Lecture 2 - GEO 160, Lecture #2: Limits of Life, p. 1...

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GEO 160, Lecture #2: Limits of Life, p. 1 Limits of Life (on Earth) (additional reading: section 5.5) Photograph of Great Fountain Geyser, Yellowstone National Park, USA Great Fountain Geyser is located in the Lower Geyser Basin in Yellowstone National Park. Prior to an eruption, Great Fountain's pool slowly fills with water and begins overflowing about 40 minutes prior to an eruption. Great Fountain is where Thomas Brock isolated the first hyperthermophilic microorganisms, Thermus aquaticus . Image was obtained from the following URL: http://www.freefoto.com/preview/1222- 02-45?ffid=1222-02-45
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GEO 160, Lecture #2: Limits of Life, p. 2 The Possibility for Extraterrestrial Life • Key question: should we expect life to be rare or common in the universe? • Basic laws of physics (e.g. gravity) and chemistry (e.g. elements, molecules) almost certainly hold throughout the universe • Universality of physics and chemistry makes it very likely that potentially habitable planets exist in our Milky Way Galaxy and beyond • Could life (e.g. like that on Earth) be common throughout the universe?
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GEO 160, Lecture #2: Limits of Life, p. 3 How Does Terrestrial Biology Inform the Possibility for Extraterrestrial Life? • Experiments and analysis of meteorites show that complex organic (carbon-based) molecules can form under extreme conditions in space…so why couldn’t they form readily and be common on many worlds? • History of life on Earth indicates that the step from pure chemistry to biology is not especially difficult
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GEO 160, Lecture #2: Limits of Life, p. 4 Membrane-Like Structures Formed from Organic Compounds in the Murchison Meteorite • Upper left: physical appearance of organic components of the Murchison meteorite • Upper right: droplets of non-polar (lipid) components extracted from the meteorite with chloroform/methanol • Lower left and right: membrane structures observed as extrusions of the droplets formed at alkaline pH Deamer, Nature , 1985
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GEO 160, Lecture #2: Limits of Life, p. 5 How Does Terrestrial Biology Inform the Possibility for Extraterrestrial Life? • Experiments and analysis of meteorites show that complex organic (carbon-based) molecules can form under extreme conditions in space…so why couldn’t they form readily and be common on many worlds? • History of life on Earth indicates that the step from pure chemistry to biology is not especially difficult Chapter 6 Chapter 6 Today’s topic
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GEO 160, Lecture #2: Limits of Life, p. 6 Extremophiles Extremophile: an organism that thrives under one or more environmental conditions that are extreme by human standards Cold Hot Acidic Basic Salty
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GEO 160, Lecture #2: Limits of Life, p. 7 But First…Water is Key If water behaved according to the properties of its constituent atoms (according to their positions in the periodic table), the substance would never be a liquid. ..it would evaporate at -70 o C and freeze at -100 o C Paradoxical behavior is due to hydrogen bonding, which causes
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This note was uploaded on 02/14/2011 for the course ORGANIC CH 341 taught by Professor Idk during the Spring '11 term at Wisconsin.

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Lecture 2 - GEO 160, Lecture #2: Limits of Life, p. 1...

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