Adam Savage and Jamie Hyneman of the Mythbusters do a great job of presenting commonly held myths and testing them in a variety of ways, trying and adjusting and retrying experiments. They even sometimes revisit myths with a new point of view and new questions. It is this that I think is the key to their success. They present science as a series of questions and experiments, revising and retesting, a dynamic process. Starting with what people believe and then presenting the evidence to show the real answer is an important part of the educational process. Derek Muller, who runs the Veritasium Youtube channel, did his PhD dissertation on just this topic, showing that simply providing the information did not increase learning. Unless the misconceptions the audience already held were first acknowledged and dealt with, people thought the material was clear and that they understood it, when in fact they had learned nothing at all.
All of this involves asking lots of questions. But what some teachers view as a downside to this approach (although it absolutely is not) is that invariably you will wind up with lots of questions you can’t answer. Your students will ask questions you have no idea what the answer might be. So what do you do in this case?
Hopefully, you already knew which of these options is the better choice. But where do you go to learn more? Some questions can be rather esoteric or have answers that can’t be easily looked up. Fortunately, hordes of scientists are at your beck and call to save the day. Here are four websites where you can ask real scientists any question you like. None of the scientists on these sites will do people’s homework for them, but are enthusiastic about answering questions.
Ask a Scientist has 30 scientists that will answer questions on biology, chemistry, physics, space, earth and environment, health, technology, and science careers. In addition, they have links to videos for some questions. You can look at answers to past questions and ask your own. Even though it is based in the United Kingdom, with all the scientists being from the U.K., they will answer questions from anyone.
This site is also based in the United Kingdom, but has scientists from all over the world. This site is limited to biology and paleontology, but it has over 100 scientists who can answer questions. Some are doctoral students, some are the tops in their field with decades of experience. All of them are experts in what they do and all of them are there to help. They have answered thousands of questions, all of which can be searched and read. If you don’t find what you are looking for, ask your own question. You might even find that you have started a lengthy discussion of your question between several experts, as has happened from time to time.
This Ask A Biologist is a National Science Foundation grantee and is hosted by Arizona State University. Again, it is limited to biology and is run by the biology faculty and graduate students of ASU. So on the one hand, you might think they might be more limited. But ASU has an extensive biology department and this site has much more ancillary material than most of the others. They have activities, stories,coloring pages, tons of images, videos, and links to other information. They have a teacher’s toolbox, providing easy searches for teachers to find exactly what they want, searchable by topic, activity, and grade level. In short, while they have several scientists available to answer questions, that is but one aspect of this educational site.
The Mad Sci Network has a huge amount of information. You can ask a question about anything. The site has experts from world class institutions available to answer questions. They have a searchable archive of over 36,000 questions already answered, so they may have already answered your question. In addition to the search features, they have several categories listed, in which you can pull up all the questions in those categories. They have a “Random Knowledge Generator” if you just want to have fun browsing at random. They also have a series of what they call “Mad Labs”, which are activities and experiments you can do at home or in the classroom. They have links to more information and resources elsewhere, including general science, educational methods and techniques, museums, science fairs, suppliers, and more.
So there you have it. When you are faced with questions you can’t answer, don’t try to bluff your way through. Who ya gonna call? Hundreds of scientists from around the world, that’s who.
In the last post, I covered good places to find 3D fossils. This post I want to cover how to make your own 3D images using photogrammetry. Photogrammetry is the process of turning a bunch of 2D photos into an interactive 3D image. Since I am not an expert on doing this, I am simply going to link you to a series of tutorials put together by Dr. Heinrich Mallison. Dr. Mallison describes himself as “a dinosaur biomech guy working at the Museum für Naturkunde Berlin.” If you would like to read more of his work, I suggest you check out his blog, Dinosaurpaleo, in which he blogs about his research. He also has links to a lot of his research papers and will happily send you pdfs of any other papers of his you want. Dr. Mallison is an expert on making 3D reconstructions using photogrammetry and has already done the legwork to give you all the information you need to get started.
Getting the Right Photo
Photogrammetry tutorial 1 begins with the logical starting point: the equipment. He recommends getting a good DSLR camera with a Life View touchscreen, circular polarizing filter, good tripod, turntable, and a ring flash for optimal pictures. Also, don’t forget the scale bar and stickers. The stickers will be helpful if you have to take our photos in two sets (for instance, if you have to move the object between sets). This will require making two models and stitching them together, which will be aided by small stickers that will serve as easily findable common points so you can properly align the models.
Photogrammetry tutorial 2 discusses general suggestions on how to take good pictures that you can use for the 3D model. Here he gives advice, such as maximizing the F-number to increase depth of field, balancing your exposure, the use of HDR (high dynamic range) images, and proper cropping of the images.
Photogrammetry tutorial 3 covers the use of turntables. He covers the type of specimens that work best, how to place the camera for the needed pictures and how to photograph with an eye for aligning the 3D models you create.
Photogrammetry tutorial 4 discusses techniques for photographing large, bulky specimens.
Photogrammetry tutorial 5 provides a ideo of the turntable method described in part 3.
Making the 3D Model
Finally in tutorial 6, Dr. Mallison finally gets around to actually building the model from the photos. If this indicates to you that getting good photos is essential to making good models, you would be correct. To add more to this, the writers of the blog Sauropod Vertebra Picture of the Week, or SV-POW, have a series of useful posts on how to take good photographs, manipulating them for good effect, making stereoscopic images, and much more great advice.
In this tutorial, Dr. Mallison discusses some of the programs that are available. He prefers Photoscan Pro from Agisoft. The downside to this program is that it costs $549, which is probably out of the price range for many people. The upside is that it is a versatile program designed for non-specialists. He discourages use of Autodesk 123D even though it is free because all of your work becomes the property of Autodesk 123D. He also states that others prefer Image Modeler, which is the professional version of Autodesk. It can do more than Photoscan Pro, but it will cost you much more. He also mentions VisualSFM and Meshlab, open source programs which together can be used to make 3D models and provides a link to a tutorial by a fellow paleontologist, Peter Falkingham, who tells you how to use those programs.
Of course, this isn’t the only wayto make 3D objects. Photogrammetry is only way to make quality 3D images. Laser-scanning is another great way to do so. If you have a few thousand dollars, I might recommend the NextEngine 3D laser scanner. It is not as expensive as some of the other laser scanners and does quite a bit at a comparable or better quality. As a caveat, neither the photogrammetry nor the 3D laser scanning will create the most detailed images. If you want truly detailed, high resolution images, then you really need a computed tomography, or more commonly just called CT, scanners. The downsides to that is that CT scans do not preserve the color of the objects, so you lose surface details related to color, and they are hideously expensive. But at least they are not as expensive as synchotron scans. Synchotron scanners are similar to CT scanners, but are much more powerful and can create images with much greater detail, but with only five available scanners, probably not something your average paleontologist, much less a hobbyist, is going to ever see.
Once you have your 3D objects of course, there is always the next possibility: 3D printing! For that, contact your local high-tech Maker Spaces, such as the Arkansas Regional Innovation Hub. There are several places you can go to buy your own 3D printer, such as Quintessential Universal Building Device, or QU-BD, in Little Rock, AR.
Full Disclosure: I have no monetary interests or any other vested interests in any of the people or companies linked to in this essay.
Jim Lane is talking about something that has been on the mind of a lot of education researchers lately. If you read much in the way of education literature at all, I am sure you will have run across many a discussion of how to improve learning by engaging the students with materials they find interesting and challenging them to solve relevant problems in a creative manner. Doing that means moving beyond the simple worksheets and memorization. It means using the newly available tools to bring the material to life and having the students work on, as one of Mr. Lane’s students called it, the edge of science.
Some of those new tools are in the realm of 3D scanning and modelling. This has allowed many museums and researchers to put some of their work online in a way that allows much more interaction than simple photos. You can, for instance, examine the head of a 2,200-year-old Chinese terracotta warrior housed at the Emperor Qin Shi Huang’s Mausoleum Site Museum or skeletons in an underwater cave from the comfort of your own home. This has great benefits for conservation and research, allowing digital preservation of fragile artifacts and researchers from all over the world to view the objects without having to spend the money to physically examine them. Much of the time, researchers will still want to see the real thing, but there are numerous studies that can be done with only the scanned images. There is even some research that can only be done on the scanned items, making the scans in a way, more important than the item itself. More to the point here, 3D scanning also opens up the object to viewing by people the world over, the vast majority of whom will never have the chance to visit the museum and see the real item.
So where can you see some of these items? There are several places on the net you can go. Here we will focus on those useful for evolutionary topics, such as fossils and anatomy (comparative anatomy with modern organisms is the heart of paleontological research). Many of the sites allow you to download the scans and print them out if you have access to a 3D printer, which are becoming increasingly common as the prices drop down to the point many individuals can buy their own and schools are starting to make them available to their students. Be warned, interactive 3D elements generally take a lot of graphics computation, so try to limit any other graphics you have up, i.e. close other browser windows, don’t try running a game in the background, the general rules of using a program with a lot of graphics. But as long as you have an up-to-date browser with Quicktime and Java, most computers these days should be able to handle it just fine (although a warning about Java, the security updates in the past year or so have made the more recent versions of java incompatible with earlier versions, so unless the developer for the site has updated their program, it may not work).
The following sites are in no particular order, so with that in mind, the first place on this list you might want to visit is Smithsonian X 3D, a website the Smithsonian recently put up showcasing objects from their collection they have scanned. At the moment, there is not a lot, but the site is new and they will be adding much more as they go along, so be sure to check back regularly. Right now, you can see 3D images of whale fossils, a mammoth, a blue crab, an orchid, a bee, and several other historical objects. Included in the collection is a scan of President Obama, the first ever 3D Presidential portrait. The basic 3D viewer is easy to use, although a few of the more advanced controls are not altogether intuitive. The website provides a brief description of each item, along with articles and videos on some of the items and the process of scanning them, including a page for educators on the use of the objects in the classroom. The Smithsonian also has more 3D collections on their human origins site. You might think that they would only have human fossils, but they have much more. You can certainly find hominid fossils, but along with them are numerous primates from Aye-Ayes to gorillas, and a large variety of other animals, from bears and cheetahs to komodo dragons and vultures. While you are there, you can a diverse array of information on human evolution, including teacher guides, lesson plans, multimedia, current research, everything you need to teach a human origins unit.
Another place you will want to check out is the Visual Interactive Anatomy pages by Dr. Lawrence Witmer at Ohio University. He and his students spend a lot of time scanning fossils and modern animals using a medical CT scanner at nearby O’Bleness Hospital or a micro-CT scanner on campus. They have put together several pages that illustrate the anatomy of several modern animals, including an opossum and the heads of a human, rhino, iguana, alligator hatchling, and ostrich. They have also collaborated with Dr. Casey Holliday on an adult alligator. The adult alligator page even has individual pages for every bone in the skull. On these pages, you will find interactive 3D pdfs and videos of the scans and reconstructions, which have a variety of structures labeled, identifying the bones, brain cavity, nasal passages, etc. In addition, you will find news and behind the scenes excerpts, and links to the published research on the specimens. On the 3D Visualizations page, you will find similar movies and 3D pdfs for a variety of dinosaurs (including Tyrannosaurus rex, Majungasaurus, and Euoplocephalus, along with several birds) and mammals from the platypus to deer to Archaeotherium, one of the group of animals often called “terror pigs”.
A website that is sure to grow is the NIH 3D Print Exchange. This site allows people to share their own 3D files for other people to download and use. The website focuses on biomedical applications, but currently you can find a variety of brains, bones, molecules, DIY lab equipment, and more. The more part I am sure will grow as people explore the site and add their own models. You can also find tutorials for making your own 3D models using 3D visualization software, and links to open source software such as Blender, FreeCAD, and Google Sketchup, as well as 3D printing services such as i.materialize and Makexyz and others.
Digimorph, or more properly Digital Morphology, a National Science Foundation Digital Library, is a site run by the CT facility at the University of Texas at Austin, one of the premier CT facilities in the country and the primary place American paleontologists go to get their fossils scanned. Digimorph provides access to these scans for the public and researchers the world over. On this site, you can find videos of scans and 3D reconstructions, some of which can be downloaded for 3D printing, for hundreds of animals, including a variety of avian and non-avian dinosaurs, along with extinct and modern species of mammals, reptiles, amphibians, fish, and even plants, coral, crustaceans and other invertebrates. Along with the scans and 3D reconstructions, you can find descriptions of each specimen, a bibliography of research published on them, and links to useful sites for software, information on CT scanning, and other related sites. The downside to the site is they provide nothing specific for educators and the specimens that have downloadable 3D renderings are a small fraction of the total specimens available in video form, and none of them of the dinosaurs, which are only available as video animations. Nevertheless, for sheer quantity of 3D images for a diversity of animals, there is no place better.
The final site on the list is swiftly becoming the place to go for virtual fossils.GB3D Type Fossils Online project, or simply GB3D, is a website run by the British Geological Survey, Amgueddfa Cymru (National Museum of Wales), Oxford University Museum of Natural History, and the Sedgwick Museum of Earth Sciences. As the name suggests, the site is a repository for information of “type” fossils. If you don’t know what a “type” is, they have a handy guide explaining the different types. In this case, they aren’t talking about what kind of fossil it is, but things like holotypes, fossils designated in the original description of the fossil, which all others are compared to, which make them very important to scientists studying those kinds of fossils. If you want to see United Kingdom fossils, this is the place to go. They have hundreds of fossils in 3D and hundreds more in 2D. On this site, you will find a great diversity of plants and animals with high quality photographs, many of them also have stereophotos (get your 3D glasses with those red and blue lenses) and 3D models. In addition, you will find information about the fossil, such as what it is, when and where it was collected, how old it is, and contact information for the institution that holds the fossil itself. They also have a page describing the more commonly found fossils, all of which happen to be various invertebrates or fish. You will also find free programs used to view and work with 3D images you can download. They have available MeshLab, SPIERSview, and Adobe 3D Pdf Reader. Finally, you will also find links to a variety of educational resources for primary and secondary schools, universities, and the public.
If you want to inspire people to learn, you have to bring them right up to the edge of that knowledge cliff so they can peer over it at the wondrous space beyond, exposing them to the unknown in all its glorious mystery. Help them understand the foundations of the cliff, teach them how to build their own wings, and then push them off that cliff so they can soar into uncharted regions. When they return, they will have a better grasp of how the cliff is formed and what its boundaries are. They just might also find that cliff sticking out a little farther than when they flew off it. And when they do, you won’t have to push them, they will leap on their own. Of course, you will then have another problem: keeping up with your students. So keep your own wings in good repair. I do hope I have helped you build your wings a little stronger. If you know of any other sites that may be of use, please let us know in the comments section.
I will let Dr. Witmer finish this out and let him explain a bit about his projects and why approaches like this, particularly with dinosaurs, are useful educational tools.
In a quick review, I would like to discuss the website by Lin and Don Donn, http://earlyhumans.mrdonn.org/evolution.html.
This website is part of a much larger website that is filled with a lot of information on all sorts of history. As Mr. Donn states, they do not claim to be experts in anything, so do not claim everything on the site is correct, although they do try. It is clear they have put a great deal of time and effort into making a substantial site with the honest intention of providing accurate and useful information to teachers. They have won awards for an impressive site. However, in the evolution of humans, they seriously fall down.
The early humans website has several links to good resources. Unfortunately, it has two things that destroy the science educational credibility of the site completely. The first is a link to a presentation teaching Biblical creationism, a subject that has no place in a public school as it is both scientifically invalid and pushes one specific religious view, which is illegal in the United States. Regardless of whether one believes in creationism or not, it is not legal to teach a specific religion in public schools and it is especially not valid to teach that religious view in a science class. The only way to make this legal would be to teach the creationism stories of every other religion equally, without comment as to which one the teacher believed, which would be impossible. Even then, it would have to be in a religious studies class, not a science class. If we are to preserve everyone’s First Amendment rights to freedom of religion, we simply cannot have government-run public schools teach one religious view and we certainly cannot teach that view as a scientifically valid theory. I am hitting this point especially hard because it is a serious point of controversy in the United States, but it should not be. Keeping creationism out of the schools is not an attempt to suppress anyone’s views. It is an attempt to preserve everyone’s right to make their own religious choices without government interference.
That leads me into the second problem, one which is stated boldly right up front. One of the big problems we have in science literacy is that many people do not understand the difference between the colloquial use of the term “theory” and the scientific meaning of the term. To quote the website: “A theory is a guess based on some facts. Remember a theory is not proven. One of the great controversies of our time has been the theory of evolution.” This is massively wrong in two areas.
The term they have defined is NOT a theory. What they defined was SPECULATION. Anyone can come up with an idea, but that does not make it a scientific theory. First, one must have a hypothesis, which is a testable idea, based on observation, that explains a relationship between two or more measurable things. There are two critical parts to this. The observations, so it must be an attempt to explain something we actually see in the real world. Second, that explanation must be testable. If there is no conceivable way to test it, the idea remains in the realm of speculation and can never be taken as a scientific theory, or even a valid hypothesis.
Once one has a series of hypotheses that have been tested by many people, none of whom have been able to disprove the hypotheses, one can formulate a scientific theory. That theory ties the hypotheses together, explaining numerous detailed observations into an explanatory framework that applies broadly. An example of this is the Theory of Gravity. Numerous observations were made showing gravity exists, there is no doubt about that. Many observations showed precisely how it worked and the relationship of different masses to each other, both on earth and in the universe as a whole. However, to make a theory, we needed more than these observations, we needed a way to accurately describe and predict these relationships. Isaac Newton discovered a mathematical equation that could be used to predict the motions of the planets. That equation was then tested many times and found to be valid everywhere, at least at the speeds attained by most things in the universe. Einstein went further with his Theory of Relativity, which extended our understanding of gravity into realms beyond the experience of everyday existence. Even here, these started out as hypotheses, requiring many people to test over and over gain. Not only has no one been able to prove them wrong, but no one has come up with an explanation that better fits the data. Therein lies the key, testing and testing and basing the acceptance of the theory on data, evidence that either supports or disproves the theory. Without that, it is not a theory.
As such, there is no Law of Gravity. We know it exists, it is fact that is undeniable. The Theory of Gravity provides a framework in which gravity works that has been put to the test. In a similar fashion, there is no Law of Evolution. We know it exists, it is a fact that is undeniable. Why? Because the idea that biological life forms change over time is something that cannot be argued against. All one has to do is acknowledge we are not clones of our parents, or look at the diversity of changes brought about by dog and cat breeders, sheep and cow breeders. We see biological change all around us. Evolution is therefore a fact, just like gravity. The Theory of Evolution put forth by Darwin is more properly called the Theory of Natural Selection, which explained this change through the aforementioned natural selection. It has been tested numerous times and shown to work. Is natural selection the only way in which species change? No, but it is a major mechanism. But the point here is that it has been tested and retested. Like all scientific theories, it is not simply a guess based on a few facts. It is permissible to argue about specific mechanisms, but trying to argue whether or not evolution occurs is like arguing whether or not the earth is flat or that we need air to survive.
I have been working on lectures on early amniote evolution, along with the following reptilomorph and synapsid lectures for my vertebrate paleontology course. We will be getting into dinosaurs and the other Mesozoic animals very soon, hooray! However, in preparing these talks, it has brought to my attention just how prevalent two sites in particular are: Reptileevolution.com and Pteresaurheresies.wordpress.com.
When I did a search for “pterosaur”, Google actually responded by saying “Did you mean pterosaur heresies” and provided images that all but one are either from the site or sites complaining about the site.
This is quite unfortunate. Both sites present an abundance of beautiful artwork done by a stellar paleoartist. There is an abundance of information on the animals and their relationships. All in all, the websites look fantastic and are quite the draw for paleo-enthusiasts.
But it is all wrong.
None of the hypotheses presented on these pages is accepted by virtually any other paleontologist. The techniques used to gather the information is not considered valid and no one who has tried to reproduce the data using the methods have had any success.
I won’t get into details about why the websites are wrong. I am frankly not qualified enough to provide a step-by-step breakdown of the problems (not being an expert in either pterosaurs or basal tetrapods), nor do I really have the time. I will say that many years ago, I heard the author of these websites give a talk about his evidence for a vampiric pterosaur and even as a young undergraduate, it was clear to me that neither the technique nor the conclusions were valid. I found it very unfortunate because the idea of a vampiric pterosaur was incredibly cool and the technique, which involves detailed image study, is useful in many contexts. However, it is very easy to let personal biases enter into conclusion based on these methods, to allow oneself to extrapolate well beyond anything the data can actually support. Oftentimes, those biases are completely unknown to the observer simply due to the way our brains interpret sensory input and modifies them based on past experience. We really do not see everything we think we see, which is why the scientific method requires other scientists examining your conclusions and your methods and trying to poke holes in your ideas. So it is vital to recheck one’s conclusions with many detailed images from various angles and lighting methods and, most importantly, detailed examination of the fossil itself.
So instead, I will point you to articles written by people who are experts in the very animals that are discussed on those pages and what they have to say about them. The first is an article by Dr. Christopher Bennett, who is an expert on pterosaurs. In this article, he discusses the validity of the techniques and discusses specific claims of two pterosaurs in particular, Anurognathus and Pterodactylus. Anurognathus is a very odd-looking pterosaur and is quite aptly named “frog mouth.” Pterodactylus is probably the most famous pterosaur next to Pteranodon and is why so many people mistakenly refer to all pterosaurs as pterodactyls. Dr. Bennett does an excellent job critiquing the science in a professional and readable way.
The second article is a blog post by Darren Naish, a noted researcher and science author that has researched pterosaurs and many other animals who has a deep understanding of both the accepted science and the author of these websites and the work presented therein. Here is what he says: “ReptileEvolution.com does not represent a trustworthy source that people should consult or rely on.Students, amateur researchers and the lay public should be strongly advised to avoid or ignore it.” The emphasis is completely his. The post is quite long and discusses several aspects of the work, discussing the accepted science and the material on the websites that is not accurate, including the techniques used to arrive at the conclusions, both accepted techniques and those by the website author that are not.
The next site is an article by Pterosaur.net, a website devoted to research on pterosaurs by pterosaur researchers. It is a brief article that uses Naish’s article as a starting point and continues on with a discussion of why they think it important for people to know why these sites should be avoided. To quote: “The issue taken with ReptileEvolution.com is not that it exists, but that it’s internet presence has grown to the point that it is now a top-listed site for many palaeo-based searches. Tap virtually any Mesozoic reptile species into Google and either ReptileEvolution.com or the Pterosaur Heresies is likely to be in the first few hits. The situation is even worse for image searches, which are increasingly dominated by the many graphics that Peters’ uses on his sites.” This would not be a problem that the sites are so well known if they were correct, but their prevalence presents a highly flawed version of what scientists really think. People are taking these sites as truth, when in fact they are regarded by professionals as seriously wrong.
Finally, Brian Switek, a science writer who authors the blog Laelaps, which moved from Wired Science Blogs to National Geographic and the now-defunct blog Dinosaur Tracking for the Smithsonian, wrote a piece on the site, in which he urged more paleontologists and paleontology blogs to call out misleading websites like these. In that spirit, I hope I can help some avoid getting a mistaken impression of dinosaur science and help steer them to better, more reliable sources.
* If you are wondering why I say “the author” or “the artist” rather than using the person’s name, it is because I don’t want this to be about the person, but the information. I don’t personally know the author, nor have I ever had direct contact, so I have nothing to say about the person. The work, however, can be and should be open for criticism, just like any other researcher, including my own.
Teaching how all life is interrelated is a whole lot easier if you can show something akin to a family tree for living organisms. The Paleobiology Database has all the fossils organized by taxonomic relationships to help you find things in the database, but it is not very useful for visualizations. The Encyclopedia of Life has lot of information and multimedia available for over a million individual species and shows how they are classified and is quite useful if one is looking for information on a particular species. But again, it is not very visual.
The Tree of Life website is an excellent website providing a great deal of information on phylogenetic relationships (for good discussion of phylogenetics, try here and here), providing abundant references on the primary literature discussing how scientists think various organisms are related. They work in collaboration with the Encyclopedia of Life, with the EOL focusing on species pages and TOL focusing on relationships. On TOL, one can start at the base of the tree and click on various branches following different groups into smaller and smaller groups, with each page providing what groups are descended from the starting group. For instance, the base of the tree starts with links to eubacteria, eukaryotes, and archaea, with viruses with a question mark. Each one is hyperlinked to a page discussing relationships within that group. It also provides a discussion of possible alternative branchings as well. Thus, the relationships are not presented as “we know this to be true,” but as an active, ongoing process of discovery and research. It is often highly technical, but would be extremely useful for high school students working on an evolutionary or biodiversity topic.
The Tree of Life and the Encyclopedia of Life are great sources for information on species and their phylogenetic relationships, but if you want better visualizations of the sum total of biodiversity, there are other websites that are definitely worth your time.
The first I would like to mention is the Tree of Life interactive by the Wellcome Trust and BBC. Watch the great video with David Attenborough first, then dive into the tree itself. The tree simplifies life to about 100 representative species. It is seriously weighted toward mammals, so provides a very skewed version of biodiversity, but the presentation should appeal to those who are most interested in the overall development from bacteria to humans. If once clicks on any individual species, it highlights the path to the base of the tree and provides a text description and in some cases pictures, a video, and locations. Click on another species and the path to the last common ancestor of the two selected species is highlighted. All the files are open source and available for free download, including the images and videos.
Another interesting site is the Time Tree. This site has a poster that shows 1610 families of organisms available for free download. The poster does a better job of showing the true diversity, but is still heavily weighted towards eukaryotes. However, the real purpose of the site is to provide divergence dates between two species. Simply type in two species names using either scientific (say, Homo sapiens and Gallus gallus) or common name (say, human and chicken) and it will provide how long ago their last common ancestor lived. It should be noted here that the dates listed are estimates based on molecular data. They should not be considered as conclusive dates or anywhere near as precise as listed. Indeed, the value given is a mean value of several estimates, with the median value also given, as well as what they call an “expert result” (which they sadly do not explain). In addition, they provide the scientific references the results came from and the dates provided for each, which can be quite broad. In the example above, those values range from 196.5 to 328.4 million years ago, but of the nine studies listed, all but two fall within 317.9 and 328.4 million years ago. There is also a mobile version of the site, as well as an iPhone/iPad app, as well as a book.
Another site of interest is Evogeneao.com. They have an interesting Great Tree of Life, as they call it, which like most others is heavily weighted toward eukaryotes. They have good explanations of evolution, along with a set of resources for teachers, including an interesting suggestion for how to introduce evolution to students. The interesting part of this site is their discussion of evolutionary genealogy, in which they extend the idea of a family tree farther back than it typically seen. They provide methods to calculate how far removed you are from other species. You can pick from a list of animals and it will tell you how closely you are related. For instance, choosing dolphin returns an estimate of 27 millionth cousin, 9 million times removed. That nicely encapsulates not only the idea of relatedness, but the immense scales of time we are talking about.
The Interactive Tree of Life, or iTOL, is another interesting site that may be of interest to high school teachers. This site utilizes genomic data as the basis of its trees and, unlike the others, provides a better visual indicating how truly diverse prokaryotes are in relation to us. It also allows you to print out phylogenetic trees in different formats, depending on your preferences and what sort of information you want to display. You can even upload your own data if you wish, but most teachers will likely choose to stick with the displays already provided, as there are simpler programs to deal with trees that any but the most precocious senior high school student (or college student for that matter) may wish to create.
There are a few other interactive trees out there that may be more appropriate to younger viewers. One is at the London Natural History Museum website. This one is very simplistic, having only sixteen branches, with four of them being primates, but it gets the point across. This interactive is limited to providing the link between any two branches and the name of the group containing both. For instance, clicking on the banana and the butterfly gives the name Eukaryota. Another site provides an interactive for the poster Charles Darwin’s Tree of Life. This interactive allows one to zoom in on any part of the tree and if one clicks on an animal, a short description of the animal is provided. Sadly, the two best interactives I have yet seen are not available on the internet. I had the opportunity to explore DeepTree at the Harvard Natural History Museum and it is truly spectacular, as is their FloTree. If you get a chance to see them, you should. Hopefully, one day they will be available in a broader format than now.
All of this assumes of course, that people actually know how to read these trees, which is a false assumption in that most people really do not. So it would be useful to spend some time getting familiar with proper interpretation of them before using them in class. There are several resources explaining this (such as here and a really excellent video here), so I will not put a tutorial on here unless there are requests to do so.
All images posted here are from the websites being discussed and are copyrighted to them.
It may seem that the earth is pretty stable. You can always count on the mountains being there when you look for them. But the Earth is a dynamic place. Volcanoes, floods, landslides, and earthquakes all change the landscape in ways we can see quickly. What we don’t typically see is that if we expand these processes over long periods of time, those same processes alter the landscape far beyond our experiences. The surface of the Earth is covered in a crust broken up into numerous plates, which are constantly shifting and moving. The plates only move between 2.5 – 15 cm/year (the previous link contains information on how this is measured and provides activities for teachers for use in the classroom), but add this up over millions of years and the Earth looks quite different. Add into this mountain-building and erosion wearing down the mountains and you get radically different geographies for the planet.
So what did the Earth look like in the past? There are two excellent sources providing maps of the planet through time. The first is the PALEOMAP Project, by Dr. Christopher Scotese. On this website, you will find maps ranging from 650 million years ago to the modern day and even into the future. There are 3D animated globes and interactive maps. He includes a methods section for how the maps wer put together and a list of references and publications. There is also a climate history section providing brief descriptions of the climate at various points in time. For teachers, there are several educational resources available, some of which are free, but others are available for a fee. There is even an app for the iPhone/iPad. It is not available yet for either android or Windows, but that has been admirably taken care of by the Howard Hughes Medical Institute with their Earthviewer app and they have done a wonderful job. the app is fully interactive, allowing easy scrolling through time and full rotation of the globe. You can also track atmospheric oxygen and carbon dioxide, day length, important fossils, biological and geological events, and major meteor impacts. The app even provides a bibliography of their source material. In addition to the maps from Dr. Scotese, the app extends the timeline back to 4.5 billion years (although this extension is obviously not nearly as detailed as the Scotese maps due to the greatly extended time and the greatly decreased amount of available data). All in all, a great app, also reviewed by the NSTA.
The second site that will be of interest is the Library of Paleogeography run by Dr. Ron Blakely. These maps cover approximately the same time frame as those provided by Dr. Scotese and are not animated. However, Dr. Blakely provides maps in different projections and provides regional coverage beyond that of global maps. So if you are specifically interested in paleogeographic maps of North America and Europe, this is an excellent resource.
A third site also provides paleogeographic maps which are very useful. In this case, the maps are secondary to the main purpose of mapping fossil locations. The Paleobiology Database contains records of fossil locations that have been published in the primary literature. One can perform a search by organism or group, country, rock unit or type, time interval, paleoenvironment, or publication. The results from the search are mapped onto global maps based on the PALEMAP Project.
All of these sources are available to the public and are used by professional researchers. Therefore, one can safely assume they represent accurate assessments of current, generally accepted thoughts on our Earth through time. You may notice that maps from Scotese and Blakely may not completely agree on all aspects. This is because it is very hard to piece together all the evidence and trace the movements of the continents backwards through time. Often, the data is incomplete and they have to make judgment calls based on the available evidence. Not everyone makes the same choices. This is true even for maps of current geography and is even more so for paleogeography. As we get more data and better techniques, those disagreements become fewer and fewer, but there is still much work to be done, so these maps can and will most likely be refined in the future to reflect new research.
Time. My day job has kept me extraordinarily busy and away from paleoaerie for a while, thus the lack of new posts here recently, so I thought now would be a good time to discuss temporal issues. Fortunately, things have calmed down a bit and I can get back to working on evolving the website. Speaking of which, it is time I got started.
Time is a subject about which much has been written, especially about our perceptions of time. One of the difficulties some people have with evolution is they don’t see how small changes in a population could lead to the diversity of life we see. They read about small changes in bacteria or they hear about how the average height and longevity of people have changed in the past few decades. They understand that a wide variety of dogs have been created through artificial breeding. But, the dog is still a dog, the bacterium is still a bacterium, people have not changed in their personal experience.
Unfortunately, they do not see how their personal experience misleads them. To them, the world is essentially unchanging. While human culture may change, the mountains do not move and species do not change. It is a common human tendency to assume that whatever is now has been and will always be. However, while we may think of hundreds of years as ancient history and thousands of years as vast swaths of time, they are a tiny speck of how long evolution has been altering life on this planet.
So how does one get people to comprehend the incomprehensibly vast time frames we are talking about? People have tried several ways. One could always simply show them the geologic time scale.
This is the standard geologic time scale used by professionals the world over, put out by the Geological Society of America. But to most people, this doesn’t really help. It is words and numbers and humans are just not that good at really getting a gut level understanding of figures like this. So many people have come up with a variety of metaphors. A common metaphor is compressing the age of the universe into a single year, a la the Cosmic Calendar, as popularized by Carl Sagan and expanded upon nicely by Arif Babul at the University of Victoria.
The idea of condensing all of time into a calendar can be re-envisioned as a clock. If we extend the circular motif to three dimensions, we find another popular image in that of a great spiral of life.
We could also think of time as distance. If, for instance, we decided to get in our car at the Jacksonville, FL airport and drive west and we thought of each mile being 1,000,000 years, we would have to drive to Fairbanks, AL to reach the whole age of the earth. All of human history would be passed by in less than two standard car lengths. An hour into your drive you would pass the asteroid marking the end of the Cretaceous Period and the demise of the non-avian dinosaurs. You would barely be into Tennessee before you passed the Cambrian Explosion over 500,000,000 years ago. By the time you got back to the origins of life, you would be entering the Yukon territories in Canada.
Perhaps you would prefer an interactive in which time was expressed in terms of size.
These are just a few of the ways that time spans can be visualized. Are you looking for something you can bring into a classroom that the students can touch and experiment with? Try having them build a timeline of their own. What is your favorite? Do you have other ideas?