Developing Marine Ecosystems (September 18-22)

Our topic this week  is the rise of animal life and the early development of marine communities. A good place to start on the Web is at Queen’s University’s Ediacaran fauna page. (Canadians are big on the earliest rocks and fossils for good reason — they have a lot of them!) The Wikipedia pages on all these topics are very good and authoritative. An 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 last year. 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.

Here’s a nerdy but fun music video on the Cambrian Explosion, complete with your favorite Burgess Shale creatures. (It also includes a photo I took of the Burgess Shale in the field.)

Here are the Monday class notes for those of you who could not attend class. It is always useful to also look at a classmate’s notes for any items I may have added during class.

Your first lecture examination is on Friday, September 22. For preparation, I’m giving you a copy of the Spring 2017 first HOL test with student answers as a pdf. I highly recommend reading it through. (See if you can find the errors in the time scale that sharp-eyed Paige discovered!) 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 lecture through Wednesday, September 20. Test seating: Students with last names starting with A through H in Room 205 (our regular room); I-Z in Room 216 (across the lobby). Test doors open at 7:50 a.m.; all tests due at 8:50 a.m. Review session on Wednesday, September 20, 3:30 – 4:30 p.m. in Room 205.

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

Geology in the News –

The remarkable Cassini spacecraft will have ended its existence with a planned crash into Saturn by the time you read this. What a spectacular project … and dramatic conclusion.

Portuguese Man-of-Wars in the news! Nothing exceptional — I just like these complex and dangerous hydrozoan colonies.

Here’s a good article about the hunt for soft tissue preserved in Cretaceous dinosaur bones. It is a complex story, and the initial findings have not been replicated in other labs. We may see developments here before the end of the year.

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