Bryozoans! Everyone’s favorite fossils. When I took this course my professor mumbled at the start of this section, “I hate bryozoans. When I find them, and no one’s looking, I smash them with my hammer!” Bad form. I hope you learn to love the little critters. They can tell us much about evolution and paleoecology. You can start your browsing with the Bryozoa Home Page. Many links here, including sites on both recent and fossil bryozoans. SUNY Cortland also has a good tutorial on bryozoans. Here is the useful Wikipedia page on bryozoans. You also want to be sure to visit the page of my friend Paul Taylor, who is one of the top bryozoologists in the world. Here’s a page from The Netherlands on freshwater bryozoans. Some are huge. YouTube has bryozoan movies (of course!), like this one showing the action of cilia in feeding and a double feature of a bryozoan and Hydra. The Bryozoan Fossils of Kentucky page has some types you’ll find familiar, as will this page of bryozoan specimen images, most without adequate scales (a mistake you will never make). In the Paleozoic, especially the Ordovician, bryozoans are very common on carbonate hardgrounds.
I hope you’re keeping up with Wooster’s Fossil of the Week!
The bryozoan Esthoniopora from the Upper Ordovician (Kukruse) of Estonia.
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.