Please review the links from last week as we continue discussing the Mammalian Radiation in the Cenozoic.
One of the interesting questions in the history of Earth’s climate is why the planet began a precipitous cool-down in the middle Eocene, about 49 million years ago. You know that the most likely answer is that carbon dioxide levels were reduced, lessening the Greenhouse Effect and leading to global cooling. How would that happen? One strong hypothesis is that the rapid growth of an usual fern, Azolla, in the Arctic Ocean drew down carbon dioxide levels and then, by dying and being buried in ocean sediments, sequestered that carbon away from the atmosphere. This is called the Azolla Event. Azolla is still very much with us today. Maybe it can help with our current global warming problem?
Here is the Fall 2018 Final Exam description. (Test seating: Students with last names starting with A through L in Room 205; M-Z in Room 216.) You’ll want to start studying. Those superquizzes will be your encouragement!
The review session this Friday will be 3:00 – 4:00 pm in Scovel 205. (I have a 4:00 pm meeting.)
Mammoth tooth surface (Pleistocene of Ohio).
Geology in the News –
The hemimastigophorans are a strange group of organisms currently classified at the phylum level. Recent genetic studies show that they are radically different from animals, protists, fungi and plants, meaning they represent a branch of life at the ‘supra-kingdom” level. There is still so much we don’t know about life, let alone life’s history.
A 31-kilometer-wide impact crater has been discovered under Greenland’s shrinking icecap. So far it has been dated to be sometime in the Pleistocene, but there is much speculation that is is connected to the Younger Dryas climate event. For an excellent review of the topic, see Dr. Crawford’s recent blog post.
A cuddly little therapsid named Kayentatherium has been found preserved with 38 tiny babies. This discovery has implications for mammal evolution because this clutch size is more reptilian than mammalian.