Tag Archives: art and science

Descent with Modification

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At this time last year, Fernbank Museum of Natural History was hosting the Darwin exhibit. On loan from the American Museum of Natural History, this exhibit was a major coup for the museum and the Atlanta area, which has enjoyed a growing culture of celebrating science during the past few years. Along with this exhibit, the museum also planned and concurrently displayed an evolution-themed art show, appropriately titled Selections, which I wrote about then here.*

Descent with Modification (2011), mixed media (colored pencils and ink) on paper, 24″ X 36.” Although this artwork might at first look like a tentacled creature infested with crustaceans and living on a sea bottom, its main form actually mimics a typical burrow system made by ten-legged crustaceans (decapods). Yet it’s also an evolutionary hypothesis. Intrigued? If so, please read on. If not, there are plenty of funny cat-themed Web sites that otherwise require your attention. (Artwork and photograph of the artwork by Anthony Martin.)

One unusual feature of this art show was that five of the eight artists were also scientists (full confession: I was one of them). Furthemore, one of the other artists was married to a scientist (fuller confession: that would be my wife Ruth). The show stayed up for more than three months, which was also as long as the Darwin exhibit resided at Fernbank. Thus we like to think it successfully exposed thousands of museum visitors to the concept that scientists, like many other humans, have artistic inspirations and abilities, neatly refuting the stereotype that not all of us are joyless, left-brained automatons and misanthropes.

Last week I was reminded of this anniversary and further connections between science and art during a campus visit last week by marine biologist and crustacean expert Joel Martin (no relation). Dr. Martin was invited to Emory University to give a public lecture with the provocative title God or Darwin? A Marine Biologist’s Take on the Compatibility of Faith and Evolution. His lecture was the first of several on campus this year about the intersections between matters of faith and science, the Nature of Knowledge Seminar Series. This series was organized as a direct response to the university inviting a commencement speaker this past May who held decidedly strong and publicly expressed anti-science views.

Dr. Martin, who is also an ordained elder in his Presbyterian church and has taught Sunday school to teenagers in his church for more than 20 years, gave an informative, organized, congenial, and otherwise well-delivered presentation to an audience of more than 200 students, staff, faculty, and other people from the Atlanta community. In his talk, Martin effectively explored the false “either-or” choice often presented to Americans who are challenged by those who unknowingly misunderstand or deliberately misrepresent evolutionary theory in favor of their beliefs. Much of what he mentioned, he said, is summarized in a book he wrote for teenagers and their parents, titled The Prism and the Rainbow: A Christian Explains Why Evolution is Not a Threat.

I purposefully won’t mention any of the labels that have been applied to the people and organizations who promote this divisiveness between evolutionary theory and faith. After all, words have power, especially when backed up by Internet search engines. Moreover, it is an old and tired subject, of which I grow weary discussing when there is so much more to learn from the natural world. Better to just say that Martin persuasively conveyed his personal wonder for the insights provided by evolutionary theory, how science informs and melds with his faith, and otherwise showed how science and faith are completely compatible with one another. You know, kind of like science and art.

Previous to his arrival, his host in the Department of Biology asked Emory science faculty via e-mail if any of us would like to have a one-on-one meeting with Dr. Martin during his time here. I leaped at the chance, and was lucky enough to secure a half-hour slot in his schedule. When he and I met in my office, we had an enjoyable chat on a wide range of topics, but mostly on our shared enthusiasm for the evolution of burrowing crustaceans, and particularly marine crustaceans.

Ophiomorpha nodosa, a burrow network in a Pleistocene limestone of San Salvador, Bahamas. In this instance, the burrows were probably made by callianassid shrimp, otherwise known as “ghost shrimp,” and are preserved in what was a sandy patch next to a once-thriving reef from 125,000 years ago. (Photograph by Anthony Martin.)

Interestingly, during this conversation we also touched on on how art and science work together, and I was pleasantly surprised to find out that Dr. Martin is a talented artist, too. It turns out he has illustrated many of his articles with exquisite line drawings of his beloved subjects, marine crustaceans. Yes, I realize that some artists like to draw a line (get it?) between being an “artist” and an “illustrator,” with the latter being held in some sort of disdain for merely “copying” what is seen in nature. If you’re one of those, sorry, I don’t have the time or inclination to argue about this with you. (Now go back to putting a red dot on a white canvas and leave us alone.)

Cover art of branchiopod Lepidurus packardi from California, drawn by Joel W. Martin, for An Updated Classification of the Recent Crustacea, also co-authored by Joel W. Martin and George E. Davis: No. 39, Science Series, Natural History Museum of Los Angeles County, Los Angeles, California.

During our discussion in my office, I pointed out a enlarged reproduction of a drawing of mine depicting the burrow complex of an Atlantic mud crab (Panopeus herbstii). He immediately recognized it as a crustacean burrow, for which I was glad, because it is an illustration of just that in my upcoming book, Life Traces of the Georgia Coast.

Burrow complex made by Atlantic mud crab (Panopeus herbstii), originally credited to a snapping shrimp (Alpheus heterochaelis). Scale = 5 cm (2 in). (Illustration by Anthony Martin, based on epoxy resin cast figured by Basan and Frey (1977).

After his campus visit, though, I realized that an even more appropriate artistic work to have shown him was the following one made for the Selections art exhibit last fall, titled Descent with Modification. This title in honor of the phrase used by Charles Darwin to describe the evolutionary process, but also is a play on words connecting to the evolution of burrowing crustaceans.

Descent with Modification again, but this time look at it as an evolutionary chart, where the burrow junctions in the burrow system reflect divergence points (nodes) from common ancestors. For example, from left to right, the ghost shrimp is more closely related to a mud shrimp, and both of these are more closely related to the ghost crab (middle) than they are to the lobster and freshwater crayfish (right). The main vertical burrow shaft represents their common ancestry from a “first decapod,” which may have been as far back as the Ordovician Period, about 450 million years ago.

The image shows five burrowing crustaceans, or to be more specific, ten-legged crustaceans called decapods. Along with these is a structure, which has a burrow entrance surrounded by a conical mound of excavated and pelleted sediment, a vertical shaft connecting to the main burrow network, and branching tunnels that lead to terminal chambers. A burrowing crustacean occupies each chamber, and these are, from left to right: a ghost shrimp (Callichirus major), a mud shrimp (Upogebia pusilla), a ghost crab (Ocypode quadrata), a marine lobster (Homarus gammarus), and a freshwater crayfish (Procambarus clarkii).

Here’s the cool part (or at least I think so): this burrow system also serves as an evolutionary chart – kind of a cladogram – depicting the ancestral relationships of these modern burrowing decapods. For example, lobsters and crayfish are more closely related to one another (share a more recent common ancestor) than lobsters are related to crabs. Mud shrimp are more closely related to crabs than ghost shrimp. Accordingly, the burrow junctions show where these decapod lineages diverged. So the title of the artwork is a double entendre with reference to Darwin’s phrase describing evolution as a process of “descent with modification,” along with burrowing decapods undergoing change through time as they descend in the sediment.

Modern decapod burrows and trace fossils of probable decapod burrows support both the science and the artwork, too. Here are a few examples to whet your ichnological and aesthetic appetites:

Thalassinoides, a trace fossil of horizontally oriented and branching burrow systems made by decapods in Early Cretaceous rocks (about 115 mya) of Victoria, Australia. In this case, these burrows were likely by freshwater decapods, such as crayfish, which had probably diverged from a common ancestor with marine lobsters more than 100 million years before then. Scale = 10 cm (4 in). (Photograph by Anthony Martin.)

Thalassinoides again, but this time in limestones formed originally in marine environments, from the Miocene of Argentina. Note the convergence in forms of the burrows with those of the freshwater crayfish ones in Australia. Think that might be related to some sort of evolutionary heritage? Scale = 15 cm (6 in). (Photograph by Anthony Martin.)

Horizontally oriented burrow junction of a modern ghost shrimp – probably made by a Carolina ghost shrimp (Callichirus major) – exposed along the shoreline of Sapelo Island, Georgia. Note the pelleted exterior, which is also visible on the burrow networks of the fossil ones in the Bahamas, pictured earlier. So if fossilized, this would be classified as the trace fossil Ophiomorpha nodosa. Scale in centimeters. (Photograph by Anthony Martin.)

Two ghost-shrimp burrow entrances on a beach of Sapelo Island, Georgia, with the one on the right showing evidence of its occupant expelling water from its burrow. No scale, but burrow mound on right is about 5 cm (2 in) wide. (Photograph by Anthony Martin.)

Burrow entrance and conical, pelleted mound made by a freshwater crayfish (probably a species of Procambarus) in the interior of Jekyll Island, Georgia. Scale = 1 cm (0.4 in). (Photograph by Anthony Martin.)

So the take-away message of all of these musings and visual depictions is that evolution, faith, science, art, trace fossils, modern burrows, and burrowing decapods can all co-exist and be celebrated, regardless of whether we sing Kumbaya or not. So let’s stop dividing one another, get out there, and learn.

*I’m also proud to say that my post from October 17, 2011, Georgia Life Traces as Art and Science, was nominated for possible inclusion in Open Laboratory 2013. Thank you!

Further Reading

Basan, P.B., and Frey, R.W. 1977. Actual-palaeontology and neoichnology of salt marshes near Sapelo Island, Georgia. In Crimes, T.P., and Harper, J.C. (editors), Trace Fossils 2. Liverpool, Seel House Press: 41-70.

Martin, A.J. In press. Life Traces of the Georgia Coast: Revealing the Unseen Lives of Plants and Animals. Indiana University Press, Bloomington, IN: 680 p.

Martin, A.J., Rich, T.H., Poore, G.C.B., Schultz, M.B., Austin, C.M., Kool, L., and Vickers-Rich, P. 2008. Fossil evidence from Australia for oldest known freshwater crayfish in Gondwana. Gondwana Research, 14: 287-296.

Martin, J.W. 2010. The Prism and the Rainbow: A Christian Explains Why Evolution is Not a Threat. Johns Hopkins University Press, Baltimore, MD: 192 p.

Martin, J.W., and Davis. G.E. 2001. An Updated Classification of the Recent Crustacea, No. 39, Science Series, Natural History Museum of Los Angeles County, Los Angeles, California: 132 p.

 

Life Traces as Cover Art

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I’ve been a long-time admirer of the artistic appeal of tracks, trails, burrows, nests, and other traces of animal behavior. My fondness for the beauty of traces also no doubt contributes to my science: after all, the longer I look at a trace, the more I learn about it. This sentiment accords with a long-time principle of paleontology, botany, and other facets of natural history, which is, “If you draw it, you know it,” with the added benefit of expressing your appreciation of natural objects to others through visual depictions.

Here it is: the cover for my upcoming book, Life Traces of the Georgia Coast: Revealing the Unseen Lives of Plants and Animals! The book is scheduled to be published by Indiana University Press in the fall of 2012, so be watching out for it then. But in the meantime, look at the beautiful cover art. Who created it, what inspired it, and what science lies behind its aesthetically pleasing composition? Please read on to find out.

My thinking about traces as objects of art is not very original, though, and in fact has been preceded by most of humanity. For example, animal tracks and other traces were common subjects of rock art extending back to the Pleistocene Epoch. Whether made as pictographs or petroglyphs, these traces of traces are in Australia, southern Africa, Australia, and Europe, with some tens of thousands of years old. Based on this tantalizing evidence, one could reasonably propose that the representation of animal traces through art composes an intrinsic part of our heritage as a species. Yes, I know, that’s a tough hypothesis to pursue any further. So I’ll leave it to my paleoanthropologist colleagues to work out (or not).

Petroglyphs that likely represent bird tracks, etched in Triassic sandstone by Native Americans hundreds of years ago (sorry, I’m a paleontologist, not an archaeologist). The pair of marks on the right is similar to the tracks made by a perching bird with three forward pointing toes and one rearward-pointing toe – such as an eagle – whereas those to the right may be like those of a roadrunner, which has an X-shaped foot. Petroglyphs are in northeastern Arizona, near Petrified Forest National Park.

Much more recently, trace fossils similarly inspired renowned ichnologist Dolf Seilacher, who also saw these vestiges of past behavior as lovely objects that fill us with wonder. As a result, in the mid-1990s, he conceived of a traveling exhibit and book showcasing tableaus of trace fossils and other sedimentary structures, titled Fossil Art. For this show – embraced by natural-history venues but mostly rejected by art museums – Seilacher prepared it by: (1) making latex molds of sedimentary rock surfaces; (2) pouring epoxy resin into the molds to make casts mimicking the original bedding planes; and (3) using indirect lighting to enhance details; and (4) assigning creative titles to each piece as if they were works of art.

So these artificial slabs are not human-made art in the traditional sense, but nonetheless invoke marvel, project splendor, and otherwise make us think, engaging the same senses and thought processes that accompany an appreciation of art. Moreover, the slim book Seilacher authored for the exhibit contains explanatory text about each of the objects, illuminated further by his marvelous illustrations and visual interpretations. I remember first seeing a version of this exhibit in Holzmaden, Germany in 1995, near Seilacher’s home in Tubingen, and most lately enjoyed strolling through it with other many ichnologists – and Seilacher himself – in Krakow, Poland in 2008.

World-renowned ichnologist and (oh yeah) Crafoord Prize winner, Dolf Seilacher, lecturing about the planning and execution of Fossil Art as an exhibit while it was showing at the Geological Museum of Jagiellonian University in Krakow, Poland in September 2008. Photograph by Anthony Martin.

A close-up of Wrong Sided Hands, one of the pieces displayed in Fossil Art, cast from a latex mold of a sample from Lower Triassic Buntsandstein of Germany. The piece is so-called because the false appearance of a “thumb” on the outside of the tracks originally led to the mistaken idea that the animal awkwardly crossed its own path with each step. This turned out to be wrong. Also, check out the mudcracks! Photograph by Anthony Martin.

Another close-up of a piece from Fossil Art, titled Shrimp Burrow Jungle (helpfully translated into Polish here). This one is based on burrow systems made by crustaceans during the Late Triassic in Italy, which became densely populated over time and hence contributed to overlapping systems. Photograph by Anthony Martin.

Hence during my writing of a book about the modern traces of the Georgia barrier islands, I was well aware of how some of these traces could likewise lend to artistic expression. Some of this mindfulness was applied to a collaborative artwork done with my wife, Ruth Schowalter, in which we took an illustration of mine from the book and used it as the inspiration for a large watercolor painting depicting traces that would form with rising sea level along the Georgia coast (discussed in detail here).

Nonetheless, it was especially important to think about traces as art when considering a potential cover for the book. Book authors know all too well that a well-designed, attractive cover is essential for grabbing the attention of a potential reader, so I had that practical consideration in mind. But I also wanted a cover that pleased me personally, sharing my love of beautiful traces with others, especially those varied and wondrous tracks, burrows, and trails I had seen and studied on the Georgia barrier islands during the past 15 years.

In such an endeavor, I also faced the added pressure of precedence set by my publisher, Indiana University Press. My book is part of a series by IU Press, called Life of the Past, which is widely admired not only for its comprehensive coverage of paleontological topics, but also for its fine cover art, showcasing works done by a veritable “who’s who” of “paleoartists,” So I knew the cover art for my book needed to both conform to this legacy of artistic excellence, but also stand out from other books in the series because of its unique themes. After all, this would be first book in Life of the Past focusing specifically on ichnology. Moreover, the book is more concerned on modern tracemakers and their environments, rather than plants and animals of pre-human worlds. This was done with the intention of demonstrating how our knowledge of modern traces helps us to better understand life from the geologic past, an intrinsic principle of geology called uniformitarianism.

Ideally, as an ichnological purist, I would have had a cover devoid of any animals, and just shown environments of the Georgia of the Georgia coast with their traces. Indeed, I did just that in some of my illustrations in the book, in which I purposefully omitted animals and left only their traces. This “ichno-centric” mindset actually serves a pedagogical purpose, in that it would echo the truism that many sedimentary rocks are devoid of body fossils, yet are teeming with trace fossils.

Figure 1.3 from Life Traces of the Georgia Coast, conveying a sense of the variety and abundance of traces on a typical Georgia barrier island, from maritime forest (left) to shallow intertidal (right). I purposefully drew this illustration using a more cartoonish technique to introduce broad search images of traces for people who may not ordinarily think about these. But also notice what’s missing from the figure: the animal tracemakers. Instead, only immobile plants are depicted. Would this make for good cover art? No and no, especially if you’ve seen the typical covers done for Indiana University Press books. Illustration by Anthony Martin.

Realistically, though, I also knew that modern traces, particularly those made in places as easy to visit as parts of the Georgia coast, would be more eye-catching if accompanied by some of their charismatic tracemakers in a beautiful, natural setting. After all, the Georgia coast has lengthy sandy beaches, dunes, maritime forests, and salt marshes, inhabited by a wide variety of animals, such as sea turtles, shorebirds, alligators, horseshoe crabs, ghost crabs, and many others.

I also knew that a paleoartist would not be as well suited to the task of creating a cover as someone who works more with modern environments. A better pick would be someone who was familiar with the landscapes, plants, and animals of the Georgia barrier islands, but also a fine artist. I briefly toyed with the idea of doing it myself, but already felt like far too much of the book had been “DIY,” and was not confident enough in my skills to put together a compelling cover in enough time before the book came together. An artfully done photograph was another possibility, so I sent several prospective examples to the editors for their appraisal, but these were all shot down for not having enough aesthetic elements for an attention-getting cover (i.e., traces + landscapes + sky + water = very difficult to get into a single photo).

Fortunately, through social connections that still happen despite the Internet and its incentives for becoming increasingly introverted, I met Alan Campbell through mutual friends in December 2008 at a dinner party on the Georgia coast. Fortuitously enough, our meeting was also just before Ruth and I did three weeks of field work on the barrier islands for the book. It was only fitting, then, that our first meeting was spent dining with both of us facing a Georgia salt marsh, filled with fiddler crab burrows and other such traces. Alan is a Georgia artist with much life experience along its coast, he has often portrayed its environments through gorgeous watercolors, and he has worked with scientists in the field.

Consequently, I kept Alan in mind as a potential cover artist for the next few years, and after I had finished the text and all figures for the book, I contacted him last year about my idea, while simultaneously suggesting him to the editors at IU Press. After much back-and-forth negotiations, with me in the middle, both parties finally came to an agreement, and Alan had a contract to do the artwork for the cover by December 2011.

To help Alan in researching his task, I sent him all of my illustrations and photos used in the book so that he would have an extensive library of trace images on hand for reference. He also had this blog as a source, in which I regularly write about Georgia-coast traces, explanations that are always accompanied by photographs and an occasional illustration. We also exchanged many e-mails and talked on the phone whenever needed. I told Alan my preferred cover would feature a coastal scene, but one filled with traces. He voiced a concern that the painting might become too “busy,” and the details might be lost in reduction of the image to the size

Alan’s contract specified that he would have preliminary study sketches would be done by February 1, and the final cover art was to be finished by March 30. He was only a little late with the study sketches (delayed by a minor operation), and I was delighted to see the following sketch in mid-February.

Study sketch by Alan Campbell for the cover of Life Traces of the Georgia Coast. Reprinted with his permission, and anyone else who want to use it, you have to ask him, too. By the way, every time you use original artwork without permission, a little kitten dies.

After a little bit of feedback from both me and graphic designers at IU Press, Alan went back to the drawing board (so to speak), and came up with the following watercolor painting.

Life Traces of the Georgia Coast, 2012, watercolor on paper, 14” X 18” by Alan Campbell. Again, if you want to use it, you have to ask him first and get permission. Remember those kittens? They’re alive now, but there’s no guarantee they’re going to stay that way.

I gave this artwork a big thumbs up, as did the people at IU Press. So once approved and the scan was sent to IU Press, it was up to the graphic designers there to pick out the typeface, color of the type for the main title, subtitle, author name, and placement of type without covering up the main composition of the painting. I had no say in this, and that’s a good thing, because they really knew what they were doing. It is a very nicely designed cover, and the only thing that would please me more is if they had produced a holographic image of it. (Maybe next year.)

The final cover art for Life Traces of the Georgia Coast revisited. Does it look a little different, now that you know more about how it came about?

I won’t spoil the fun for potential readers, scientists, and art appreciators by explaining in detail all of the ichnological, ecological, and geological elements incorporated into the cover. After all, I’d like to sell a few copies of the book, while also letting readers make their own personal discoveries. But hopefully all of you now have a better appreciation for how traces made by animals, our recognition and admiration for these, and artistic expression of them can all combine to contribute to a book that can be accurately judged by its cover.

Further Reading

Leigh, J., Kilgo, J., and Campbell, A. 2004. Ossabaw: Evocations of an Island. University of Georgia Press, Athens, Georgia.

Martin, A.J., in press. Life Traces of the Georgia Coast: Revealing the Unseen Lives of Plants and Animals. Indiana University Press, Bloomington, Indiana.

Morwood, M.J. 2002. Visions from the Past: The Archaeology of Australian Aboriginal Art. Allen & Unwin, Sydney, Australia.

Seilacher, A. 2008. Fossil Art: An Exhibition of the Geologisches Institut. Tubingen University, Tubingen, Germany.

Tomaselli, K.G. 2001. Rock art, the art of tracking, and cybertracking: Demystifying the “Bushmen” in the information age. Visual Anthropology, 14: 77-82.

 

Georgia Life Traces as Art and Science

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This past Friday evening (October 14), Fernbank Museum of Natural History in Atlanta, Georgia hosted the official opening of Selections, a visual-art show themed on evolution, especially as it relates to Charles Darwin. Many other art shows or other creative ventures have revolved around evolutionary themes, especially in 2009, which marked the 150th anniversary of On the Origin of Species and the 200th of Darwin’s birth. But two aspects of this display make it distinctive: (1) it was planned more than two years in advance to accompany the traveling exhibit Darwin, on loan at Fernbank from the American Museum of Natural History; and (2) five of the eight participating artists, all local to the Atlanta area, are also scientists.

Other than once again disproving the notion that artists and scientists live in divergent intellectual realms, once lamented by C.P. Snow in 1969 (for a few other examples of how this false dichotomy is becoming less and less defensible, look here, here, here, here, and here), I am pleased to share that my wife Ruth Schowalter and I are two of the artists in this show. Seven drawings and paintings of ours are on display, with three of those collaborative works, in which we freely mixed scientific concepts with our respective artistic expressions.

Here I will focus on just one of those works, a collaborative piece titled Abstractions of a Rising Sea (2011). My reason for taking a closer look at this one exclusively is because of its having been visually inspired by plant and animal traces of the Georgia barrier islands. Also, in keeping with a Darwinian theme, it depicts how changing environments – in this case, rising sea level – can likewise impact the survival of species, thus affecting the types of traces that are formed and preserved in a given place.

Abstractions of a Rising Sea (2011), by Ruth Schowalter and Anthony Martin: watercolor on paper, 66 X 101 cm (26” X 40”), on display at Fernbank Museum of Natural History until January 1, 2012. But this isn’t just abstract art: it’s also a scientific hypothesis. How so? Please read on. (Photograph taken by Anthony Martin.)

Although this painting may look abstract to most viewers, given its strange, funky shapes and patterns expressed with a colorful palette, its basic elements actually embody an evidence-based prediction. The artwork design, shown below, originated as a conceptual drawing I made for my upcoming book, Life Traces of the Georgia Coast; in fact, it will be the last illustration in the book. The drawing, which I later scanned and modified slightly with Adobe Photoshop™, portrays a vertical sequence of traces made by plants and animals on a typical Georgia shoreline, but considerably altered as sea level went up along that shoreline. In short, it reflects my prognosis of how a coastal dune will become inundated by the sea over the next few decades, with traces of marine animals succeeding those of terrestrial plants and animals.

The original illustration that inspired the artwork, which I drew to portray the sequence of traces that would be made in a given place on the Georgia coast as sea level goes up in the next few hundred years. (Illustration by Anthony Martin.)

So if you’ll bear with me for a few minutes, here’s a more detailed explanation. The traces at the bottom of the illustration represent those of a coastal dune, with plant-root traces, insect burrows, and sea-turtle nests. Just above, those traces are replaced by the burrows of ghost crabs, which are semi-terrestrial animals, but dependent on the sea. A typical Y-shaped burrow of a ghost crab (Ocypode quadrata), viewed in longitudinal section in the eroded face of a coastal dune on Sapelo Island, Georgia. This formerly open burrow was filled from above by sand of a slightly different composition, making it easier to spot. But also note that it cuts across the layering (bedding) of the dune, showing that the crab burrow is relatively younger than the dune deposit. (Photograph by Anthony Martin.)

Next are burrows made by marine invertebrates that live in the intertidal and shallow subtidal areas of a beach, such as polychaete worms, sea cucumbers, and acorn worms.

A variety of abandoned polychaete worm burrows, all washed out of their original places by a vigorous waves and tides and found along a beach on Sapelo Island, Georgia. Although each burrow is distinctive, what they share are behavioral adaptations to living in sandy environments dominated by the surf, shown by their reinforced walls. All four species of worms also orient their burrows vertically, which helps prevent too-frequent exhumation. (Photograph by Anthony Martin.)

Accompanying these is a snail shell (lower third, center) with a drillhole, a cannibalism trace made when a moon snail preyed on its own kind.

Drillhole in the shell of a common moon snail (Neverita duplicata) caused by another moon snail, a trace of both predation and cannibalism: Sapelo Island, Georgia (Photograph by Anthony Martin.)

A broken clam shell to the right of the snail is a likewise a predation trace, but attributable to a seagull. (The bird flew up with the clam in its beak, dropped it onto a hard-packed beach sand at low tide, and dined on its freshly killed contents.)

Broken shell of the giant Atlantic cockle (Dinocardium robustum), caused by a sea gull that picked it up, flew with it, and dropped it onto a sandflat at low tide on Sapelo Island, Georgia. Scale in centimeters. (Photograph by Anthony Martin.)

The upper half of the figure is then dominated by traces of marine invertebrates that live fully submerged offshore, such as ghost shrimp and other crustaceans, other polychaete worms, sea urchins, and brittle stars.

Labeled version of the illustration, depicting an overall progression from onshore traces (bottom) to offshore traces (above). If this sequence of sand and mud were to fossilize, this is how paleontologists and geologists would interpret it. (Illustration by Anthony Martin.)

The preceding artistic-scientific deconstruction should also help a viewer to better understand how geologists think when they look at a vertical sequence of sedimentary rock. For example, geologists follow several basic principles when trying to figure out the relative timing of different events in the geologic past.

One of these is called superposition, in which the effects of the oldest (first occurring) event in a given sequence of sedimentary rock are at the bottom, and the effects of subsequent events are recorded in progressively younger rocks toward the top.

The second principle is cross-cutting relationships, in that whatever is cutting across a previously existing structure must be younger than it. Think about how an animal burrow may cut across burrows made by previous generations of animals, and how you could unravel the sequence of “burrowing events” by simply observing which intersects which burrow.

A third principle is Walther’s Law, named after German geologist Johannes Walther (1960-1937) which states (more-or-less) that laterally adjacent environments succeed one another vertically. In other words, where a maritime forest and coastal dune are next to one another today on the Georgia coast, a drop in sea level means that coastal dunes might by succeeded vertically by the forest. Conversely, sea level going up implies that sediments of offshore environments, which are currently next to the beach and dunes, will some day overlie those of the dune.

Hence the illustration shows all three principles at play with a rising sea. For example, ghost-crab burrows cut across a sea-turtle nest from above, vertical burrows of a polychaete worm in turn dissect ghost-crab burrows below them, and a ghost-shrimp burrow from above interrupts one limb of a U-shaped acorn-worm burrow. Even better, a trained ichnologist can look at this sequence of traces and discern the environmental change that happened over the time represented by the sediments.

You can test this supposition by showing the illustration to other ichnologists, and I predict they will say, “Looks like sea level went up.” As a result, seemingly abstract patterns can become meaningful as we apply these images within the context of time passing, a concept we think Darwin – as a geologist and biologist – would have appreciated.

When I first showed this illustration to Ruth, she was quite taken by its forms and compositions, and she imagined what it would look like made much larger and in color. So we got to work on it, purposefully choosing a large piece of watercolor paper, onto which I drew the ichnological design. She then composed the color scheme, using a combination of water-color pencils and brushes, and I painted in a few details here and there, but most of the hard work was hers.

Ruth and my artistic styles are quite different – she’s a visionary artist, whereas I’m a more of a surrealist – but we both agree that meaningful art should provoke thought. So we very much like how this artwork also addresses and combines two contentious issues in American society: evolutionary theory and global-climate change. In Georgia, as in many other places in the U.S., scientists and science-educators still encounter resistance to the teaching of evolution, despite its extensive testing during the past 150 years and its consequent acceptance by virtually all scientists worldwide. Likewise, in recent years, so-called “global-warming deniers” have put much effort into rebuffing, ignoring, or otherwise downplaying the effects of human-caused climate change – despite near-universal scientific consensus – resulting in the twisting of scientists’ words or outright censorship.

For the plants, animals, and people who live on the Georgia coast, politically charged arguments become pointless as the shoreline moves up and over the land. As global climate continues to change and sea level goes up along the Georgia coast, how will life respond to these changes, especially if the sea rises faster than most organisms can adapt? This is a question we could have put to Charles Darwin, and one we attempt to pose through this synthesis of art and science.

(Acknowledgements to my wife and art-science collaborator, Ruth Schowalter, for her invaluable input on this post: thank you! Selections, featuring the artwork discussed here as well as others by us and six other artists, will be showing at Fernbank Museum of Natural History in Atlanta, Georgia until January 1, 2012. Admission to the museum includes viewing of the artwork, permanent exhibits, and the Darwin exhibit.)

Further Reading

Pilkey, O.H., and Fraser, M.E., 2005. A Celebration of the World’s Barrier Islands. Columbia University Press, New York: 400 p.

Purcell, W.S., and Gould, S.J., 2000. Crossing Over: Where Art and Science Meet. Three Rivers Press, New York: 159 p.

Trusler, P., Vickers-Rich, P., and Rich, T.H., 2010. The Artist and the Scientists: Bringing Prehistory to Life. Cambridge University Press, Cambridge, U.K.: 320 p.