Jurassic Park, etc.: The Evolution of Reptiles (March 25-29)

This week we return to those wonderful reptiles, finally covering the dinosaurs. As you may imagine, the Web is rich in sites about these beasts. Some of these pages are excellent, some are horrible, most are tolerable (and long). The American Museum of Natural History has an excellent dinosaur website. Their dinosaur facts page is good too. You want YouTube dinosaurs? Click away and spend hours. Other impressive dinosaur websites include that of Paul Sereno, one of the most productive dinosaur paleontologists in the world and virtually an industry to himself. I can vouch for the accuracy, more or less, of the Wikipedia page on dinosaurs. The Dino Directory from the Natural History Museum in London is useful and current. The LiveScience site has the latest dinosaur news.

Your second test will be on Friday, April 5. Our review session is on Thursday, April 4, 3:30 – 4:30 p.m. Here is a copy of the Fall 2018 second test for your study. (No student answers this time.) Your test, of course, will be different. Those student answers are not optimum, just good enough for full credit. As with all sample tests, our current class has covered somewhat different material. Test seating: Students with last names starting with M through Z in Room 205 (our regular room); A-L in Room 216 (across the lobby). Test doors open at 7:50 a.m.; all tests due at 8:50 a.m.

Here  is our Classification of the Phylum Chordata used in this course. It is a list edited just for you. Yes, you do need to know all these names.

Girl and dinosaur at the Creation Museum in northern Kentucky. For this to make any sense, you’ll want to read my Wooster Geologists blog entry about our visit. (Click to expand the image.)

Geology in the News –

At least one Cretaceous shark (Squalicorax) ate one pterosaur (Pteranodon) based on a chewed-up wing bone. Must have been quite a scene at the time!

Here’s an interesting article speculating on how the dinosaurs would have fared without the asteroid impact. It turns out to be a complex statistical problem to solve. Of course, we mean the non-avian dinosaurs!

A new reconstruction of Tyrannosaurus rex is now on display at the American Museum of Natural History, and it is a feathery masterpiece. Not without controversy, of course!

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Plate Tectonics (March 4-8)

Our primary topic this week is the Theory of Plate Tectonics, with an emphasis on how the dynamic Earth has affected the evolution of life. We can start with this beautiful world map, showing continents, mountains, ridges, transform faults and trenches in the Pacific and Atlantic Oceans. An excellent, world-class site for ancient maps of the evolving Earth is the Paleomap Project. The US Geological Survey has a thorough site called This Dynamic Earth which covers the basics of plate tectonic theory. The University of Texas hosts The Plates Project which concentrates on producing accurate plate reconstructions of the past. Of course, plate tectonics is an ideal subject for web animations. PBS reviews plate tectonic theory with a simple and clear set of images and animations. Here is a global history of continental movement in the last 750 million years from UC Berkeley. This YouTube video on plate tectonics is narrated with a cool Irish accent.

Here, by the way, is a description of the Ordovician fossiliferous marine limestone at the top of Mount Everest. That fact alone shows the incredible dynamic nature of the Earth’s crust.

As for the primary effect of plate tectonics on us, visit the real-time global earthquake website maintained by the U.S. Geological Survey. You will see how very common earthquakes are around the world, and where you do not want to buy a house. PBS has a nice set of animations of earthquakes from a global perspective, along with volcanoes and the geological phenomenon we now know all too well, tsunamis. Here are summary pages on the devastating 2004 tsunami in the Indian Ocean, the January 2010 Haiti Earthquake and the 2011 earthquake and tsunami in Japan. Note that geologists are still debating the origins of the tsunami.

Remember: Osgood Lecture on March 5, 7:30 pm, Lean Lecture Room (required) — “Invasive species, mass extinctions, and biotic radiations: lessons for today from oceans of the past” (Dr. Alycia Stigall, Ohio University).

Bristlecone Pine in the White Mountains of eastern California.

Geology in the News –

Your fellow student Grant found this YouTube posting of Walking With Monsters. The first half-hour has many dramatic reconstructions of animals you now know, from the Burgess Shale critters and earliest fish to amphibians. Thanks, Grant.

Climate change is both threatening archaeological (and geological) sites and revealing new artifacts and rocks. I suppose we can conclude that there are some silver linings as the ice relentlessly retreats.

Nice images of dry river beds on Mars, showing direct evidence for its watery past. Where all that water went is a mystery.

Did you know that two-thirds of known meteorites have been collected in Antarctica? You’ll see why after reading this recent account of a British expedition.

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The Amniotic Egg: Amphibians to Reptiles (February 25 – March 1)

I’m ignoring the fact that we’re still a day behind, alas. Please review the links for last week so you’re up to speed on the amphibians. Their descendants the reptiles are an enormously successful class, and their diversity is reflected in the websites devoted to them. I can only give you links to a few of the many groups we will discuss in class this week. (Just wait until we get to the dinosaurs!) You will want to study the wonders of the amniotic egg. Here’s an introductory page to the turtles, and then another for the diapsids. Everything you want to know about the therapsids (“mammal-like reptiles”) can be found here. The best general reptile page I’ve found is from Heidelberg, Germany. It has many  informative (and richly illustrated) pages in English. I’m sure you’ll also like this mosasaur page from the South Dakota School of Mines and Technology Museum of Geology. (I learned a cool mosasaur story during a visit to The Netherlands.) The Wikipedia pages on plesiosaurs and ichthyosaurs are well done. (If they weren’t, we would fix them!) I enjoy this elaborate Oceans of Kansas site, which concentrates on the Late Cretaceous reptiles of the Western Interior.

An amphibious ancestor to the ichthyosaurs was recently discovered in the Triassic of China. This is big news because prior to this the origin of these elegant marine reptiles was a mystery.

A pivotal event in Mesozoic reptile evolution was the Triassic mass extinction, which is well covered (yet again) by Wikipedia. The rise of the dinosaurs starts soon after.

Here  is our Classification of the Phylum Chordata used in this course. It is a list edited just for you. Yes, you do need to know all these names. This is the fish evolution diagram we’ve been using in class.

Mosasaur front paddle (Cretaceous); Natural History Museum of Maastricht, The Netherlands.

Geology in the News –

Here is a recent story on Dickinsonia from the Ediacaran. Biomarkers (you remember those) show that it was an animal. This is not a surprising conclusion, but a cool technique.

A newly discovered sauropod dinosaur in Argentina has extended neural spines, headlined as having a “bony Mohawk”. These spines were not weapons and may have had sexual selection value.

Melting glaciers in Greenland (bad news) are forming new deposits of sand (good news). I had no idea plain old quartz sand had such economic value. There are even sand-based mafia!

A gorgeous multi-layered, multi-spectral view of the Whirlpool Galaxy, courtesy of the venerable Hubble Space Telescope.

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From Fins to Feet: Early Vertebrate Evolution (February 18-22)

This week we return to the Paleozoic and examine developing marine communities, followed by a discussion of the causes of the Permian Mass Extinctions — the greatest disaster in the History of Life. Paleogeographic maps of Pangaea at the end of the Permian can be found on the Paleomap website (note that it was not “99% of all life” which went extinct). Wikipedia has a good Permian Extinctions article, although the topic is controversial enough that some parts of it may be biased by partisan editors of one cause or another.

The End-Permian Extinction happened much more rapidly than we previously thought. In fact, from this study, it was geologically instantaneous. Life was doing OK until quite suddenly a tipping point was reached to throw it into catastrophe.

Probably on Friday our vertebrate cousins will appear in our narrative. The best place on the Web for simple and thorough descriptions of the chordates and their history is at the University of California Museum of Paleontology. Check out their pages on the urochordates (tunicates), cephalochordates, and chordates in general. The Berkeley tetrapod (four-legged) webpage is especially useful for us. I like this website lovingly devoted to the ancient coelacanth fish Latimeria. It has many illustrations and an extensive history of what we know about this remarkable evolutionary survivor. The Tree of Life page on terrestrial vertebrates will show you current ideas about the relationships of fish and early amphibians. It is a rich source of further links. You might like the short Japanese 3-D animation of Eusthenopteron (an ancient bony fish near the origin of the amphibians) embedded in this link.

Here is a good general page from Wikipedia on amphibians.

Your first test results: The average for Test #1 was 85%. The breakdown was 90s (12), 80s (8), 70s (6) 60s (2), below 60 (1). The highest score was 98.5%. Two-thirds of the scores were essentially A or B, which is very good. here are the Spring 2019 student HOL test #1 answers.

A pycnodontid fish tooth, Menuha Formation (Upper Cretaceous), southern Israel. Collected by Andrew Retzler. (Click to enlarge.)

Geology in the News –

The insect apocalypse is upon us. We are in the midst of a terrible Mass Extinction equivalent to some of the worst we’ve seen in the fossil record. Insect losses signal ecosystem collapse. Yikes.

Hummingbirds, little sweet hummingbirds, have a fantastic evolutionary history of violent competition with their elaborate beaks. This is a well-written and illustrated account in the New York Times.

It’s not very often we see evidence of cancer in the fossil record. Recently a leg bone of one of the earliest turtles (Triassic) was found to show signs of bone cancer. Most unusual.

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Developing Marine Ecosystems (February 11-15)

Your first lecture examination is on Friday, February 15. For preparation, linked here is a sample test and the Fall 2018 student HOL test #1 answers. I highly recommend reading it through. The student answers are not necessarily the best, but they were good enough to receive full credit. Note that there are always topics we covered in the past that we may not have done this semester, and vice versa. Test seating: Students with last names starting with A through L in Room 205 (our regular room); M-Z in Room 216 (across the lobby). Test doors open at 7:50 a.m.; all tests due at 8:50 a.m.

Our topic this week is the rise of animal life and the early development of marine communities. A good place to start is with the Wikipedia page on the Ediacaran Biota. The Wikipedia pages on all these topics are good and authoritative. Another example is the Cambrian article.

We will spend time on the appearance of skeleton-bearing invertebrates in the Cambrian. I hope you enjoy the Burgess Shale (this is the Smithsonian’s main page on it), found in the Middle Cambrian. Here is the Smithsonian’s Burgess Shale reconstructed images page. (I was fortunate to visit the Burgess Shale quarries in British Columbia.) This virtual submarine website from the Royal Ontario Museum has great animated images of the Burgess Shale fauna. A new site of Burgess Shale-type fossils in Kootenay National Park in Canada was announced recently. It may soon rival the original for number and diversity of soft-bodied fossils.

You may enjoy this blog post from the superlative science writer Carl Zimmer on the Cambrian animals. (The illustrations by Quade Paul are stunning.) Zimmer also has a New York Times article on new ideas about “Evolution’s Big Bang” in the Cambrian.

Anomalocaridid “arm” from the Burgess Shale, Walcott Quarry, British Columbia, Canada.

Geology in the News –

Dr. Rick Lehtinen recently named a new frog species after our treasured College of Wooster. This is an honor for Wooster and an accomplishment for Dr. Lehtinen. Guibemantis woosteri is a cute little critter who lives in Madagascar.

Here is a very cool story about an ambitious experiment in natural selection. It is long, but worth reading. You should recognize all the principles involved.

Later this month the Japanese spacecraft Hayabusa 2 will attempt to collect a sample from the asteroid Ryugu and return it to Earth. Fantastic!

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The First Record: The Oldest Fossils (February 4-8)

Hard to believe we’re already in the fourth week. We are a class behind because of our “too cold for school” day, but we’ll gradually catch up. With this online material I’ll pretend we’re on schedule!

We will begin with continued discussions of origins, especially hypotheses about the origin of life. Please be sure to look at the links listed for last week on this topic. We will also examine the earliest fossil record, which goes back at least 3.5 billion years. Rhode Island College has a nice page on the six kingdoms of life, which makes a good start. For an updated summary (and way more than we can cover) the Wikipedia page on the evolutionary history of life is very good. Our whole course in one page! Just read the first parts relevant to this topic for now. Here is a good article on the oldest fossils we know thus far (in the traditional meaning of fossils).

Your first lecture examination is on Friday, February 15. For preparation, linked here is a sample test and the Fall 2018 student HOL test #1 answers. I highly recommend reading it through. The student answers are not necessarily the best, but they were good enough to receive full credit. Note that there are always topics we covered in the past that we may not have done this semester, and vice versa. Test seating: Students with last names starting with A through L in Room 205 (our regular room); M-Z in Room 216 (across the lobby). Test doors open at 7:50 a.m.; all tests due at 8:50 a.m.

Trace fossils from the Gog Formation (Middle Cambrian), Lake Louise, Alberta, Canada.

Geology in the News –

Mutant blue-eyed coyotes invading California! Two interesting themes for us here; mutations (and thus far there is no indication that this one is being selected for or against) and the amazing spread of coyotes throughout the urbanized West. Evolution in action.

Your classmate Dan gives us this older study suggesting that Medieval diseases like The Plague and smallpox may have selected for mutations conferring immunity to HIV infection for some modern Europeans. Grim, but a good example of natural selection for humans.

We live in an anti-science age in which scientists and scientific ideas have lost considerable credibility with the public. Here is an interesting take on why we should not call this a “war on science” as so many do. Such aggressive language usually has a negative effect on audiences. What we should do to restore respect for the scientific method and discourse is unclear.

Here is a related study of the public attitudes towards science these days. When it comes to assessing evidence, “people think more like lawyers than scientists“. It is not education levels, knowledge, or even interest in science — people often cherry-pick those “facts” that support their preconceptions. It is the end of the Enlightenment Age.

NASA has released Hubble Space Telescope images showing “the farthest-ever view” of the Universe. Stunning. A triumph of science, creativity and investment. Beautiful perspective, too.

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The Very Beginning: Origin of the Universe, the Early Earth & Life (January 28 – February 1)

We’ll start the week finishing the biological basis of evolution, and then work into physical origins. Please review the links from last week, especially on DNA.

Here’s a cool YouTube video of the “known universe” produced by the American Museum of Natural History. This puts us in our place (cosmically!) and demonstrates the awesome dimensions of this week’s topic. I also enjoy this digital atlas of the Universe from the Hayden Planetarium. It is a significant download, but very nice. Here is a great interactive website on the Scale of the Universe. These sites give us perspective.

NASA has an excellent website on cosmology. For those of you looking for a simple red shift explanation, click away on this colorless but useful PBS webpage. It even has exercises you can try. There is a nice Big Bang animation on this French website; I may use it in class (despite the French).

This star formation site is easy to follow and understand (more or less). The JPL-NASA Solar System site has the latest news and fantastic images. The NASA Mars Missionwebpages are, of course, incredible. This webpage from NOVA has superb animations of the “Big Whack” hypothesis for the origin of the Moon.

Here is the homepage of NASA’s “Stardust” project, which brought to Earth the “dust” of a comet. Now you know the importance of this study to our ideas about the origin of the solar system because comets are samples of the original solar nebula.

Now for the complex and contentious ideas about the origin of life. The elaborate and elegant Exploring Life’s Origins website from the Museum of Science in Boston is the best on the topic. Here’s a good animated Miller-Urey experiment webpage I may use in class.

Chemists have found a recipe to build all four nucleotides of RNA in a way that could have happened on the surface of the early Earth. This is a biological breakthrough that could show a theoretical pathway to the RNA World. Very cool. Even more recently, an inorganic process has been discovered below the seafloor that produces the amino acid tryptophan. We’re closing in on a coherent hypothesis for the origin of life.

Late-breaking news: Here is a fascinating new narrative for the origin of life, including some possible solutions for other geological mysteries. I’m not sure how we’ll reduce the complexity for class, but we’ll try! As with all brand new scientific ideas, we eventually need thorough testing and review.

If you are interested in being on the e-mailing list for the Department of Earth Sciences, please send me a note. You will receive departmental announcements about upcoming lectures, picnics, field trips, and internship opportunities.

Bivalves and brachiopods in the Logan Formation (Lower Carboniferous) of Wooster, Ohio.

Geology in the News –

Earth’s oldest rock was apparently found on the Moon by Apollo 14 astronauts. It is about 4.1 billion years old and was blasted off the Earth by a giant impact. You know there’s a good story here.

The Earth’s magnetic field  is acting strangely of late, and geologists are puzzled. We depend on the magnetic field to protect us from very harsh solar radiation, so this is a bit concerning.

The headline says it well: “People with extreme anti-science views know the least, but think they know the most: study.” No surprise.

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Mechanisms of Organic Change: Evolution (January 23 & 25)

Remember that Monday is Dr. Martin Luther King, Jr., Day. There will be no classes. Instead, how about attending a Justice Dialogue session or three? See you there.

Lots of material this week. Note that you do not need to read every word of every source. These are supplementary resources for your understanding of the topics. Start with a good definition of evolution, for you will soon see that dorm room conversations on the topic often have significant errors and misconceptions. The University of California Museum of Paleontology at Berkeley has an excellent website on the history of evolutionary theory, including good sections on pre-Darwinian thinkers. The Berkeley pages on “Understanding Evolution” are the best on the web. Charles Darwin is well represented web-wise, and Alfred Russel Wallace is the subject of this excellent site by Charles Smith of Western Kentucky University. The full text of Darwin’s most famous work, The Origin of Species (which appeared over 150 years ago), is available on-line. It is not scintillating reading, at least not on a computer, but you may want to peruse the preface and the conclusions. For a simple and effective presentation on evolutionary theory, try this YouTube video by “Stated Clearly”.

This excellent computer graphics animation of DNA replication is helpful, as is this animation of DNA and the construction of proteins. They hit all the major points of the process we will discuss in lecture (and a few more). The “Stated Clearly” channel has a useful tutorial on DNA and its functions. The Crash Course on DNA replication is also very good. Here is yet another animation of protein synthesis. I’m obviously repeating this important material several times!

Here’s a good article on the problems inherent in defining biological species. Evolution is at the species level, but we have difficulty grasping a concept of species.

Anomalocaridid “arm” from the Burgess Shale, Walcott Quarry, British Columbia, Canada. (Click to enlarge.)

Geology in the News –

The Universe Is Disappearing, And There’s Nothing We Can Do To Stop It.” A dramatic headline that is certainly true. This is a good article in Forbes discussing modern ideas of cosmology. The future looks very cold and dark, but at least it is a long time from now!

Interesting idea about extending the Anthropocene concept to Mars (and I would think the Moon as well). This would be the first time an interval of Earth’s geologic time scale (although Anthropocene is not yet approved) to another planet. The Anthropocene is essentially dated as the interval from the time humans first leave a geological record.

Poaching of African elephants for their ivory is apparently producing genetic changes in their populations that favor offspring without tusks. This is a brutal but effective demonstration of selection leading to evolutionary change.

For a lighter touch, puzzle out the origins of giant spinning ice disks!

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Antiquity of the Earth and Life (January 14-18)

Geologic time is a fascinating topic. It is so unimaginably long it has been called “deep time”. Please learn the Geologic Time Scale as soon as possible because it is the chronological language of this course. Because you certainly don’t want to memorize all those terms, I’ve posted a pdf version of our required-time-scale. You will see that I recognize the Ediacaran before the Cambrian, and the Paleogene and Neogene instead of the old Tertiary. You need to know only the eras, periods, and Cenozoic epochs. (For the professional chart, see this beauty. You don’t need to know all these names!) William Smith was an Englishman responsible in many ways for the principles behind geologic time. James Hutton was a Scot who first effectively described and applied the concept of “uniformitarianism” in geology, which requires vast amounts of time.

Geologists distinguish between relative and absolute time, with the first being the ordering of events, and the second using measurements of time. We will most often use relative time (such as the “Cretaceous Period”) in this course, but also occasionally cite absolute time (“65 million years ago”).

The concepts of radioactive decay and its use in the dating of Earth materials take some time to master. Wikipedia has an excellent explanatory website on radiometric dating. (I’m a Wikipedia fan and editor, by the way.) A nice online radioactive decay simulation provides a visual of the process. Set the number of atoms high (I use 1600) and the time long (I use 3.0) Turn on “both” to see atoms and graph. A more detailed explanation of how half-lives are really calculated is shown here. See what I have spared you? Fortunately we have handy online calculators for radioactive decay.

As a preview of what’s coming, I give you the evolution of Homer Simpson! As another preview of coming attractions, play with this interactive globe to see what the world looked like at various times. You can even search for your hometown’s location.

You may not be surprised to learn that the scientific framework of this course is considered a lie or delusion by just over a third of Americans (which is, in fact, a new low point). “Young Earth Creationists” believe that the Earth and the Universe are a few thousand years old, and that evolution did not occur. This is radically different from the cosmological and evolutionary models supported by scientists. Creationist arguments sometimes appear scientific, but you will quickly see that they are based on misconceptions, misrepresentations, mysteries, and zealotry. For example, take a look at this page citing “evidence for a young Earth” from Answers in Genesis. These are the people who produced the multimillion-dollar Creation Museum in Kentucky (“Prepare to Believe”). Check out this visit I had with First-Year Seminar students. Don’t miss the comments by Answers in Genesis officers). These are the same people who spent millions building a full-scale version of the Ark. (Apparently visiting this Ark is a very boring experience.) We will not be covering creationist arguments directly in this course (we have real science to do), but I will always answer any questions you have. I am an evolutionary paleontologist and geologist, but please be assured that you will not be judged or graded on your personal beliefs. What you believe is always your business; what you understand about evolution and the history of life is mine.

The new Time Scavengers blog is an excellent resource for geology students, especially those interested in paleontology. University of Tennessee graduate students Jen Bauer and Adriane Lam have put together a fantastic collection of articles, teaching aids, and links just for students like you!

Finally, have a look at this website: From the Big Bang to the World Wide Web. You will have fun exploring this site. Great theme song.

A trilobite from the Middle Cambrian of Utah.

Geology in the News —

On New Year’s Day, NASA’s New Horizons spacecraft flew by and photographed the most distant object observed in our Solar System: Ultima Thule. It’s a binary object looking a bit like a snowman. It is apparently reddish in true color. It will take 20 months for all the data collected to be received on Earth. Amazing.

We all know that the asteroid that slammed into the Chicxulub region 66 million years ago generated a huge tsunami that devastated southern North America. Now the global spread of this tsunami has been modeled. May we never see the likes of this in our species’ time!

The Little Ice Age ended more than a century ago, but cold seawater still lingers from that time. Cold waters that were once on the surface of the Pacific have been found very deep, and they’re still sinking. The Earth System responds to climate change on a wide range of time scales.

 

 

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