From Fins to Feet: Early Vertebrate Evolution (September 24-28)

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. 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 class average was 78%, with a high of 100%. There were 10 tests 90-100%, 10 from 80 to 89%, 6 in the 70s, 3 in the 60s, and 5 below 60%. Well over half the class earned the equivalent of an A or B, which is good. Here are the Fall 2018 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 –

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!

Paleontologists are now using neutron scanners to make ultra-high resolution images of vertebrate fossils. Very cool results.

Arctic lakes are now bubbling out massive amounts of the potent greenhouse gas methane. This is not good.

 

Posted in Uncategorized | Comments Off on From Fins to Feet: Early Vertebrate Evolution (September 24-28)

Developing Marine Ecosystems (September 17 & 21)

It is an unusual week for us. We have class on Monday, no class on Wednesday, a review session on Thursday (3:30 – 4:30 pm, Scovel 205). Then your first lecture examination is on Friday. For preparation, I’m giving you a copy of the Fall 2017 student HOL test #1 answers as a pdf. I highly recommend reading it through. The student answers are not necessarily the best, but they were good enough to receive full credit. Also note that there are always topics we covered in the past that we may not have done this semester, and vice versa. You will be tested over only what we have completed in class through Monday, September 17. 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 on Monday 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 rise 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 guy who lives in Madagascar.

Here’s a beautiful map showing streams and rivers of the United States. The watersheds are in separate colors.

Wish we could spend more time with the Kingdom Fungi. Here’s a nice modern summary of their diversity and utility.

Posted in Uncategorized | Comments Off on Developing Marine Ecosystems (September 17 & 21)

The First Record: The Oldest Fossils (September 10-14)

Hard to believe we’re already in the fourth week. 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, September 21. For preparation, I’m giving you a copy of the Fall 2017 student HOL test #1 answers as a pdf. I highly recommend reading it through. The student answers are not necessarily the best, but they were good enough to receive full credit. Also note that there are always topics we covered in the past that we may not have done this semester, and vice versa. You will be tested over only what we have completed in class through Monday, September 17. 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 –

Here is a brand new study on the evolutionary origins of animal diversity. “Our results show that fundamental evolutionary change was not limited to an early burst of evolutionary experimentation. Animal designs have continued to evolve to the present day—not gradually as Darwin predicted—but in fits and starts, episodically through their evolutionary history.”

New coral reefs have been found in deep water off the coast of South Carolina. Note these are in dark waters, unlike the far more common shallow-water coral reefs. These discoveries are important for our calculations of the oceanic carbon budget, among other things.

New evidence suggests that climate changes may have led to the disappearance of our Neandertal cousins about 40,000 years ago. There’s a lesson here!

Posted in Uncategorized | Comments Off on The First Record: The Oldest Fossils (September 10-14)

The Very Beginning: Origin of the Universe, the Early Earth & Life (September 3-7)

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 Mission webpages 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.

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 –

The headline of this story is odd (“Dinosaur DNA clues unpicked by researchers at University of Kent“. What does “unpicked” mean?), but the story is interesting. It is an attempt to describe non-avian dinosaur diversity by estimating what their genome looked like. Birds (which are dinosaurs) are used for the calculations.

A cool new fossil turtle was recently found in China. It is not surprising that it lacks a shell; it is the preservation that is remarkable. It is 228 million years old. What geological time period is this?

Check out this frozen horse 30,000 years old! It is an extinct Lenskaya horse found in melting permafrost in Siberia. Check out the details preserved. I imagine DNA could be easily extracted from the carcass.

Posted in Uncategorized | Comments Off on The Very Beginning: Origin of the Universe, the Early Earth & Life (September 3-7)

Mechanisms of Organic Change: Evolution (August 27-31)

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.

(You can find the definition of a crystal here.)

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!

These giant pterosaurs are so cool, and the actually flew. They looked something like giraffes with wings.

This is a nice profile of the research ship JOIDES Resolution, which travels the world hosting oceanographic and geological research. Some of our most important data about recent and past climate was generated onboard.

Posted in Uncategorized | Comments Off on Mechanisms of Organic Change: Evolution (August 27-31)

Antiquity of the Earth and Life (August 22 & 24)

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!

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. 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 about them. 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 —

If you want some early preparation for the first part of this course, try the wonderful Crash Course in Astronomy, starting with this episode about Big Bang Cosmology. Note that it starts with Darwin!

Our big toes were the last parts of our feet to evolve. You’ll see why much later in this course. A related question is always what’s up with our littlest toes. Are we losing them?

Viruses, phytoplankton and clouds. How would have guessed they are connected? A common type of oceanic phytoplankton (coccolithophores) covers itself with tiny mineralized (calcite) plates. Some get infected by a virus, which causes them to shed the plates. Waves throw the plates into the atmosphere, where they provide the seeds for clouds. One theme of this course is that life and the physical Earth are complexly intertwined. Life is a geological process.

 

 

Posted in Default | Comments Off on Antiquity of the Earth and Life (August 22 & 24)