Re-Defining the E-Word

What does the word “evolution” mean?

In last week’s post on this blog, I argued (as have a number of others before me) that the “e-word” should be expanded beyond biological evolution to include no less than the “history of the universe.” In this more comprehensive sense, evolution is able to capture in a single word the unified story of the cosmos, life, and culture. In response to this post, one of the comments I received came from Kenneth (last name not included), who argued that evolution should be restricted to biological evolution. In his words,

"So much of the refusal to accept evolution (in this country at least, the US) comes from those who think evolution explains the origin of life. It, of course, does not and has nothing to do with abiogenesis. But presenting the origin of the cosmos as "the epic of evolution" is just going to further that divide. We need to teach about the Big Bang, stellar birth and refinement, how planets form, the Miller-Urey experiment's results, and evolution and natural selection. But we can't put them all in the same basket since they're not actually related (and saying that non-reproducing things "evolve" is adding gasoline to the fire, too).

Kenneth raises a critical issue, and I thank him sincerely for taking the time to articulate it. Because “evolution” has become such a loaded word in the United States (and a number of other countries), I have thought long and hard about whether or not to expand the word to refer to the history of the universe. After all, I reasoned, people might reject the Great Story out of hand, effectively tossing out the baby with the bathwater because of a bias against anything evolutionary. Eventually, however, I came to think that the two truly deserve--even need--to be linked. Not only is the teaching of biological evolution a critical endeavor worthy of our energies—so too is the teaching of the Great Story. And I’m convinced that this pair of ideas can be mutually reinforcing. I devote today’s post to a brief outline of my position.

Ultimately, of course, how we decide to define the word “evolution” is a matter of semantics, and words can have multiple meanings. For example, at Dictionary.com, the biological definition of evolution is, “change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift.” However, nine other definitions are also listed, including one that applies to the history of the universe: “any process of formation or growth; development.” So the question is this: Do we elucidate or muddy our understanding of nature if we refer to the Great Story of everything as the “epic of evolution”?

Kenneth contends that the expanded version of the word gives ammunition to those who conflate the process of (biological) evolution with the origin of life, suggesting that evolution has nothing to do with life’s beginnings. I would disagree with at least the latter half of this claim. Recent work by origin of life researchers have revealed remarkable continuities between geochemistry and biochemistry, between the living and nonliving worlds (1). My strong hunch—likely bolstered by the announcement this week of the first synthetic life (2)— is that resolution of the origin of life problem, one of the greatest mysteries in science, will reveal blurry boundaries between the animate and inanimate, akin to what we see between major groups of biological ancestors and descendents (e.g., theropod dinosaurs and birds).

On a larger scale, I think that using evolution to describe the Great Story serves at least two important purposes. First, it underlines the fact that the evolution of life (and humans in particular) is not separate from the rest of nature. Rather, life’s origin and expansion is merely one of the latest examples of increasing complexity within a single, unified, and stunningly creative whole. By treating biological evolution as an entirely distinct process, we tend to construct a false dichotomy and ignore the many similarities between organic and inorganic transformations.

For example, although increasing diversification has been a major trend in both cosmic and biological evolution, another frequently overlooked propensity is toward unification. As I described in a previous post, “The numerous and dramatic increases in complexity, it turns out, have been achieved largely through a process of integration, with smaller wholes becoming parts of larger wholes. Again and again we see the progressive development of multi-part individuals from simpler forms. Thus, for example, atoms become integrated into molecules, molecules into cells, and cells into organisms. At each higher, emergent stage, older forms are enveloped and incorporated into newer forms, with the end result being a nested, multilevel hierarchy.” Indeed a strong argument can be made that the major steps in complexification over the past 14 billion years have been achieved large through unifying rather than diversifying (3).

A Darwinian sense of evolution has also helped to inform ideas about evolution in the nonliving realm. Perhaps the most surprising case in point is Lee Smolin’s cosmological natural selection theory (4,5). Smolin, a theoretical physicist, has suggested that the rules of biology apply on the scale of the cosmos. Specifically, the eventual collapse of a black hole may result in the creation of another universe on “the other side.” If so, each universe generates as many universes as it does black holes, the equivalent of reproduction. Due to a number of physical constraints, the majority of these universes may undergo “heat death” before they can generate stars and black holes; that is, they die off before reproducing. If so, there would be a kind of natural selection favoring the formation of universes of that could successfully spawn new universes!

The second important reason I advocate use of the e-word to describe the Great Story is that it increases the scope of the challenge facing those who oppose the notion of organic evolution. That is, opponents of evolution, especially young Earth creationists who argue that the universe is a mere 6,000 years old, must contend not only with the Everest of evidence supporting biological evolution, but also with the equally abundant evidence in favor of cosmological evolution (the origins of the universe, galaxy, solar system, etc.) and cultural evolution (e.g., evidence of tool use within the hominid lineage). Anti-evolutionists typically search for supposedly “fatal flaws” (e.g., structures showing “irreducible complexity”) that might indicate the work of a “Designer.” But there will always be things in science that cannot be fully explained (at least not yet), and overthrowing the notion of evolution requires that one upturn the entire mountain rather than a few grains of sand. Explicitly linking the evolution of life with the evolution of the non-living universe greatly increases the size of that mountain.

Finally, much of my confidence in promoting an expanded definition of evolution comes from such luminaries as biologist E. O. Wilson (6), who made this argument long before I did. I recently received additional assurance when I ran into my friend Eugenie Scott, Executive Director for the National Center for Science Education (NCSE; the leading organization promoting). Arguably more than anyone else in the country, Genie and the NCSE are on the frontlines fighting to keep the teaching of biological evolution in the science classroom (and creationism out). When I asked for her view on the matter, Genie responded in wholehearted agreement with me, adding that she too defines evolution as “the history of the universe.”

So let’s feel free to refer to our cosmic story as “the epic of evolution,” and then recognize biological evolution as a subset of this grand narrative (7). At present, the general public is effectively illiterate with regard to both, a dire situation that, as argued last week, deserves immediate and widespread attention.

References and Suggested Sources
1) To give just one example, check out a terrific talk by one of these workers, Eric Smith (http://fora.tv/2007/04/18/Inevitable_Life).

2) Wade, N. Researchers say the created a “Synthetic Cell.” New York Times, May 20, 2010. (http://www.nytimes.com/2010/05/21/science/21cell.html).

3) Margulis, L. 1998. Symbiotic Planet: A New Look at Evolution. Sciencewriters, Amherst.

4) Smolin, L. 1997. Life of the Cosmos. Oxford University Press, Oxford.

5) Lee Smolin Wikipedia entry: http://en.wikipedia.org/wiki/Lee_Smolin

6) Wilson, Edward O. 1978. On Human Nature. Cambridge, Mass.: Harvard Univ. Press. Pp. 206-207.

7) For additional reading on this topic, I recommend:
- Cosmic Evolution Wikipedia page: http://en.wikipedia.org/wiki/Cosmic_evolution

- Epic of Evolution website: http://epicofevolution.com/celebrate.html

- Chaisson, E. 2006. Epic of Evolution: Seven Ages of the Cosmos

Images
All images courtesy of National Geographic: http://photography.nationalgeographic.com/photography/

The Great Story

Do you know your origin story—the evolutionary account of your roots and those of everything else? If you’re like most people in Western societies, your honest answer is no. And that, it turns out, is a BIG problem.

What’s the problem with being story-less? We’re in the midst of a gargantuan sustainability crisis, the greatest challenge ever faced by humanity. The vast majority of scientific experts, from ecologists to climatologists, are in full agreement that we are currently on a collision course with ruin, involving human suffering and devastation to the biosphere on an almost unimaginable scale. Finding and following a new, more sustainable path will require much more than new technologies. Any solution demands no less than a novel way of seeing the world, one that gives our lives greater meaning and causes us to take action to protect and nurture our native places. In other words, we must foster a new worldview that roots humanity in both local places and deep time—exactly the kind of thing that origin stories do best.

Fortunately, an astonishing, awe-inspiring, and staggeringly beautiful story of our origins is now readily available, one with the potential to unite humanity at this critical juncture in our history. Variously called the Great Story, the Universe Story, the New Story, or the Epic of Evolution, this grand narrative is founded on several centuries of scientific inquiry [1,2]. Evolution isn’t just Darwin, natural selection, and mutation. Evolution is the history of the universe, from the Big Bang to the present day. And far from leading to a view that the universe is random and meaningless, as commonly conceived, this saga provides the foundation for seeing ourselves as deeply embedded within the fabric of a creative cosmos.

Indeed the Great Story is arguably the greatest contribution of science, offering a direct glimpse into where we come from and what it means. More than three decades ago, famed biologist E. O. Wilson [3] stated that, “the evolutionary epic is probably the best myth we will ever have.” He added that this same story, “retold as poetry, is as intrinsically ennobling as any religious epic.” In the intervening decades, fields like cosmology, geology, paleontology, and archaeology have greatly augmented this saga, generating for the first time a unified, evidence-based narrative encompassing the cosmos, life, and culture.

Over that same time period, a number of people, in particular the late “geologian” Thomas Berry [1], have argued strongly for the importance of a general understanding of this unified epic. Yet the Great Story has remained virtually absent from all arenas of education. Today, few of us can convey anything of this story beyond perhaps an incomplete sequence of origins—for example, galaxy, Earth, bacteria, worm, fish, amphibian, mammal, upright primate, Homo sapiens—with humans generally placed atop the pile as the “king of the world” (if not king of the universe). It is ironic that we who have access to the most rigorous and complete story of everything do not use it to inform the arc of our lives.

I agree wholeheartedly with Thomas Berry that the Great Story, expanded beyond biology to encompass cosmos and culture, deserves to reside at the very core of the education curriculum. This astounding epic deserves to be told and retold, with appropriate increases in complexity, from childhood through adulthood. Education is currently focused almost entirely on the present day, with the unspoken assumption that everything that came before is meaningless and irrelevant. Yet meaning, purpose, and belonging have less to do with where we are at any given moment than where we’ve been and where we’re going. So, in addition to the horizontal perspective offered by understanding the present day world, education must convey the vertical context that roots us in deep time. Humanity must reinvent the sacred [4] and learn to see that everything around us has its origins in deep time stardust.

But isn’t the Epic of Evolution incompatible with the beliefs of major religious traditions? So it might seem, given ongoing media coverage of this conflict. It’s true that, despite resounding acceptance by the scientific community, biological evolution remains a hotly debated topic within the general public, particularly in the United States. About one half of all Americans currently support the statement that “God created humans pretty much in their present form at one time within the last 10,000 years.” And many scientists, educators, and parents, responding to attempts by Christian fundamentalists to discredit Darwin and re-inspire a dominant role for a Creator throughout the history of life, have been fighting to keep evolution in America’s classrooms.

So embittered is this conflict that rarely is much thought given to why evolution education is important. Scientists and educators often state that learning the fundamentals of evolution is necessary because this idea is central to biology, or because evolutionary concepts underlie hot button topics like genetics. Such arguments miss a fundamental point. Teaching evolution is critical because the underlying concept of transformation is the very glue that holds together the epic of cosmos, life, and culture. And understanding this story could change the world by shifting the human conception of nature.

Ultimately, I can’t envision the necessary shift in worldview occurring (at least not in the brief time allotted to us) in the absence of a dialogue between the science and religion communities [4-6]. Fortunately, attitudes toward evolution, within and outside of religious circles, are far more nuanced than generally believed and great potential exists to integrate the Great Story with traditional theist views [6]. Spiritual leaders as diverse as the Pope and the Dalai Lama have advocated acceptance of evolution (though, granted, sometimes with caveats pertaining to human origins). Theologian John Haught [7] declared that, “Darwin has gifted us with an account of life whose depth, beauty and pathos—when seen in the context of the larger cosmic Epic of Evolution—exposes us afresh to the raw reality of the sacred and to a resoundingly meaningful universe.” Michael Dowd, minister and author of Thank God for Evolution [5], has adopted the role of “evolutionary evangelist,” preaching the Great Story to church congregations throughout North America.

“The universe is made of stories, not atoms.” So said poet Muriel Rukeyser, underlining the power of narrative. Why does the Great Story merit a central place in our culture? Because this grand epic represents our best understanding of the evolving universe; because internalizing the idea of common ancestry through deep time will help us reconnect with nonhuman nature; and because disseminating this story widely may well be critical to shifting worldviews and achieving sustainability. Only when the Great Story is finally expressed throughout our culture—not just in science, but in poetry, song, fine arts, and dance—will we begin to truly understand what it means to be part of a single, evolving universe at this pivotal moment in deep time. Only then will we begin to conceive of nature as relatives deserving of our compassion and empathy rather than resources for our exploitation. We need a story.

References
1) Berry, T. 1999. The Great Work: Our Way into the Future. Bell Tower, New York.
2) Swimme, B. and T. Berry. 1992. The Universe Story: From the Primordial Flaring Forth to Ecozoic Era. Harper Collins, New York.
3) Wilson, Edward O. 1978. On Human Nature. Cambridge, Mass.: Harvard Univ. Press. Pp. 206-207.
4) Kauffman, S. A. 2008. Reinventing the Sacred: A New View of Science, Reason, and Religion. Basic Books, New York, 320 pp.
5) Dowd, M. 2005. Thank God for Evolution. Council Oak Books, San Francisco.
6) Phipps, C. 2007. The REAL Evolution Debate. EnlightenNext Magazine. http://www.enlightennext.org/magazine/j35/real-evolution-debate.asp
7) Haught, J. F. 2008. God After Darwin: A Theology of Evolution. Westview Press (quote: p. 2).

Images
Top image courtesy ofSky Image Labe: http://www.skyimagelab.com/
All other images courtesy of National Geographic: http://photography.nationalgeographic.com/photography/

Dinosaurs of the Lost Continent

In my last post, I addressed the hypothesis of dinosaur provincialism—that is, isolated communities of giant dinosaurs—on North America during the Late Cretaceous. Specifically, I discussed a recent paper by Vavrek and Larsson (1), who concluded on the basis of a rigorous statistical analysis that Maastrichtian dinosaurs (i.e., those living in the final 6 million years of the Mesozoic immediately prior to the K-T extinction) were not split into isolated provinces, as argued previously, but rather formed a single community. I cautiously agreed with their findings and noted a few caveats. For example, their study was restricted geographically—limited to the four most dinosaur-rich geologic units in the northern part of the Western Interior—leaving plenty of terrain for possible dinosaur provinces elsewhere.

Today I want to focus on another of my caveats: dinosaur provincialism in the preceding Campanian Stage (83.5 – 70.6 million years ago). If your goal is to understand large scale patterns and processes in the Mesozoic world of dinosaurs, the best place and time to look for answers is Campanian-aged rocks from the Western Interior on North America. Period. Nowhere else on Earth do we have continent-scale sampling of fossiliferous formations from the Mesozoic that have been intensively worked for more than a century. Literally dozens of different kinds of dinosaurs, many of them exceptionally preserved, have been recovered from as far north as Alaska and as far south as Mexico. And the great bulk of these occur in a 2 million year window of time, between about 77 and 75 million years ago.

The importance of this particular slice of Mesozoic time and space is heightened by the geographic context of the fossils. The Mesozoic was a hothouse world virtually devoid of polar ice caps. As a result, sea levels tended to be much higher than they are today, often flooding low-lying regions of continents with shallow seas. In North America, the Cretaceous Western Interior Seaway, extended from the Arctic Ocean in the north to the Gulf of Mexico in the south. For almost 30 million years (~95-67 million years ago), this so-called “epeiric” sea subdivided the continent into eastern and western landmasses, known as Appalachia and Laramidia, respectively. We know little of the dinosaurs of Appalachia, but geologic activity in the west has exposed an abundance of Campanian rocks along the eastern margin of the “lost continent” of Laramidia. Key geologic units that have yielded dinosaurs include the Dinosaur Park Formation of Alberta, the Two Medicine and Judith River formations of Montana, the Kaiparowits Formation of Utah, the Kirtland and Fruitland formations of New Mexico, and the Aguja Formation of Texas.

Campanian Laramidia was home to arguably the greatest known fluorescence of dinosaurs, and the emerging diversity patterns are stunning. On the one hand, wherever we look, the same groups of dinosaurs tend to show up. Bird-hipped herbivores include horned dinosaurs (ceratopsids), duck-billed dinosaurs (hadrosaurs), smaller ornithopod dinosaurs (hypsilophodonts), armored ankylosaurs (nodosaurids and ankylosaurids), and dome-headed dinosaurs (pachycephalosaurs). Lizard-hipped theropods are also very diverse, including ostrich-like ornithomimids, beaked oviraptorosaurs, and sickle-clawed dromaeosaurs and troodonts, with giant tyrannosaurs invariably filling the role of top predator. (Although poorly known, a great diversity of smaller-bodied theropods, such as feathered microraptorines and birds were almost certainly present.) On the other hand, the species-level representatives of these groups appear to be limited to small ranges. In particular, as first argued by Dale Russell (2), and later by Thomas Lehman (3), we find different genera and species in the north (Alberta and Montana) than we do in the south (Utah, New Mexico, and Texas). So, for example, Chasmosaurus is a horned dinosaur known only from the north, whereas Pentaceratops is limited to the south. Similarly, some species of Gryposaurus are known only from the north, whereas at least one species is restricted to the south.

Until recently, a relative dearth of identifiable dinosaurs from southern Laramidia made it difficult to test the provincialism hypothesis. This “southern gap” has now been partially remedied by a decade of fieldwork in the Kaiparowits Formation, abundantly exposed in Grand Staircase-Escalante National Monument, southern Utah. Working in close collaboration with the Bureau of Land Management, our interdisciplinary team—based out of the University of Utah, but including researchers from multiple institutions—has unearthed an entirely “new” assemblage of dinosaurs in the Kaiparowits,16 different dinosaur varieties so far, 11 of which can now be identified to the level of species (4). Several of these animals are represented by exceptionally preserved skulls and partial skeletons, often with skin impressions. Some of these species have been named and described, including the oviraptorosaur Hagryphus giganteus (5) and the hadrosaur Gryposaurus monumentensis (6). Other studies are nearing completion or well under way. I am happy to say that the discoveries keep on coming; the most recent field season yielded a plethora of amazing finds from a single quarry. First to be found was a hadrosaur about the size of T.rex; excavation of this specimen, which includes a nearly complete skull, yielded one skull and skeleton of a crocodilian and another of a turtle, as well as an ankylosaur with what appears to be an intact skull, and a possible pterosaur! All this from a single (albeit very large) site.

Remarkably, of the dozens of dinosaur species now identified from the Campanian of Laramidia, none can be confidently placed in both the north and the south—strong support for the notion of dinosaur provincialism. Sullivan and Lucas (7) argued previously that this provincialism is illusory, the result of animals arrayed in time rather than space. But recent advances in both the number and precision of radiometric dates (8) conclusively demonstrate temporal overlap of key formations (e.g., Dinosaur Park and Kaiparowits), as well as species belonging to particular groups (e.g., horned dinosaurs, hadrosaurs, and tyrannosaurs). A recent faunal review and statistical analysis by our working group (9) supports earlier claims from Lehman, showing that the late Campanian provincialism extends well beyond dinosaurs to encompass a variety of vertebrates.

These findings have profound implications for our understanding of dinosaur ecology and evolution. The “island continent” of Laramidia was less than 20% the size of present day North America. Much of this landmass was covered with rising mountain ranges (primarily the Cordilleran Overthrust Belt, but perhaps the Laramide orogeny as well), sandwiching known Laramidian dinosaurs between a restless seaway to east and rising mountains to the west. So it’s remarkable to contemplate the notion of one diverse assemblage of dinosaurs—many with body masses in the rhino-to-elephant range—let alone multiple assemblages of such animals. To add insult to injury, some of these dinosaurs, especially among the hadrosaurs and ceratopsids, appear to have lived in large herds numbering at least in the hundreds of animals. How could so many giants make a living and persist over geologic time spans on such a diminutive landmass. Likely answers involve greater volumes of available plant food (primary productivity) and/or decreased dietary needs relative to modern-day warm-blooded mammals.

Given that most northern and southern dinosaur species within a given group appear closely similar, differing primarily in features associated with reproductive success (horns, frills, crests, etc.), they may well have played similar ecological roles. For example, the long-frilled horned dinosaurs (chasmosaurines) in the north and south, although distinct species, may well have consumed very similar kinds of plants. If so, the ecological niches filled by dinosaurs might have changed very little for millions of years during the Late Cretaceous. Behind this apparent ecological stasis, however, a variety of factors—perhaps including seaway migrations and other environmental changes—appear to have resulted in rapid evolutionary turnover of species (10). Like a long-running Broadway show, the players changed while the same story played out endlessly.

We have only begun to plumb the depths of knowledge relating to Laramidian dinosaurs. And we can count on many surprises to come. I will use this blog as an outlet to update readers on new discoveries as they are announced.

References
1) Vavrek, M. J. and Larsson, H.C. E. 2010. Low beta diversity of Maastrichtian dinosaurs of North America. Proceedings of the National Academy of Sciences,
2) Russell, D. A. 1967. A census of dinosaur specimens collected in western Canada, National Museum of Canada Natural History Papers, 36:1-13.
3) Lehman, T. M. 1997. Late Campanian dinosaur biogeography in the western interior of North America. Dinofest International Symposium Volume, pp. 223-24.
4) Sampson, S. D., Gates, T. A., Roberts, E. M., Getty, M. A., Zanno, L. E., Loewen, M. A., Smith, J. A., Lund, E. K., Sertich, J., and Titus, A. L. in press. Grand Staircase-Escalante National Monument: A new and critical window into the world of dinosaurs. Learning from the Land Symposium Symposium Proceedings.
5) Zanno, L. E. and Sampson, S. D. 2005. A new oviraptorosaur (Theropoda: Maniraptora) from the late Campanian of Utah and the status of the North American Oviraptorosauria. Journal of Vertebrate Paleontology, 25(4): 897-904.
6) Gates, T. A. and Sampson, S. D. 2007. A new species of Gryposaurus (Dinosauria: Hadrosauridae) from the Upper Campanian Kaiparowits Formation of Utah. Zoological Journal of the Linnean Society, 151:351-376.
7) Sullivan, R. M. & Lucas, S. G. 2006. The Kirtlandian land-vertebrate "age" – faunal composition, temporal position and biostratigraphic correlation in the nonmarine Upper Cretaceous of western North America. New Mexico Museum of Natural History Science Bulletin 35, 7-29.
8) Roberts, E.M., Deino, A.D., and Chan, M.A. 2005a. 40Ar/39Ar age of the Kaiparowits Formation, southern Utah, and correlation of coeval strata and faunas along the margin of the Western Interior Basin: Cretaceous Research, 26:307-318.
9) Gates, T.A., Sampson, S.D., Zanno, L.E., Roberts, E.M., Eaton, J.G., Nydam, R.L., Hutchison, J.H., Smith, J.A., Loewen, M.A., and Getty, M.A. in press. Biogeography of terrestrial and freshwater vertebrates from the Late Cretaceous (Campanian) Western Interior of North America: new information from the Kaiparowits Formation, south-central Utah. Palaeogeography, Palaeoclimatology, Palaeoecology.
10) Sampson, S. D. 2009. Dinosaur Odyssey: Fossil Threads in the Web of Life. University of California Press), 332 pp.
(Note: One of the book's chapters is dedicated to the story of Laramidian dinosaurs.)

Images (from top to bottom)
1) Late Cretaceous (Campanian) North America, showing the Cretaceous Western Interior Seaway subdividing North America into Laramidia (western landmass) and Appalachia (eastern landmass). Image credit: Ron Blakey http://jan.ucc.nau.edu/~rcb7/
2) The Kaiparowits Formation, Grand Staircase-Escalante National Monument, southern Utah. Image credit: Rebecca Hunt-Foster.
3) Reconstruction of the oviraptorosaur Hagryphus giganteus. Image credit: Michael Skrepnick.
4) The skull of Gryposaurus monumentensis, a new duck-billed dinosaur from the Kaiparowits Formation.
5) The skull of an unnamed horned dinosaur from the Kaiparowits Formation.

Provincial Dinosaurs

This week, a pair of authors from McGill University, Matthew Vavrek and Hans Larsson, published a paper in the prestigious Proceedings of the National Academy of Sciences in which they argued that dinosaurs living in North America during the last few million years of the Cretaceous Period were not divided up into distinct, geographically separated communities, or “provinces” (1). These authors plumbed a large storehouse of paleo data known as the Paleobiology Database in order to collect information about which kinds of North American dinosaurs lived in different locales during the Maastrichtian stage, spanning almost 6 million years (~71.3 - 65.5 million years ago). Among the varieties examined were Tyrannosaurus and Triceratops, as well as somewhat lesser known forms like the duck-billed Edmontosaurus, the long-necked Alamosaurus, the dome-headed Pachycephalosaurus, and the bony-armored Ankylosaurus. Vavrek and Larsson subjected these data to a rigorous statistical analysis, focusing in particular on the four most fossiliferous geologic units (i.e., those that have yielded more than 100 dinosaur specimens): the Horseshoe Canyon Formation of Alberta; the Hell Creek Formation of Montana and North Dakota; and the Lance Formation of Wyoming. They concluded that the evidence strongly supports the presence of a single dinosaur community inhabiting western North America during the Maastrichtian.

So what’s the big deal? Given that all of the animals noted above qualify as giants, shouldn’t we expect to find one community of dinosaurs living in Western North America during a single chunk of time? Well, yes, that would be the natural assumption, since bigger animals require more space to find sufficient food. The problem is that, beginning almost 50 years ago (2), paleontologists began noting that different varieties of Late Cretaceous dinosaurs tend to show up in the southern and northern parts of the Western Interior. For example, the giant sauropod Alamosaurus is known only from the south (e.g., New Mexico, Utah, Texas), whereas Triceratops tends to occur further north (e.g., Wyoming, Montana, Alberta, North Dakota). Thomas Lehman of Texas Tech University undertook an in depth study of the matter and concluded that dinosaurs were divided into northern and southern “provinces” during the Maastrichtian and (the preceding) Campanian stages of the Late Cretaceous (3,4,5).

Lehman expanded the scope to investigate the spectrum of vertebrate groups (animals with back bones), and found the same pattern; fishes, amphibians, lizards, turtles, crocodiles, and mammals all occurred in both north and south, but distinct representatives of these groups tended to be clumped latitudinally—that is, distinct genera and species were recovered in Alberta and Montana than in New Mexico and Texas. Even pollen fossils seemed to yield a parallel signal. Lacking any evidence of a physical barrier to north-south dispersal, Lehman hypothesized that some sort of climatic gradient must have caused the formation of unique plant communities, which in turn resulted in semi-isolated vertebrate communities.

Vavrek and Larsson’s study seems to fly in the face of any purported dinosaur provincialism. Their argument focuses attention on problems related to sampling and the vagaries of the fossil record. Based on probabilities alone, paleontologists are bound to recover the most common components of a fauna first. Sample sizes—that is, the number of specimens found—need to get relatively big before many of the rarer species are likely to show up. So any perceived differences between geologic formations and geographic regions may be due to biases in sampling rather than actual differences in the community composition. This is exactly what Vavrek and Larsson argue has occurred with our understanding of the Maastrichtian dinosaurs from North America. The paper’s closing statement sums it up: “These results suggest that dinosaurs were not as restricted in their ranges as once thought and that the fauna as a whole was largely homogenous.”

For the most part, I find these conclusions reasonable. Based on the four best-sampled geologic units of Maastrichtian age, I concur that there is no compelling evidence of geographically separated and biologically distinct dinosaur communities. I also applaud the application of rigorous statistical methods to the study of dinosaur paleobiology, something that has occurred all too infrequently in the past (once again, largely due to small samples).

Is that it then? Is the dinosaur provincialism hypothesis dead? By no means.

First off, Vavrek and Larsson focus their study only on dinosaur genera rather than species (for example, Triceratops versus Triceratops horridus). This strategy makes some sense, given that most Maastrichtian dinosaur genera contain only one species, and that many fossil specimens can only be identified to the genus level. Yet it must not be forgotten that genera are human categories with no biologically reality, and what we are really interested in here is communities of species—that is, populations of animals that are reproductively isolated from their near relatives elsewhere. In the much better sampled Campanian stage, several North American dinosaur genera (e.g., Parasaurolophus, Gryposaurus) include distinct, apparently latitudinally separated species. So it’s certainly conceivable that a similar pattern pertained to the Maastrichtian. Indeed some previous authors have raised the possibility of distinct species of Triceratops north and south within the Western Interior.

Second, the restricted quartet of geologic units (three formations in four places) used by Vavrek and Larsson covers a relatively limited latitudinal span, from southern Alberta in the north to Wyoming in the south (on the order of 10 degrees of latitude). So their study leaves wide open the possibility of distinct communities further south in Western Interior (and elsewhere on the continent). The south-only distribution of Alamosaurus is interesting here, perhaps reflecting a semi-isolated, upland, intermountain community (3,6).

Third and most important, a lack of dinosaur provincialism in the North American Maastrichtian does not negate the growing abundance of evidence documenting distinct dinosaur communities during the preceding Campanian Stage (~83.5 - 71.3 million years ago). The Campanian of the Western Interior of North America is much better sampled than the Maastrichtian, with more dinosaur species known from a 2 million year interval (about 76-74 million years ago) than for the entire 6 million years of the Maastrichtian. Moreover, in stark contrast to the Maastrichtian, most of the key fossil-bearing formations of the Campanian are now well dated, with multiple radiometric age estimated (i.e., absolute dates based on the decay of certain unstable radioactive isotopes found in volcanic ash) (7). So we can now begin to state with confidence which Campanian dinosaur species overlapped in time, but not in space.

Research conducted by our working group points to a very different picture for the Campanian than the Maastrichtian. In particular, a decade of work in the Kaiparowits Formation of Grand Staircase-Escalante National Monument (GSENM), southern Utah, has resulted in an entirely “new” dinosaur fauna (8,9), including the duck-billed Gryposaurus monumentensis (10) and the oviraptor theropod Hagryphus giganteus (11). Most of these new animals are still under study, with publications and announcements forthcoming. A comprehensive statistical analysis by Gates et al. (12), partially based on our GSENM results, finds robust support for Lehman’s hypothesis of vertebrate provincialism in the Western Interior during late Campanian. Remarkably, to date not a single dinosaur species can be confidently placed in both the south (e.g., Texas, New Mexico, Utah) and the north (e.g., Montana, Alberta).

Suffice it to say that the hypothesis of Late Cretaceous dinosaur provincialism in North America remains alive and well—and, in the opinion of our working group, robustly supported—at least for the Campanian. In my next post, I’ll address this topic again, describing some of our recent results in GSENM and probing deeper into the notion of provincial dinosaurs. Along the way, I’ll tell the story of a lost continent with grand implications for our understanding of the Mesozoic world of dinosaurs.

Notes and References
1) Vavrek, M. J. and Larsson, H.C. E. 2010. Low beta diversity of Maastrichtian dinosaurs of North America. Proceedings of the National Academy of Sciences, published ahead of print doi:10.1073/pnas.0913645107.
2) Russell, D. A. 1967. A census of dinosaur specimens collected in western Canada, National Museum of Canada Natural History Papers, 36:1-13.
3) Lehman, T. M. 1987. Late Maastrichtian paleoenvironments and dinosaur biogeography in the western interior of North America, Palaeogeography, Palaeoclimatology, Palaeoecology, 60:189-217.
4) Lehman, T. M. 1997. Late Campanian dinosaur biogeography in the western interior of North America. Dinofest International Symposium Volume, pp. 223-24.
5) Lehman, T. M. 2001. Late Cretaceous dinosaur provinciality. In D. H. Tanke and K. Carpenter (Eds.), Mesozoic Vertebrate Life (pp.310-328) Indiana University Press.
6) Sampson, S. D. and Loewen, M. A. 2005. Tyrannosaurus rex from the Upper Cretaceous (Maastrichtian) North Horn Formation of Utah: biogeographic and paleoecologic implications. Journal of Vertebrate Paleontology, 25(2): 469-472.
7) Roberts, E.M., Deino, A.D., and Chan, M.A. 2005a. 40Ar/39Ar age of the Kaiparowits Formation, southern Utah, and correlation of coeval strata and faunas along the margin of the Western Interior Basin: Cretaceous Research, 26:307-318.
8) Sampson, S. D., Gates, T. A., Roberts, E. M., Getty, M. A., Zanno, L. E., Loewen, M. A., Smith, J. A., Lund, E. K., Sertich, J., and Titus, A. L. in press. Grand Staircase-Escalante National Monument: A new and critical window into the world of dinosaurs. Learning from the Land Symposium Symposium Proceedings.
9) Sampson, S. D. and Loewen, M. A. 2010. Unraveling a radiation: a review of the diversity, stratigraphic distribution, biogeography, and evolution of horned dinosaurs. (Ornithischia:Ceratopsidae). Pp. 405-427 in M. J. Ryan, B. J. Chinnery-Allgeier, and D. A. Eberth (eds.), New Perspectives on Horned Dinosaurs. Indiana University Press.
10) Gates, T. A. and Sampson, S. D. 2007. A new species of Gryposaurus (Dinosauria: Hadrosauridae) from the Upper Campanian Kaiparowits Formation of Utah. Zoological Journal of the Linnean Society, 151:351-376.
11) Zanno, L. E. and Sampson, S. D. 2005. A new oviraptorosaur (Theropoda: Maniraptora) from the late Campanian of Utah and the status of the North American Oviraptorosauria. Journal of Vertebrate Paleontology, 25(4): 897-904.
12) Gates, T.A., Sampson, S.D., Zanno, L.E., Roberts, E.M., Eaton, J.G., Nydam, R.L., Hutchison, J.H., Smith, J.A., Loewen, M.A., and Getty, M.A. in press. Biogeography of terrestrial and freshwater vertebrates from the Late Cretaceous (Campanian) Western Interior of North America: new information from the Kaiparowits Formation, south-central Utah. Palaeogeography, Palaeoclimatology, Palaeoecology.

Images
Top: Tyrannosaurus and Triceratops, by Michael Skrepnick
Upper Middle: Corythosaurus, by Michael Skrepnick
Lower Middle: Albertosaurus and Bambiraptor, by Michael Skrepnick
Bottom: Centrosaurus, Origin of a Mass Death Assemblage, by Michael Skrepnick
For more from Michael Skrepnick, go to: http://www.dinosaursinart.com/

The Illusion of Self

We think of ourselves as separate beings isolated from the rest of the world, with our skin forming the barrier between inside and outside. This sense of separateness runs deep within the human psyche, guiding our thinking about such fundamental issues as being, life, and (particularly) death. Among Westerners, the notion of isolation extends outward to embrace humanity and exclude the nonhuman world; in this conception, humans exist outside, usually above, nature. The end result of all this externalization is billions of “skin-encapsulated egos,” each of us consumed by thoughts of furthering our own ends and protecting ourselves from the outside world.

But what if we are not separate at all? What if we are fully immersed into the ebb and flow of everything around us? Would such knowledge change how we think and act? I’m not certain about the answer to the third question, but there’s now little doubt about the first two. Scientific insights over the past several decades mirror much older insights derived from a variety of wisdom traditions. Despite its near ubiquity, we can state with confidence that the notion of a separate self is largely illusory.

The most obvious challenge to the concept of separateness is our need to consume air, water, and food. At what point did your last breathe, sip, or bite cease to be part of the outside world and become you? The truth is that we constantly exchange matter with the outside world, replacing every atom in our bodies every seven years or so. And your metabolism is intimately linked to Earth’s metabolism. Energized by sunlight, life converts inanimate rock into nutrients, which then pass through plants, plant-eaters, and animal-eaters before being decomposed and returned to the inanimate Earth. Humans fit into this amazing planet-scale metabolic system as major consumers of plants and animals. Isolation from any aspect of this metabolic flow translates to death.

If all that isn’t enough to dampen your sense of separateness, how about the fact that the body you identify with consists not of one lifeform but many? Your mouth alone contains more than 700 distinct kinds of bacteria. Carving out a variety of roles over every square millimeter of tongue, teeth, and gums, many of these microbial partners serve as armed guards, improving health by fighting disease-causing bacteria. Others can cause dental cavities if you don’t brush. Your skin and eyelashes are equally loaded with bacteria (no matter how long you shower) and your gut has a bevy of bacterial sidekicks (on the order of another 500 varieties) that are essential to converting food to useable nutrients. Although this still leaves several bacteria-free regions in a healthy body (e.g., brain, spinal cord, blood stream, etc.), current estimates indicate that, of the 10 trillion cells that compose your physical self, 9 out of 10 are not human cells. This means that your body is home to more lifeforms than there are people on Earth, or stars in the Milky Way galaxy.

If your bias is to count genes instead of cells, the truth of the matter becomes even more stark. You house about 30,000 human genes, versus about 100 times as many bacterial genes. In short, depending on how you make the calculation, you are somewhere around 1-10% human, and 90-99% nonhuman (1). A large-scale, five-year research effort called the human microbiome project (HMP) is currently underway (2). Five main body areas are being targeted in the HMP -- skin, mouth, nasal cavity/lungs, vagina, and gut -- but the goal is to indentify and characterize all the microbes inhabiting the human body. If you’re immediately inclined to regard these multifarious bacterial hitchhikers as freeloaders, or even parasites, keep in mind that these trillions of microbes are indispensible to your health, helping to regulate not only your physical well being—digesting food, processing vitamins, keeping out bad bacteria, etc—but perhaps your mental and emotional vigor as well.

And just in case you attempt to cling to some kind of special status for your human cells, it turns out that even they are likely the result of ancient evolutionary mergers with bacteria. Each of your human cells contains a “mitochondrion,” a membrane-enclosed “organelle” that is responsible for generating most of the cell’s energy, as well as such activities as cell signaling, growth, and death. Hundreds of millions of years ago, mitochondria evolved from certain types of bacteria that were engulfed by other bacterial forms. A mutually beneficial relationship developed between the host cells and the newly incorporated bacteria and this successful partnership was passed on to all animal cells, including our own. A similar merger occurred in the evolution of another cell structure called chloroplasts, which are big players in plants and other photosynthesizing lifeforms.

So, if you continually exchange matter with the outside world, if your body is completely renewed every few years, if you are walking colony of trillions of lifeforms, and if your human cells still incorporate bacterial ancestry, exactly what is this self that you view as separate? You are not an isolated being. You’re an ecosystem, a complex, self-regenerating amalgam of lifeforms that interact communally to form a larger whole. Metaphorically, to think of your body as a machine, as current bias would hold, is inaccurate at best and destructive at worst. You’re far more akin to a whirlpool, a brief, ever-shifting concentration of energy in a vast river that’s been flowing for billions of years.

We’ve only begun to fathom the implications of this profound notion, but it’s one that deserves to be disseminated and discussed widely. I think that the dissolution of our separate selves can help us see the world in new, more accurate, and even sustainable ways. What do you think?

Notes and References
1) A quick search will reveal many sources online that cite similar numbers, but I recommend a wonderful TED talk on bacteria by Princeton University microbiologist Bonnie Bassler: http://www.ted.com/talks/lang/eng/bonnie_bassler_on_how_bacteria_communicate.html

2) http://en.wikipedia.org/wiki/Human_microbiome_project

3) This is called endosymbiosis theory. For more information, check out: http://en.wikipedia.org/wiki/Mitochondrion

All images courtesy of the public commons website Wikimedia.

National Tour Hits High Gear

A national tour to promote my book, Dinosaur Odyssey, and the PBS KIDS show, Dinosaur Train, hits high gear this week. This past Thursday and Friday, I was at the Florida Museum of Natural History in Gainesville, where I did a lecture one evening and four Dinosaur Train-related events for kids the following day. The latter attracted more than 1500 children and adults, resulting in a fun and chaotic morning for all involved! Tomorrow (Tuesday, March 30th) I will be in San Diego at the San Diego Natural History Museum to give a book talk at 6:30 pm (http://www.sdnhm.org/exhibits/dinosaurs/programs.php), followed by a similar event close to home at the California Academy of Sciences in San Francisco on Thursday evening (April 1st). The latter talk will occur as part of the weekly “Night Life” festivities at the Cal Academy, with a live DJ and other activities. (For tickets, go to: https://www.calacademy.org/event_tickets/index.php?d=April%201,%202010&e=Nightlife%206:00%20PM). Then, this weekend, I head to Washington, DC, to participate in the annual White House Easter Egg Roll on April 5th, where, in the guise of “Dr. Scott the Paleontologist,” I'll be talking with hundreds (thousands?) of Dinosaur Train fans on the White House South Lawn, encouraging them to get outside, get into nature, and make their own discoveries! (For more information, see: http://www.whitehouse.gov/easterEggRoll). A number of other book talks and Dinosaur Train events are currently in the works, so stay tuned. For updates on upcoming events, visit: http://www.scottsampson.net/index.php?page=talks

I'll be back to generating a regular blog post/essay next week when I return from my travels. Meanwhile, thanks very much to all of you who are participating in these events!!

Note: Promotional image for Night Life at the Cal Academy in San Francisco, property of the California Academy of Sciences.

From Sand Monsters to Rock Stars

Most posts on The Whirlpool of Life deal with weighty issues like mass extinction, sustainability, and shifting worldviews. Today’s offering stands in stark contrast, yet it addresses a question that I am asked frequently. How do paleontologists go about naming dinosaurs and other extinct creatures?

The trigger for this discussion is yesterday’s announcement of a new dinosaur, Seitaad reussi, from the high desert of southern Utah. Seitaad’s world debut was made in conjunction with publication of a paper in the online, open-access journal PLoS ONE describing this new Jurassic-aged beast (1). The exquisitely preserved partial skeleton was collected several years ago near Bluff, Utah, by the paleontology team from the Utah Museum of Natural History, where I am a research curator. The two authors of the study, Joe Sertich and Mark Loewen, are ex-students of mine (Sertich is now a doctoral candidate at Stony Brook University, and Loewen is now an instructor at the University of Utah).

Seitaad is (or, more precisely, was) a prosauropod dinosaur: a mid-sized, long-necked, small-headed, two-legged herbivore that was a locomotory switch-hitter—capable of walking on two or four legs. It belonged to the first major radiation of dinosaurs (formally referred to as basal sauropodomorphs) that swept across much of the supercontinent Pangaea during the Late Triassic and Early Triassic. Seitaad lived in an arid desert setting, and the only known individual apparently experienced a premature demise in a dune collapse. Although small as dinosaurs go (~10-15 feet long; 150-200 lbs), this prosauropod may well have been the largest herbivore in its habitat, with titanic relatives like Brachiosaurus and Diplodocus still millions of years away. I greatly enjoyed Mark and Joe’s excellent study of this ancient desert denizen.

I also enjoyed their choice of moniker, which is both interesting and pretty typical of the process that paleontologists (and biologists generally) go through in naming newly discovered animals. The first part of the name, Seitaad, refers to a mythological sand-desert monster from Navajo (Diné) lore, simultaneously honoring the local indigenous peoples and the name of the rock unit entombing the specimen (the Navajo Sandstone). The latter part of the name, reussi, derives from Everett Ruess, a famous young explorer, poet, artist, and historian who mysteriously disappeared in the southern Utah desert in 1934.

So here’s the deal. You can name a dinosaur, or any other newly discovered organism, after a place, a time, a person, some particular feature of the creature in question, or just about anything at all, as long as the name has not been used previously. One caveat. It’s regarded as highly uncouth (and, for all I know, against the rules) to name a new species after oneself. With that single exception, however, the honoree may be real or fictitious, human or nonhuman. Once the subject(s) of the name is (are) chosen, you must then follow a formal (though not cumbersome) set of do’s and don’ts dictated by International Code of Zoological Nomenclature.

The two-part name—for example, Seitaad ruessi, Tyrannosaurus rex, or Homo sapiens—is a biological standard set in the 18th Century by the famed Swedish biologist Carolus Linnaeus, and still used to this day. The first part of the name is called the “genus,” whereas the latter is the “species.” The genus-species duo represents a hierarchy, with the genus being the more inclusive category. So a single genus often contains multiple species (e.g., Homo sapiens, Homo erectus, Homo ergaster, etc.).

Mark and Joe are certainly not the only paleontologists with a penchant for mythology. If one looks solely among dinosaurs beginning with letter “A,” examples include: Achillobatar (named for the mythical hero Achilles), Aeolosaurus (named after the Greek god of winds), and Atlasaurus (for Atlas, a giant who, in Greek mythology, held up the heavens). In 1995, I added another to the bunch (2)—Achelousaurus, a ceratopsian (horned) dinosaur named after Achelous, a mythological river god of the ancient Greeks who was capable of shape-shifting. In order to fight Heracles (Hercules of Roman mythology) over (what else) a woman, Achelous changed himself into a bull. Heracles won the battle when he ripped off the horns of the bull. The name fits because Achelousaurus was a hornless ceratopsian dinosaur that evolved from horned ancestors. Many, many more mythological creatures can be found embodied in the names of dinosaurs.

Just as mythology is one common theme used for naming dinosaurs and other animals, famous characters are another. Indeed fame seems to be a regular attractor for scientists naming new critters, whether the honoree is real or fictitious. As noted, Seitaad’s second name refers to legendary adventurer Everett Ruess. Extending the scope beyond dinosaurs, we might cite the wasp named Mozartella beethoveni, the snake Montypythonoides, the trilobite Mildesdavis, the crustacean Godzillus, or the diminutive midge Dicrotenipes thanatogratus (“thanatos” is Greek for “dead” and “gratus” is Latin for grateful, in honor of the Grateful Dead). Another of my favorites is a fossil turtle dubbed Ninjemys, after the cartoon Teenage Mutant Ninja Turtles.

My single nomenclatural foray into the realm of celebrity is Masiakasaurus knopfleri, a little buck-toothed, dinosaurian predator found on the island of Madagascar. The genus designation up front combines the Malagasy word for vicious and the Latin word for lizard, whereas the species name honors singer, song-writer, and world renowned guitarist Mark Knopfler, ex-lead of Dire Straits. The full translation is “the vicious lizard of Knopfler.”

Why Mark Knopfler? Well, way back in the mid 1990’s, when there were still cassette tapes and Sony Walkmans (remember those?), one of the crew members brought a pair of small speakers along with her tape player. Among the bands featured on the quarry playlist that summer was Dire Straits, a particular favorite of expedition leader David Krause. As serendipity would have it, when we played Knopfler’s music, we tended to find more fossils of the new little meat-eater, whereas these bones were few and far between when the music wasn’t playing. Back in camp one night, my longtime friend and colleague Cathy Forster (George Washington University) suggested that we name this new dinosaur after our musical talisman, Mark Knopfler. For some reason, the consensus among crewmembers (perhaps influenced by beer consumption) was enthusiastic support for the idea.

When Masiakasaurus made its first public appearance on the cover of the British journal Nature (3), the media response was swift, overwhelming, and, shall we say, unanticipated in its direction. While some reports addressed the interesting scientific aspects of this theropod dinosaur, the bulk of the media coverage concentrated on the Knopfler reference. Needless to say, I was not used to receiving phone calls for interviews from Rolling Stone or Guitarist magazine. Some media outlets, in particular the British tabloids, went so far as to question our motives, suggesting that the moniker referenced Knopfler’s physical appearance, or perhaps his status as a rock dinosaur! As for Knopfler himself, I am pleased to say that he accepted the honor in the spirit intended, stating for the record, “The fact that it’s a dinosaur is certainly apt, but I’m happy to report that I’m not in the least bit vicious.”

So that’s my two bits on names. Hearty congratulations to Joe Sertich and Mark Loewen on their big announcement. Oh, and keep your eyes open for more announcements of new Utah dinosaurs in the near future . . .

References
1. Sertich, J.J.W and Loewen, M. A. 2010. A new basal sauropodomorph dinosaur from the Lower Jurassic Navajo Sandstone of southern Utah. PLoS ONE, 5 (3), DOI: 10.1371/journal.pone.0009789

2. Sampson, S. D. 1995. Two new horned dinosaurs from the Upper Cretaceous Two Medicine Formation of Montana, USA, with a phylogenetic analysis of the Centrosaurinae (Ornithischia: Ceratopsidae). Journal of Vertebrate Paleontology, 15(4): 743-760.

3. Sampson, S. D., Carrano, M. T., Forster, C. A. 2001. A bizarre predatory dinosaur from Madagascar: implications for the evolution of Gondwanan theropods. Nature, 409: 504-505.

Images (from top to bottom)
1. The partial skeleton of Seitaad reussi, which preserves the central portion of the body.
2. The skeletal reconstruction of Seitaad reussi, with the preserved elements highlighted.

3. Joe Sertich with Seitaad reussi specimen.
4. Prosauropod dinosaurs in desert setting. Painting by Eleanor Kish.

5. Mark Loewen with Seitaad reussi specimen.
6. Masiakasaurus knopfleri, the buck-toothed predator from Madagascar. Artwork by Bill Parsons.