Eyes, brains and thumbs: the wonders of primate evolution (December 4-8)

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“. Try the interactive “skull module” website where you can take pieces of a human skull and manipulate the images on your screen. Very cool. Think evolution here, especially of the mandible and cranium. The Wikipedia page on primates and their evolution is an excellent summary and source of references.

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 Fall 2017 Final Exam description. (Test time: December 12 (Tuesday), 9:00 a.m. to noon. Test seating: Students with last names starting with A through H in Room 205; I-Z in Room 216. Don’t miss the final exam — if you do I’m required to give you a zero.)

Remember: Our last review session is Wednesday, 3:30 – 4:30 pm, in Scovel 205. Your final quiz is a superquiz covering the entire course. Study early, study hard!

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

Geology in the News –

Another amazing paleontological discover in China: Hundreds of pterosaur eggs, including embryos. What we know about pterosaur biology has just increased an order of magnitude. From the abstract: “Fossil eggs and embryos that provide unique information about the reproduction and early growth of vertebrates are exceedingly rare, particularly for pterosaurs. Here we report on hundreds of three-dimensional (3D) eggs of the species Hamipterus tianshanensis from a Lower Cretaceous site in China, 16 of which contain embryonic remains.”

A new bird species is appearing in the Galapagos, and it is a hybrid. “In the past, it was thought that two different species must be unable to produce fertile offspring in order to be defined as such. But in more recent years, it has been established that many birds and other animals that we consider to be unique species are in fact able to interbreed with others to produce fertile young.” The Species Concept is in considerable flux right now.

What distinguishes humans from the other great apes? The brain, my friends, the brain. Tiny genetic changes made for massive differences in brain form and function. They’ll never catch up to us.

It’s not often we get a new genus of fossil vertebrate, especially among Pleistocene horses. Meet Haringtonhippus from Ice Age North America.

Posted in Uncategorized | Comments Off on Eyes, brains and thumbs: the wonders of primate evolution (December 4-8)

Our Cenozoic Mammalian Cousins (continued) (November 27 – December 1)

Please review the links from last week as we continue discussing the Mammalian Radiation in the Cenozoic.

Here is the Fall 2017 Final Exam description. (Test time: December 12 (Tuesday), 9:00 a.m. to noon. Test seating: Students with last names starting with A through H in Room 205; I-Z in Room 216. Don’t miss the final exam — if you do I’m required to give you a zero.) Those superquizzes are your encouragement to study!

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

Mammoth tooth surface (Pleistocene of Ohio).

Geology in the News –

Amazingly, 208 of the more than 5,200 minerals are related to human activity. New minerals have formed in all sorts of human-created niches, from shipwrecks to cabinetry. Welcome to the Anthropocene.

Here’s a cool look at the surface under an Antarctic ice sheet. There is more topography than previously thought, which may be good news as it may be retarding overall melting.

There was once a view that liquid water, even if a salty brine, still flowed on Mars. Geologists put an end to that speculation.

Posted in Uncategorized | Comments Off on Our Cenozoic Mammalian Cousins (continued) (November 27 – December 1)

Our Cenozoic Mammalian Cousins (November 20)

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, which has been made more complex by recent genetic findings that mammal diversification was not entirely due to the dinosaur extinctions. Note in that story 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, and of course make a side visit to the Rat and Mouse Club of America (where one of their ethical principles is that they don’t sell their pets to the Snake and Tarantula Club). 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 Fall 2017 Final Exam description. (Test seating: Students with last names starting with A through H in Room 205; I-Z in Room 216.) Even though the final is about a month from now, you’ll want to start studying. Those superquizzes will be your encouragement!

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

Mammoth tooth from the Pleistocene of Ohio.

Geology in the News –

There is a new and interesting argument that the Late Cretaceous asteroid hit just the right spot to cause the global extinctions. The hypothesis is that striking an area rich in petroleum injected massive amounts of soot into the atmosphere that further cooled climate. There will be debates soon over this.

The end-Cretaceous Chicxulub Crater is in the news as scientists publish the results of a drilling expedition into it. They have supporting evidence for why this crater has a peak ring that is unique on Earth but common elsewhere in the Solar System. There are cool images in the version of the story from The New York Times.

The BBC has a separate story on the drilling results that includes a cool animated model of how the Chicxulub Crater was formed. There were for a few minutes mountains as high as the Himalayas!

How long did it take for life to recover from the Cretaceous extinctions? New studies suggest about four million years, but up to nine million years in North America, which was hit hardest.

Posted in Uncategorized | Comments Off on Our Cenozoic Mammalian Cousins (November 20)

Catastrophe: The Cretaceous Mass Extinctions (November 13-17)

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. The Great Chicxulub Debate hosted by the Geological Society of London was several years ago, but the arguments are worth visiting. Let’s not forget, though, that the basic scenario of the impact hypothesis is supported by most scientists.

Here is the Fall 2017 Final Exam description. (Test seating: Students with last names starting with A through H in Room 205; I-Z in Room 216.) Even though the final is about a month from now, you’ll want to start studying. Those superquizzes will be your encouragement!

Remember: Review sessions every Wednesday, 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 –

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.

A new great ape species has been identified in Indonesia. This doesn’t happen often!

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.

Posted in Uncategorized | Comments Off on Catastrophe: The Cretaceous Mass Extinctions (November 13-17)

Our Furry Kin and The Greening of the Earth: Evolution of Mammals and Plants (November 6-10)

We’ll start Monday with a review of your second test results, then begin our discussion of early mammals. On Wednesday we’ll be deep into the woods with the Kingdom Plantae.

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.)

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 Berkeley’s fossil plants page. Their 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. If you want professional detail of fossil plant systematics and distribution, click the homepage of the International Organisation of Palaeobotany. Berkeley’s “Deep Green” website on plant diversity is also useful.

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. 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.

Here is the Fall 2017 second test answers pdf. There were 9 tests in the 90s, 15 tests in the 80s, 5 tests in the 70s, 4 tests in the 60s, and 3 tests in the 50s. Two-thirds of the class thus earned A or B on the test. The high score was 96%, the average 80.8%. On the first test about half of the class earned A or B and the average was 78%, so this is an improvement.

Merycoidodon skull, left side (Oligocene of Nebraska).

Geology in the News –

Here’s a nice octopus-like fossil from the Jurassic. It’s not often invertebrate paleontology makes the BBC news!

It’s not often I cite the Daily Mail here, but this is a good popular account of how volcanoes change climate, and why warmer oceans may increase the effects.

A 200-million-year-old “megacarnivore” new theropod dinosaur found, sort of. We only know its footprints, so Kayentapus is a trace fossil, not the actual dinosaur. Impressive nonetheless.

A new pterosaur was found (in part) in Mongolia. It is Late Cretaceous and had a wingspan of about 10 meters. It may have eaten baby dinosaurs!

Posted in Uncategorized | Comments Off on Our Furry Kin and The Greening of the Earth: Evolution of Mammals and Plants (November 6-10)

Part II of The Evolution of Reptiles (October 30 – November 3)

This week we will continue with dinosaurs, so please see the links and prose from last week. We will then explore the development of flying vertebrates, including pterosaurs and the evolution of birds (“avian dinosaurs”).

Your second test will be on Friday, November 3. Because I have a doctor’s appointment, there is NO review session on Wednesday, November 1. Instead our review session that week is on Thursday, November 2, 3:50 – 5:00 p.m. Here are the Spring 2017 second test answers for your study. 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 A through H in Room 216 (across the lobby); I-Z in Room 205 (our regular room). 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 [updated October 29]. It is a list trimmed 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 –

Geological processes on Mars! Check out how the annual freeze-thaw cycles on Mars produce changes in sand dunes. Mars is not nearly as dynamic as Earth when it comes to modern processes, but it was back in the day. No fossils on Mars, though. Yet.

Back on Earth, three scary new studies show that sea levels may be rising faster and higher than we thought. Hold off on buying that cute little cottage on the shore — a new shore is coming. (And I’d avoid moving to Miami.)

Here’s a good analysis in The New York Times on concepts of skin color, race and genetics. You know some of the basic principles here.

Posted in Uncategorized | Comments Off on Part II of The Evolution of Reptiles (October 30 – November 3)

Jurassic Park, etc.: The Evolution of Reptiles (October 27)

Remember that there are NO classes or review sessions on October 23 and 25, so this post is an advance welcome back! First some program notes. The review session this week is on Friday, October 27, 3:30-4:30 p.m. in our classroom. Your second test will be on Friday, November 3. Because I have a doctor’s appointment, there is NO review session on Wednesday, November 1. Instead our review session that week is on Thursday, November 2, 3:50 – 5:00 p.m. Here are the Spring 2017 second test answers for your study. 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 A through H in Room 216 (across the lobby); I-Z in Room 205 (our regular room). Test doors open at 7:50 a.m.; all tests due at 8:50 a.m.

Today we will return to reptiles, exploring the remaining diapsids and others. Please see the previous links. We will also begin 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). Let’s begin our explorations at where I used to work as a student: the University of California Museum of Paleontology at Berkeley. They invented the concept of the “on-line museum” many years ago. Start with their general dinosaur page, which has numerous images and links. Then take a guided tour of the Berkeley Dilophosaurus exhibit and their “T. Rex Expo“. I suggest ending your Berkeley dinosaur visit with their “Dinobuzz” page which has excellent explanations and discussions of the latest dinosaur research. 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 very useful and current. The American Museum of Natural History always has good dinosaur information and news.

Here  is our Classification of the Phylum Chordata used in this course [updated on October 29]. It is a list trimmed 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 –

Have we been reconstructing Dimetrodon incorrectly all these years? I’m certain the answer is yes, but the real question is how off have we been. Unfortunately this article does not give a new image of the beast, but we may have one soon.

Half of the Universe’s missing matter has been found! This is not as exciting as it sounds because this is not “dark matter”. Apparently we have had an undercount of the ordinary matter in the Universe that is now rectified with new observations of tenuous gas tendrils.

Here’s a YouTube video projecting plate tectonic movements 250 million years into the future. You should be able to predict the pattern!

 

Posted in Uncategorized | Comments Off on Jurassic Park, etc.: The Evolution of Reptiles (October 27)

Plate Tectonics (October 16-20)

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. I especially like their new 3-D moveable globes of various periods. 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.

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.)

Remember: No classes on October 23 and 25. I’m at a geological meeting in Seattle.

Bristlecone Pine in the White Mountains of eastern California.

Geology in the News –

Here’s a nice summary of the latest ideas on the evolution of modern birds. It appears that the Cretaceous extinctions may have sped up their evolution, primarily by selecting for small body sizes which have higher rates of evolution.

Nice rotating globe showing earthquake locations and magnitudes from 2001 through 2015. Note the dramatic activity along the “Ring of Fire” (the Pacific Rim.)

More museum science: A paleontologist studying old ichthyosaur specimens discovered one with remnants of its last meal still preserved. Squid!

Posted in Uncategorized | Comments Off on Plate Tectonics (October 16-20)

The Amniotic Egg: Amphibians to Reptiles (October 2-6)

The sixth week already. It must be time to really “conquer the land” as we say too often. 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 on this webpage from the University of Bristol. The rise of the dinosaurs starts soon after.

Here  is our Classification of the Phylum Chordata used in this course [updated on October 29]. It is a list trimmed 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 –

Another important lesson from genetic research: physical appearance does not always track evolutionary relationships. The example here is the genetic heritage of living nautiloids. Turns out even in this relatively small group we thought we understood, there is plenty of evolutionary convergence going on.

Here’s a cool video of the Earth’s surface evolution projected over the next 250 million years. The Wilson Cycle continues!

Giant wombats (that alone should bring some clicks) apparently had mass migrations in Australia during the Pleistocene. The clues to these journeys are carbon isotopes found in their fossilized teeth.

Posted in Uncategorized | Comments Off on The Amniotic Egg: Amphibians to Reptiles (October 2-6)

From Fins to Feet: Early Vertebrate Evolution (September 25-29)

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.

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. This page on limb evolution from an anti-creationist website is very useful, even if the illustrations are a bit clunky. 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. If you want to freak out your roommate, crank up the volume on a few frog calls.

Test results! Here is the Fall 2017 student HOL test #1 answers pdf. The grade range was 42%-100%, with 11 students earning 90-100, 11 earning 80-89, 7 earning 70-79, 4 earning 60-69, and 6 with scores below 60. About 28% of the class has A grades on the test, and about 25% has D and F grades. Over half of the class earned A or B. The class test average was 78%. This is good, overall, but if you earned below 80% you need to reform your study habits. You can make an appointment to talk to me by signing up on my weekly schedule posted on my office door (Scovel 120).

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

Geology in the News –

You may have heard that mammoths are about to be cloned. Fake news!

Great music video on evo-devo. Starts with hox genes. “This is how we go from single cells to people.” The channel A Capella Science is highly recommended!

Cnidarians in the news! Sleeping jellyfish, even though they have no brains. It is also a great example of how science is really done.

Posted in Uncategorized | Comments Off on From Fins to Feet: Early Vertebrate Evolution (September 25-29)