Eyes, brains and thumbs: the wonders of primate evolution (April 29 – May 3)

During our last week we will concentrate on primate and specifically human evolution. We look closely at our own lineage not just because it is of immediate interest to us, but also so we can directly apply concepts of evolutionary theory to organisms intimately familiar to us. The Web has almost as many sites on issues of human evolution as it does on dinosaurs, so most of the pages I link you to provide many other connections. Start first with the Institute of Human Origins based at Arizona State University. They have an excellent additional website called “becoming human“. The Wikipedia page on primates and their evolution is an excellent summary and source of references.

Note the Australopithecus sediba story. And that for Homo luzonensis. And Homo floresiensis. There are so many new finds on this topic that we’re still sorting them out.

As you examine these websites, please also keep in mind that the fossil record of hominid evolution has produced numerous competing hypotheses, so you will find many disagreements, even on what seem to be basic observations. (Note, for example, the popular pseudoscience surrounding the “aquatic ape hypothesis“.) As an example of the hype and expectations that have dogged the study of human evolution for over a century, here is the classic story of Piltdown Man.

Here is the Spring 2019 Final Exam description. (Monday, May 6, Noon-2:00 pm; test seating: Students with last names starting with A through L in Room 205; M-Z in Room 216.) Our review session will be Friday, May 3, 3:30-4:30 pm.

Mastodon tooth surface (Pleistocene, Holmes County, Ohio).

Geology in the News –

When methane hydrates are in the news, it is rarely good. The warming of the Arctic with the epic thawing of permafrost, is already producing thermal feedback and massive expenses.

With new technology (and ideas), our concepts of the Earth’s interior have become more complex. The core-mantle interface is especially interesting. We may at last be learning about the origin of mantle plumes.

Check out this newly described carnivorous mammal larger than a polar bear. It is 22 million years old and African. The specialized teeth of Simbakubwa kutokaafrika are impressive.

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Our Cenozoic Mammalian Cousins (April 22 & 24)

We had our introduction to mammals back in the Triassic. They were ratty little critters then, but now that the non-avian dinosaurs are gone our mammals have become very serious and prolific.

So many mammal groups appeared in the early Cenozoic that we cannot cover them all in this course, or even mention many of them. That diversity dilemma is actually part of the story of the extraordinary adaptive radiation of the mammals. Note that the three-part division of mammals we see today (monotremes, marsupials and placentals) began in the Cretaceous. You may also want to refer to the mammal evolution site on Wikipedia, which is very well updated.

Again, the webpages from Berkeley will be highlighted here because they are organized in the most useful ways for us. You will want to look at their short rodents page. Now jump WAY up to the proboscidean (elephants, mammoths, mastodons) page just to delight in the wondrous variety in modern mammals. There are many sites devoted to mammoths, mastodons and other “Ice Age” mammals, including the Pleistocene exhibits at the Russian Paleontological Institute. Carnivores are always interesting, and are in themselves highly diverse. They include wolves, dogs, cats, raccoons, bears, weasels, hyenas, seals, and walruses. A hero to your cat is the ancient sabretooth, highlighted in special exhibits this year at Berkeley and the Illinois State Museum. (Watch an old school animation of a sabretooth from the BBC.) You can now make another mammal diversity leap to our unlikely cousins the cetaceans (whales and dolphins; here’s an Eocene whale found a few years ago in Egypt). The ungulates, or hoofed mammals, are an excellent group to use in a study of evolutionary patterns. The artiodactyls (cloven-hoofed mammals) include the prosaic sheep, goats, camels, pigs, cows, deer, giraffes, and antelopes (and now whales!). Their relatives the perissodactyls (“odd-hoofed” mammals) include rhinos, horses and tapirs today, but they were much more diverse in the past. The evolution of the horse is a classic story, told well at the “Fossil Horses in Cyberspace” site at the Florida Museum of Natural History.

Here is the Spring 2019 Final Exam description. (Monday, May 6, Noon-2:00 pm; test seating: Students with last names starting with A through L in Room 205; M-Z in Room 216.) Those superquizzes will be your encouragement to study! Our review session will be Friday, May 3, 3:30-4:30 pm.

Remember: Review sessions every Friday, 3:30 – 4:30 pm, in Scovel 205.

Mammoth tooth from the Pleistocene of Ohio.

Geology in the News –

Geological time scale showdown! This month it may be “officially” decided whether we’re now in a new geological time interval: the Anthropocene. The levels of controversy are delicious, from when the Anthropocene would start to whether we need a new term at all. Right now there is progress towards making 1950 the boundary year.

Was a fireball meteor which struck Earth in 2014 actually from outside our Solar System? This was not even thought a possibility a few years ago.

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Catastrophe Again: The Cretaceous Mass Extinctions (April 15-19)

The story of the Cretaceous Mass Extinctions is amazing. The “Impact Hypothesis” was developed at the University of California, Berkeley, in 1980 when I was there as a graduate student (to my great fortune, even if I had nothing to do with it). It seemed a real stretch at the time, but now we know it as one of those intellectual breakthroughs which changed our perspective on the History of Life. The Wikipedia page on the Cretaceous Extinctions is very good and kept updated by experts. The Sam Noble Museum has a good executive summary of the extinctions. In 2010 an Independent Study student (Megan Innis) and I had a great time at the Cretaceous-Paleogene boundary in Alabama and Mississippi.

We will emphasize the Impact Hypothesis in this course because I think it is the one best supported by the evidence. If you like your extinctions via YouTube, watch these Discovery Science videos, part 1 and part 2. The volcanic hypothesis is still alive, although on life support. Here is a nice summary of the most recent attempts to link volcanoes to the Cretaceous extinctions. In contrast with these reasonable (more or less) disputes, there are many more exotic ideas about dinosaur extinctions specifically, some tallied here and here. Let’s not forget, though, that the basic scenario of the impact hypothesis is supported by most scientists.

The end-Cretaceous asteroid impact may have had an even more dramatic effect on climate than we thought (and that was pretty bad). I notice here that the asteroid is now expanded from 10 to 12 km in diameter. Here’s a BBC account of the same research.

For the extraordinary story about the end-Cretaceous extinction deposits recently described in North Dakota, first read this BBC account, which is typical of the hundreds of news stories about the finds. Next read this long but entertaining story in The New Yorker. Finally for a more mixed (and realistic) appraisal, read this news article in the journal Science. It is becoming a fascinating scientific and cultural narrative. The actual PNAS paper is linked here. [Update: Another  perspective on this story.]

Remember: Review sessions every Friday, 3:30 – 4:30 pm, in Scovel 205.

The view of it here in The Netherlands, though, is far different. We explored it from below in the Maastrichtian tunnels at Geulhemmmerberg (N50.86692°, E5.78357°).

Geology in the News –

Here’s the best account I’ve found describing the marvelous image of a black hole revealed last week. An historical moment. If you’re not impressed it is because you don’t understand the gravity of the situation.

And then there’s a new extinct hominin in the Philippines! Homo luzonensis lived between 50,000 and 67,000 years ago on a Philippine island. Let”s watch how this story develops.

Finally, and it sounds now so prosaic, there are some newly discovered dinosaur skin impressions. Early Cretaceous of South Korea.

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The Greening of the Earth: Evolution of Plants (April 8-12)

Plants have been in this course for awhile as a leafy background to tetrapod evolution, but now it is time to take them seriously. The best place to start a general survey of our very distant green cousins is with the summary Tree of Life page on land plants (embryophytes). There are lots of links there. Berkeley’s fossil plants range chart may be especially useful, although we won’t be using most of the names given there. The most detailed plant website is the University of California on-line paleobotany lab. The diagrams and hierarchical systems of detail here are impressive. You may want to scan these pages for the beautiful line drawings alone.

Here’s a ginkgo webpage for everything you want to know about this beautiful tree common on our campus (although it is hardly the only “link between the lower and higher plants”). What is the tallest plant and where is it? A redwood in California measures an astonishing 379 feet.  Check out the oldest living plant — an impressive 13,000 years of life as a clone. It’s also in California. Here’s a short video of pollen stirred up by a helicopter in Georgia. Finally, a short video clip of stomata in action.

The evolution of angiosperms (flowering plants) is a bit contentious these days. Most paleontologists agree that the first definite angiosperm fossil is Cretaceous, but genetic and molecular studies suggest they evolved sometime in the Jurassic. There are disputes over what the fossil record really shows.

Now that you’ve accumulated quite a bit of life’s history, you might appreciate this deep-time clock. I can’t guarantee that all the dates will be correct, but the order of events is good. The main thing you will gain from this page is an appreciation for the scale of geologic time.

Exam #2 results: The average is 78%, with 5 scores in the 90s, 7 in the 80s, 11 in the 70s, 4 in the 60s, and 3 below 60. The range was 45-97%. Here are the Spring 2019 second test answers. (Each answer is from a different student. These are not optimal answers necessarily, but good enough for full credit.)

Merycoidodon skull, left side (Oligocene of Nebraska).

Geology in the News –

For the extraordinary story about the end-Cretaceous extinction deposits recently described in North Dakota, first read this BBC account, which is typical of the hundreds of news stories about the finds. Next read this long but entertaining story in The New Yorker. Finally for a more mixed (and realistic) appraisal, read this news article in the journal Science. It is becoming a fascinating scientific and cultural narrative. [Update: Another  perspective on this story.]

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Part II of The Evolution of Reptiles; Early Mammals (April 1-5)

This week we will start by exploring the development of flying vertebrates, emphasizing pterosaurs.

Mammals evolved so gradually from the reptiles that it becomes difficult to say when the first mammal appeared. (A familiar story that you’ve heard with the fish, amphibians, dinosaurs, and “birds”.) The Wikipedia page on the evolution of mammals is quite good, and the related page on the cynodonts (a type of therapsid which includes the mammal ancestors) is useful. We will talk in detail about the various innovations which characterize the mammal-like reptiles and the early mammals. (And we won’t use all the terms in these pages, of course.)

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.

Gigandipus, a dinosaur footprint in the Lower Jurassic Moenave Formation at the St. George Dinosaur Discovery Site at Johnson Farm, southwestern Utah.

Geology in the News –

There has been a fantastic discovery of soft-bodied fossils in the Cambrian of China. The Qingjiang Biota rivals the Burgess Shale Fauna — at least half of the species are unknown to science. Bob Gaines of Pomona College is one of the co-authors on the first of what will be many papers.

Here’s a bit from the world of nonsense: “Why do flat-earth believers still exist?“. The most archaic and ridiculous ideas about our Universe are increasing in popularity, despite unprecedented access to real science. Explore why.

Here’s a story about dinosaur reconstructions (as in museums) catching up with the science.

Finally, check out the departmental blog describing our recent field research in the Jurassic of southwestern Utah. Spring Break is a great time for geology out West.

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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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