Eyes, brains and thumbs: the wonders of primate evolution (December 4-8)

During our last week we will concentrate on primate and specifically human evolution. We look closely at our own lineage not just because it is of immediate interest to us, but also so we can directly apply concepts of evolutionary theory to organisms intimately familiar to us. The Web has almost as many sites on issues of human evolution as it does on dinosaurs, so most of the pages I link you to provide many other connections. Start first with the Institute of Human Origins based at Arizona State University. They have an excellent additional website called “becoming human“. Try the interactive “skull module” website where you can take pieces of a human skull and manipulate the images on your screen. Very cool. Think evolution here, especially of the mandible and cranium. The Wikipedia page on primates and their evolution is an excellent summary and source of references.

As you examine these websites, please also keep in mind that the fossil record of hominid evolution has produced numerous competing hypotheses, so you will find many disagreements, even on what seem to be basic observations. (Note, for example, the popular pseudoscience surrounding the “aquatic ape hypothesis“.) As an example of the hype and expectations that have dogged the study of human evolution for over a century, here is the classic story of Piltdown Man.

Here is the Fall 2017 Final Exam description. (Test time: December 12 (Tuesday), 9:00 a.m. to noon. Test seating: Students with last names starting with A through H in Room 205; I-Z in Room 216. Don’t miss the final exam — if you do I’m required to give you a zero.)

Remember: Our last review session is Wednesday, 3:30 – 4:30 pm, in Scovel 205. Your final quiz is a superquiz covering the entire course. Study early, study hard!

Mastodon tooth surface (Pleistocene, Holmes County, Ohio).

Geology in the News –

Another amazing paleontological discover in China: Hundreds of pterosaur eggs, including embryos. What we know about pterosaur biology has just increased an order of magnitude. From the abstract: “Fossil eggs and embryos that provide unique information about the reproduction and early growth of vertebrates are exceedingly rare, particularly for pterosaurs. Here we report on hundreds of three-dimensional (3D) eggs of the species Hamipterus tianshanensis from a Lower Cretaceous site in China, 16 of which contain embryonic remains.”

A new bird species is appearing in the Galapagos, and it is a hybrid. “In the past, it was thought that two different species must be unable to produce fertile offspring in order to be defined as such. But in more recent years, it has been established that many birds and other animals that we consider to be unique species are in fact able to interbreed with others to produce fertile young.” The Species Concept is in considerable flux right now.

What distinguishes humans from the other great apes? The brain, my friends, the brain. Tiny genetic changes made for massive differences in brain form and function. They’ll never catch up to us.

It’s not often we get a new genus of fossil vertebrate, especially among Pleistocene horses. Meet Haringtonhippus from Ice Age North America.

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