair of the committee that produced our standards:

But this alone won’t solve the problem, for students arrive at the University already hypersensitive and dependent:

We have raised a generation of young people who have not been given the opportunity to learn how to solve their own problems. They have not been given the opportunity to get into trouble and find their own way out, to experience failure and realize they can survive it, to be called bad names by others and learn how to respond without adult intervention. So now, here’s what we have. Young people,18 years and older, going to college still unable or unwilling to take responsibility for themselves, still feeling that if a problem arises they need an adult to solve it.

Gray suggests that the cause of this problem is “helicopter parenting”: the tendency of parents to hover about their children, protecting them from all possible ills, dangers, and offenses. Those of us of a certain age know this: when I was a kid of 10 or so, I was allowed to walk to school on my own and, after school, ride my bike over to my friends’ houses, where we’d then take off in juvenile packs to explore our surroundings. There was no adult supervision save the order that we be home by dinner. That not only doesn’t happen any more, but parents who permit such roaming can (and have been) arrested.

Gray adds, though, that “helicopter parenting” reflects of other social trends, including “the continuous exhortations from ‘experts’ about the dangers of letting kids be, victims of the increased power of the school system and the schooling mentality that says kids develop best when carefully guided and supervised by adults, and victims of increased legal and social sanctions for allowing kids into public spaces without adult accompaniment.”

Yes, but why now? If Gray is right, what has happened in society to create people’s need to protect children from everything?

h/t: Cindy

 

https://en.wikipedia.org/wiki/Peter_Gray_(psychologist)

Exceedingly small snails!

September 29, 2015 • 10:00 am

This morning, Matthew Cobb sent me the needle’s-eye photo below, and then reader Dom conveniently sent the article from which it was taken: a new paper in ZooKeys by Barna Páll-Gergely et al. (reference below) describing what are among the smallest snails in the world. And when I say “small,” I mean TINY!

The group of researchers described seven new species of snails recently collected in Guangxi Province, China. One of them, Angustopila dominikae (photo below), has a shell height of about 0.9 millimeters, and a width of about 0.8 mm, with an aperture about 0.3 mm across. As the authors note, these are close to the smallest land snails ever found, but don’t quite hold the record:

These data suggest that Angustopila subelevata sp. n. and A. dominikae sp. n. are amongst the smallest land snails ever reported if the largest measurement of the shell is considered. If however, shell volume is calculated according toMcCain and Nekola (2008) and Nekola (2014), there are even tinier land snails (e.g.Punctidae spp) occupying the lowest rung of the volume/size scale.

Here’s the holotype (the specimen used to name the species, and which will serve as its representative in a museum) of A. dominikae:

oo_58422
Holotype of Angustopila dominikae Páll-Gergely & Hunyadi, sp. n. (HNHM 99435). All images: B. Páll-Gergely.

Well, the key gives an idea of how small it is, but the picture below really tells the tale. Remember, that’s an adult snail! A camel might not fit through the eye of a needle, but these snails can; ergo they can go to Heaven.

oo_58433
The holotype of Angustopila dominikae sp. n. in the eye of a sewing needle to picture its extraordinary small size. Photo: B. Páll-Gergely and N. Szpisjak.

But these aren’t close to the smallest of all snails: that record goes to marine snails less than half the size of the one shown above:

. . . The smallest snails are, however, certainly marine species. The smallest recorded gastropod seems to be Ammonicera minortalis Rolán, 1992, ranging in size from 0.32 to 0.46 mm.

You can find a paper on this species, found in Cuba, Florida and the Caribbean, here. And here’s a photo with scale:

Ammonicera-minortalis-40.jpg_1629876086

That is one small snail.

h/t: Dom
___________

Páll-Gergely, B., Hunyadi A., Jochum A. and T. Asami. 2015. Seven new hypselostomatid species from China, including some of the world’s smallest land snails (Gastropoda, Pulmonata, Orthurethra). ZooKeys 523:31-62.

Water on Mars: what does it mean?

September 29, 2015 • 8:45 am

Lots of folks have gone gaga about the discovery of salty water on the surface of Mars, and the excitement centers on one thing: the possibility that there could be life there. Well, we can’t rule out life yet, but the four Mars Rovers haven’t found any. What they have found are organic chemicals on the planet and sedimentary rocks with features resembling those formed by microbes on Earth, like stromatolites, stony structures built by cyanobacteria and—with some dated about 3.5-3.8 billion years old—the oldest definitive evidence of life on Earth. But what we see on Mars are only sort-of-similar rock structures; so far there has been nothing remotely resembling strong evidence of life (either past or present) on the Red Planet.

In a really nice post at the Planetary Society website, senior editor and “planetary evangelist” Emily Lackdawalla assesses the new evidence of briny water on Mars, and how it relates to the Big Question.

First, some photographic evidence for liquid water, with the caption:

Recurring slope lineae are narrow (0.5-5 m wide), relatively dark-toned features that form on steep (25-40˚), southern-hemisphere slopes, and that appear in early spring, grow longer in the downslope direction during spring and summer, and fade during autumn and winter.

The “linae” are the dark streaks that look like broomstraws; you can see them better in the black and white photos below.

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Photo: NASA / JPL / UA / Emily Lakdawalla

Here are some of the seasonal changes that suggest moving water, as the “linea” (putative water channels) get longer over a season as they “flow” downhill toward the left (length of lines increases by the length of the white overlays). As noted below, these are probably growing channels of damp soil caused by moving water, rather than water rivulets themselves:

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Photo: NASA / JPL / UA / Joe Levy

Here’s some of Lackdawalla’s summary, taken directly from her text (my emphasis):

  • Past work on slope lineae, with the HiRISE camera on Mars Reconnaissance Orbiter, showed that they form in warm seasons when temperatures reach 250-300 kelvin [JAC: on Earth pure ice melts above 273 kelvin, or 0°C], which strongly suggested that a volatile species like water was responsible.
  • The newly published work involves data from the CRISM spectrometer on Mars Reconnaissance Orbiter, and shows spectral evidence for hydrated salts (minerals containing molecular water in their structures) during the times when the slope lineae recur.
  • The best mineral matches to the spectral data are magnesium perchlorate, magnesium chlorate, and sodium perchlorate.
  • The presence of perchlorate salts could lower the melting temperature of water at Martian conditions by 40 kelvins, making it much easier for water to melt.
  • This work is considered very strong evidence that at widespread locations on present-day Mars, conditions sometimes arise for brief flows of briny liquid water — probably not rivulets, just spreading wetness in the soil.
  • The widely varying locations and geologic settings where slope lineae have been observed to form and recur make it difficult to identify a single mechanism for replenishing liquid water to drive the recurrent activity.
  • The science team including Ojha and Alfred McEwen favor deliquescence as the source: perchlorate salts adsorb water vapor from the atmosphere until enough water is available to form a liquid and dissolve the salts.

That’s all pretty clear, but what does it mean for the possibility of life? Lackdawalla doesn’t see these seasonal rivulets as propitious, but perhaps there’s life elsewhere on Mars:

Personally, I don’t think extant life on Mars is any more likely because of today’s announcement than it was before. An incredibly salty, corrosive, transient water environment is not a very good place to look for life. I think a much more habitable environment is available in the thin films of water that Phoenix observed in the soil at its near-polar landing site. A less-accessible, but also less-radiation-fried and more-continuously-habitable place would be deep underground, where Mars’ internal heat could keep groundwater liquid for very long periods of time.

Lackdawalla points out one concern that I hadn’t absorbed, also discussed by Lee Billings in a post at Scientific American: how can we find out whether there’s life on Mars if there’s a chance that, by visiting the planet, we ourselves could infect it? As Billings notes, spacecraft are scrupulously sterilized before launch, but that doesn’t solve the problem:

Microbes that stubbornly refuse to die nonetheless turn up with regularity in NASA’s supposedly sterile clean rooms for preparing interplanetary spacecraft. Apollo astronauts even found bacteria on the moon that had survived an almost total vacuum inside the robotic Surveyor 3 lander that had touched down more than two and a half years earlier. If terrestrial microbes could live in places like that, why not in some of the more habitable parts of Mars?

The issue becomes worse if humans, who are of course ridden with microbes, are sent to the planet, something that Lackdawalla, but not I, see as inevitable.

I’m not sure how serious this problem is, for, after all, all life on Earth shares certain features implying descent from a common ancestor. That includes the similarity of the genetic code, the use of L-amino acids, and the similarity of gene sequences among diverse species. Presumably if we found Earth-derived microbes on Mars, their DNA—and again, Mars-evolved life probably wouldn’t even contain DNA as we know it—would tell us. I suppose a greater problem is if Earth-derived life were to extirpate or outcompete Martian life, rendering us unable to detect the latter, but that seems unlikely as well. Martian life would probably be competitively superior to that from Earth, though we don’t know for sure (think of all the island species on our planet wiped out by colonizers!).

To cover my tuchus, let me add that it’s not impossible that life on Earth could have descended from life that evolved on Mars, or vice versa. In that case we’d see fundamental similarities among the genomes of species upon each planet, but big disparities between the heredity material of organisms from the two planets, reflecting their independent evolution since the colonization event.

Finally, Google has honored the finding in today’s Google Doodle:

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h/t: Matthew Cobb