HONR 219D

Charles Darwin’s discovery of evolution is the pivotal event in the history of biology. His breakthrough not only accounts for organismal changes over time, it implies that living lineages share common ancestry, forming an all-encompassing “tree of life.” Surprisingly, the detailed description of this tree has only been a primary goal of Biology for the last quarter century. This seminar is designed for students who want to explore the tree of vertebrate evolution that late 20th century research has yielded, and who are curious about the human events that led to the comparatively recent “jump starting” of evolutionary historical sciences.

The course has three goals:
-To understand the methods by which the evolutionary tree is reconstructed.
-To explore the known vertebrate tree, survey the organisms on its branches, and highlight major events in their evolutionary history.
-To identify and examine some of vertebrate evolution’s persistent enigmas.

Pursuing them will take us through many evolutionary and paleontological topics. For example, the closet fossil relatives of vertebrates have a mouth, gills, and a spinal column of sorts, but nothing resembling a head. How did this featureless front end give rise to our brains, jaws, eyes, ears, and noses? In how many separate ways did vertebrate anatomy change to facilitate the momentous transition to life on land? How did their ancestors’ jaw bones get transformed into part of the mammalian ear? Why do a turtle’s ribs grow outside of its arms and legs? Why does an adult crocodile’s heart resemble that of a human fetus? These and many more intriguing topics await.

Investigations of the history of evolutionary studies, from its pre-Darwinian beginnings to its late twentieth century explosion will center on the modern method of phylogenetic systematics, the premier technique for reconstructing evolutionary history. We will learn how it came to be and how it differs from earlier, more subjective methods. To understand how it uses anatomical or genetic information to reconstruct the evolutionary tree, students will not only study the method’s theory, they will become familiar with its practice through their research projects.

The course culminates in a look beyond the vertebrate tree to ask, “So what? How is the tree of evolution useful to other areas of science?” Here, we will address such issues as the relationship between evolution and ecology–how an organism’s history constrains its future evolutionary options, and between evolution and Geology–how geological data influence our interpretation of evolutionary history, and vice versa.

Seminar sessions are divided between lectures, large group discussions, or small group exercises. No prior college-level knowledge is assumed, however a basic familiarity with evolution and vertebrate diversity will be helpful. A genuine interest in animals is essential. Readings are from primary and secondary scientific literature.

Assignments include:

• The grade is based on two exams, short proof-of-concept exercises, and a research project.