Chapter forms

I asked students in my “Environmental and Biological Non-fiction” class to represent in sketches and geometrical forms the structure of chapters from four books. Here’s what they drew. Can you recognize any of the books? (click on images for an enlarged view; thank you to Laney Wood for taking and sharing the photos.)

The answers:

Yuval Noah Harari. 2015. Sapiens: A Brief History of Humankind. New York: Harper.

Rachel Carson. 1962. Silent Spring. New York: Houghton Mifflin.

Elizabeth Kolbert. 2014. The Sixth Extinction: An Unnatural History. New York: Henry Holt.

Jane Goodall. 1971. In the Shadow of Man. London: Collins.

All the representations included some of the books’ content. The drawings varied in how effectively they showed narrative structure. Perhaps the most interesting was Silent Spring shown as a series of narratives that rise then crash, repeated over and over, with little clouds of hope, all shown as a musical score. This anticipates Carson’s moves later in the book where she takes us even lower, then expands and elevates the cloud.


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The tree that owns itself?

Finley Street in Athens, Georgia, is partly blocked by a curved stone wall. Cars must slow and twist their way around the obstruction. As they do so, they pass under the branches of an aristocratic white oak tree: this plant is, they say, landed gentry. The oak owns the land on which it stands.

Such a tree deserves a high-five:

tree that owns itselfii

From the deed, first reported in the Athens Weekly Banner in 1890:

“I, W. H. Jackson, of the county of Clarke, of the one part, and the oak tree, (giving location) of the county of Clarke, of the other part: Witnesseth, That the said W. H. Jackson for and in consideration of the great affection which he bears said tree, and his great desire to see it protected has conveyed, and by these presents do convey unto the said oak tree entire possession of itself and of all land within eight feet of it on all sides.”

A great story, but no such deed was ever recorded in the Clarke County courthouse. Yet the story lived on and, therefore, so did the tree. Legal title is not the only way to avoid the ax, a catchy narrative will do the same. By 1906, the tree was protected behind decorative chain and granite posts. The posts were accompanied by a plaque, standing to this day, with a quote from the non-existent deed.


In 1942, a windstorm killed the oak, but the tree’s admirers — humans, not the oaks’ usual squirrel attendants — were prepared and had already gathered and germinated acorns. Today, the force shield of human story-telling still protects the tree’s offspring from development and road-straightening. Can stories be as powerful as legal paperwork?


The map from by the county tax assessor’s office shows a jog in the road, but no property lines. Does the tree pay taxes? I could find no record of the portion of the annual oak mast taken by local government. What might happen to revenue from an oak tax? Acorn-fattened hog is a southern delicacy: pork barrel spending?

tree owns itself tax map


Special thanks to Dorinda Dallmeyer and Claiborne Glover who took me to see the tree during my visit to Athens last week. My thanks also to the sponsors of my lecture at the University of Georgia: the Environmental Ethics Certificate Program, the Integrative Conservation Graduate Student Organization, and the Wilson Center for Humanities and Arts.


Athens-Clarke County Board of Tax Assessors & Appraisal Office.

E. M. Coulter, 1962, The Georgia Historical Quarterly 46: 237-249

Photo credits: D. Dallmeyer (palmed tree)




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Continental gyre of birds.

A paper published this week by scientists at the Cornell Lab of Ornithology uses eBird data to map the migratory paths of birds in the Western Hemisphere. eBird is a free online checklist program used by tens of thousands of bird watchers. The database now has millions of observations from across the world, most of them in North America. This latest study used 6.1 million eBird checklists to find the “center” of bird species’ ranges through the year. The summary below shows, for 118 species, how these centers move. Each point is one species, tracked through checklists over a year.

bird map

A pattern emerges: birds tend to “loop” clockwise, migrating north in the spring overland through Central America and Mexico, then flying south in the autumn over the Gulf of Mexico and the Atlantic. These loops are caused by prevailing winds, especially the northeast trade winds over the ocean. Turn, turn, turn: sung by the Byrds.

To my eye, deviations from the pattern are just as fascinating. Why do some species veer so far east? Why do some linger in the south, then zip north in a rush? A map with each dot labelled by species lets us peer into these mysteries.

To write honestly and with conviction anything about the migration of birds, one should oneself have migrated. Somehow or other we should dehumanize ourselves, feel the feel of feathers on our body and wind in our wings, and finally know what it is to leave abundance and safety and daylight and yield to a compelling instinct, age-old, seeming at the time quite devoid of reason and object.” — William Beebe


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De rerum…corpus individuum? On the nature of the periodic table.

Through the caprices of classroom scheduling, I find myself teaching a writing class in a seminar room usually devoted to the study of the grammar of electrons and the narratives of covalent bonds. My colleagues in the Chemistry Department have posted a periodic table on the wall at the front of the classroom. This arrangement is typical. You’ve likely sat in such a room. Science classrooms, especially lecture halls, often have the Table lifted in front of and above the pews, in the same location as the stained glass window or crucifix above a church’s high altar.

There is a message here that extends beyond the practical utility of having a convenient chart of the elements at hand. Behold, congregation: This is the nature of our Universe. Order exists beyond the confusion of form. And indeed, this is the nature of things (thank you, Lucretius), if we restrict our gaze (as we must when we teach any class) to one particular scale of our world (about 0.3 nanometers, atom size). But the Table’s lofty and lonely position — it is seldom accompanied by any other words or symbols — is also misleading. The world is ranged in rows and columns only in one very particular way. For a biologist or a subatomic physicist, other images are more appropriate. Years ago, when I taught Introductory Biology to a large lecture-hall of first-year students, I would lower the projection screen to veil the Table, replacing it with images of ecological communities or individual living creatures. My purpose was not to deny the power or utility of the atomistic view, still less to claim that the study of chemistry is not relevant to biology, but to reclaim visual space within our science classrooms for the messy beauty of life: unpredictable, diverse, braided.

From Darwin, at the close of The Origin (I quote from the first edition):

It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us…whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

Out of physical order, an unfolding process, one that cannot be contained within ruled lines.

In every classroom from whose walls the Table gazes, let us place an equally-sized artwork of the local community of life, humans included. A twin for what Whitman called “the figures…ranged in columns before me.” An entangled bank interpreted through art and science, the “endless forms most beautiful and most wonderful” of the human mind. That, or a classroom window.

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Gannets, tough heads, and offshore oil drilling.

On a beach on the Isle of Palms, South Carolina:

gannet wing

…an immature Northern Gannet, washed ashore after a sea burial. Cause of death unknown. This bird’s brown plumage identifies it as a first-year bird, hatched this spring. Adults are white (seen here in my visit to a gannet colony in Scotland); second- and third-year birds are white splashed with brown.

North America hosts only six breeding colonies, all in Canada (three in the Gulf of St. Lawrence and three in coastal Newfoundland). Adults and youngsters alike head to southern waters for the winter, feeding offshore before returning to their rocky breeding sites in April. Overwinter survival for adults is often higher than 90%, but young birds have a harder time.

Gannets are plunge-divers, folding their wings and arrowing into the water, head-first. They use the momentum of the dive to swoop into schools of fish. If they miss on the first strike, they oar the water with their wings as they twist through the water after prey. Their bodies are well adapted to this punchy way of getting lunch. Air pockets and strong shoulder bones cushion the body. The conical head and chest offer little resistance to the flow of water or air. A study of Cape gannets found that they pierced the ocean’s skin like needles, barely decelerating as they hit. The beak has no nostrils, just a tiny slit that closes tight when water pushes against it. Gannet eyes are directed forward in a binocular gaze, protected by a movable transparent membrane. One tenth of a second after immersion, gannet eye lenses compensate for the changed refraction of light and snap into underwater mode.

North American gannets comprise about one quarter of the world population. The rest breed in Northern Europe and winter off the coast of Africa. After many decades of over-hunting and disturbance, American colonies have lately been growing. Aerial surveys of nesting sites indicate a annual increase of 4.4% from 1984 to 2009. After the Deepwater Horizon disaster, though, some breeding populations dipped. After the spill, gannets were the third most common bird species recovered (dead, sick, or oiled) by rescuers. Because the explosion and spill happened in late April, most adult gannets had left the Gulf. Immature birds lingered and were caught.

Now, the Atlantic waters off the southeastern coast are slated to be opened for drilling, despite opposition from the many human residents of the coast whose interests coincide with those of seabirds.

Photo and bird-finding credits: Katie Lehman and Eva Miller.

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Beach stroll. “And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it.”

Dune grasses, mist. Isle of Palms, South Carolina.


A ten minute walk north, wave-bitten condos:


The ground floor: collapsed. Condos in the back of the building: still occupied, it seems.


Can sand bags and plastic pipes muzzle the chewing maw of the Atlantic? Now taking bets.


IMG1777IMG1771Just north of the foundering land-ship, the sea plays a few rounds on the golfing green and takes home some souvenirs:


On the eroding sand escarpments, plants trained by hundreds of thousands of years of beach life grasp their opportunity, then set seed and move on to the next shifting wave of sand. Here is Oenothera drummondii, Beach evening-primrose. The plant is in full bloom in December, as are other species on the island. A crazy-warm winter; the sea feels it too.


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Salamanders of early winter (guest post by Saunders Drukker)

I’m delighted to share this guest blog post written by Saunders Drukker. Saunders is an Ecology and Biodiversity major at Sewanee (Class of 2017). He’s been studying salamanders and other herps for years. I hope you’ll enjoy his observations and photographs.

As the days here in Sewanee start winding down toward winter, many nature lovers’ subjects begin to disappear. Birds make their way south, mammals start looking for places to hide until spring, and trees go dormant, leaving many of us struggling to find things worth searching for. Thankfully, as everything else goes away, one group begins their most active period of the year: salamanders. Each year in winter salamanders become active by the thousands, moving about the forest floor searching for places to breed.

One of the main groups active at this time year is the Ambystomatids or Mole Salamanders. These stout little amphibians spend much of their year hiding underground, but when the weather cools down and the rains start up they begin to move toward their ephemeral breeding ponds. One of the most striking and most active at this time is the Marbled Salamander, Ambystoma opacum.

Marbled Salamander

Marbled Salamander

These salamanders come out from their underground hideaways and move to the locations of ponds before these depressions fill with water. Here, the salamanders breed and lay eggs in the muddy bed of the pond, where they guard them until the rains come. Once the pond fills with water, the adults return to the forest. The eggs hatch, filling the pool with thousands of larval salamanders. By laying their eggs in the pond before all the other species arrive, the Marbled Salamanders give their young quite the advantage. By hatching earlier than all others, larval Marbled salamanders become large enough to prey upon the smaller larval Spotted Salamanders Ambystoma maculatum once they arrive in spring.

Three Ambystomatid Salamanders of Sewanee, Spotted, Marbled, and Mole Salamanders

Three Ambystomatid Salamanders of Sewanee, Spotted, Marbled, and Mole Salamanders

It is not just the mole salamanders moving this time of year, though. The cool wet weather is ideal for almost all species found here on the plateau, especially the lungless species that require cool, wet conditions to be active. These salamanders, as their name implies, do not respire by use of lungs, instead they take oxygen from the environment around them, using their permeable skin to transfer oxygen and carbon dioxide. Some of the most easily found genera in Sewanee are Plethodon, Pseudotriton, Eurycea, Aneides, Hemidactylum, and Desmognathus. 

Zig Zag Salamander (Plethodon dorsalis)

Zig Zag Salamander (Plethodon dorsalis)

Two Lined Salamander (Eurycea cirrigera)

Two Lined Salamander (Eurycea cirrigera)

Northern Slimy Salamander (Plethodon glutinous)

Northern Slimy Salamander (Plethodon glutinous)

Red Salamander (Pseudotriton ruber)

Red Salamander (Pseudotriton ruber)

Green Salamander (Aneides aeneus)

Green Salamander (Aneides aeneus)

Green Salamander (Aneides aeneus)

Green Salamander (Aneides aeneus)

Four-Toed Salamander (Hemidactylum scutatum)

Four-Toed Salamander (Hemidactylum scutatum)

Cumberland Dusky Salamander (Desmognathus abditus)

Cumberland Dusky Salamander (Desmognathus abditus)

Cave Salamander (Eurycea lucifuga)

Cave Salamander (Eurycea lucifuga)


On any rainy cold night large numbers of these salamanders can be found moving across the forest floor, or even across roads, so keep an eye out when you’re driving on backroads. Sewanee boasts a huge diversity of salamanders, and winter is by far the best time to go out looking for them.

All text and photographs on this post, copyright Saunders Drukker, 2015.

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Steven Vogel, an appreciation.

Steven Vogel, biologist and author, has died. Jim Gorman’s article in the New York Times gives us a glance at the man behind the books. Through Jim Gorman’s interviews we learn that Vogel’s generous enthusiasm and love of learning, so clearly expressed in his writing, were also evident in his relations with colleagues and students.

I remember picking up some of Vogel’s books as an undergraduate and seeing the living world for the first time through his eyes, the eyes of a biologist engineer. Life is made from substances with strange physical properties. We move through fluids whose frictions, flows, and viscosities not only differ from one medium to another, but change as living creatures speed up and slow down, grow or shrink. How do leaves move in the flow of air? How does a limb work with and against gravity and friction? How does the cell swim?

Vogel’s words showed the beauty that emerges through the play of life’s evolution against the world’s physical laws — a dynamic explored in a million ways by a million species — and shared it with those of us who are not engineers or bio-mechanics experts. What joy there is in understanding that the Bernoulli principle powers, in part, the airfoil of birds, the ventilation of termite mounds, and the feeding currents of marine sponges! Thank you, Steven.

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Turkey carving and muscle physiology. Prepare your dissection equipment, please.

Thanksgiving week promises many things, foremost among these delights are the physiology lessons offered by turkey carving.

The bird is presented to the world belly upward, as if in a dissecting dish. The carving knife scalpel slides through the skin, crossing feather tracts still visible as goose (really?) bumps, and cleaves a slice of pectoralis muscle. Who wants light meat? Then, after more blade-work, the femurs are dissociated from the pelvic girdle. Dark meat for anyone?

So many questions on one serving platter. Why the difference in color and taste? Are all birds this way? If we were to throttle then roast that insufferable Thanksgiving guest, would we have the same choice of meat cuts for our plates?

Turkeys are walkers. They fly only in short, plosive bursts. A startled turkey is a trebuchet of feathers. It twangs from the forest floor before smashing into the trees’ ramparts. The projectile moves fast — as much a forty miles per hour, I’m told — but has no staying power. Such bursts of power are delivered by “fast-twitch” muscle fibers that excel in anaerobic bursts, but then sag into exhaustion. Such muscles need relatively little oxygen and so their meat, when cooked, has none of the stain of blood or blood vessels.

Muscles in the legs are aerobic. They squeeze and pump all day without tiring. Such continual low-intensity activity requires “slow twitch” muscle fibers that are amply supplied with blood, capillaries, mitochondria, and oxygen-holding myoglobin. Under the knife: dark meat.

Turkeys are avian curiosities, though. Most other bird species use their wings for sustained flight and their legs for occasional strutting. In these species, therefore, the locations of dark and light meat are the reverse of the turkeys’ arrangement. A chickadee Thanksgiving would be instructive, although the meal would be short. From the roastlings’ chests we could carve slices of dark flight muscle, from the legs, the whiter meat.

As the breeders of industrial monstrosities know, most Americans prefer light meat to dark. By picking out the birds with the thickest and widest chest muscles, poultry scientists have bred varieties that by conforming to the desires of shoppers have lost the ability to grow to full adulthood without leg, lung, and wing problems. A pardoned turkey is not necessarily a lucky turkey.

And for that special Thanksgiving guest, the one whose boorishness or political rants add a spice of loathing to the table, remember that humans, too, have fast and slow twitch muscle fibers. Mostly, our muscles comprise a mix of the two, but the lower back and calf muscles are like turkey legs, always in use and so very dark. When the conversation reaches its nadir, such knowledge can provide a self-protective glaze of therapeutic imaginings.

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Creative writing assignments as glyphs

After my students turned in their latest assignment — a creative piece on “place” — I asked them to represent the form of their writing through a few wordless chalk marks on the board. They also summarized the main themes of content and form in a couple of sentences. This was improvised work: no preparation, go to the board and write.

The diversity of their subjects (what is “place”?) and the divergent ways in which they chose to represent the flow of their writing is intriguing and encouraging. I’m very pleased when I see a set of assignments that have emerged from the particularity of the students’ experiences, rather than from a template. Bring on the grading!

Click on any thumbnail image to scroll through examples of their work.

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