Time for Another Forum Friday
Time for another Forum Friday. Since last time, we learned that our grants did not come through, so our search for funding to expand the site continues and the teacher training programs and other events remain in the planning stages. We hope to see those ideas come to fruition, but for now, this site will continue to expand, just not at the rate we hoped.
Since the last Forum Friday, we have reviewed Dr. Holtz’s Dinosaurs: the most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, and Dr. Sampson’s Dinosaur Odyssey, both of which come highly recommended. We also learned about the Cambrian rocks of Arkansas and the dinosaurs of Arkansas. We also learned how scientists really define dinosaurs and why most people’s conceptions about what dinosaurs are is incorrect.
Over on our Facebook page, we watched bacteria evolve, why saying they are still bacteria is silly, and how understanding bacterial evolution can help us clean up toxic waste.
We learned about dinosaur egg-laying, how pterosaurs could fly and be so big, and Arkansas trace fossils. We saw pictures of dinosaur feathers in amber and how to identify a fossil. We learned the Cambrian Explosion was caused by multiple factors and what the earth in the paleozoic looked like, along with how to visualize geologic time.
Evolution, by Matt Bonnan.
Speaking of new ways to look at things, we saw an evolution cartoon by paleontologist Matt Bonnan and art in science. We heard about Using rap music to teach the history of science and a song about evidence-based medicine. But we also saw why good intentions to help the oceans don’t help when you don’t know what you are talking about. Among problems in science education, we learned about unicorns and the dragons of inaction. Biology textbooks are written for pre-meds, providing short shrift for evolution and ecology. On the plus side, we also saw students fighting bad science and why generosity beats greed in the long run.
We found free tech, iPad apps for the classroom, an iTunes earthviewer, online modules to teach ecology and evolution, among other topics, and educational videos for the classroom, as well as brain-training to cut through bias. We found Citizen science opportunities for the classroom. Although we had to warn against the Exploring the Environment website. We also saw why simply asking students to write scientists without oversight is wrong and some resources to help.
We learned about the evolution of the avian flu, insects evolving gears, why asexual populations fare poorly, and how to breed a better cat. We saw how fish survive icy water by evolving antifreeze, adapt to puddles, and learned to walk on land. Finally, we saw that humans are still evolving and why being smart is cool.
So what was your favorite story? Did you have any questions, comments, complaints? Feel free to share.
Myths and Misconceptions #1: Allosaurus rex, or That is NOT a Dinosaur
When I worked at the Denver Museum of Nature and Science as a volunteer in the educations collection (if you ever get the chance to volunteer at a museum, do it, it was a lot of fun and very educational), I happened upon a man with a young boy by his side, whom I presume was his son, looking at an impressive skeleton. I thought how great it was the man took time to bring his son to the museum. But when the boy asked what the skeleton was and the man answered, “Allosaurus rex,” my opinion of the experience dropped. I’m still glad he brought the boy to the museum, but it could have been so much better.
Allosaurus rex? Actually, a blue whale. Definitely NOT a dinosaur. Also, not DMNS. Really, the London Natural History Museum. Photo by author. Click to enlarge.
So what was wrong with what he said? There is no such creature as an “Allosaurus rex.” There is an Allosaurus and there is a Tyrannosaurus rex, but not the two together. It also did not help that the man was standing directly in front of the plaque that read, “Fin whale.”
Much has been written on what a dinosaur is and what is not, but considering the extreme levels of confusion in the general populace, I thought it worth discussing it here. Not everything that is a big skeleton and/or extinct is a dinosaur. In addition to the above whale, I have heard dimetrodons, pterosaurs, saber-toothed cats, mammoths, giant rhinos, mosasaurs, modern elephant skeletons and many other things called dinosaurs, when in reality, NONE of the previous creatures qualify as dinosaurs.
So, if none of those are dinosaurs, what is? What are some of the things people think about when they try to define dinosaurs? The first thing that most people think about is a giant, scaly reptile. However, some dinosaurs were the size of chickens, so not all of them were big. Many also had feathers, so the scaly motif is not altogether correct either. They are reptiles, but unlike anything most people would consider a reptile today.
Quetzalcoatlus northropi. UT Museum. Not a dinosaur either. Photo by author.
Other traits people often use to distinguish dinosaurs are that none of them were aquatic and none of them flew. These aren’t really true either. Some will say they only lived in the Mesozoic Era and died out at the end of the Cretaceous Period 65 million years ago. Again, false. It is true that most animals considered dinosaurs did indeed live only in the Mesozoic Era, but not all died out at the famous K-T extinction event. Some of you may be thinking to yourselves the author has no idea what he is talking about. Nevertheless, as we will see, some dinosaurs are quite at home in both air and water, especially the ones that lived past the Mesozoic.
Even if all these things were true about dinosaurs, none of it really matters. These traits are all distinguishing characteristics that are generally true about most dinosaurs, but not necessarily true about all. What defines an organism is not the same as the diagnosis. Definitions are done by evolutionary relationships. Diagnoses tell us how we can recognize them, what distinguishing characteristics can be used. However, distinguishing characteristics do not necessarily describe all the members of the group. For instance, one might distinguish all members of a family by their last name, but if people get married and change their last name, they do not suddenly stop being a member of the family. A daughter, for example, is defined by who her parents are, not by what name she has. Likewise, her distinguishing characteristics tell us who she is as an individual and can give us clues to her family relationships, but her definition as a daughter depends solely on her relationship to her parents.
The discredited and completely unaccepted haemothermia hypothesis: Mammals and birds are both warm-blooded; therefore, they must be related. I.e., superficial similarities can be misleading. Image from wikipedia.
I should note here that it wasn’t always this way. Back in the old days, organisms were grouped by similarity, who looked like whom, so at that time, there was really no difference between definition and diagnosis. But as people studied organisms more closely, they found that a lot of times, superficial similarities masked deeper differences, which indicated they weren’t really related at all. So for most of the last century, scientists have tried to find real, evolutionarily related groupings to build something akin to a geneology of life. To do so, it became evident that definitions and diagnoses of groups had to be different, so for the last couple of decades, definitions have been based on relationships and diagnoses based on characteristics. This system of classification by defining groups according to their relationships is called phylogenetic systematics.
So, how then do we define a dinosaur? The standard modern definition of a dinosaur has been stated as the most recent common ancestor of Triceratops and modern birds and all of its descendants (Padian, 1997). Note this means that all birds are, by definition, dinosaurs. So it is obvious that some dinosaurs are quite small (e.g. hummingbirds), flew (most birds), and could reasonably be called aquatic (e.g. penguins). The reason for this is because the earliest birds are clearly closely related to animals, such as Velociraptor and its close relatives, which are indisputably dinosaurs. If one took a picture of Archaeopteryx which had no feathers to a bunch of elementary school kids and asked them to identify it, the general answer is that it is obviously a dinosaur, but put feathers on it and they call it a bird. They are thus both correct answers. Dr. Thomas Holtz has proposed a slightly different definition: the most recent common ancestor of Megalosaurus and Iguanodon and all of its descendants. Both definitions encompass the same groups of animals as far as our understanding goes, but Holtz’s definition includes the dinosaurs that were first discovered, so is considered by many to be a superior definition.
Dinosaur family tree, by Nobu Tamura (paleocritti.com). Click to enlarge. Note on trees like this, the branches can be pivoted on their branch points without changing relationships (e.g.,it makes no difference whether you say “your brother and sister” or “your sister and brother”), so anything in Saurischia is equally related to anything in Ornithischia. Thus, it doesn’t really matter what animal in each group you choose as the representative of each group as long as the groups as a whole remain intact.
Unfortunately, scientists don’t always talk about these terms correctly either, making the whole process confusing. Michael Benton, a leading paleontology researcher with numerous well-respected publications, got it wrong when he defined dinosaurs according to synapomorphies in The Complete Dinosaur. While synapomorphies are used in developing modern classifications, they are used for diagnoses, not definitions of groups, which Dr. Benton assuredly knows (as evidenced by the fact he normally states it correctly in his other works), but when someone is as prolific as Dr. Benton, the occasional error is bound to slip in now and then.
Synapomorphies are very important in figuring out relationships. Unlike any old similarity, synapomorphies are shared, derived characteristics, meaning that the character is the same in the organisms being compared because they share a common ancestor, i.e. they are derived from the same source. Of course, because it requires knowledge of the common ancestor, synapomorphies can only be identified AFTER one has a hypothetical relationship. Thus, to discover strong relationships, scientists will create (mathematically, using a computer because it is way too complex to try doing by hand for anything beyond a few species), all the possible relationships between all the organisms under consideration and then map all the characteristics they can onto every possibility. The relationships requiring the fewest inconsistencies and providing the simplest explanation is considered the most likely. Inconsistencies can occur due to convergent evolution (organisms not closely related developing similar characteristics due to similarities in environmental constraints) or homoplasies (characteristics changing back to a previous form), but with examination of enough characteristics, good relationships usually appear. Of course, the more data you can put into the analysis, the better the results normally get, which is why we continue to study and try to find new fossils and collect more data (and who wouldn’t want more fossils?).
This is all well and good, but how then do we recognize a dinosaur when we see one? Dr. Benton provided a good list of skeletal characteristics, which really won’t mean a lot to people who are not very familiar with skeletons and scientific terminology (but a basic description can be found here and Wikipedia has a surprisingly in depth description). Nevertheless, there are some generalities we can make. If we exclude birds, we can say the non-avian dinosaurs (that we know of) died out at the end of the Cretaceous Period. They all carried their legs underneath their bodies like mammals (and birds of course) and were decidedly unlike other reptiles. None were fliers, although the most bird-like ones got close, and none were aquatic, although some did indeed at least go wading. But remember, these are generalities and if we find a dinosaur with flippers, as long as it otherwise appears related to other known dinosaurs, it will still be a dinosaur. But if it does not fall within the relationships defined above, it will not be a dinosaur, no matter how much it may look like one.
I don’t have an online source for the Padian article, so here is the reference.
Padian, K. 1997. Dinosauria: Definition. pp. 175-179. In Currie, P.J. and K. Padian (eds.) Encyclopedia of Dinosaurs. Academic Press.
Dinosaur Odyssey: a Journey You Should Take.
Dinosaur Odyssey: Fossil Threads in the Web of Life
By Scott D. Sampson
Publication date 2009 (hardback) 2011 (paperback). 332 pg. University of California Press. ISBN: 978-0-520-24163-3.
Suitable for junior high students and up.
Author: Dr. Sampson is best known these days as Dr. Scott the Paleontologist, from Dinosaur Train on PBS KIDS (a children’s show I can recommend). But he doesn’t just play one on TV, he is a real-life paleontologist, and a well-respected one at that, best known for his work on late Cretaceous dinosaurs in Madagascar and the Grand Staircase-Escalante national Monument. He is Chief Curator at the Denver Museum of Nature and Science. He has a blog called Whirlpool of Life and can be found on Facebook. Dr. Sampson has had a longstanding interest in public science education, particularly about connecting children with nature. That interest is clearly evident in Dinosaur Odyssey.
This book has been out a few years, but its main message is more deeply relevant now than ever before. This book is not really about dinosaurs. It is about the interconnectedness of all things. Dinosaurs are simply a fascinating hook for discussing ideas about evolution and ecology. If you are looking for a book that just talks about dinosaurs, look elsewhere. But if you want a book that puts dinosaurs in context as part of a complete and ever-changing ecosystem, if you want to learn about the Mesozoic world as a stage upon which dinosaurs are only a part, however awe-inspiring and prominent, of a much larger web of life, this book is for you. In Dr. Sampson’s hands, dinosaurs are not skeletons of bizarre creatures, they are living organisms interacting with others, changing and being changed by their environment. In a similar vein, our ideas about them are neither set in stone nor idle speculation, they are dynamic and changing, based on new discoveries and scientific understanding, circling ever closer towards a deeper understanding.
The book is written for someone with decent reading ability, but not a dinosaur aficionado. No real prior scientific knowledge is required, simply a desire to learn about the natural world. For those who want more, or find some of the terminology daunting, there is a wealth of notes and references at the end, along with a substantial glossary. The book begins with a short history of the scientific study of life and Sampson’s personal experiences searching for dinosaurs in Madagascar, which led to some of his thinking for the book as an introduction to what follows. Throughout the book, he uses his personal experiences to enrich the scientific discussions, making it a personal story, not just an academic one. Chapter two is an ambitious glimpse at the history of the universe until the dinosaurs appear, along with a short discussion of the geological principles forming the foundations of our understanding of geologic time. Chapter three introduces the dinosaurs, defining what is meant when a scientist talks about dinosaurs and the different groups of dinosaurs. Along the way, he discusses what species are, how they are named, and how we figure out relationships, although not in detail, just enough for a non-science person to understand the broad concepts. Chapter four discusses the physical world of the Mesozoic in terms of plate tectonics and how the movement of the continents shaped the world and thus the evolutionary history of dinosaurs. He even discusses the role of the atmosphere and oceans in climate. Chapter five builds the basics of ecosystems and nutrient flow, chapter six provides a background in evolutionary theory, chapter seven discusses how dinosaurian herbivores adapted to changing plant communities and how the dinosaur and plant communities may have co-evolved, each influencing the other. Chapter eight adds predators to the mix and chapter nine finishes the ecological chain with decomposers. Chapters ten and eleven discuss sexual selection and metabolism in dinosaurs.
Michael Skrepnick contributed several paintings for the book, such as this one of Daspletosaurus attacking an Einiosaurus herd.
The chapters to this point built up how dinosaurs fit into the ecosystem and the workings of evolutionary theory. The next three chapters then take that information and discuss the dinosaurs rise to prominence in the Triassic, development of dinosaur ecosystems in the Jurassic, and their ultimate development through the Cretaceous period. Chapter fifteen, as might be expected, discusses the extinction ending the Mesozoic Era and the dominance of dinosaurs as major players on the world stage.
One might think the book would end at this point. But Sampson has one final chapter to go, which is probably the most important message in the book. He finishes the book by discussing why dinosaurs are important today. We are facing an extinction event equal to the end of the Cretaceous in terms of biodiversity loss, yet few people seem to notice just how comparatively depauperate our global ecosystems are becoming. Because dinosaurs draw peoples’ attention, they are the perfect tool to discuss evolutionary and ecological issues. In this chapter, Sampson discusses how to use dinosaurs to reach people and teach them about our own ecosystems, how we are affecting it and the problems we are facing. In this way, looking at our past through a dinosaurian lens can help us find our way forward.
In the final analysis, this book is a must-read for anyone interested in the natural world and how it works, especially if they love dinosaurs.
“Arkansaurus,” the only Arkansas Dinosaur
Welcome to the first of a series on Arkansas fossils. Arkansas is not generally known as a mecca for dinosaur lovers. Most of the dinosaurs in Arkansas are statues created by a man named Leo Cate, which have all the accuracy of the old plastic toys on which he based the statues, which is to say, not much (of course, he made them for enjoyment, not as anatomical models, so they serve their purpose). Nevertheless, dinosaurs are the first thing I get asked about when I give talks in schools, so I decided to start off with a discussion of our one and only dinosaur, called “Arkansaurus fridayi.”
Ordinarily, I would not delve into how a fossil was found here, but because Arkansaurus is unique and illustrative of how many fossils are brought to the attention of science, a brief synopsis of the story of how it was brought to the attention of science may be of interest. In August, 1972, Joe Friday was searching for a lost cow on his property near Lockesburg in Sevier County, when he found some bones eroding out of a shallow gravel pit. He showed them to a Mr. Zachry, whose son, Doy, happened to be a student at the University of Arkansas in Fayetteville. Doy showed the bones to Dr. James H. Quinn, a professor at UA, who identified them as part of the foot of a theropod dinosaur. He contacted the Arkansas Geological Survey and Dr. Quinn, Ben Clardy of the AGS, and Mr. Zachry went back to the site where they found the rest of the bones. Dr. Quinn presented the bones at a meeting of the Society of Vertebrate Paleontology where he discussed the bones with Dr. Edwin Colbert, a noted paleontologist who was an expert in dinosaurs and vertebrate evolution. They came to the conclusion that the bones probably came from some type of ornithomimid, a group of ostrich-like dinosaurs (the name literally means bird-mimic), one of which, named Gallimimus, was made famous in Jurassic Park. Despite further excavations, no additional bones have been found. Dr. Quinn never officially described the bones, publishing only an abstract for a regional meeting of the Geological Society of America in 1973. It remained for Rebecca Hunt-Foster, now a paleontologist for the Bureau of Land Management, to publish the official description 30 years later in the Proceedings Journal of the 2003 Arkansas Undergraduate Research Conference.
The first thing to know about this particular dinosaur is that “Arkansaurus fridayi” is not its real name. In fact, it doesn’t even have an official name. The reason for this is because all we have of it is part of one foot. Specifically, we have the metatarsals, a few phalangeal bones, and the unguals. In non-science speak, on humans, they would refer to the bones making up the front half of your foot. The metatarsals are the long bones the toes are attached to forming the front part of the arch, the phalanges are the toes, and the unguals are the bony cores of the claws. The pictures show the actual bones and a cast, in which the missing phalangeal bones have been restored. The real fossil has all the phalangeal bones connecting to the metatarsals and all the unguals, but a couple of the middle phalanges are missing. We have no ankle bones and nothing at all of the rest of the animal. With such little to go on, it has been difficult to determine exactly what kind of dinosaur it is, so no scientist has been comfortable giving it an official name yet. To add to the complications, not a whole lot of feet from theropod dinosaurs are known, so good comparison material is limited, and little is known about theropods in the southern United States to begin with. (Aside: dinosaurs are separated into two groups. The Ornithischia, which are comprised of the herbivorous, mostly four-footed dinosaurs; and the Saurischia, which include the giant, long-necked sauropods and the bipedal, mostly carnivorous theropods.)
So why only one foot? What happened to the rest of it? I’ll let Rebecca Hunt-Foster explain it, as she did an excellent job: “There are several possibilities that would explain the occurrence of a single foot at the Friday site. It is a possibility that the rest of the Friday specimen could be gravel on highway 24. Road crews could have cut into the Trinity Group (Ed. Note. The rock formation in which the bones were found) when excavating the Quaternary gravel that lies directly above it, when building the road in 1954. As another theory, the animal may have begun to decompose before its body was carried by water to the site of deposition. Consequentlly, bits and pieces could have been scavenged by predators in the Lower Cretaceous, resulting in only a single foot remaining for preservation. Finally, it is possible that the entire specimen was preserved but that most of the skeleton was lost to Pleistocene erosion.” So just think about that the next time you go driving down the road. What fossils might you be driving upon?
Even if we don’t know for sure what it is, we do have some clues and can narrow down, at least a little, what it might be. What we know for sure is that it is some kind of coelurosaur. That, unfortunately, doesn’t help us a lot because coelurosaurs cover everything from little compsognathids to giant tyrannosaurs to modern birds, known principally for having bigger brains than earlier theropods, slender feet with three toes, and many of them had feathers. It does tell us it is not closely related to dinosaurs like allosaurs and spinosaurs, nor to early theropods like ceratosaurs and Coelophysis. Dr. James Kirkland opined that it was similar to Nedcolbertia, a small coelurosaur found in Utah. The problem here is that no one knows much more about Nedcolbertia either and its relationships to other dinosaurs are unclear. Quinn and Colbert thought it may have been an ornithomimid, but closer inspection by Rebecca Hunt-Foster and comparison with known ornithomimids indicates this is unlikely. Right now, all that can really be said is that it is likely a small coelurosaur, but not a tyrannosaurid, ornithomimid, or advanced form more closely related to birds, which leaves a small group of poorly known coelurosaurs no one really knows what to do with.
Using these animals as a comparison, what can we say about what kind of animal “Arkansaurus” was? It was likely a fast runner with probably an omnivorous diet, eating smaller animals and supplementing its diet with plants. It would likely have stood somewhere between 2-4 meters (6.5-13 feet) tall. It would have looked something like an ostrich with long arms ending in hands with three functional fingers, with one of them being at least semi-opposable, and a jaw filled with small teeth. If it had feathers (which seems increasingly likely), the feathers would have looked more like fur than the large feathery plumage seen on ostriches today. It would also have had large eyes like ostriches, with excellent color vision, based on the fact that its nearest living relatives, crocodilians and birds, all see a broad spectrum of colors (even better than humans).
The rocks the bones were found in were part of what is called the Trinity Group. These rock layers (or strata) consist of layers of sand, clay, gravel, limestone, and gypsum laid down in the Early Cretaceous Period, roughly around 100-120 million years ago (what is known as the Albian and Aptian Ages). The rocks indicate that during the time the rocks were formed, the environment was a shallow marine coastal area not unlike south Texas near the Rio Grande or in the Persian Gulf. Our dinosaur would certainly not have been alone. There were other dinosaurs in the vicinity, we just know very little about them. Sauropods left thousands of tracks in the coastal sediment forming a massive trackway found in a Howard Country gypsum mine in 1983. Another trackway found in 2011 has tracks from sauropods such as Pleurocoelus and Paluxysaurus (which may or may not refer to the same species and may or may not also be called Sauroposeidon) as well as tracks from what was probably the giant theropod Acrocanthosaurus.
Howard County trackway.
Most of the information and images in this post not directly linked to came from the following sources. Many thanks to Rebecca Hunt-Foster for clean pictures from her paper, which she also graciously supplied.
Hunt, ReBecca K., Daniel Chure, and Leo Carson Davis. “An Early Cretaceous Theropod Foot from Southwestern Arkansas.”Proceedings Journal of the Arkansas Undergraduate Research Conference 10 (2003): 87–103.
Braden, Angela K. The Arkansas Dinosaur “Arkansaurus fridayi”. Little Rock: Arkansas Geological Commission, 1998.
The top image is a Leo Cate T. rex. Photo by Debra Jane Seltzer, RoadsideArchitecture.com.
UPDATE: Arkansaurus has recently been named the Arkansas official state dinosaur, reviving interest in the fossil. It is currently being re-examined by Dr. Rebecca Hunt-Foster, with the hopes that new fossils and information that has come to light since her last publication will provide a more refined determination of its relationships.
The Cambrian of Arkansas
Our tour of Arkansas fossils and geology should begin, like any tour, at the beginning. The oldest rocks found in Arkansas in which fossils may be found were formed in the Cambrian Period, the earliest part of the Paleozoic Era. When the Paleozoic Era was first named, it began with the rocks containing the oldest known fossils. We now know of fossils far older than that. Nevertheless, it marks a good starting point for rocks in which fossils become commonly found and are easily recognizable. So while Arkansas does not have the earliest fossils, we do have fossils dating back through most of the history of life once hard parts developed.
Painting by D.W. Miller of the Cambrian world as seen in the Burgess Shale
The Cambrian Period started about 540 million years ago and lasted until 485 million years ago. During that time, while the land was mostly barren, the seas were full of life. Much of what people know about the Cambrian comes from the Burgess Shale in Canada, possibly the best known example of a lagerstätten, a fossil site rich in either fossil diversity or exceptional preservation, of which the Burgess Shale has both. From the Burgess Shale and other localities, we know that the Cambrian saw the rise of most of the major groups of animals we see today. In addition to the comb jellies, sponges, algae and anemones, brachiopods and bristle worms, velvet worms and crinoids; the Cambrian also arthropods of several kinds, most in particular the trilobites, the first chordates like Pikaia, and bizarre creatures like Anomalocaris and Hallucigenia.
The rise of such a diversity of animal life during the Cambrian has been termed the Cambrian Explosion, leading some people to assume it appeared suddenly and without precedent. In truth, the Cambrian “explosion” took tens of millions of years and was preceded by a diverse fauna known as the Ediacaran or Vendian fauna, which first appeared almost 100 million years earlier. The end of the “Garden of Ediacara” and the rise of the Cambrian fauna is thought to have come about due to the evolution of the first predators, necessitating hard shells for defense and hard claws and teeth to kill prey.
Purple represents area Collier Shale can be seen.
The only place in Arkansas to find Cambrian rocks is in the Collier Shale, which was formed in the Cambrian through the Lower Ordovician.
Outcrops for the Collier Shale are limited to a small set of ridges in the Ouachita Mountains, within Montgomery County between Caddo Gap and Mt. Ida, just to the east of state Highway 27. However, most of this area is part of the Ouachita National forest and is ILLEGAL TO COLLECT anything without a permit.
The Collier Shale is a large unit at least 1000 feet thick formed mostly of gray to black clay shale that was intensely crumpled during the formation of the Ouachitas. Interspersed within the shale are thin layers of black chert, which together indicate a deep water environment. However, there are also thin layers of dark gray to black limestone, which contain pebbles of chert, limestone, quartz, and even sandstone. It is thought that these layers initially formed in shallower water on the continental shelf before some event caused them to slide off the continental slope into the abyss.
Housia sp. British Columbia
The Collier Shale is not known for abundant fossils, but it does have some. In the Cambrian section of the formation, several genera of trilobites have been found, chiefly of the groups known as Asaphida and Ptychopariida. For more information on trilobites and the different types, try the Fossilmuseum.net and Trilobites.info websites. The trilobite genera found in the Collier Shale have been from what is known as the Elvinia and Taenicephalus Zones. These are specific groups of trilobite genera that, when found together, allow the age of the rocks to be determined using correlative dating. These groups, or assemblages, of genera have been found in other parts of the world in rocks that have been able to be dated using rigorous and independent methods, such as radiometric dating. We know that rocks elsewhere in the world containing these fossils are roughly between 490 and 500 million years old, indicating the rocks forming this part of the Collier Shale are the same age. This conclusion is supported by fossils in the rock units overlying this part of the Collier matching those found in rock units over similar rock units of known age elsewhere. The trilobites in the Collier are found in the lower part of the formation. The upper part of the Collier contains fossils known as conodonts, but they are Ordovician in age and will be discussed later.
Trilobite images from www.fossilmuseum.net and www.trilobites.info. The Cambrian painting by Miller can be found at http://paleobiology.si.edu/burgess/cambrianWorld.html, along with more Cambrian information. The map of the Collier Shale can be found at www.geology.ar.gov and the continental shelf image is from kids.britannica.com.
Hart, W. D., J. H. Stitt, S. R. Hohensee, and R. L. Ethington. 1987. Geological implications of Late Cambrian trilobites from the Collier Shale, Jessieville area, Arkansas. Geology 15:447–450.
Hohensee, S. R.; Stitt, J. H. 1989. Redeposited Elvinia zone Upper Cambrian trilobites from the Collier Shale, Ouachita Mountains, west-central Arkansas. Journal of Paleontology 63(6): 857-879
Loch, J.D. and J.F. Taylor. 2004. New trilobite taxa from Upper Cambrian microbial reefs in the central Appalachians. Journal of Paleontology 78(3):591-602. Online publication date: 1-May-2004.
UPDATE: I thought I would add a little more information about the “Cambrian Explosion,” or as Dr. Donald Prothero calls it, the “Cambrian slow fuse.” The reason for this is because of how long it really took for multicellular life to develop. We have evidence for the earliest life going back over 3.5 billion years, but the earliest agreed upon multicellular life appeared in the Ediacaran fauna (Grypania is a possible multicellular organism dating back 2.1 billion years, but may not be a true multicellular organism and really a colonial organism). 
The diagram to the right (click to enlarge) is from Prothero’s book, Evolution: What the fossils Say and Why it Matters, and reproduced on a review he wrote of another book. In the diagram, he shows the Ediacaran as starting about 600 million years ago, but now most researchers peg that to about 635 million years ago, so the slow fuse is actually even longer than he shows. The Collier Shale in Arkansas is in the late Cambrian, so as you can see, several other groups are already present. The fact that we have thus far only found trilobites means that we may yet find more diverse types of fossils, so keep looking (and if you find anything, let us know)!
Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages.
By Dr. Thomas Holtz, Jr. Illustrated by Luis V. Rey.
Publication date 2007. 427 pg. Random House. ISBN: 978-0-375-82419-7.
Author: Dr. Holtz, self-proclaimed “King of the Dino Geeks,” or as I like to call him Dr. Tyrannosaur, is a well-known and respected paleontologist who’s understanding of all things tyrannosaur is unparalled. As a senior lecturer at the University of Maryland and the Faculty Director of the Science & Global Change Program for the College Park Scholars, he has extensive teaching experience. I have had the pleasure of attending several of his talks at meetings of the Society for Vertebrate Paleontology and he has always been informative and interesting and his students have always been very positive about him.
Illustrator: Luis Rey is an accomplished and respected artist, known especially for his paleo art. He has won the Society of Vertebrate Paleontology Lazendorf Award, given to outstanding artists and his artwork can be seen in several museums, books, and other outlets. He is known for very colorful dinosaurs with close attention to anatomical detail. He makes huge efforts to bring dinosaurs to life as actual, living creatures with as much accuracy as possible. A few have criticized his artwork for being too fanciful, in that he draws wattles and other structures on dinosaurs for which we have no hard evidence. But these structures are extremely difficult to preserve in fossils and their living relatives do have them. Matt Wedel, a noted dinosaur researcher in his own right (although he studies sauropods, not theropods like Dr. Holtz) has said, “If you go bold, you won’t be right; whatever you dream up is not going to be the same as whatever outlandish structure the animal actually had. On the other hand, if you don’t go bold, you’ll still be wrong, and now you’ll be boring, too.” Luis Rey has never been called boring.
I decided to start off my reviews with this book, even though it has been out since 2007, because I think every school should have it. There are good reasons it won “Outstanding Science Trade Books for Students K to 12: 2008 by the National Science Teachers Association. It is called an encyclopedia and it does have chapters describing all the various dinosaur groups, but it is so much more. It is not a small book and here is my only real criticism of the book. Despite its title, it is not quite a book for all ages (School Library Journal rated it Grade 5 and up and it would take an exceptional 5th grader to read it). If you are looking for a book to read to little kids, look somewhere else. It is called an encyclopedia for a reason. Nevertheless, with that caveat in mind, if you are looking for a book to give your dinosaur-obsessed kid who can read well, this book is for you. It is not just for kids though. Adult dinosaur enthusiasts will like it too.
What I like best about this book is that it does not simply focus on the dinosaurs. There are plenty of books that will give you an A-Z description of dinosaurs. Holtz gives the reader a feel for what paleontology is and how it works. The goal of this book is to explain why we think what we do about them, how we know what we know. He starts off the book discussing how science, particularly as it applies to paleontology. He then has a chapter on the field’s history, followed by three chapters of geology and geologic time to put everything into perspective. Chapters 5-9 discuss how paleontologists find fossils and attempt to reconstruct what they looked like and how they are related to each other. It is not until chapter 10 that he even starts talking about dinosaurs themselves and that chapter simply explains how they are related to other vertebrates. Chapters 11-35 are the meat of the book that everyone would expect. This is where he discusses the amazing diversity of dinosaurs. The last five chapters discuss dinosaur behavior and metabolism and how we approach topics like this that are not so easy to see in the fossils. The last three chapters then put the dinosaurs in context of time and ecology. Contrary to popular opinion, dinosaurs did not all live at the same time. They spanned a vast length of time and these chapters give the reader some sense of what the earth was like during the major time periods, who lived when and what other animals they lived with. The last chapter ends predictably with a discussion of extinction, but rather than just say the asteroid killed them all off, Holtz discusses some of the complications of that hypothesis, finishing off with how life continued after the asteroid impact (including the dinosaurs, who were only mostly dead, not completely dead, a few made it through and thrived as birds). At the end of the book is a series of tables listing all the dinosaurs, including where and when they lived and their estimated size and weight.
Holtz doesn’t go it alone either. Scattered throughout the chapters are inserts from other researchers (such as Dr. Kristi Curry Rogers shown here) explaining various topics related to their own research, so the reader gets the perspective of many paleontologists, not just the author’s.
A serious bonus for this book is that Dr. Holtz has attempted to keep the book as current as possible by posting online corrections necessitated by new research, which you can find here.
As a final word, the book is superbly illustrated with numerous drawings, both in monotone and vivid color, by Luis Rey. There are no images of actual fossils, which some have criticized the book for, but my personal feeling is that the book was not designed to be a textbook for dinosaurs. It was designed to show the dinosaurs as living animals, not simply as their bones. There are plenty of other places one can find that. This book is for a view of what they were like alive and most importantly, why we think they were like that shown here and how we study them.
For other reviews of this book, try here, here, here, and here, among others. All illustrations above can be found within the book, as well as the linked sites for Luis Rey and Dr. Rogers.
Forum Friday
Our first few posts here on Paleoaerie have discussed what we are about, why and what we are planning. Over on Facebook, we’ve discussed a lot of things that may be of interest to readers. We have discussed how to reach kids, why teaching how science works matters to everyone and certain TV shows and books that don’t think so or do it badly, as well as some that do it well. We noted interesting goings-on at the Museum of Discovery.
We found informative videos and free online courses on dinosaurs, evolution, the genetics of evolution, and human evolution. We found fossil databases, museum collections, and maps of the earth through time. We examined software available to teach science methods and concepts, use 3D modeling in class, upcoming TV shows, Next Generation Science Standards apps, as well as discussing the use of iPads in class. We found a request for scientists willing to work with classes. We even found card games of interest and the Whirlpool of Life.
We’ve discussed the role of evolution in pathogen virulence in disease, antibiotics and cancer, and how it can help manage fisheries .
We’ve covered the evolution of weird sharks, giant viruses, early mammals, and the earliest eukaryote. We learned about tyrannosaurs and why they weren’t scavengers, how dinosaurs grew feathers, lost their tails evolving into birds, what is and is not a dinosaur, and using dinosaurs to teach anatomy. We learned about exhibiting extinctions and what they mean to ecosystem health, surviving them, as well as de-extinctions. We learned when teeth evolved, the use of half a sucker, how carnivores become herbivores, and the evolution (or not) of intelligence. We learned about the role of chance in evolution and the haphazard way evolution builds things. We met Mouseunculus and found out just how big a billion really is.
We saw science art, art and science, and art in technology. We talked about Darwin and Wallace, asking scientists about their research, and the process of science correcting itself. And that’s not all.
Roman forum. Image from Wikipedia
We’ve said a lot, but a communication is not a one-way street. I’ve referred to Paleoaerie as “we” many times. Thus far, it’s mostly been “I” that has done the communicating. But let’s change that dynamic. Every couple of weeks or so, we will have Forum Friday. What’s a forum, you ask? Forums were originally a “marketplace or public square of an ancient Roman city” (Merriam-Webster). But more importantly, they were places people gathered to discuss things of interest to them, or simply just to converse and connect with others. Paleoaerie is more than what I bring to it. To really work, others need to contribute. Forum Fridays is a designated space for you to tell me what you want to see, what you want discussed, provide feedback and discussion on topics presented during the week. So let’s talk. I have one simple question: What do you want? (I promise, my name is not Morden, it will turn out better that it did for Ambassador Mollari).
But what have you done for me lately?
“No matter who you are, engaging in the quest to discover where and how things began tends to induce emotional fervor—as if knowing the beginning bestows upon you some form of fellowship with, or perhaps governance over, all that comes later. So what is true for life itself is no less true for the universe: knowing where you came from is no less important than knowing where you are going.” Neill DeGrasseTyson. “In the Beginning“. Natural History Magazine. September 2003.
Now that we’ve covered just what this blog is all about and why, it’s time to give you a more detailed look at what we propose to do and what you will find here. On this site, you will find blog posts, links to a variety of websites providing resources and information that have been either put together or verified by content experts, contact information for people that may be of use, and collections of material that are free to use. In the future, we hope to include material created by students and teachers that have been submitted for public dissemination.
The blog on the website will provide essays on several topics. The first and most common will be reviews of books, videos, games, and other resources, both online and off. Because few teachers can afford to go out and buy books for their classroom on a regular basis, they often rely on donations or library book sales to stock their book collections, so reviews will cover a variety of books, both old and new. As a parent myself, I have seen books in classrooms and ones used by teachers that were more than twenty years old. A few are still great books, a lot are either woefully out of date or were terrible to begin with and should be expunged. Hopefully, these reviews will help guide people to books that have quality information in them that are suitable to classrooms. Some books, like The Complete Dinosaur, 2nd edition or The Dinosauria, 2nd edition, are fantastic books, but are in many places rather technical and probably not something most teachers would stock in their classes (although they would have a happy home in a high school library).
Arkansas’s only dinosaur.
Another series of essays will cover the fossils and geologic history of Arkansas. Arkansas has a variety of fossils, from trilobites and bryozoans, fossil oysters and shark teeth, to saber-toothed cats, mastodons, whales, and even dinosaurs. One series will cover individual fossils highlighting the different types of fossils. If we get funding, we will include a 3D interactive image with every fossil we can. Another series will cover Arkansas through time. We have rocks from the Cambrian to the modern. Each essay will cover a selected time period, tell you where in Arkansas you can find rocks of that age, what type of environments they represent, and what sort of fossils you might find in them. It will take a long time, but should be an exciting series to write and as much fun to read. A third paleontologic series will cover common myths and misconceptions of dinosaurs, other prehistoric animals, and paleontologic concepts.
A simplified image of the Arkansas geologic map, available at http://www.geology.ar.gov
New resources will be added to the website as they become available. Pending funding, a series of teacher workshops are planned, with as much of the material as possible available for free download. Interactive lessons made using SoftChalk, Articulate, or other programs will be added. Additionally, other people are encouraged to design materials that, after being checked for accuracy, will be made available to everyone. The more people participate, the better and more useful the site will be. From teacher-designed tools to student presentations, all accurate and topical material will find a home here.
Education is more than just the transference of information. It is a discussion. An important part of this website will be to put people in touch with each other. Posting information by others is just one part. Discussions of how to teach difficult topics will be another. An important goal of this website is to connect scientists with educators in both formal and informal environments with parents, students and anyone else with an interest in learning more. Together, we can get more questions answered as we find ever more questions to ask. Change may be scary, but refusing to change is to be doomed to failure. Finding the right path forward, the right change, means we keep asking questions and helping each other find the answers.
Neil DeGrasse Tyson, Reddit IamI, 2012.
So what’s the problem and what do you plan to do about it?
In the first post, I outlined why I think evolution is important and a few reasons why I think people refuse to accept it. In this post, I will discuss a little more about why it is not taught much in Arkansas and the rest of the United States and what you can expect from this website to help change that.
Teachers make a difference in the classroom, what they teach and what they believe affects their students. Thus, it is disconcerting that only 28% of public school biology teachers consistently teach evolution according to the National Research Council science standards, with 13% actively teaching creationism, despite it being illegal. A full 60% ignore the topic altogether. This perhaps explains why the United States trails most other countries in science aptitude. Arkansas is on average a conservative state, with lower than average income and education levels, and so it is no surprise that Arkansas is below average in science aptitude as well.
So why do so many educators fail to teach evolution in their classes, particularly in Arkansas? There are several reasons. Educators often avoid teaching or only give a cursory introduction to these subjects out of personal ignorance and/or religious beliefs. Many of those who do teach it are unaware they are teaching highly inaccurate and out of date material and must contend with outright hostility from school administrators and parents who do not themselves understand or accept evolution. More than 20% of Arkansas secondary teachers are teaching out of their certified field and the requirements for certification are low to begin with (Arkansas is not alone in this and in fact is only marginally higher than the national average). For example, elementary teachers are often not required to have had any science beyond the minimum standards for their college education degree. Home schooling is also becoming more prevalent, with education provided by parents or informal educators with typically little training in either science or education. It’s also not enough to simply know the facts. There is a long path from the content to education. Getting students to learn accurate information requires passing through a number of filters. Even before that can happen, people have to realize that what they intuitively believe may not be right and their gut feelings may be wrong.
Educational path from content to youth. Content is filtered through the imperfect knowledge and abilities of educators in structured activities or other sources, which may or may not be accurate. Education is heavily influenced by the degree of parental involvement, which may be positive or negative, and is filtered through prior beliefs, which are themselves heavily influenced by parental beliefs. Image by Joe Daniel
How can we combat this problem? We cannot expect educators with little training in schools or homes that are cash-strapped and lacking resources to do a good job on their own. So we help them by providing resources they can access online for free (preferably) or small fees (if necessary). The internet is full of resources to fill every need and educators in the know can access myriad sources of knowledge and lesson plans. But the key to this is “in the know.” The internet is also full of misleading and false information. How is an educator that feels insufficiently prepared (be that learning the material, just looking for new ways to teach it, or wanting to provide additional resources for students and parents) to sort through the chaff and find the kernels of quality material? That’s where we come in, we can help them be “in the know.”
The Philosopher Diogenes searches for an honest man,1607 (woodcut) by English School, (16th century); Bibliotheque des Arts Decoratifs, Paris, France;
http://www.bridgemanart.com
This website is designed to provide information on resources that have been checked by content experts, so educators, parents, and students may be able to rely on the information. The website will take no position on religion, as it has no bearing on the science and the science is what this is all about. In addition to information on the science itself, information on educational methods, lesson plans, and available resources will be provided. We will help connect scientists with the rest of the public (scientists are people too). We hope to be a lantern in the darkness of confusion, a sieve to separate the gold from the fool’s gold. In the next blog post, I will cover just exactly how we plan to do that.
Greetings and Welcome!
Dinosaurs! In all the natural world, there is little that excites the imagination of most people as much as dinosaurs. They were big, bold, awe-inspiring and terrifying. Dinosaurs were giant reptilian monsters that ruled the earth until a giant meteor hit and wiped them all out, or a world-wide flood drowned them all.
At least, that is what many people imagine. For many people, their understanding of dinosaurs is vastly incomplete and outdated. For many others, it is wildly incorrect. For the vast majority, their view of dinosaurs is a tiny sliver, the smallest glimpse of the wonders dinosaurs truly represent.
This website is not really about dinosaurs, although we will talk about dinosaurs from time to time. We are really here to talk about evolution, to serve as a portal to resources available to teachers, students, parents, and the general public. So why start with dinosaurs? Because dinosaurs are endlessly fascinating, it is easy to start a conversation about dinosaurs. But like dinosaurs, the public view of evolution is incomplete, distorted, and in many cases, completely wrong.
Evolution is not well accepted in the United States. Most people will say it conflicts with their religious beliefs, but there are far too many people who share the religion and accept evolution for me to think religion is really why people do not accept evolution. I think it is a combination of four factors. 1) A fundamental misunderstanding of the nature of science and how it works. 2) They don’t understand what evolution really means because of how badly it generally gets taught, if it is taught, and the lies and distortions swirling about. 3) It is really hard to conceive of the vastness of time represented by the age of the earth. People simply are not used to thinking in terms of millions and billions of years. The monumental scale is beyond their experience. 4) But the biggest reason, I think, and the most important, is fear. If there is one thing people are afraid of and hate more than anything else, above even those of rival political parties, is change and uncertainty. Change is, without a doubt, stressful.
Evolution is the scientific embodiment of change and uncertainty in the living world. It is all about change, so of course evolution is frightening to many people. But life IS change. People are born, they grow old and die. The telegraph gave way to land-line phones, which gave way to smart phones and texting. We went from a nation in which only white male landowners could vote to one in which any adult was allowed to vote. We have witnessed the revolutions of the home computer and the internet; magnetic tapes to mp4 files in the cloud; letters to wireless communication supporting diverse, interconnected, social media networks. We have gone to the moon and back and sent probes out of the solar system. Life changes all around us every day and these changes we have witnessed are nothing compared to what is before us. The rate and scale of change is increasing and we have to prepare for that. We either embrace change and learn to adapt to it or we can try to deny it, resist it, and become roadkill, forgotten memories of a bygone era. If we want our children to succeed, we have to teach them to accept and deal with change or we are dooming our children and ourselves to failure.
Science literacy is crucial for understanding many of the most serious problems affecting society today and the unprecedented changes taking place in our society and the world as a whole. Evolutionary theory in particular forms the foundation of all modern biological thought and impacts our understanding of such diverse areas as medicine, climate change effects, agriculture, water and sewage treatment, sanitation, and overall ecology. As Dobzhansky famously stated, “Nothing in biology makes sense except in the light of evolution.”
But I have never understood the fear of evolution. Ignoring the practicalities of why understanding evolutionary theory is important to understand, it is just a grand way of viewing the world. Darwin said it well:
There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved. On the Origin of Species, 1860.
There truly is grandeur in the history of life on earth as seen through an evolutionary lens. Life is a marvel to behold. In the next post, I will discuss what this site is all about and what you can expect to find here (and why dinosaurs, in addition to they are just cool). I will go more in depth on the resources you may find here and the sorts of blog posts I will make, which will range from reviews and recommendations of books and other media, both old and new, descriptions of Arkansas fossils and geology, and myths and misconceptions. But for now, I invite you to come with me as we journey into the history of life on earth (and most especially in Arkansas). Learn about the fascinating creatures that once lived here and how the current ones came to be, how they live together in a living world, how and why we think what we do; and perhaps most importantly, learn ways to help others learn as well. As John Boswell portrays so magnificently at the Symphony of Science, it really is the greatest show on earth.
paleoaerie 
