Life with Lepidoptera

Peter Marren. Rainbow Dust: Three Centuries of Butterfly Delight. University of Chicago Press. 2016.

This was subtitled “Three Centuries of Delight in British Butterflies,” when it was first published in the UK in 2014. The Chicago edition has a preface for American readers, making some comparisons between the American and European faunas. He briefly mentions the great American collectors of the nineteenth century (see my post from February 2015) and introduces his favorite butterfly lover, Vladimir Nabokov, to whom he will return  throughout.

Marren begins with personal recollection and reflection on his early days as a butterfly collector: the joys of pursuit and capture, the thrill of discovering a new species to add to his collection and the less easily expressed delight of simply being alive and out in a world inhabited by beautiful, delicate beings.

In discussing this aesthetic joy and recounting the history of the long fascination that butterflies have exerted on the minds of human beings, Marren does a great job of presenting the collectors, artists and writers who left behind a record of their pursuits. Among those he most admires are the Rothschilds, who have probably done more for entomology than any of the other great families of England. Nine different members are listed in his index. His account of the lives and works of the many notable painters and engravers of butterflies, from the late Renaissance to the 21st century, reminds us of the enormous labor involved and the many disappointments and financial failures that dogged their efforts. It is very helpful to have a computer or tablet handy while reading this chapter, so you can search out examples of work by Moses Harris (see example above) Henry Noel Humphries, F.W. Frohawk, Richard Lewington and David Measures. The book itself has only monochrome illustrations of butterflies in the chapter headings.

I was rather less taken by Marren’s attempt to write a literary, cultural and psychological history of the passion for butterflies. The familiar identification of the soul (psyche) with a butterfly and the various ways butterflies appear in poetry do not seem to add up to much in terms of understanding human responses to the natural world. Nor do his forays into mythology make compelling reading for me. His accounts of the people who established our understanding of the lives of butterflies are much more interesting. The tribulations of women who shared the passion are especially telling: from Lady Glanville whose interest in butterflies was grounds for suspecting her sanity and thus contesting her will, to her successors in the eighteenth and especially the nineteenth century, who contributed much to entomology, despite a “men only” attitude among most organizations and institutions.

One of the best features of this book is Marren’s fascination with the names that people have given to butterflies over the centuries and in different parts of the world. Here, I think his cultural reflections are on firmer ground. Besides, the names are just amazing and fun to wonder about. Why is a beautiful flying insect called a red admiral or a golden hog? He also comments on how names and naming conventions have changed over the centuries. Luckily, we have the Linnean system to impose a more or less uniform system so serious students can keep things straight.

Marren also does a fine job of describing the butterflies themselves and their habitats all across England and Scotland. He talks about the plants they rely on and the plant communities they inhabit, with much attention to how changing ecology, driven by modernizing agriculture and the rise of suburbs, have affected species, some for the better, but more for the worse. His 12th chapter on butterfly monitoring and preservation efforts is one of the best reflections on the dilemmas of trying to maintain and protect natural habitats that I have read in a popular work.

Marren chronicles the decline of butterfly collecting as a hobby and even as a scientific endeavor in Great Britain. More and more areas prohibit collecting, and more and more of the public is openly hostile to the idea of killing and preserving butterflies. Marren’s own collection from his youth in the 1950’s and 60’s was accepted by the Natural History Museum, because well-documented specimens from the latter part of the 20th century are scarce and valuable records of the state of the fauna, which help scientists today understand how things have changed. The anti-collecting bias of many current environmentalists and natural history enthusiasts is understandable, given the decline of so many species, but largely misguided, at least if they care as they claim to, about protecting these natural wonders. We need more solid documentation, not less, for butterfly populations, and although photographs and even unvouchered reports can be helpful, serious conservation needs specimens to verify what it is that is there and to enable us to trace the shifting makeup of populations. As Marren makes clear in his chapter on efforts to save England’s butterflies, simply trying to freeze things in place is a sure route to failure. Too many organizations and agencies, at least here in my home state, still seem to think that way, though.

 

 

Moth Lady

Moths of the Limberlost by Gene Stratton Porter. Doubleday, Page and Co. 1921. I listened to the Librivox version, beautifully read by J M Smallheer.

I would not have thought that listening to a book about insects, least of all large moths, without being able to see the illustrations, could be utterly absorbing, but Gene Stratton Porter’s descriptions of the finding and rearing of some dozen species certainly is. All of them came from from around her home near the great Limberlost Swamp of northeast Indiana, found by herself, her husband and numerous friends and neighbors, some of whom went miles out of their way to bring her specimens. Besides her accounts of the finding of the adults or caterpillars and her meticulous descriptions of each species behavior and development, there are her minute descriptions of the patterns and colors of all stages, carefully based on the freshest individuals. As a photographer and painter of birds and insects in the days of black and white glass plates, she had to be a very close observer and recorder of colors, if she wanted to get good illustrations based on her photos. A look at the illustrations from the book shows that she did extremely well.Moths_of_the_Limber crop

Her life history observations, such as how hawk moth larvae pupate, burying themselves in the ground and then wriggling back to the surface, posterior end first, while still in the pupal case, so they can spread and dry their wings upon emergence, are fascinating. I like her attitude towards the published literature on moths. She mentions many famous lepidopterists (see my post from on Butterfly People from last February) has read their work, but is willing to point out the shortcomings of their accounts of the actual lives of the insects they describe and illustrate.

Her anecdotes of catching and keeping moths are delightful. Her home must have seemed like more of an insectarium at times, with moth eggs carefully marked and protected on the floors and carpets, because a gravid female escaped and could find no host plant to lay them on. The effort put into successful rearings and the failures that invariably accompany attempts with unfamiliar species must have been very demanding, and the moths were not even her chief occupation. Her novels, the most famous being A Girl of the Limberlost, 1909 and bird photography and illustration took even more time.

Even as she studied them, species like the Cecropia moth and the Polyphemus were losing out to expanding agriculture, lumbering and drainage of swamps like the Limberlost. Later would come DDT and street lights to put still more stress on their populations. Parasites introduced to control gypsy moths have added to the widespread decline, especially in the Northeast. Today, aerial images of the Limberlost show mostly agricultural fields and only a few remnant woodlands, including one small restoration site on Loblolly Creek. We can be grateful that Gene Stratton Porter left us such a beautiful record of what was there before.

Death Valley Days

Land of Little Rain by Mary Hunter Austin, first publication 1903 by Houghton Mifflin.

The Librivox recording of this wonderful book from the first decade of the twentieth century is a pleasure to listen to. Mary Austin’s descriptions of the desert country east of the southern Sierra Nevada are beautifully clear, evoking the harsh land, the hardy plants and animals and the various humans who live among them. My favorite was the pocket hunter, a prospector traveling with his burros and a gold pan that is cleaner than his cooking pots, and who dreams of finding a strike rich enough to allow him to set up as a middle class Londoner. Twice, he made enough to visit England, but each time he returned, with only a pair of elegant green canvas traveling bags to show for the trips. He told how once in a blinding snowstorm he sought shelter with what he thought were a flock of domestic sheep. Looking about in the morning, he saw he had slept among wild mountain bighorns. They bounded away through the drifts like God’s own flock. Breathtaking.

Whether it is the denizens of a mining town or the native Paiute, among them the blind basket weaver and the Shoshone exile medicine man, who must be killed when he can’t prevent an epidemic of pneumonia from taking away a third of the band, Austin tells the stories simply and with evident deep compassion.

She has a soft spot for the coyote, that butt of Warner Brothers cartoons, but in her view far from a fool. She gives loving descriptions of the numerous desert rodents and the jackrabbits whose tracks lead to the waterholes like the spokes of giant wheels, along with their enemies the birds of prey and the scavengers who watch all that goes on from far above, waiting for the predator’s kill or the dying gasp of the starving.

Plants get just as careful attention, some of the best botanical description I’ve read. Whether in her neighbor’s field or on the mesa, she evokes the marvels of the California desert flora with its tough shrubs and delicate ephemerals that blossom only in years when enough rain falls to waken the seeds out of dormancy.

Everything about this book makes me want to visit this land.

Looking for the logos of life VI: Gaian analysis

Williams, G. R. 1996. The Molecular Biology of Gaia. Columbia University Press. 210 pp.

This is a book I wish I had read when it was first published. Williams lays out so many interesting scientific problems so clearly that I would have expected that it would have considerable influence on subsequent research, somewhat as Schrodinger’s What is Life? the subject of the first post in this series. I was somewhat surprised that Google Scholar only finds a few citations of this book. Perhaps William’s scholarly papers have been more extensively cited.

William’s goal is to see why the famous Gaia hypothesis has attracted so much popular interest, while receiving little positive notice from practicing biologists. He wants to determine whether the hypothesis is actually useful, either as a metaphor or a verifiable model of the function of the biosphere. The central question is whether it can explain why the Earth has remained habitable throughout the several billion-year history of the biosphere. That it has is not in question: all evidence points to the occupation of Earth continuously by the descendants of the first living things, which originated 3.5 billion years ago. This strongly implies that the earth has not frozen or boiled and that life has not otherwise been poisoned or starved during that time. Some factor or factors has kept the conditions on at least some of the Earth within the ranges essential to living organisms of some kind. In fact the conditions have not become intolerable to land plants and metazoans at least for hundreds of millions of years. The concept of the continuity of descent, expressed beautifully by Loren Eisley’s image of each of us trailing a long chain of ghostly ancestors, stretching back to those first living things, is to me one of the most useful ways to imagine what evolution is all about. If there had ever been a break in that chain, you and I would simply not exist.

The Gaia hypothesis states that this stability is the result of homeostasis: the regulation by negative feedback (like a thermostat) of a living super organism, Gaia. In its strongest form, the hypothesis is that life on the planet, the biosphere, regulates itself just as a single organism, whether a single cell or a multicellular individual, does. This idea has an obvious appeal: just as networks of interacting macromolecules make up a cell, which is capable of regulating its internal environment, so do networks of interacting cells make up tissues, organs and whole organisms that are able to regulate their internal environment. At least some organisms, like ants and bees, live in self-regulating colonies. Why shouldn’t all the organisms on earth form a self-regulating system?

Williams answers that for biologists the problem is how such a self-regulated super organism could be put together in the first place. Natural selection can explain how self-replicating systems can evolve, because natural laws can discriminate among multiple variant copies that compete for limited resources. The Earth is not self-replicating. There are no variants among which nature can select. There is only one. This problem led Lynn Margulis to argue that Darwinian evolution was not really that important, and that symbiogenesis was the true explanation. Margulis’s great contribution was the discovery that certain cellular organelles, chloroplasts and mitochondria, were once free-living organisms. More broadly, she showed that evolutionary advances by the incorporation and integration of separate living parts were behind the origin of the eukaryotes and that similar processes continue to operate in the form of horizontal gene transfer. The trouble with claiming that symbiogenesis is a replacement for Darwinian natural selection is that it appears obvious that all such new combinations remain subject to survival of the fittest.

Would it be possible for a Gaia-like system to arise in part of the biosphere and then spread, supplanting the less effective parts? Only if it’s self-regulating effects were confined to where it first existed, as might work for something like the terrestrial nitrogen cycle. It seems less likely where the atmosphere and oceans are involved, since they carry the products all over the planet.

Williams also points out that there is more than one possible explanation for the continuous suitability of the Earth for living things. He lists four: luck, inertia, equilibrium, and homeostasis. He analyzes each possibility in turn, and shows how each may contribute to the persistence of habitable conditions. In the case of homeostasis, he distinguishes between negative feedbacks from purely physical and chemical forces involving the lithosphere, atmosphere and hydrosphere and ones that require the biosphere. It is possible that even if there were no life on Earth, the temperature would stay within habitable limits (basically the range where liquid water can exist) just because of feedback among the temperature and the release and sequestration of carbon from air, ocean and rocks.

According to Williams, if you try to assess this possibility, the difficulty is that today the rates of almost all steps in this process, except volcanism, are under catalysis by organisms. We don’t know what an abiotic planet would be like. As of the time he wrote this book, not enough was known about the global chemical cycles at the molecular level to settle the question how much life matters. He gives an example of what was known about the molecular biology of nitrogen to show how complex the regulation of these cycles is likely to be. Nutrients move among four pools: inorganic forms in the lithosphere, hydrosphere and atmosphere; nutrients in forms available for uptake by organisms in the same three spheres and the biosphere itself as accumulated by organisms; nutrients incorporated into living cells and tissues; and bio products, from the cellulose of wood in trees to dead plants and animals to dissolved organic compounds to fossil fuels. All these are connected by flows and many of those flows (mobilization, assimilation, regeneration, sequestration and excretion) are controlled by living organisms, via enzyme-catalyzed, energy-requiring reactions.

I like this book because Williams thinks about Earth and ecology very much as I do. I learned from my professors at Cornell in the early 1970s about five processes of ecology: population dynamics, natural selection, energy flow, nutrient cycling and cultural evolution. These are closely interrelated ways of looking at the overall phenomenon of life on earth, or as I like to define ecology, the structure and function of the biosphere. Is the function of the biosphere to regulate the habitability of the planet, or does the planet have the property of remaining a stable habitat for life without life being involved? You can’t really answer that question with only one habitable planet and one biosphere to study.

I will add that I tried to read another account of the same problem of why the Gaia hypothesis had been largely criticized by biologists while being so well received by non-biologists: The Gaia Hypothesis: Science on a Pagan Planet by Michael Ruse (University of Chicago Press, 2013) I did not find it helpful, being mostly a historical narrative, with a focus on a wide variety of –isms, such as Platonism, Mechanism, Organicism, Hylozoism (the belief that all matter possesses life) and Paganism. I have never been much interested in –isms or cultural explanations for why people accept of don’t accept given ideas. Williams gives us a scientific way of thinking about the problem.

Looking for the Logos of Life IV

Pross, Addy. 2012. What is Life? How chemistry becomes biology. Oxford University Press. 200 pp.

Chapter 5: Origin of life

Pross gives a summary of research on this question that seems fairly reasonable, although he clearly doesn’t think much of historical approaches. I wonder whether he is not giving enough credit to geochemical analysis of rocks from the period before we find microfossils, that is to possible evidence of biogeochemistry back before the oldest fossil organisms. Also, he has not mentioned cosmochemistry – what was available in the part of the solar nebula that became the earth? None of that evidence in itself would answer the question, but he earlier talked about how historical studies could supply useful constraints on the free flow of speculative ahistorical studies of prebiotic chemistry.

He says sequence analysis fails on the origin problem because of horizontal gene transfer. If you start to see networks instead of trees, he claims that you can’t tell anything from the results. Is that so, or is that just a further challenge for clever analysts to overcome? After all, trees took a while to be generally useful. There still are lots of difficulties, but horizontal gene transfer isn’t just chaos. The process must have some logic, ultimately controlled by natural selection, like “normal” vertical gene transfer. I think he might be giving these approaches short shrift, because he has his own agenda.

He also assesses RNA world as unlikely, given the failure to create really complex self-catalyzing molecules in decades of lab studies. This despite his earlier claim that negative findings could not be used to rule out this very scenario. Well, if there was an RNA world, we haven’t been able to create a similar thing in vitro.

The other current scenario has a closed metabolic cycle evolving before self-replication kicked in. He calls such a cycle, “holistic autocatalysis.” So far, attempts to develop such systems by evolution in vitro have also not gone very far, according to Pross.

Biology’s Crisis of Identity

Pross asks three questions: what is life? How did it originate? And how would one make it? He says biology has reached a point, with the completion of the human DNA sequence project, that physics had reached in the late 19th century, prior to relativity, quantum mechanics and subatomic particles. How you can judge the state of mind of a body of scientists, I don’t know, but such an assessment feeds into his attempt to portray himself as breaking through confusion and complacency. To him, the problem is complexity. Is complexity a substance? Can there be a theory of complexity, as opposed to a complex theory?

Does all complexity go back to symmetry breaking, like quantum theory says, if I understand correctly? Life’s complexity clearly arises from the pure combinatorial possibilities of sets of fairly simple elements – four nucleotides, twenty amino acids, thousands of enzymes and similar numbers of intermediary products to create all those metabolic cycles. But they wouldn’t be of much use in a totally homogeneous environment. That’s the competitive exclusion principle. Life is complex because it exists in a large and complex environment, whose complexity is the result of irregularities in composition and past impacts, etc. leading to plate tectonics, and the uneven heating of a rotating almost sphere by the sun, leading to circulation of atmosphere and hydrosphere.

Pross says, “It is the organization of life, rather than the stuff of life, that makes life the unique phenomenon that it is.” Well, duh. He says “systems biology,” which tries to explain cells functions using mathematical ideas like “network topology, ” has not produced much in the way of insight. He also says that a holistic approach can be reductionism “dressed up.”

Another favorite of complexity mavens: non-equilibrium thermodynamics. Life, Pross says, can be said to be a dissipative structure, but what further insight comes from that? None, he thinks.

He then turns to John Conway’s Game of Life, the cellular automaton computer program, beloved of Gaia worshipers. These programs illustrate how simple deterministic games can generate complex patterns, but like the physical insights into complexity, there mathematical discoveries don’t seem to throw light on what Pross claims is the tough question about life: how does teleonomy arise within non-teleonomic worlds? I wonder if there is a fallacy in looking for the origin of “apparent purposiveness” when things apparent are clearly in the mind of the beholder. Can science find any sort of purposiveness at all? That’s a philosophic problem, as Socrates pointed out long ago. And as to “apparent purposiveness” is that anything at all? It’s not hard to explain how natural selection acts to give things apparent purposiveness: purposelessness is clearly maladaptive, it is not bothering to try. Is this his great insight?

Biology is Chemistry

The answer, he says, lies in systems chemistry. What defines it is that it deals with simple chemical systems that have life-like properties of self-replication. After dismissing all the previous attempts involving RNA or metabolic cycles, what is he offering that is different? He starts by justifying all over again the utility of simple systems, with the argument that since we think life started from simple stuff it will be informative to experiment with simple systems. This, however, is unproved: what if comets bombarded the proto-earth with really complex stuff, like Buckyballs and other cosmic macromolecules? Also, this comes after he says that we have no idea what sort of simple stuff life came from. I wonder if he’s headed for another case like those he dismisses.

He claims that systems chemistry is like looking at the Wright brother’s flyer to understand flight, as opposed to a 747. That is, if we can strip down to the simplest possible replicating system, we can get somewhere. But he just said that’s not possible because we don’t have any idea what the earliest living organisms were like. As if we did not know anything about airplanes prior to say, WWII, and we’re trying to imagine the ones from1903, could we do it? He seems to be saying both yes and no.

So here comes his “bombshell,” Darwin applies to replicating chemical systems, thus removing the distinction between chemistry and biology. Fine. But if this is really a momentous original discovery, a lot of folks must not have been thinking very clearly. Anyhow, we know Darwinian theory can apply to designing electrical circuits, why not replicating molecules? But can you actually use that to account for life on earth, more than just in principle? Now he brings in competitive exclusion, and we are off to the races. How well can you demonstrate this principle in a purely chemical system? He says replicating RNA molecules competing for different substrates, evolved to optimize their use of two different substrates, thus precisely mimicking the evolution of Darwin’s finches. Well, precisely is putting it a bit strongly. He claims totally without conclusive evidence that the finches are only doing what molecules were doing five billion years ago. He says that somehow replicating molecules transformed into living cells. I agree, but this is no profound insight, just an attempt to dress up a few clever experiments as a major breakthrough. And maybe the fact that a chemist can learn something from paying attention to ecology and evolution.

The earlier chemists, whose work he seems to dismiss, we’re studying the same things as he is, and he still has no idea what molecules to study. It seems exactly like non-equilibrium thermodynamics or systems biology or Game of life: some clever demonstrations, but no meaningful answers. On pages 132-134, he cites experiments that laboriously mimic the process that was already obvious, that evolving systems become more complex over time, but actually the experiment only shows that two interacting molecular species replicate more efficiently than a single species. Cross catalysis, in this case, speeds things up. So is all life one giant cross catalytic system? Of course it is. Herclitus’s ONE:EVERYTHING::EVERYTHING:ONE holds. Yes, it is chemical; life is an interacting system of macromolecules in an aqueous medium, but it is more. For one, it is largely cellular. Why? Can Pross explain that transition from chemistry to biology with more than a somehow?

Pross wants to add complexification into the sequence replication, mutation, selection, evolution. He puts it after mutation, but that makes no sense, and in his experiment it was the experimenter who in effect introduced it. Even the bare sequence is not right. Evolution doesn’t belong. It is not inevitable, it only happens if the frequencies of the interacting elements change, and that requires an outside physical/chemical/biological cause, a selective force. The system only evolves because of some constraint. Complexification is not a force, no more than evolution; it is the outcome of selection operating under varying conditions. It isn’t a cause. Evolution is change. Complexity is variability, they are not causes, they are results. True, it seems as if complexity is somehow auto catalytic, generating more and more complexity, but there is no law that says that has to be. Diversity does not necessarily result in stability or increasing diversity. Those outside constraints ultimately set the limits. Pross knows a little ecology and evolution, but not enough.

Pross says chemistry and biology are connected by a complexity continuum. What does that mean? Just that he’s repeating his claim in a different way? Wouldn’t discontinuity be more complex? His holistic claims seem more like good old reductionism dressed up. Is his bridge between the two more than just analogical? Physically, of course, it is the same stuff, but until you can actually make molecules evolve into living cells, what have you added to our understanding?

Is the first gene or the first enzyme buried somewhere in our cells, still doing a job, albeit not necessarily what it did billions of years ago? Or did it go the way of the protobiont and so many other species that are now extinct? If we could reverse engineer a simple bacterium into an even more minimal creature, would we be replicating our now vanished ancestors, or just making test tube freaks that never could have competed in the biosphere? Pross says the bacteria have remained simple, but how does he know? Is the bacterial component of the biosphere becoming ever more complex, just in a different way, than the higher plants and animals?

Assume he’s right, and some bit of RNA started the whole thing. Did it manage to do this in some primordial soup competing with uncounted numbers of other molecules, or was it in some incredibly sheltered, simplified environment, like those laboratory test tubes? One thing you don’t have to worry about is sufficient numbers to let mutation and selection act on. Enough might be produced in seconds, if you hit on the right mix. Even if it was much less rapid, as Pross notes, there was certainly plenty of time back then.

Natural selection is kinetic selection

Are competing organisms much like competing molecules? That’s a very loose analogy. Organisms don’t just compete for substrate. He claims we have to explain biology in the language of chemistry, but he uses all language very loosely. He really makes an unwarranted jump in equating chemical kinetics with biological reproduction. If you say that one species winning out over another is just chemical kinetics, I think you will get demurrals from most biologists. He’s back to hiding crude reductionism under his holistic claims. What he says about chemical systems being more amenable to mathematical analysis is just wrong, too (p. 139-140).

Fitness equals dynamic kinetic stability

He’s already in trouble by claiming fitness is a population phenomenon, not an individual one. Even chemically, I’d say that’s dubious, although there may be a population aspect. He is shoehorning a biological idea into a much simpler chemical concept. He claims you can focus on the population aspect, evidently without considering the individuals. But that is just wrong. The only real aspect of fitness is which individuals are the parents of future generations. Who is going to have descendants? Perhaps highly predictable with molecules that replicate. Not so easy with organisms. Even in general it isn’t easy. Who would have picked out the ancestors of angiosperms and placental mammals in the Jurassic? Connecting fitness to stability seems hugely wrong. On the level of the persistence of simple forms, maybe. Lots of genes seem not to have changed all that much.

His attempt to explain fitness landscapes and to make an analogy to a flock of birds seeking higher peaks is not particularly helpful, and didn’t that come from Richard Levin’s work in ecology? Actually the Eigen-Schuster Quasispecies concept is a neat mathematical formulation, but it is not clear what it applies to. Maybe viruses, maybe the origins of DNA RNA transcription/translation! maybe sex (see Wikipedia on quasispecies model) Certainly nothing like all evolving species. This is another analogy that seems to break down on close inspection. He’s trying to bridge the gap by forcing these analogies to do more than they are suited to do. After all, the real unification would mean that you can reduce equations of population genetics to chemical equations, doesn’t it?

He ends up not making a clear connection to the quasispecies concept and goes on to talk about his dynamic kinetic stability, which he admits can’t be measured absolutely, just like fitness, which also depends on the environment in which it is measured. Given how vague DKS seems, it does share the character of “fitness,” in as much as both can be what you want them to be. He suggests (p. 146-147) two measures: abundance and persistence, that are like part of Wilson’s definition of ecological success.

Incidentally, why does he not discuss the Eigen-Schuster hypercycle idea, which seems like a real theory of evolution of simple replicating molecules into linked pathways?

He now says that the cause of evolution is the drive toward greater DKS. But isn’t the cause self copying, with imperfections in a variable, limited environment? It’s differential reproduction, not any drive to achieve stability in any sense of stability I understand. A driving force towards something that he admits can’t be quantified and a mechanism that is a process of becoming a mechanism that is made up of more diversely interacting components (complexification) Seems pretty incoherent to me. He can’t put this into an equation, can he?

In arguing for the idea that life has undergone complexification he points to the fragility of self replicating molecules in the lab. I don’t see that that self-evidently applies to the first replicators in nature. Maybe we are all descended from a horrendously tough little replicator that just happened along out of the seemingly infinite possibilities. Maybe there are theoretical limits set by the problem of mutation in a small set of elements, something seemingly discussed by Eigen and Schuster. Small sets are inherently unstable, so it’s hard to conserve the replication when the replicates are too unlike the original. If a sequence is going to assume the role of a template, or even just determine catalytic properties, it can’t vary too much. Isn’t that just a trivial result, though? It sounds more profound if you introduce the term information into the discussion, but is that really necessary? Jacob Klein always denied that what geneticists talked about was information. I’ll stop at this point, because I think I have about reached my limit in thinking about where life comes from. Pross has made an interesting attempt to  define a new agenda for research in this area. I don’t think he’s got anything really significant, though. Perhaps if we can ever find another biosphere to examine, we will see just how narrow or how loose the constraints are.

Looking for the Logos of Life III

Pross, Addy. 2012. What is Life? How chemistry becomes biology. Oxford University Press. 200 pp.

Chapter 2 The Quest for a Theory of Life

Pross discusses previous attempts to develop what he calls a theory of life, beginning with Aristotle. The only aspect of Aristotle’s views that he describes, though, is telos. He also characterizes Copernicus, Bacon, Descartes, Galileo and Newton as banishing telos from the universe, instead of only from their philosophical explanations of motion. [It is worth noting that he retrospectively applies the name “science” to what they and others were doing.] Pross quotes Jacques Monod as saying that a purposeless cosmos is the most important discovery of the past 200,000 years. Besides being completely unverifiable and hence clearly unscientific, the supposed discovery doesn’t even seem that obviously useful. I guess you could say it frees us to do destructive experiments on animals, but our current regulations suggest that we don’t think that. Pross says it propels us into a new conceptual reality. What does he mean by that? Pross also adds that Schrodinger, in his What Is Life, said that the explanation of living things would involve as yet unknown laws of physics.

Pross thinks, along with Monod, that teleonomy requires an explanation. Isn’t teleonomy only supposed to be apparent purposiveness? So what is the problem? If we assume organisms lack real purpose and simply obey the laws of chemistry and physics, then there is nothing to explain except our perception of purpose. That may be a problem, the problem of consciousness. Is he going to solve that with his chemistry?

In his section on definitions of life, he carefully distinguishes individual living things, which cannot evolve, from populations, which can evolve, but he then talks about a population of mules, possibly not seeing that there can be no such thing.

He does seem to be on track in suggesting that most attempts to define life fail. The examples given either make mistakes like saying life is self-sustaining without qualification, instead of pointing to reliance on energy inputs, for instance, or only list some characteristics of life as known to us, or seem just ridiculous, like Freeman Dyson’s information definition.

Chapter 3 Understanding “Understanding”

Pross links understanding to induction, citing Bacon. He says all scientific explanations are inductive, being based solely on pattern recognition. True, patterns in some sense must match, but induction is a reasoning process, so it should describe not the explanation but the way it was derived. In that case, it seems clear that deduction plays as great a role as induction in our understanding. In talking about mathematics’ role in explanations, he goes from pattern recognition to pattern formulation, without noting that he’s moving between induction and deduction.

In discussing the problem of where the underlying patterns come from, that is, what is the reality behind them, he denies we can know that scientifically, and he quotes Wittgenstein to that effect. This would seem to put him into the linguistic positivists’ camp, but I doubt he’s that clear about questions like realism vs. anti-realism, although so far, his statements seem consistent with anti-realism. He does however seem to qualify himself at one point by saying that patterns are to some degree subjective. He also distinguishes quantitative, qualitative and statistical patterns. Then we get a dose of pragmatism to the effect that adequate understanding is whatever works. Then, in another twist, he says that the patterns we recognize are only reflections of the underlying reality of nature. Once again, it is not clear whether he’s an anti-realist, as he seemed to say earlier, or some sort of Kantian realist. Could he even be a Platonist? Images of reality?

The reductionism vs holism section doesn’t add anything. The problem is that he’s leaving out any discussion of the environment of life. If you frame the problem as what environment and what inputs do I have to supply to create a self-replicating molecular system that can undergo natural selection, you have a pretty good reductionist program for developing an understanding of life. If by life, you mean the biosphere, then you still have a long way to go, and it becomes necessary to use more complex terminology than what you would use to describe life in a simple experimental system.

Chapter 4 Stability and Instability

Pross agrees with my idea of auto catalysis: if something is auto catalytic the rate of formation increases as there is more of it around: dn/dt = rn provided you maintain steady inputs of reactants, while in a normal chemical reaction with a catalyst dn/dt = r, where n is the concentration of product and r is the rate of conversion of reactants to products. He expresses the idea in terms of the time required to produce a given amount of product, if you have a given amount of catalyst. For the Spiegelman RNA autocatalysis, you should get a logistic growth pattern, because the rate will be constrained by both the RNA and the protein enzyme acting catalytically. This seems like it ought to apply to PCR, for example.

Another thing about the RNA replication reaction is that it is template replication, so it actually yields copies with a highly specific structure – meaning that analogies to information become possible. Is that what all the talk about “information” in biology is, a physical analogy? How would the idea of a physical analogy apply to a computer or a brain? It seems as if information theory is a mathematical formulation applicable to understanding a variety of things, some of which (cells, telephone signals, computers) we think of as physical and others (language) that seem not to be. I would say that what goes on with cells is physical and the information is only metaphorical. A computer seems more problematic, especially since what it does can be represented as a Turing machine, and even though it isn’t a machine but a mathematical hypothesis its relation to meaningful information seems very immediate. Since information theory involves representations in mathematical symbols of concepts that are not physical, why invoke physical analogies? In all the physical systems covered by information theory, is there a point at which a mind is needed to interpret the meaning of the information? That seems to have been the original motivation in fields like cryptography, communications, etc. but in cybernetic systems there may be times when the information is used only by the machine. Still, someone has to eventually determine whether the machine is doing what it is supposed to, at least until we find ourselves in the Matrix, etc. Stephen Hawking apparently worries that this is where Artificial Intelligence is leading us. A biosphere is like that. It doesn’t need to be meaningful to us to be a biosphere.

What about crystal growth? Clonal growth?

What sense does it make to talk about kinetic dynamic stability or about the “efficiency” of maintaining a large population (p. 74) by rapid replication? I would think that in a way, autocatalysis is very unstable, because it tends to exhaust resources so quickly. He talks about Cyanobacteria being around for billions of years. Is persistence of a clade with little obvious development or change the meaning of stability? Success, might be a better term. To me, the Heraclitean flux is the only really persistent feature of the biosphere. Moreover, it looks as if the pace of change is accelerating: metazoans only in the last billion years, a full terrestrial biosphere only in the last 300 million years, hot blooded life only in the last hundred million, and cultural evolution only in the last six million? Is this all the result of auto catalysis? Is dn/dt = rn, where n is “information?”

It seems as if “stability” is not a very good word to encompass the persistence of biological entities through time, given the tremendous range of life histories found among living things. The mathematical complexities are very great (cf. Cole, L.C. The population consequences of life history phenomena. Quarterly Review of Biology Vol. 29, No. 2, Jun. 1954, pp. 103-137) and there are many dimensions to the whole problem of what is it that persists: genes, phenotype, species, clades? What about the stability of Redfield ratios? If true, it is an indication of an extremely widespread pattern. He claims the more stable replaces the less stable. Doesn’t that imply that species should last longer and longer in the fossils record? What is the actual pattern? TO BE CONTINUED

Looking for the Logos of Life II

Pross, Addy. 2012. What is Life? How chemistry becomes biology. Oxford University Press. 200 pp.

I found this an interesting and generally readable book, but I think it promises more than it delivers. My reflections on it are rather lengthy, so I’ll begin with:

Prologue and Chapter 1

Pross’s question is, “What is Life?” His book is offered as an advance over Schrodinger’s 1944 essay, What is Life? He will use “Systems Chemistry” to state a new law on the “emergence, existence and nature,” of living things. He claims to have found an overlooked form of stability in nature. According to Pross, “Darwinism is just the biological manifestation of a broader physical-chemical description of natural forces.” This will allow him to put forward a “generalized theory of evolution.”

Like Schrodinger, he starts with the laws of thermodynamics – heat transfer, entropy, etc. He sees his task as like Schrodinger’s: to account for the stability of a living cell, despite its being far from thermodynamic equilibrium. He also wants to explain how the first one could arise. He says the goal of that understanding is to be able to synthesize a living organism from scratch. I wonder whether in his “generalized theory of evolution” there is a deliberate echo of general relativity? Does this point to scientific hubris or is it an attempt to pump us a thesis is that is really not all that revolutionary?

The discussion begins by identifying certain “strange” characteristics of life that he thinks are problematic: life’s organized complexity, its purposeful and dynamic character, diversity, far-from thermodynamic equilibrium state and chirality (the “handedness” of amino acids)

Like almost every discussion of the origin of living cells, his begins by emphasizing the cell’s complex structure. I think he confounds small size with intricacy of design, which is ok, if you want to compare a cell to a refrigerator, but it seems odd to claim that an eye is a less intricate design than the ribosomes in the cells the eye is composed of. He tries to define complexity in terms of organization. Does that make sense? He uses the shape of a boulder to define complexity one way – what would it take to describe it precisely, I guess he means. He introduces the idea of information at this point. He claims that as far as the definition of a boulder, the exact shape is arbitrary, implying that the information describing a living cell is less so, but is this only because he ignores the internal composition of the boulder, how it acquired its particular shape and the relation between composition and shape, etc? He points out that even tiny changes in DNA can alter a cell, but this is potentially true of boulders as well, if we alter the makeup or distribution of components. Also, both cells and boulders can vary in exact makeup over quite wide ranges.

He says organized complexity and the second law of thermodynamics are inherently opposed. Cells need energy to maintain their ordered state. Does this really mean complexity is opposed to the second law? I find that physical scientists and some biologists make a very big deal out of what seems to me to be an artifact of looking at their experimental subjects in isolation. The opposition only arises if you ignore part of the system – the biosphere as a whole. Pross admits that this is the reason for the apparent contradiction.

Now he sets up another straw man: Darwinian theory only deals with biological systems, so it can’t account for the origin of the first, self-replicator, the protobiont. Darwin’s theory is biological and does not try to account for the origin of life, but does that mean a Darwinian theory can’t? Darwin himself says that natural selection is the result of natural laws, including presumably, those of chemistry and physics. In fact, apart from these, what are biological laws? Geometric growth is in a sense purely mathematical, but arguably so is a lot of physics and chemistry. Genetic variation and struggle for existence, even natural selection, are expressible in mathematical language. His question, “how did a system capable of evolving come about in the first place?” seems wrongly expressed, possibly because evolving is not the fundamental thing. Darwin’s is a theory of the origin of species. Is evolution a capacity or a faculty of living things? It seems more like the overall pattern that emerges. The word evolution has that troubling sense of preordination or unfolding.

He brings up chance and talks about how unlikely a cell is to form spontaneously. I guess you have to rule that out at some point. He refers to the “first microscopic complexity” coming into being, which seems to ignore that things are “complex” at the microscopic level in many ways other than being living things. He does not begin his argument by saying self-replication is the fundamental defining character of life, which I think unnecessarily draws out his discussion.

Talking about the apparent purposiveness of living organisms, he uses the word “teleonomy,” a coinage designed to avoid the supposed meanings of “teleology.” Pross says our interactions with the non-living vs the living world have a different quality, because of living things’ teleonomic character. He says we don’t use teleonomic explanations in the non-living realm, but then why is he always saying systems seek a lower energy state? Is the conservation of energy teleonomic? We can think of machines as having needs and of animals as machines. Teleonomy is a function of our way of seeing the world, not a measurable property of things: you can certainly think of a rock as wanting to fall or electricity wanting to discharge itself, and contra Pross, you can get some guidance from the laws of physics about the likely behavior of animals as well as trying to read their intentions in postures and expressions or consulting your own likely responses (putting yourself in their shoes). He sets it up as a stark duality, but is it? He then lumps under teleonomy things as diverse as chemotaxis and human voluntary behavior. He also identifies function with teleonomy.

In his long discussion, Pross never mentions the telos of teleonomy: self replication. Pross’s rhetorical withholding continues. It gets murkier when he does bring it up, because he says, while we can have a lot of goals as a human, we need to look at simple organisms to get at the real one. So is our purposiveness different from that of living things generally? He refers to it as a powerful replicating drive. What does “drive” mean? He claims teleonomy is as “real” as gravity. But gravity is in some way fundamental, as the physicists say, or at least an aspect of something more fundamental still, while teleonomy seems a by-product of self-replication. Teleonomy cannot, can it, be unified with the other forces of physics. He says gravity is quantifiable and teleonomy is not but that it doesn’t make teleonomy less real. He claims we stake our lives on the teleonomic principle when we drive our cars. What does he mean? Is it the design of the car or my ability to drive it to where I want to go and avoid hitting obstacles or going over cliffs?

Part of the problem is he starts talking about a teleonomic principle, not just teleonomy. Where did the principle come from? Teleonomy seems like an analogy to our own purposiveness, but what laws govern it? Is there any real similarity? Is the analogy in any way useful to reasoning accurately about living things?

Pross says, “Metaphysically…gravity and teleonomy are mental constructs that assist us in organizing the world around us [does he mean sense data?] So is he an anti-realist in the school of Hume and logical positivism or a Realist of the idealist school like Kant? Then again, the Scholastic ideas of gravity and teleology are organizing principles. Is teleonomy like the Scholastic gravity, going to be swept away by a better concept? At one point, he says “all inferred patterns are conceptual and are found nowhere else than in our minds.” How closely can he stick to this principle, and in that case, what is his book going to explain, patterns in our minds?

I think simply admitting that self-replication is a property of living systems, and not the goal, would obviate the need for teleonomy. If there is a need to talk about “purpose” to avoid prolixity when describing biological structures and behaviors that are aspects of self-replication, we should just use the term and not invent new words because we fear someone will accuse us of teleological thinking. I wonder if these constant verbal contortions are because we are still fighting battles with those who identify the ultimate cause with a Creator whose plans are often crudely anthropomorphic, like his appearance.

In the section of life’s great variety, Pross says, “non-living diversity is arbitrary.” That hardly seems true of geology or the atmosphere. Perhaps he means it is easier to see the relatedness of living organisms: classification of plants and animals by non-literate people is often very close to the scientific classification. He repeats the false characterization of species as, “each perfectly adapted to function and survive in its particular ecological niche.” So, he’s not an ecologist or evolutionary biologist, but even popular books like those by Steven Jay Gould warn against that sort of talk.

He claims further that there is an inescapable contradiction between the principle of natural selection and the principle of divergence [of character]. Again, this is not a bad point to bring up, but if it really were a contradiction, then something would be seriously wrong with our theories on the origin of species, and this is not the case. There is nothing preventing diverse things from being selected. If the conditions of life were always and everywhere identical, then selection would prevent divergence. The problem goes away once you include the idea that organisms exist in varying environments. He seems to confuse debates over mechanisms of speciation with debates over these two principles.

In the section on life’s far-from-equilibrium state, he seems to be setting up a straw man to knock over later. Yes, non-equilibrium thermodynamics is exceptional, but it is not confined to living things. The lithosphere, hydrosphere and atmosphere are not in equilibrium, so why should it be surprising that processes occurred at some point that led to small parts of these moving further from equilibrium? As long as there is sunshine and radioactive decay, there’s the possibility of a system being supplied with enough energy to move it far from equilibrium. By far the trickiest part is to get the autocatalytic process going in an environment where it can be safe from degradation long enough to become robust enough to deal with the challenges of a changing environment and to diversify so as to occupy more places. But with no competition from already-existing organisms and billions of years…

I suspect the mystery of chirality (as he calls it) will prove to be another straw man. A phenomenon to be explained, yes, but not really that much of a mystery, at least not in the sense of requiring new principles to account for it.

His claim that we fully understand and can explain the characteristics of water or other inorganic substances, while we can’t understand living things also seems problematic. Do we really know all there is to be known about water? Again, he seems to be trying to hype up the level of mystery, instead of just saying that it’s a really complex problem. This would make his supposedly new principle seem more marvelous, I suppose. His promise is that he will reveal the hitherto hidden essence of life. TO BE CONTINUED.