Life, What's Luck Got to Do With It?

Paleontologist Stephen Jay Gould, in his book Wonderful Life:  The Burgess Shale and the Nature of History (1989), introduced a broad swath of the reading public to the concept of historical contingency.  In the book, he explores how the world of living organisms could move from the many "weird" forms of Cambrian life (at a juncture some 530 million years ago) fossilized in the Burgess Shale, to creatures such as us.  He states that there are no natural laws requiring a particular outcome (e.g., us), rather, he posits, what's at work, and what shaped our world, is historical contingency which is:

an unpredictable sequence of antecedent states, where any major change in any step of the sequence would have altered the final result.  The final result is therefore dependent, or contingent, upon everything that came before - the unerasable and determining signature of history.  (Wonderful Life, p. 283)

When considering the final product of such a process, apparently luck, or chance, plays a determinative role.  The previous post on this blog (the one about watches, God, and evolution) draws on some different work by Gould to posit that evolution through natural selection, not some divine force, shaped the biological world around us.  What role has chance played in life, what's the connection between chance and evolution, and what does historical contingency have to say about that connection?  I address those questions in this post through a review of a book which I read only by chance or, more precisely, by mistake.

In that earlier post, I reference Sean Carroll's book The Big Picture:  On the Origins of Life, Meaning, and the Universe Itself (2016) when asserting that the human eye came into being through natural selection.  Afterwards I went in search of other works by Carroll, and came upon the thoroughly enjoyable A Series of Fortunate Events:  Chance and the Making of the Planet, Life, and You (2020)  The title is a nice play on Lemony Snicket's series of books titled A Series of Unfortunate Events.  Wait, I will forestall a rise in your blood pressure, by hastening to admit that it took me an embarrassingly long time to realize that the Sean Carroll whose book I mention in that previous post is a physicist and is NOT the author of A Series of Fortunate Events who is biologist Sean B. Carroll.  A whole different kettle of fish.  Fittingly, had I not made that error, I might never have read A Series of Fortunate Events, at least not when I did, which would have been an unfortunate event.

The biologist Carroll's A Series of Fortunate Events is a brief, graceful, and often funny read about the central role chance has played, and plays, in determining how the world and everything in it - organic and not - has come to be.  Carroll structures his exploration of chance around its role in two broad realms:  the "inanimate" (read cosmological and geological), and the "animate" (read biological).  There are two components to the biological realm:  a part embracing life in general where evolution through natural selection as well as mutation are at work, and a part focused on the way chance affects how each of us individually is conceived, lives, and dies.  Quite ambitious and he pulls it off with surprising ease.

I think it useful at the outset to draw attention to the two pages that mark the transition from Carroll's discussion of the inanimate to that addressing the animate.  In them, he explains what he means by chance:  "a rare, unpredictable, or random event, or one that entails so many variables or forces that is near enough to be random,"  (p. 59)  And, perhaps even more important, he defines the concept of historical contingency:  "a past event or process that was necessary for a particular outcome."  (p. 59)  He captures the significance of the relationship between the two when he writes:

Chance here, then, pertains to an event itself, while a contingency emerges through the benefit of hindsight.  The interrelationship between the two is that a chance event can become a historical contingency through its effects.  Contingency is the aftermath of chance.  (p. 59-60)

Carroll presents various examples of chance in the broad realms around which the book is structured.  I mention a few of the most prominent.  The star of the inanimate realm is cosmological in nature:  the asteroid that smashed into the Yucatan Peninsula 66 million years ago, dooming the non-avian dinosaurs and myriad other species of animals and plants.  This asteroid was a great big ball of chance.  As Carroll point out, a mere 30 minutes was key.  Had the asteroid hit Earth that many minutes earlier or later, it would have landed in deep ocean waters and likely not played havoc with the world.  Instead, the bolide landed on a part of the planet that magnified its most lethal effects.  And, so, the asteroid "hit the reset button" for life on Earth.

Regarding chance in the biological realm for life in general, Carroll focuses on a biologist about whom I knew nothing - Jacques Monod whose work included exploring how genes control enzyme production.  He shared the 1965 Nobel Prize in Physiology or Medicine.  With the publication of his book Chance and Necessity in 1970, Monod achieved an unexpected degree of fame and notoriety.  Carroll asserts that, when Monod wrote about how mutations appeared in DNA, "he delivered one of the most powerful ideas in five centuries of science."  (A Series of Fortunate Events, p. 8)  Monod stated that

chance alone is at the source of every innovation of all creation in the biosphere.

Pure chance, absolutely free but blind, at the very root of the stupendous edifice of evolution:  this central concept of modern biology is no longer one among other possible or even conceivable hypotheses.  It is today the sole conceivable hypothesis, the only one that squares with observed and tested fact."  (Text is from Chance and Necessity as quoted in A Series of Fortunate Events, p. 8)

Amazing.  Carroll is equating in importance Monod's claim about chance with, say, Darwin's theory of evolution through natural selection.  In fact, the two go hand in hand.  Without the possibility of change in living organisms, there would be no variation for natural selection to work with.  That the variation occurs and is random speaks to the role of chance.  Darwin, Carroll says, had no knowledge of the actual process that generated variations, but characterized them as "accidents."

Carroll devotes a couple of chapters to mistakes or mutations that can occur in the genome, showing that they are random, a matter of chance in how the genetic code might be altered.  The key is that the four bases that constitute the alphabet of which DNA is composed exist in two alternate forms and can shift from one to the other.  If, during copying, the rarer form of a base is present, it will bond with the "wrong complementary base," yielding a mutation.  Carroll labels the shifting between forms as "quantum fibrillation," a feature inherent in the bases, meaning:  "Mutation, then, is a feature, not a bug in DNA."  (p. 95)  He sums up the interplay between mutation (the product of chance) and natural selection:  "Chance invents, and natural selection propagates the invention."  (p. 118)   But propagation may occur only if the mutation offers an organism some advantage in the struggle for survival.

As for the role of chance in my life or yours, Carroll starts with our conception.  It's not just how, out of some 100 million of a male's sperm streaming toward the female's egg, only one will fertilize it.  More impressive is that, based on any male and female's chromosomes, there are some 70 trillion different, genetically unique children that a couple might create in that moment, but only one is.  (p. 131)  Other aspects of chance playing out in our lives that Carroll explores include some unfortunate events, among them having cancer.

He nicely sums up what I believe are the overall takeaways from the book:

I have shown how we know that we are all here, both collectively and individually, through a series of accidents – cosmological, geological, and biological accidents. I have also shown how and why some of us will depart via accident.

Our chance-driven world is a profound revelation. It is astonishing that blind chance is the source of all novelty, diversity, and beauty in the biosphere. I hope that you are wonderstruck at what an asteroid, sliding tectonic plates, and a fibrillating polymer of just four bases have wrought. (p. 164-5)

As much as I liked the book, I do have a couple of quibbles.  First, contingency is at the heart of Carroll's assertion that we, and all life around us, is here by virtue of chance.  It's the sequences of chance (i.e., "rare, unpredictable, or random") events in the histories of all taxa that create the contingencies necessary for the very existence of all types of organisms.  The longer that sequence, I would suggest, the more unlikely the ultimate outcome.  Since this is his argument, I find it curious, to say the least, that Gould doesn't appear in the index (and I don't think I encountered his name in the text) of A Series of Fortunate Events, and that there's no entry for Wonderful Life or anything else by Gould in Carroll's bibliography.  That's a shame because Gould's analysis of historical contingency is exactly on point and, indeed, the metaphor he used to capture its essence is stellar.  Gould asked, what we'd end up with if "we rewound life's tape to a distant past."  (p. 308, emphasis added)  His answer and, clearly Carroll's as well, is that, replaying the tape would lead to a planetary biota quite different from today's and one that almost certainly would not include anything closely resembling us.

A second quibble which speaks to the rewinding and replaying of life's tape.  I think Carroll should have dealt with the implications for chance of convergent evolution, the process through which the same features arise independently in different taxa.  I'm not prepared to treat it here, other than to note that it suggests that some paths that evolution might take may be more likely than others, regardless of the starting point.  There may, in fact, be guardrails for the development of life, so, maybe, not anything goes.  [Later edit:  I discovered several weeks after writing this post that I'd already written about convergent evolution and its import for Gould's thought experiment of rerunning the tape.  It was in a post reviewing Jonathan Losos excellent book Improbable Destinies back in 2017.  Losos came down on Gould's side with caveats.]

That said, I have to salute the wonderful outcome of having misidentified the author.

An Abundance of Forams and a Few Thoughts on D'Arcy Thompson

The sand my wife brought back from St Andrews, Scotland, in a small vial was filled to abundance with foraminifera (those tiny, single-celled protists, many of which secrete graceful calcium carbonate shells).  The hook for me was the nexus of forams and St Andrews because it was at the University of St Andrews that the biologist and classical scholar D’Arcy Wentworth Thompson (1860 – 1948) taught for over 30 years, and where he wrote the second edition of his magnum opus, On Growth and Form (the first edition was published in 1917).

In this hefty tome, Thompson espoused the singular importance of physical laws (those of engineering and physics) and mathematical principles in the shaping of organic morphology, laws and principles which in his view largely trumped evolution through natural selection.  A centerpiece for his argument was the minute foraminifera, and it’s not hard to see why.  The shapes of many foraminifera shells shout quite loudly “mathematics” and these shells have been used by Thompson and others to illustrate how mathematical spirals are found in nature, evidence, he would argue, of the preeminence of those governing forces.  Thompson wrote:

It is obvious enough that the spiral shells of the Foraminifera closely resemble true logarithmic spirals.  Indeed so precisely do the minute shells of many Foraminifera repeat or simulate the spiral shells of Nautilus [the quintessential exemplar of a logarithmic spiral in nature] and its allies that to the naturalists of the early nineteenth century they were known as Céphalopodes microscopiques [microscopic cephalopods], . . . .  (On Growth and Form, 1917 edition, p. 591)

To get some flavor of how Thompson shaped his argument with these microscopic shells, here is part of the opening paragraph of Chapter XII:  The Spiral Shells of the Foraminifera:

We have already dealt in a few simple cases with the shells of the Foraminifera; and we have seen that wherever the shell is but a single unit or single chamber, its form may be explained in general by the laws of surface tension: the assumption being that the little mass of protoplasm which makes the simple shell behaves as a fluid drop, the form of which is perpetuated when the protoplasm acquires its solid covering. . . .  When the foraminiferal shell becomes multilocular [having more than one chamber], the same general principles continue to hold; the growing protoplasm increases drop by drop, and each successive drop has its particular phenomena of surface energy, manifested at its fluid surface, and tending to confer upon it a certain place in the system and a certain shape of its own. (p. 587)

Indeed, as evolutionary biologist Stephen Jay Gould observed in a lengthy and devastatingly critical dissection of On Growth and Form, it’s at this microscopic level, the level of the foraminifera, that Thompson’s contention that physical laws are paramount in creating the shapes of living creatures may have its greatest (though certainly not complete) validity.

D’Arcy Thompson continued to maintain – and he may well have been right in some cases – that good matches between simple organic conformations (primarily the outward forms of unicellular creatures) and geometric shapes of well know mathematical definition and easily accomplished mechanical construction probably illustrate his favored principle of direct imposition by physical forces.  But he had to admit that he could not apply this line of reasoning to the basic form of a horse or a tuna.  (The Structure of Evolutionary Theory, 2002, p. 1197)

Frankly, I come away from On Growth and Form wondering whether its message for me is a truism:  evolution through natural selection cannot fashion a living shape that defies the basic laws of physics and certain mathematical principles.  In other words, there are some givens that have to be accounted for.  Science writer Philip Ball puts a positive spin on this, noting that Thompson was arguing against the propensity at the time for Darwinians to posit that every feature of an organism was an example of adaptation.  “Thompson’s insistence that biological form had to make sense in engineering terms was a necessary reminder.”  (In Retrospect:  On Growth and Form, Nature, February 2013.)

I would acknowledge that Ball seems to call me out in his article when he notes that “On Growth and Form is a book more often name-checked than read.”  Yes, I admit I’ve only dipped into it, enjoying some of its literary flourishes (which admittedly can go over the top) and appreciating some aspects of his argument, but never aspiring to read it cover to cover (the 1942 edition is over 1,000 pages long).

Ball rightly identifies the logarithmic spiral as the “central motif” of the book (which he notes “appears on the plaque commemorating Thompson’s former residence in St Andrews”).  Here is a representation of the logarithmic spiral.

(This image is in the public domain and was downloaded from Wikimedia Commons [].)

Earlier this year, my wife during her stay in Thompson’s city climbed down some steps to the shoreline of St Andrews Bay at low tide and scraped some sand into a vial.  She came away with a rich mixture of quartz, mica, bits of mollusc shell, fragments of ostracode tests, broken sponge spicules, and a wealth of foraminifera shells.  [Later edit:  I should note that I assume all of the foram shells in my sample of St Andrews sand are from organisms that recently died (hopefully not in the vial of sand as it was transported back to the States).  So, if I'm correct, they are not fossils.]

 Here’s the same image of this smidgeon of St Andrews sand with some of the prominent forams marked.

The most abundant species in this sand are from at least two genera:  Elphidium and Ammonia, shown below in that order.

For these identifications I have relied on the very nice taxonomic appendix in Quantifying Holocene Sea Level Change Using Intertidal Foraminifera:  Lessons from the British Isles by Benjamin P. Horton and Robin J. Edwards (University of Pennsylvania Scholarly Commons, 5-1-2006; originally published as Cushman Foundation for Foraminiferal Research, Special Publication, Volume 40, 2006).

I’ll close by suggesting that in the following passage from On Growth and Form is a hint that foraminifera held some intimate, personal significance for Thompson (or perhaps he was simply waxing eloquent as was his want):

But in days gone by I used to see the beach of a little Connemara bay bestrewn with millions upon millions of foraminiferal shells, simple Lagenae, less simple Nodosariae, more complex Rotaliae: all drifted by wave and gentle current from their sea-cradle to their sandy grave: all lying bleached and dead: one more delicate than another, but all (or vast multitudes of them) perfect and unbroken.  (p. 609)

Evolution and Historical Contingency ~ A Review of Improbable Destinies

Stephen Jay Gould threw down the gauntlet when he argued in Wonderful Life:  The Burgess Shale and the Nature of History (1989) that, were we able to replay the tape of life – that is, erase the metaphorical tape back to some point in the distant past – then “any [subsequent] replay of the tape would lead evolution down a pathway radically different from the road actually taken.”  (Wonderful Life, p. 51)  Evolution, in Gould’s view, is clearly not deterministic, rather, historical contingency holds sway.  By historical contingency, Gould meant that any particular state (of history, of the evolutionary paths of species) was “dependent, or contingent, upon everything that came before – the unerasable and determining signature of history.” (Wonderful Life, p. 283)

Thirty years later debate over the validity of Gould’s proposition continues.  Are the various constraints on evolution through natural selection such that, regardless of where we re-start the tape, the results shown in the replay eventually would be remarkably similar to what we see around us today, or does contingency play such a powerful role that ending up in the same place is not only improbable but perhaps out of the realm of possibility, dependent as it is upon myriad events occurring in just the right order?

This is the context for evolutionary ecologist and herpetologist Jonathan B. Losos’ new book Improbable Destinies:  Fate, Chance, and the Future of Evolution, a riveting and remarkably accessible exploration of convergent evolution and its import for Gould’s thought experiment.

Convergent evolution is the phenomenon in which different species evolve similar features, that is, they converge on very similar morphological features, say, wings in insects and wings in birds among other vertebrates.  The list of examples of convergent evolution in the natural world is rich and long and growing.  As Improbable Destinies makes clear, anole lizards, an early example and the centerpiece of Losos’ research, have been joined by a host of other instances of convergence involving many different kinds of organisms, ranging from snails to guppies, from bats to stickleback fish.

The wealth of such examples has led some scientists, paleontologist Conway Morris prominent among them, to conclude that (as Losos writes), “evolution is deterministic, predictable, following the same course time after time.  The reason, they argue, is that there are only so many ways to make a living in the world,” and so the tape actually would end up in the same place every time it is replayed.  (p. 5)

At the same time, Losos shows that the list of “evolutionary idiosyncrasies” isn’t short and often features creatures, such as the kiwi or the solendon, that have evolved on isolated land masses such as New Zealand, Australia, and Madagascar.  There’s a diverse richness here.  Losos notes, “Conway Morris and his colleagues have made long lists of examples of convergence, but it would be just as easy to make comparable catalogs of species without counterparts.”  (p. 87)  He argues that these one-offs may appear because “natural selection is either not as predictable or as powerful as some make it out to be.  That is, even when species experience identical environments, they might not evolve in the same way.”  (p. 88)

Losos describes many research projects relevant to our understanding of convergent evolution.  These include observation of convergence in the wild, particularly in settings showcasing natural experiments (principally islands), deliberate experiments in the wild as scientists transfer organisms to different locations and analyze their subsequent evolution (yes, as he makes abundantly clear, evolution need not proceed at the snail’s pace that Darwin would have had it), and finally experiments in the laboratory, often in petri dishes or vials involving microorganisms, such as E. coli.

The highlight of the book for me (and here it’s a page-turning pleasure) is Losos’ account of his research on the Anolis lizard (commonly referred to as the anole lizard) and his field work in the Greater Antilles (Cuba, Hispaniola, Jamaica, and Puerto Rico).  Perhaps their most spectacular feature (reserved in most species to males) is the dewlap, “a flap of skin under their throat,” usually hidden from sight.

But when the lizard has an announcement to make – ‘Get lost, buddy, this is my territory” or “Hey, ladies, come check me out.  I’d make a good baby daddy’ – out comes the dewlap, arching downward from the jaw, forming a semicircle so large that the lizard often has to straighten its legs, pushing its body off the ground, to provide clearance.  (p. 58)

A nice example of the prose that graces the book.  Losos is able to make what is certainly tedious and physically difficult research on these lizards into an exciting narrative, a narrative that shows why the anole lizards are robust examples of convergent evolution.

He found that, although each of the four islands in the Greater Antilles has a different array of anole species, those species generally occupy similar ecological niches (bush, or different parts of trees) across the islands.  Those in each niche have evolved to be so similar from island to island that each of these “habitat specialists” can be mistaken for each other.  Yet all of the species on any of these islands are more closely related to each other than they are to any of the similar habitat specialists across the islands.

There is a great deal to absorb from Losos’ walk through the relevant research from the wild to the laboratory, much of it, particularly those natural and deliberate experiments in the wild, thoroughly engaging.  Yet two aspects of the research covered here are, to me, disquieting.

First, I appreciate what can be learned from projects that involve researchers moving organisms in the wild from one place to another (e.g., guppies from pools with predators to those without, or anoles to islands with no lizards), but, given how complex the array of contingencies is in the natural world, what are the real consequences of this manipulation?  I am reminded of how off putting I found ecologist E.O. Wilson’s research that involved fumigating entire mangrove islands in the Florida Keys to kill off all the arthropods.  Yes, he gained insight into how populations recover and how quickly, but at what cost?  Certainly I’m being overly sensitive about this and I’m sure my concerns would be discounted by those involved.  Still the deliberate interference bothers me.

Second, though much of Losos’ explication of the relevant laboratory research is extremely well done and informative, I had a nagging unease about this research.  It didn’t help that I often lost track of what the various projects were trying to prove and what they did prove.  Perhaps the more substantive part of my discomfort with the laboratory portion of the book has to do with my sense that test tube evolution with microbes is somewhat analogous to running computer programs that seek to replicate evolution:  a limited set of conditions are programmed in, with some random function added to mimic the mutations that natural selection has to work with.  The results can be instructive, yet they are, ultimately, artificial.  The full force of contingency that occurs in the natural world is largely missing in either the lab or the computer program.

None of this is to gainsay the importance of tracking myriad generations of microorganisms in controlled environments in the laboratory, not only to see if identical populations always end up in the same place, but also because, as at least one project was structured, researchers could, literally, replay the tape, taking a population to some previous generation and letting it reproduce from there. The message from such experiments, as I understand it, is that, yes, largely the tape replays exactly as it has run before.  But, and it’s a big but, not always.

Indeed, though most of the research from the field and from the laboratory would appear to support the evolutionary determinist camp – that the replay ends up in the same place – closer examination of the results, often over a longer range of time, shows that isn’t always true.  It’s most likely to be true when the populations begun with are closely related; such relatives are likely to evolve similarly when placed in new environments.  Not so when they are more distantly related.

But I didn’t think that Gould’s thought experiment envisioned the tape replaying exactly as it had before and the only thing in play being how evolution would be affected by random mutations in organisms.  Losos, citing philosopher of science John Beatty, acknowledges as much, positing that Gould actually embraced two concepts of contingency.  The first being that replaying of the tape with nothing changed to see if evolution would or could take a different course.  The second being the replaying of the tape from a specific point with the full panoply of historical contingencies allowed to be at work affecting living organisms.  Though these contingencies may be small events with important or unimportant consequences, they could, as well, be more dramatic things such as a storm wiping out the sole representatives of a species or an asteroid hitting the planet and decimating a host of species.  Each of these specific contingencies cannot be anticipated when we replay the tape – they may or may not occur – and they are likely to make all the difference in the world and we are likely not to end up in the same place with any replay.

In fact, and this needs no spoiler alert given the title of the book, I think Losos comes down largely in the Gould camp though his stance is somewhat nuanced.  As he writes,

So, can we predict evolution?  In the short-term, yes, to some extent.  But the longer the passage of time and the more different the ancestors or conditions, the less likely we are to prognosticate successfully.  (p. 336)

He adds, regarding our species,

If any of a countless number of events had occurred differently in the past, Homo sapiens  wouldn’t have evolved.  We were far from inevitable and are lucky to be here, fortunate that events happened just as they did.  Asteroids, of course, but what other events critically tipped evolution’s path in our favor?  Who knows how slight a difference in the past – a tree falling on great-great-great-to-the-millionth-degree-grandpa Ernie, a forest fire, a mutation – might have snuffed out our future existence?  (p. 335)

As he notes, we weren’t fated to evolve though possibly something like us might have.  Ultimately, no matter the outcomes one might anticipate from evolution, it is highly improbable that any specific one will occur.

In closing, I have to explain why I felt compelled to buy and read Improbable Destinies.  I had no choice after reading his interview in Current Biology (August 21, 2017).  He had me from the moment he answers the question:  How did you get started in biology?

Sure, he mentions dinosaurs as a gateway drug, but he goes wonderfully so much further, offering credit to:

a particular episode of Leave it to Beaver, the one in which the Beaver purchases a mail-order baby alligator.

According to the IMDb synopsis of this particular episode (frankly, I don’t remember this one which explains, I guess, why I didn’t become a biologist), Wally and the Beaver acquire a Florida alligator sub rosa and the laughs (such as they are) stem from their efforts to raise an alligator in the house without their parents discovering.  In contrast, Losos, smitten by the idea, was above board in his campaign to be allowed to acquire this kind of reptile.

. . . I knew that local pet stores sold baby caimans, the neotropical relative of alligators. The question was: how to convince my mother to allow a crocodilian in the house. Fortunately, my mom — not liking to say ‘no’ — passed the buck to the local zoo director, a family friend, expecting him to put the kibosh on the idea. To her dismay and my delight, however, he said that having an alligator was how he got his start in herpetology, and the next thing you know, I had a caiman in a kiddie’s wading pool in the basement.

In closing, I must say that my encountering this interview (which in turn prompted me to read and review the book) was contingent on a long, long chain of events that included spotting a turtle in my backyard several years ago and deciding to write a blog post on the turtle shell.  Current Biology had a relevant article and I actually paid for access to it (shows how desperate I was) which got me snared in the publisher's email web which meant the index to this August’s issue reached me.  Then again, even if I hadn’t seen the interview in Current Biology, given what I read I still would have seen reviews of the book and I might very well have ended up in the same place.

Take Heart, Rachael

Life’s not fair. And, in particular, a fossil hunt’s not fair. That’s a lesson a fossil hunter learns quickly. But, that’s not the central message of this posting. I think there’s yet another lesson that a fossil hunter learns that may offer some measure of consolation. More about that in a moment.

Local newspapers and TV stations recently ran a story about a find at the newly opened Dinosaur Park in Prince George’s County, Maryland. Yes, there are dinosaur fossils to be found in the urbanized Baltimore-Washington corridor. The 7 ½ acre county park provides an opportunity twice a month for amateur collectors to try their luck at turning up a Cretaceous fossil, perhaps from a dinosaur. Saturday, a week ago, a small piece of fossilized bone, tentatively identified as a dinosaur vertebra, came to light, found by a young girl. The fossil triggered a great deal of excitement and was turned over to the Smithsonian for identification and further analysis.

Here’s where the life lessons come in. Am I taking liberties with the known facts in the account that follows? Of course. But then the truth I’m looking for is behind the events and details reported in the press. And the best way I know how to do that is to project on to it my feelings and experiences as someone who has hunted for fossils, has children, and, in particular, has siblings.

The story goes like this, punctuated with my annotation, including a bit of reconstructed backstory. A family of four from a neighboring state comes over to take part in the last hunt of the month. The outing, according to the press, sounds like a piece of healthy and constructive parenting, but, I suspect there was a lot of pressure (begging and whining . . . maybe) brought to bear to make this trip a reality by Rachael, the younger daughter in the family, a child overwhelmingly infected with the dinosaur fossil bug, whose grandest dream, according to her mom, is to go on a fossil hunt in South Dakota. Her older sister, 9-year-old Gabrielle, comes along, perhaps reluctantly (I know as a child I would have protested going on a trip if it were something very special for one of my siblings). In my reconstruction, the final conversation in the car as the family caught sight of the park goes something like this:

Younger sister Rachael: “This is so cool. I can’t wait. This whole place was a swamp maybe 100 million years ago, with dinosaurs and everything.”

Older sister Gabrielle: “Whatever.”

A half later, Gabrielle finds the dinosaur vertebrae that causes all hell to break loose. Well, that’s what it must have seemed like to Rachael.

The family is interviewed by the press. The local experts at the park are ecstatic, gushing over the marvelous find by this “little girl,” thrilled at the press coverage for the park. Gabrielle has her picture taken which runs in the Baltimore Sun along with an article. The Washington Post covers her find as well, as do other news outlets. Clearly, she thoroughly enjoys her brush with fame. To add salt to Rachael’s wound, in her picture in the Sun, Gabrielle’s holding a stuffed toy, no, not a dinosaur – a stuffed walrus. As for Rachael? One reporter notes that Rachael “kind of wished she’d found the fossil herself.” A bit of understatement if I know fossil hunting and sibling rivalry. (Girl Hits Pay Dirt on a Fossil Hunt with Her Family, by Megan Greenwell, Washington Post, November 25, 2009 ; New Dinosaur Park Yields Fossil for 9-Year-Old Girl, by Frank D. Roylance, Baltimore Sun, November 24, 2009)

Take heart, Rachael. I know you’d already learned that life’s not fair – having a sibling ensured that. You’ve now learned that fossil hunting’s not fair, either. Your enthusiasm, dedication, knowledge were no guarantee of good things happening (not in this instance, but, trust me, they will pay off in the future). The whole process is too dependent on contingency, historical accidents. Your sister’s finding of that fossil is the end result of an incredible chain of events that stretches further back in time than even the moment 100 million years ago that the dinosaur sank into the mud, dead. Change one of those events and maybe the fossil’s 7 inches to the right and Gabrielle misses it or, go back even farther and tweak an initial condition and there aren’t even dinosaurs, at least as we know them, to become fossilized. Now, that would be a shame.

The debate over contingency in the paleontological world might provide some insight for you, Rachael. I'm sure you understand that we're applying it at a much more micro level than the paleontologists have.

Contingency became paleontologist Stephen Jay Gould’s watchword for life’s evolutionary history. As he wrote in Wonderful Life: the Burgess Shale and the Nature of History (1989),

The modern order was not guaranteed by basic laws (natural selection, mechanical superiority in anatomical design), or even by lower-level generalities of ecology or evolutionary theory. The modern order is largely a product of contingency. (p. 288)

Based on his interpretation of the Burgess Shale and the many anatomical designs he saw arise there only to be decimated, he came away with

amazement . . . at the fact that humans ever evolved at all. . . . Replay the tape a million times from a Burgess beginning, and I doubt that anything like Homo sapiens would ever evolve again. It is, indeed, a wonderful life. (p. 289)

Too much of the process was, in his view, historically contingent to ever replay in the same way.

Others, such as Simon Conway Morris, have rejected the extreme nature of this view, arguing that there are, in fact, a constrained number of successful evolutionary options. As a result, Conway Morris wrote, “the evolutionary routes are many, but the destinations are limited.” (Life’s Solution: Inevitable Humans in a Lonely Universe, 2003, p. 145). In the same volume, Conway Morris repeats this theme, but adds an important coda:

Thus we see that the same ends may be arrived at along various, and sometime[s] wildly different, routes. Correspondingly, very seldom is the convergence so exact as to make the organism or structure indistinguishable. (p. 301, emphasis added)

So, young Rachael, here’s the other lesson I hope you will learn from this and, I think, you’re on your way to that knowledge because you’ve promised to return to the park at the next opportunity. Be fully confident that when you and Gabrielle return to Dinosaur Park, history will not repeat itself. It will be different the next time around. Even in Simon Conway Morris’ view, the exact same outcome will not come to pass. Take solace in that, even as you lick your wounds from the experience of last Saturday.

Of course, do understand, it could well be worse.

My advice, Rachael, when you do go on that dream fossil hunt in South Dakota, follow your instincts and leave your older sister at home.

The Glamour of the Moment of Discovery

The glamour, the mystique of the moment of discovery in the sciences is, to me, irresistible. Though I’m drawn to its depiction whether it occurs in the lab, the field, or the mind, it’s the discovery in the field that I probably find most compelling. This is, I suspect, what pulls many into the sciences, particularly such fields as paleontology. It certainly is at the heart of what makes the “wannabes,” the amateurs like me, invest inordinate amounts of time learning about paleontology and going on fossil hunts, the latter offering some actual, though admittedly tenuous, connection to doing the science (the less exciting curating and trying to make sense of what one finds on the hunt probably get closer).

Carter and Tut

One of my favorite descriptions of a discovery moment was written by C.W. Ceram about English archaeologist Howard Carter and the tomb of Tutankhamen (Gods, Graves, and Scholars: The Story of Archaeology, 1951, p. 212-213). It’s 1922 and Carter is about to break through the door to the tomb’s antechamber. His patron and partner Lord Carnarvon is among those gathered with him. For a moment they fear the worst – that this tomb is a common one, has never been completed, or is lying beyond those doors plundered and laid to waste.

Their hopes, in short, for a time were dashed. The tension increased once more, however, when rubble was taken away from the second door. “The decisive moment had arrived,” Carter says. “With trembling hands I made a tiny breach in the upper left hand corner.”

Taking an iron testing rod, Carter poked it through the door and found an emptiness on the other side. He lit candles to ensure against poisonous gases. Then the hole was enlarged.

Everyone interested in the project now crowded about. . . . Nervously Carter lit a match, touched it to the candle, and held it toward the hole. As his head neared the opening – he was literally trembling with expectation and curiosity – the warm air escaping from the chamber beyond the door made the candle flare up. For a moment Carter, his eye fixed to the hole and the candle burning within, could make out nothing. Then, as his eyes became gradually accustomed to the flickering light, he distinguished shapes, then their shadows, then the first colors. Not a sound escaped his lips; he had been stricken dumb. The others waited for what seemed to them like an eternity. Finally Carnarvon could no long contain his impatience. “Can you see anything?” he inquired.

Carter, slowly turning his head, said shakily: “Yes, wonderful things.”

Doesn’t get much better than that.

Johanson and Lucy

These are heady days in the study of early hominids, those predecessors to the genus Homo. Fifteen years after the first description of a specimen of the early hominid Ardipithecus ramidus, paleoanthropologist Tim White and a phalanx of other scientists with a wide range of specialties have just presented a detailed picture of this hominid, the world in which it lived, and how it interacted with that world (see the 11 research articles published in the October 2, 2009 issue of Science -- requires a free registration – link here) White et al. have tipped over a cornucopia of findings from their research on Ar. ramidus. Even some scientists who complained about that 15 year gap between discovery and full publication have reveled in this wealth of scientific riches.

Although some 110 specimens of Ar. ramidus have been found at this site, one of them is “by far the most complete of the earliest specimens [of hominids]. It includes most of the skull and teeth, as well as the pelvis, hands, and feet.” (A New Kind of Ancestor: Ardipithecus Unveiled, article by Ann Gibbons, Science, October 2, 2009, p. 36 -- link here] The first pieces of this skeleton were found in 1994. Here's a picture of the assembled pieces of this specimen.


Of course, this striking find brings to mind another one that enthralled our collective imagination. Twenty years earlier, on November 24, 1974, paleoanthropologist Donald Johanson found the first pieces of a 40 percent complete skeleton of an Australopithecus afarensis specimen (from roughly 3.7 million years ago). Dubbed “Lucy,” this was the earliest known hominid until the discovery of Ar. ramidus (from roughly 4.4 million years ago).

In his book, Lucy: The Beginnings of Humankind (1981), Johanson describes the moment of discovery. At the end of a day in the field with Tom Gray, an American graduate student, Johanson follows an impulse to check out a gully bottom, one more time (p. 16-17):

It has been thoroughly checked out at least twice before by other workers, who had found nothing interesting. Nevertheless, conscious of the "lucky" feeling that had been with me since I woke, I decided to make that small final detour. There was virtually no bone in the gully. But as we turned to leave, I noticed something lying on the ground partway up the slope.

“That’s a bit of a hominid arm,” I said.

“Can’t be. It’s too small. Has to be a monkey of some kind.”

We knelt to examine it.

“Much too small,” said Gray again.

I shook my head. “Hominid.”

“What makes you so sure,” he said.

“That piece right next to your hand. That’s hominid too.”

[Yes, indeed it was hominid – the back of Lucy’s skull. As they surveyed the slope, they found a femur, vertebrae, a piece from a pelvis.]

An unbelievable, impermissible thought flickered through my mind. Suppose all these fitted together? Could they be parts of a single, extremely primitive skeleton? No such skeleton had ever been found – anywhere.

“Look at that,” said Gray. “Ribs.”

[That night in the celebrating camp, with the strains of The Beatles’ Lucy in the Sky with Diamonds filling the night air, Lucy received her name.]

Not too shabby a moment of discovery. It resonates with particular strength because anyone who has spent the day staring at the ground, trying to match a mental search image with the myriad objects littered around, will recognize that desire to have just one last look, even over terrain that has been scoured repeatedly.

White and Ar. ramidus?

But what about this newly publicized find, this remarkable Ar. ramidus skeleton that some insist on calling Ardi? Is there a “Lucy moment” waiting to be told (perhaps in a forthcoming book written for a popular audience) for this particular specimen?

One of White’s research articles describes the initial discovery of this particular specimen in, not unexpectedly, bloodless terms (this is, after all, Science):

[O]n 5 November 1994, Y.H.S. [Yohannes Haile-Selassie] collected two hominid metacarpal fragments . . . from the surface of an exposed silty clay ~3 m below the upper tuff . . ., 54 m to the north of the point that had 10 months earlier yielded the Ardipithecus holotype dentition.

(Ardipithecus ramidus and the Paleobiology of Early Hominids, White et. al, Science, October 2, 2009, p. 76 -- link here)

From that small start, over the course of two years, White and his teams painstakingly teased out the many pieces of the skeleton from the matrix in which they were found:

In the field, the fossils were so soft that they would crumble when touched. They were rescued as follows: Exposure by dental pick, bamboo, and porcupine quill probe was followed by in situ consolidation. We dampened the encasing sediment to prevent desiccation and further disintegration of the fossils during excavation. Each of the subspecimens required multiple coats of consolidant, followed by extraction in plaster and aluminum foil jackets, then additional consolidant before transport to Addis Ababa. (p. 77)

Wait, that sounds like a lot of excruciatingly precise work . . . so, probably not a Lucy moment. But, frankly, that’s the problem with the popular account of the discovery moment or, at least, what we, the uninitiated, remember. Its lingering image is of the moment, of that instant when Carter says, “Yes, wonderful things.” The image no longer retains (if it ever did) any remnant of his six years of fruitless searching in that small area of Egypt, or the months required to deal with the finds in the antechamber before going on into Tut’s chamber itself where the real treasures were. Then, we conveniently forget that it took ten years to remove and catalogue what was in the tomb. (Let’s also ignore the curse.) We need to be reminded, continuously that there’s so much, much more to it, long before and long after the discovery.

A Matter of Choices

A good friend raised a question that always lurks in the mental shadows for a person pursuing an avocation or interest full throttle. She asked, If I had it to do all over again, and everything else that mattered in my life would remain the same (family, steady job, nice place to live, etc.) would I have become a paleontologist? Clearly recognizing how seductive I find the fossil hunt, that hard work in the outdoors, she added a critical coda describing the intellectual and other challenges that would await a practitioner of this profession – it’s not all that grand moment of discovery in the field, she was saying, so choose wisely. In our exchange over this coda, the words spoken or mostly implied included technical, theory, research, bureaucratic demands, academic infighting, death by a thousand cuts, etc.

I gave her a glib response, but found myself continuing to ponder the basic question.

Shortly after she posed it, I stumbled across an old essay by Stephen Jay Gould reviewing John McPhee’s Basin and Range (1981 – B&R is still fun on rereading). McPhee’s book is an accessible, personal view of deep time and plate tectonics (the new geology), illustrated through a journey across the country, from roadcut to roadcut along Interstate 80, primarily in the company of geologist Kenneth Deffeyes. As much as he liked the book, Gould was critical of what he saw as McPhee’s exalting of field work:

[H]e has been beguiled by the mystique of field work. No geologist worth anything is permanently bound to a desk or laboratory, but the charming notion that true science can only be based on unbiased observation of nature in the raw is mythology. Creative work, in geology and anywhere else, is interaction and synthesis: half-baked ideas from a barroom, rocks in the field, chains of thought from lonely walks, numbers squeezed from rocks in a laboratory, numbers from a calculator riveted to a desk, fancy equipment usually malfunctioning on expensive ships, cheap equipment in the human cranium, arguments before a roadcut. (An Urchin in the Storm: Essays about Books and Ideas, 1987, p. 98)

McPhee, Gould argues, is positing that science advances only through the objective analysis of the data steadily accumulated from observation in the field. Wrong, says Gould, this ignores the fact that the scientist can never divorce himself or herself from the cultural milieu. In reality, science advances through an admixture of ideas and facts, and those ideas aren’t newly generated solely from the data (I would add, no matter how much Francis Bacon would have had it so).

Given where this post started, I would argue that there’s something else going on in this criticism, at least, there is to me. For an amateur like McPhee, field work has a mystique in the first place because there he is walking a road cut with a geologist who whacks off a piece of rock exposing, in McPhee’s words “[i]ts fresh surface . . . asparkle with crystals – free-form, asymmetrical, improvisational plagioclase crystals, bestrewn against a field of dark pyroxene.” (Basin and Range, p. 5) Listen to that language . . . it reveals how, to the amateur, even something as prosaic as this little roadcut vignette is magical and the scientist is breaking through the door and shedding light on wonderful mysteries inside. So, how could it be otherwise that, in the popular imagination (my imagination), those stories of the glorious moments of discovery in the field are what is remembered and exalted?

Louis Agassiz (1807 - 1873) -- On Being Here in His Absence

I used to work with a man, a hale-fellow-well-met sort, whose robust personality was such that when he was missing (which was often), we’d describe him as “being here in his absence.” I feel somewhat that way about Louis Agassiz whose 202nd birthday was today, May 28, 2009.

During the middle decades of the 19th Century, Agassiz was probably the most popular scientist in United States. He was a striking figure – a large man with heavy-lidded eyes set in a strong face. In later years, he became rather rotund. The cigar-smoking, Swiss-born Agassiz strode forcefully across the American scientific and cultural landscape from the 1840s until the 1870s, responsible in many ways for the maturation of science in this country and for fueling popular interest in natural history. He came to the United States in 1846, already a well-established figure in multiple scientific fields having entered the ranks of leading paleontologists with his multivolume Recherches sur les Poissons Fossiles (Research on Fossil Fishes) published during the period 1833 to 1843, and having staked a claim on geology with seminal work on glaciers.

Always a visionary, Agassiz seemed to respond to the democratic energy and spirit of America by conceiving of ever grander plans for his scientific work and that of his adopted country. New plans constantly trumped old ones. Some he brought to fruition, others, to the frustration of colleagues, fell to the wayside only partly completed. Still, Agassiz’s legacy is impressive. It includes the founding of Harvard University’s Museum of Comparative Zoology for which he was the original director and curator. He played important roles in the establishment of the National Academy of Sciences and Cornell University. As a professor at Harvard, he trained many of the leading American biologists and paleontologists of the 19th Century. He charmed the American public, who eagerly embraced him, flocking to the many lecture series on natural history he delivered in major east coast cities. He counted among his friends such leading cultural figures as the poet Henry Wadsworth Longfellow and the essayist and philosopher Ralph Waldo Emerson.

Despite the renown in his own day, he has largely faded from public consciousness. Well, not completely. The rush to honor him contemporaneously means the Agassiz name is familiar in the Boston area, adorning buildings, including schools, and communities. In the scientific world, I sense that Agassiz is really "here in his absence." One cannot contemplate 19th Century science in this country or the world without becoming aware of the Agassiz persona. Nevertheless, the marks he left on the scientific landscape that continue to exist are, for the most part, probably not the profound ones he would have hoped.

Take, for example, those who collect fish fossils, particularly from sharks. For them, there is no escaping the Agassiz name – it is everywhere, and, paradoxically, also mostly nowhere. The name appears in many of the full taxonomic names of fish species, signaling that Agassiz first identified them. Of the 99 different shark species for which a collector can find fossil teeth in the Chesapeake Bay region, 21 of them have Agassiz as the original identifier (though for only a few has the name he gave survived) and an additional species is named Hexanchus agassizi. (See Kent, Fossil Sharks of the Chesapeake Bay Region, 1994.) But, for most collectors, that’s as far as it goes – though Agassiz’s fingerprints are abundantly present, they are found in the dusty margins of scientific names. (It is in this very role that Agassiz appeared previously in posts on this blog -- see "Louis Agassiz" in Labels listing on right.) The paleontological aspects of his legacy seem pretty minor for a major scientist.

So, why is Agassiz not celebrated today for his science as his adoring 19th Century public might have expected? The man, whose work was often crowned with success, is perhaps best known to us, not for those good works, but for being the most prominent American scientist of his day to reject Darwinian evolution. Agassiz was not a biblical literalist, believing as he did in an old Earth. But, to him, that Earth was one that had experienced multiple catastrophes, each of which replaced extant species with new ones, all in line with God’s plan. Here there was no descent from common ancestors; rather, species were immutable and unrelated to each other. (That may help explain the prevalence of his name in the taxonomic histories – rather than the prevalence of variation, he saw many distinct species in differences among his specimens and, so, he named them.)

Is that the explanation for the lack of present day acclaim? That he was on the losing side?

Take the Recherches sur les Poissons Fossiles. This master work is breathtaking in its scope – a comprehensive, detailed gathering of available information about fossil fishes, illustrated with beautiful plates. (An aside: I certainly hope someone will scan the volume with the plates and post them along with the five volumes of text that are already available at the Biodiversity Heritage Library.  [Later edit:  Indeed, the atlas of plates for each volume is now available.]  Agassiz brought a scientific eye to the task, reflected in the attention to detail, and the drive to be comprehensive and thorough – sound aspects of paleontology. The Poissons Fossiles is where many of the fossil fish species are first named.

. . . and yet, this work is also something else. In some eyes, it is principally that something else. Paleontologist Stephen Jay Gould described it as follows:

Les poissons fossiles is no simple list of old fishes; it is, perhaps most of all, a closely reasoned brief for Agassiz’s creationist world view – a theory that embodied the cultural consensus of 1830, but that Agassiz maintained doggedly to his death in 1873, long after its scientific demise in Darwin’s favor. (Eight Little Piggies, p. 414, 1993)

So, the master work is a fool’s errand. Being on the wrong side has a way of undercutting your accomplishments. Clearly, his position on evolution contributed to the fading of his star. Some blame should also be attached to how he used his platform to promote racist ideas about blacks, ideas that earned him accolades in the antebellum South and opprobrium in the Civil Rights era.

But, for me, the Agassiz story has a tragic theme that centers on the very success he enjoyed. As Gould wrote, Agassiz was in the majority in the 1830s, but did not change his view in light of the evolutionary framework that Darwin later erected. I don’t believe he was capable of changing.

In 1859, Agassiz was at the pinnacle of his success in America, with an adoring public and a wide circle of influential friends and supporters, most of whom were from outside the scientific community. Paradoxically, the very scientific establishment Agassiz had worked to build, into which he instilled rigor and discipline, was now populated with scientists who could weigh the theory of evolution, question it, test it, and, ultimately, see its power and its merits. But Agassiz couldn’t.

As he gained in public stature, labored to create, fund, and administer a world class museum, and remake the education of scientists in this country, he largely stopped doing science and became increasingly isolated from the maturing American scientific community. No longer an active participant in the scientific conversation, he had no answers to evolution except his old ones that had served him well in the past.

Ironically, his very success seemingly fated him to this magnificent failure to recognize the truth of evolution.

I trust I have been fair in this portrait of Agassiz. In his time, he was a figure larger than life. Even his critics could be impressed by the boundless energy and deep knowledge of the man. While a young medical student at Harvard University, psychologist and philosopher William James joined an expedition Agassiz led to the Amazon in 1865. In a delightful letter to his father written from Brazil, James offered his insight into the man:

I have profited a great deal by hearing Agassiz talk, not so much by what he says, for never did a man utter a greater amount of humbug, but by learning the way of feeling of such a vast practical engine as he is. No one sees farther into a generalization than his own knowledge of details extends, and you have a greater feeling of weight and solidity about the movement of Agassiz’s mind, owing to the continual presence of this great background of special facts, than about the mind of any other man I know. He has a great personal tact too, and I see that in all his talks with me he is pitching into my loose and superficial way of thinking. . . . Now that I am become more intimate with him, and can talk more freely to him, I delight to be with him. I only saw his defects at first, but now his wonderful qualities throw them quite in the background. I am convinced that he is the man to do me good. He will certainly have earned a holiday when he gets home. I never saw a man work so hard. Physically, intellectually and socially he has done the work of ten different men since he has been in Brazil; the only danger is of his over doing it. ... (September 12-15, 1865)

I wish Louis Agassiz a happy birthday.


Sources
The best source of background on Agassiz is Louis Agassiz: A Life in Science, by Edward Lurie – a good, solid, readable biography, originally published in 1960. Also, of interest, are the various essays featuring Agassiz written by Stephen Jay Gould and included in his volumes of natural history reflections. The James letter can be found in The Letters of William James (Vol. 1) 1920, p. 65-66).) The citation information required by the Archives of American Art for the photograph of Louis Agassiz is: [Louis Agassiz], ca. 1860 / unidentified photographer. Photographic print : 1 item : b&w ; oval image 12 x 10 cm. on board 17 x 11 cm. Charles Scribner's Sons Art Reference Dept. records, 1839-1962. Archives of American Art. At URL: http://www.aaa.si.edu/collections/searchimages/images/item_3495.htm.