Instructor: David Catling
CLASS TIME: Tuesday, Thursday 10.30am-11.50pm; Friday 10.30am-11.20am
(No class on Tuesday Sept 30.)
CLASS PLACE: Room 406, Atmospheric Sciences-Geophysics (ATG) Building.
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Class Description
Astrobiology is concerned with the history and nature of life in the universe. To understand life elsewhere, we must start closer to home, by examining life on Earth. The most significant time in Earth's biological, geological and climate history is the Paleoproterozoic era, some 2.5-1.6 billion years ago. It is marked by the appearance of the first fossils visible to the naked eye, the formation of an oxygen-rich atmosphere, the diversification of small aerobic organisms, the possible loss of lineages of anaerobic microbes, a world-wide spread of intracontinental rifts, spectacular climate change with putative "Snowball Earth" glaciations when possibly the Earth was frozen over, and significant changes in rock and ocean chemistry. Yet these events, which proved so crucial to the development of complex life on Earth, remain poorly understood. In this course, we will review current research on the transition from an anaerobic to aerobic world: geological, biological and chemical. We will conclude by comparing the small-scale metabolism of microbes to the global-scale metabolism of the biosphere. Finally, we will examine the global bioenergetic change with the rise of oxygen, which allowed life to exist in states of lower entropy. In so doing, we will also discuss the enigmatic relationship between entropy and life.
In this course, we will range widely over the biology, chemistry, geology and physics associated with the change from an anaerobic world to an aerobic world.
This course will consist of lectures and also sessions when students critically review published papers on topics of interest. The course is for graduate students. However, senior/junior science major undergraduates may also take the course with permission of the instructor.
Course Outline
1. Geological and Geochemical Change in the Paleoproterozoic (2.5 wks)
Guest Faculty: Prof. Roger Buick (Astrobiology Program/ Dept. Earth and Space Sciences)
2. Atmospheric Change and Snowball Earth Events (2.5 wks)
3. Microbial Evolution from Anerobes to Aerobes (2 wks)
Guest Faculty: Astrobiology Program Microbiologists: Prof. David Stahl, Prof. Jim Staley, Dr. Jesse Dillon
4. Bioenergetics and Entropy in an Aerobic versus Anaerobic World (2 wks)
5. Review (1 wk)
Background Reading
The popular books below are recommended background reading for the Summer, prior to taking the course.
In the course, we will review highly technical material: research papers from the scientific literature.
For a readable background on early life on Earth:
For general background to the nature of life and some
ideas on entropy, the following is an old classic, originally published
in 1944. Amongst other things, in this essay, Nobel Laureate, Erwin Schrodinger,
first said that life must run on some kind of "code" like a computer program,
i.e., he introduced the term "genetic code" to the English language.