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.



Forgotten but not gone

Forgotten Grasslands of the South. Natural History and Conservation by Reed F. Noss. Island Press 2013

Walden Warming by Richard Primack. University of Chicago Press 2014

Reading Noss’s work, I recall Faulkner’s words, “The past isn’t gone. It isn’t even past.” Forgotten, neglected, tragically diminished, but not gone. Noss describes his travels to visit what was once a vast archipelago of grass-dominated ecological communities, ranging from endless longleaf pine savannas (see my post on Looking for Longleaf) to tiny rock outcrop barrens. This island landscape stretched across the southeastern United States from Texas to Virginia. In fact, though Noss does not discuss them, these communities are found up into the mid-Atlantic and New England. Today, the remaining islands, in a sea of agriculture, industrial forestry and urbanization  only hint at what has vanished beneath the waves of “progress.” But remarkably, there is enough to form the core of a restored landscape, something that will be a major challenge for 21st century ecologists.

Many types of habitats fit under the term “grassland.” Woodlands have trees, but their crowns cover less than three-fourths of the ground, allowing herbaceous plants, especially grasses, to thrive. Savannas have scattered trees, with less than about fifty percent cover. Meadows, glades, barrens and balds have only isolated patches of trees. Noss also describes plant and animal species endemic to the southeastern grasslands. An endemic is a kind of organism found in a particular type of community or a local area, and nowhere else. Many of these are critically imperiled, occurring today at only one or two places. The book is illustrated with his photos of the communities and the rare plants.

Noss has really interesting things to say about the factors that have maintained open, grass-dominated habitats over ecological and evolutionary time. The main ecological question is: what is preventing tall woody plants from taking over? The climate is warm enough, and rainfall is adequate for trees. It could be lack of a deep, firm soil that roots can penetrate to support tall stems. It could be that the soil stays wet or dry too much of the year. It could be constant disturbance by flood, wind, fire or herbivores. It could be lack of sufficient nutrients to support trees and shrubs. At any particular site, it’s most likely a combination of two or more of these factors.

The evolutionary question is: how have the species that comprise these ecological communities arisen and survived in a dynamic landscape? The answers are tentative and complicated, especially those related to changing climate. The distinctiveness and diversity of the endemic species, especially their adaptations to fire, imply a long evolutionary history. Some of the endemic plant species, such as those in certain rock outcrop barrens, may have evolved recently, while others, like the ones in the longleaf pine savannas, have been around for a very long time. This field of research is called phylogeography because it looks both at phylogenetic (evolutionary) relations among different populations and species and at the geographic patterns of climate (and so, the species’ habitats) now and in the past.

Many authors have stated the grasslands originated only as a result of disturbance by humans, who do not seem to have reached America before 30,000 years ago at the very earliest. If the grasslands originated before the Pleistocene ice ages, how did they survive the periods of peak glaciation and cold? Noss cites pollen data to show that most of the southeast had a cool temperate climate during the ice ages, but evidence from geomorphology suggests that there were periods of boreal conditions with deep seasonal frost or even permafrost. Aeolian landforms, created by strong winds coming off the glaciers, include dune fields, sand sheets and the famous Carolina bays. These indicate that there were periods where there was little vegetation to stabilize the surface. One possibility is that the pollen record is incomplete, because the intervals without vegetation produce essentially no pollen. Another is that, if the Gulf Stream stopped during the coldest intervals, the Gulf of Mexico would have been a tremendous heat reservoir, keeping the coastal areas warm, while inland sites were cold. On maps of the ice age drop in sea level, the additional dry land, just on the west side of peninsular Florida, looks nearly as large as North Carolina. Thus, a lot of grassland species might have retreated there.

Noss’s book and a recent article (Noss, R. F., Platt, W. J., Sorrie, B. A., Weakley, A. S., Means, D. B., Costanza, J. and Peet, R. K. 2015. How global biodiversity hotspots may go unrecognized: lessons from the North American Coastal Plain. Diversity and Distributions 21: 236–244), which includes the coastal plain up to Cape Cod, call the region a biodiversity hotspot. This is based on the great numbers of plant, vertebrate and insect species in the region and the number of those species that are endemic to it.

The article calls for the North American Coastal Plain to be listed as a global biodiversity hotspot. A colleague who studies southern grasshoppers told me that the group behind the effort to achieve listing had several more papers in the pipeline that they expected would be needed to convince the Critical Ecosystem Partnership Fund to add the NACP as hotspot number 36 They succeeded on the first try, just after the article was published ( Hooray!

Now the hard work begins: convincing people, especially government officials and private conservation groups, to take action. Here in New Jersey, most conservationists still see the coastal plain as a forest region. Natural enough, since fire suppression for the last eighty years has effectively converted what were once woodlands and savannas into dense forests of pine and oak trees and huckleberry shrubs. “Forest,” has such cultural significance in American environmentalism that it is very difficult to convince anyone that this is not what Nature intends. Add modifiers like “old growth,” “pristine,” “climax,” and you have idols that it is very hard to get environmentalists to stop worshipping.

Most people I know in the Mid-Atlantic region tend to blame “development” for loss of natural habitats. To an extent, this is true for the grasslands of the South, especially the loss in recent times of the smaller glades and barrens, but other factors are historically more important. Noss mentioned drainage and conversion to farmland, but this applies mainly to the wetter, richer grasslands. Dense tree plantations have replaced pine savannas. Another factor is loss of large herbivores, beginning with the extinction of much of North America’s megafauna – mammoths, ground sloths, etc. – around 15,000 years ago. To some degree, cattle, hogs and sheep may have supplied their place in the early post-1492 times of open ranges and even today, but livestock can do more harm than good to natural habitats, and they will never be allowed to recreate the vast network of “buffalo traces,” leading to salt licks and waterholes. These trails provided habitat and dispersal routes for grassland plants, as roadsides do today, if we don’t mow them in the growing season or allow exotic invasives to take over.

By far the clearest factor reducing grasslands is fire suppression. Since the advent of motorized firefighting in the mid-twentieth century, the number of fires has changed little, but the area burned annually has greatly decreased ( This means that fire return intervals have generally become too long to prevent establishment of closed forest canopies. This is fine if you want to grow trees for wood or fiber but terrible for the plants and animals of woodlands, savannas and grasslands.

I have tried for years to convince my friends in the New Jersey Pine Barrens that the greatly increased plant canopy cover since fire suppression began to be effective has caused much of the reported drying out of the landscape. They prefer to blame the loss of wetlands and headwater streams on wells drilled by farmers, developers and casinos sucking water out of the ground. Trees and shrubs are taking just as much water through their roots and evaporating it through leaves, 300-500 pounds of water for every pound of sugar they make in photosynthesis. Some of my conservationist friends and colleagues oppose even moderate thinning of trees in the Pine Barrens. They talk about endangered species’ need for undisturbed habitat, not recognizing that on the coastal plain, far more species are threatened by the loss of open land with herbaceous vegetation – grasslands, woodlands, savannas and meadows. A very experienced botanist I know, however, has become convinced, after seeing species like pine barrens gentian and turkey beard springing up in the wake of forest thinning and reintroduction of fire on managed lands. Too bad the New Jersey Forest Service officials still thinks Smoky the Bear has the last word. They are courting disaster as fuel loads continue to build up in the pines, but they won’t believe that a fire could occur that they could not control. This is incredibly short sighted.

I also wish our environmental community would back off its opposition to natural gas pipelines, which actually create open habitats, and devote more of their resources to stopping the motorized mayhem that’s destroying the last of our native savannas and sand ridge communities all across southern New Jersey. In the Pinelands National Reserve, motorized recreation is not a permitted land use, but pressure from the motorheads has prevented meaningful regulation or enforcement.

Besides these immediate threats, I wonder whether the coastal plain biodiversity hotspot can survive climate change. As shown by Richard Primack in his excellent book, Walden Warming (Chicago 2014) there are already substantial changes in the flora and fauna of New England since Thoreau kept a naturalist’s journal in the 1850’s. Surely, though we lack clear evidence, such changes are occurring in the North American Coastal Plain. For plant populations to persist, they must either acclimate (adjust their flowering and fruiting physiology) adapt locally (through natural selection of individuals that best match the warmer climate) or disperse their seeds northwards. Primack points out that the barriers created by towns, farms and highways make it difficult for native plants to disperse to suitable new habitat.

A look at the map of the coastal plain shows another problem: the northward narrowing of the geologic region, until it peters out at Cape Cod and in the sandy outwash plans of southern New England. Even if species can shift northwards, they will find themselves funneled into increasingly tight confines, reduced even more by sea level rise. Europe’s flora is impoverished compared to its temperate counterparts in North America and Asia, because southward dispersal during the height of the last ice ages ran into the barrier of the Alps. The coastal plain’s denizens may be similarly crushed against the rock ribs of New England.

Noss’s points out that many people feel that preserving nature for its own sake is as important as preserving it for its benefits to us. He recasts Jack Kennedy’s famous dictum as, “ask not just what nature can do for us, but also what we can do for nature.” He estimates that temperate grasslands have the lowest ratio of lands preserved to lands destroyed of any major ecological system on earth. In the North American Coastal Plain this ratio may be even lower, although perhaps with more prospect for restoration than in some areas, because so much has been lost to fire suppression, which is fixable.

Noss is a strong proponent of saving all that we can in whatever ways are effective. He is against any form of ” triage,” writing off of species and communities that we decide in advance can’t be saved. He also criticizes the Nature Conservancy for overemphasizing what they call “working landscapes,” and neglecting the smaller, uneconomical bits, those tiny glades, barrens and rock outcrops that house such amazing numbers of endemic taxa. Noss argues we need to practice preservation on many scales, beginning with a ban on development of any new natural lands. We should be redeveloping abandoned or underutilized sites, close to existing development. I agree, but we need to find some way to effectively transfer development rights, or landowners will block any such policy. He also argues that we need to change the policies and practices of our state and federal agencies and private conservation groups to better manage lands already protected. Too many of the best areas are either over-utilized or neglected.

Both these books are excellent reads, especially the authors’ descriptions of work in the field with their colleagues and collaborators. One gets a sense that there are a lot of very dedicated ecologists working to preserve biodiversity in our changing landscape and changing climate. One of the encouraging developments I have noticed is the great increase in contributions from what are now called, “citizen scientists.” People, who might once have pursued their love of plants, birds or butterflies in isolation, now contribute to both current data collection and preservation of valuable old data (Thoreau’s Journals are a prime example) through projects like iDigBio. More could be done, especially if there were a way to report and then evaluate outliers: unusual sightings, anomalous individuals and things in the wrong place at the wrong time. Where economic interests are involved, we do usually follow up, as with introduced pests, but otherwise many valuable observations in our rapidly changing environment may be written off as misidentifications or just lost. I would like to see more naturalist’s, especially our large crop of butterfly watchers learn when and how to collect proper specimens to verify their unexpected sightings. Scientific collecting is almost never a threat to populations of insects, and a specimen allows positive identification and preservation of a record in a way photographs can’t.

I would strongly recommend these two books to anyone concerned about the future of biodiversity along our Atlantic coast.

The search for Cíbola

Castañeda, Pedro de. The Journey of Coronado, with other accounts of the journey, including Jaramillo, Hernando de Alvarado and Coronado himself, translated from the Spanish by George Parker Winship. Librivox.

This was the famous expedition in search of Cíbola, the “seven cities of gold.” The search was prompted by reports from Cabeza de Vaca and his companions, when they returned to Mexico in 1535, after their eight-year odyssey from the Gulf Coast (Cabeza’s account is also available on Librivox – I may write about it later). One of his companions, the African Estevan, made it to Zuni pueblo in 1539, as part of a scouting party led by Friar Marcos de Niza. There he was killed or perhaps simply dropped out of sight. The reports of de Niza convinced Coronado and Viceroy Antonio de Mendoza to mount an expedition. In three years of exploring the southwest of what is now the United States, various parties of the expedition reached as far as the southern end of the Grand Canyon of the Colorado and its South Rim, Zuni Pueblo, the pueblos of the Rio Grande valley, Blanco Canyon in the Texas Panhandle and the Arkansas River, east of present day Dodge City, Kansas. None of these places yielded any gold or other valuables. Either de Niza had a bad case of giving the answer wanted rather than the truth, or his zeal to spread the gospel made him try to see how far he could convince the army go among these unconverted peoples. The native communities could not even feed the expedition without being reduced to near starvation themselves. Some of the Rio Grande pueblos resisted and were overcome by force in bloody assaults. The difficulties of maintaining an army in the field in that country, with only horses and humans for transport, are hard to imagine (they did have a supply flotilla sail up the Gulf of California into the Colorado, but it could not enter the Grand Canyon, and at any rate, was much too far west to help). Once they were out on the plains, east of the Rio Grande and the mountains, they found it impossible even to keep track of where they were. Hunting parties wandered lost for days in the featureless landscape of grass and shrubs, with only the occasional river canyon as a landmark.

Castañeda gives dramatic accounts of the buffalo (which the translation renders as “cows,” presumably for the Spanish, “vacas”) and the natives who hunted them, living in tents on the open plains. His other botanical and ethnographic accounts are interesting but colored by his outlook as a Spaniard: The natives in the pueblos, camps and villages are described as to dress and customs, with frequent specifics on sexual matters, as “they do not practice sodomy,” in one place or “they are very great sodomites,” in another. One peculiar topic was the deadly poisoned arrows made by some of the natives the expedition fought with, which apparently included poison from the same plant that yields Mexican jumping-beans (Sebastiania bilocularis S. Watson, arrow poision plant, according to the USDA plants database). Even more interesting was the antidote: quinces, which Castañeda notes growing in many places the expedition passed through. The quince (genus Cydonia) is native to Asia, but could have been introduced to Mexico early in the 16th century. Northern Mexico is a minor quince producing region today, according to the Wikipedia article. Perhaps it was spread by the natives ahead of the Spanish themselves, or possibly Castañeda was just confused about the identity of a native fruit, as he seems to have been about the “cows.”

Overall, this is more of a reading for the historian or ethnographer than the naturalist. To give account of the landscape you are passing through, so that it can be recognized later, you have to be interested in more than gold.

The Librivox readers were outstanding as usual.

Birding on horseback

Florence Augusta Merriam. 1896. A-Birding on a Bronco. Houghton, Mifflin and Co., The Riverside Press, Cambridge, MA .

This is a delightful book by a great late nineteenth to early twentieth century naturalist. Merriam was an ornithologist, author of Handbook of Birds of the Western United States. She was an organizer of several chapters of the Audubon Society.

This book, which I listened to on Librivox, is a set of notes from two visits to a ranch in Southern California in 1889 and 1894. Many of her observations are of the birds at their nests, an aspect of birding which seems to have fallen out of fashion. Today, there is much more emphasis on counting species and individuals seen and much less on the close observation of behavior. She does tend to use strongly anthropomorphic descriptions and to attribute a greater degree of self awareness to her subjects than would ever be acceptable today. Nevertheless, she is a fine observer and writer. Her descriptions of southern California as it was over a century ago, when life revolved around farming, ranching and orchards are a reminder of how much our landscapes have changed.

Reading her accounts of the numerous attempts at nesting by a wide variety of birds in the oak woodlands and chaparral, it came home to me very strongly how frequently they failed. I would guess that well under half of the nests she saw started produced fledglings. Most were destroyed by unknown agents or simply abandoned. Snakes, other birds and cats were likely culprits. Given the utter vulnerability of the eggs and hatchlings, it is almost surprising that any are successfully reared, though I know it’s been done for a hundred million years or more. A small bird’s life must be exhausting and frustrating, with no time to rest between the challenges of nest building, foraging, territorial defense and, for many, migration. Even during brooding, there must be constant vigilance. Their lives must be a near continual state of nervous excitement, ending in exhaustion.

The bronco in the title, was not, by the way, some half wild creature suitable for a rodeo but actually a couple of docile ranch ponies, well suited for a lady naturalist to wander the country. One in particular was so patient as to stand for hours while Merriam watched nests. The only danger was that they shied at snakes, if they sensed their presence. On occasion, bronco and rider went right past rattlers in the dense brush, but mostly they stayed away from likely snake habitat.

Horseback sounds like a wonderful way to watch birds; I will someday have to compare this book to Birding From a Tractor Seat by Charles T Flugum.

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.

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.

Assessment and the seeds of learning

“Though I do not believe that a plant will spring up where no seed has been, I have great faith in a seed. Convince me that you have a seed there, and I am prepared to expect wonders.” Thoreau

I have taught for forty years at a state institution that started out as a small state college in 1971 and has become, as of 2015, a university, at least in name. For about the past five years, the main thrust of my institution’s curriculum development efforts have been geared towards developing detailed lists of “Essential Learning Outcomes.” These are objectives that are supposed to be evaluated on a three step ordinal scale of “aware, competent, or skilled.” Faculty are being told to develop ELOs for their academic programs and individual courses and to align their assessments to their ELO rubrics (or maybe it’s their assessment rubrics to their ELOs). The goal is to demonstrate that students are learning very specific skills and “competencies” as a direct result of what happened in the classroom, during or immediately after the “activity” took place. This is no way to assess real learning, which is something beyond the reach of techniques based in so-called “learning research.”

The current drive to assess “learning outcomes” is equivalent to demanding that teachers produce fully developed knowledge in the minds of their students immediately. It it like demanding that a gardener show you a fully developed garden of plants, with flowers and fruit, in a day, or at most a few months. Such a garden can only be a hot house full of exotic plants in pots or a heavily tended garden, using every artificial help available. Hothouses and artificial landscapes have no organic connection to the environment in which they are growing. Once the heat, water and fertilizer are are cut off, the plants die.

This botanical metaphor is quite revealing. Just as there are subjects that can be learned quickly and retained if the mind is well prepared (the minds of children are extremely retentive and often not overly cluttered), sometimes the effect of seeding is immediate, and plants take root and begin to grow. More often in teaching, the best that happens is that a few weeds of false opinion are rooted out or at least identified, preparing the mind to receive something true. Teachers of science know that this weeding is essential: students do not understand and retain correct ideas if they continue to harbor false ones that interfere. Most seeds do not germinate right away. Indeed, they often wait years to develop. The teacher must have what Thoreau called “faith in a seed.” In some future circumstance of the student’s life, the environment of the mind may be right for this idea, and then it will develop. Most of the important things we learn in our lives have to develop like natural vegetation, through a process of succession in which different ideas only grow under the circumstances that are suited to them. Because natural communities have a “seed bank,” of dormant seed accumulated over many years, as well as a constant influx of seeds from outside, as one plant dies, another will immediately occupy the spot where it grew. Often many new plants will spring up and compete for the space until one takes over, or a plant that has been waiting, as it were, in the shadow of the current dominant one, will quickly grow up to fill its place.

I the human mind, if it remains active and receptive, old ideas are gradually replaced as the short-lived ones fade and are replaced by those that live longer. These may be new, but more often, I believe the best ones were first encountered earlier in life and have lain dormant, like seeds in the seed bank, or have been waiting in the shadow for us to reject an idea that up to then had been dominant. Gradually, one develops a set of ideas that have stood the test of time and the challenges of surviving in a complex world. If the good ideas are there at the time when circumstances become right for them, they will grow and flourish. All the teacher can do for the minds of his young students is to try to plant ieas of lasting potential value and have faith that they will eventually grow.

I am extremely grateful that I had the benefit of a home and school environment that made me reasonably competent as a reader, a fair master of math up through algebra and geometry, with a little bit of Latin and French, before I went to college. Furthermore, these were taught me in a way that did not kill my enjoyment of learning.

I attended Saint John’s College in Annapolis, Maryland and Santa Fe, New Mexico, as an undergraduate. The core of the all-required curriculum was the seminar, a twice weekly evening class, where for two hours or more around 15-20 students and two tutors discussed a sequence of great books, from Homer and Dante to Darwin and Freud. Discussions began with a question from one of the tutors and then went, slowly or sometimes explosively, around and through the text, following the argument where it led, occasionally being set back on course by the tutors. Some tutors were more active in pushing the question; others preferred to sit back and see what we would come up with. The outcome of a Saint John’s seminar was that, as the etymology of “seminar” implies, seeds would have been planted in the minds of the participants.

Outside of class, we students often wondered what it was we were learning. It was very hard to summarize what any seminar was “about,” and impossible to state in a few words what had been concluded from the reading and discussion. Attrition at Saint John’s was quite high, and a frequent reason was the sense that we were “not getting anywhere.” Math tutorial and laboratories, another major component of the curriculum were subject to similar criticism, as we worked our way through texts like Euclid’s Elements, Newton’s Principia and Maxwell’s Experimental Researches on Electricity. I stayed with the Program to the end and went on to a successful graduate career at Cornell in ecology. I have never regretted my Saint John’s education and still view it as the best undergraduate program in the country.

I did learn a lot of things while at Saint John’s: The rudiments of Greek and some important ideas about geometry and arithmetic, the nature of mathematical proof, etc. I could recollect some of the specific content of the many books I read. But what was really valuable was that the experience made me confident in my ability to understand texts, to dissect arguments and to hold my own in discussion. This preparation of the ground enabled me to breeze through most of what I was required to learn in graduate school and to pass my qualifying exams without difficulty. Even there, though, it was the seeds that were sown, especially while reading many key papers in ecology assigned by my professors, that were most valuable. These came to fruition over my years as a college teacher. There were quite a few subjects, animal physiology for example, which I took and passed with A’s, from which I can recall almost nothing, yet I still have the notebooks and final exams to prove I once knew them very well. I passed the graduate reading exam in German (a particularly dreaded “assessment”) without much sweat. Having, however, no necessity or leisure to read anything in German, I forgot most of it in a matter of months. Short term memory stuffing is easy; long term requires a lot more application, at least for me (and many of my students).

Many of the great books from Saint John’s and benchmark papers from my Cornell years are still part of the courses I teach, both in the Environmental Studies Program and in General Studies. I still lead discussion-based classes. Over the years, I have received some, but not much, support for this approach from colleagues and administrators.

I hear from many of my former students who have gone on to successful careers. Often I am surprised by the places they have ended up. Rarely is the memory I have of how well they did a predictor of how brilliantly they have succeeded. Many an ugly duckling has proved to be a swan. Of course, the love of a subject, if it is a real passion, often grows into a brilliant career, but it is not necessarily the case that those students would have come off well in assessments of their learning at the time. Quite a few were low B and even C students in many of their courses.

Colleges and universities and those that fund them have to learn to deal with the fact that short term assessment is not a good predictor of future success. Changes made in teaching methods and curriculum will not show up until long after the students have gone on. It is far more important to look carefully to the quality of the seed being planted. This can only be done if you have a faculty who are willing to think long and hard about what things are important to include in the curriculum and who are not forced to waste their time developing short term assessments, rubrics and other specious projects that only value pretty but ephemeral flowers.