Microbial communities (September 17 & 19)

Our first test is on Thursday. This is the first paleoecology exam for all of us! We’ll spend some time talking about it on Tuesday. Remember it is an open-note test, meaning you can use any of your hand-written notes. It covers from our first day through whatever we complete on Tuesday, including what we covered in lab (except for the specimens).

We will finish trace fossils on Tuesday with some applied examples of trace fossils in paleoecology. Please review the previous links.

Our main topic will be microbial communities in the fossil record and how they are a fundamental factor in evolutionary paleoecology. Please start your web-reading with the Wikipedia page on stromatolites. These are not the only microbial structures we’ll study, but they are the most prominent. Next meet our main prokaryotic players, the cyanobacteria. Oddly enough, a colleague and I actually described cyanobacteriial mats from the Upper Ordovician of the Cincinnati area. These are rare because they are replaced with pyrite and three-dimensional.

Our primary paleoecological case study with microbial mats will be the Cambrian Substrate Revolution. Microbial mats served us well as oxygen-producers and sediment stabilizers, but the tie finally came for animals to break through them to exploit the nutrients in the sediment and do all those other infernal activities we talked about with trace fossils. A Wooster alumnus, Steve Dornbos, is one of the paleontologists who developed this scenario.

Geology in the News —

Here’s a fascinating set of Neanderthal footprints found in France. Human trace fossils! They may tell us something about Neanderthal family life, information we can’t get from bones alone.

Here’s a cool super-sized pterosaur found in the Cretaceous of western Canada. Note the complicated taxonomic history to finally get this critter a proper name and description.