Astrobiology
		Letters and Science 117
		Weeks 9 & 10: Readings and Links Early Life: Evolution and Extinction Midterm #2

"Snowball Earth":

• Scientific American: Snowball Earth
• Scientific American: The First Ice Age
• Science News Online: Popsicle Planet
• "Slushball Earth"
• SpaceRef: "Snowball Earth" May Not Have Been That Bad After All
• Great Moments in Science: Snowball Earth
• Nature Online: Snowball Fight
• inScight: A Refuge for Life on Snowball Earth
• University of Toronto: Equatorial water may have provided means of survival for early life

		Vendian Fauna: UCMP: Introduction to the Vendian Period Ediacaran Fossils of Canada Early Metazoan Life Precambrian Life Access Excellence: Old Worms, New Theories Adolph Seilacher Home Page

	Mass Extinctions: BBC Evolution Files: Mass Extinctions Mass Extinctions of the Phanerozoic In the Wild: Spotlight - Mass Extinctions Mass Extinctions and Cosmic Dust
		Catastrophitism and Mass Extinctions Meteorite Impact and Mass Extinction - ScienceWeek ZoomDinosaurs - Mass Extinction DinoBuzz - The Great Mystery 101 Crazy Theories about Dinosaur Extinction
	Exam #2 Alert! Click here to view slides from lecture.