EESA01H3 Lecture Notes - Lecture 2: Panspermia, Chemotroph, Murchison Meteorite
11 Dec 2017
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Document Summary
The heterotrophic hypothesis life evolved from a primordial soup of inorganic chemicals dissolved in the ocean. It proposes that first life forms used organic compounds from the environment as energy. Miller and urey passed electricity through a mix of water vapor, hydrogen, ammonia, and methane, mimicking early atmosphere. Later experiments confirmed the validity, but amino acids on their own are not life. The panspermia hypothesis microbes from the solar system travelled on meteorites that crashed to. Scientists rejected this idea, believing that searing temperatures that comets and meteors attain as they enter our atmosphere should destroy them. However, the murchison meteorite (australia, 1969) contained amino acids. The chemoautotrophic hypothesis life originated at deep-sea hydrothermal vents. In this scenario, the first organisms were chemoautotrophs, creating their food from h2s. A related hypothesis suggests life originated in the hot, moist environment of thermal pools and hot springs, favored by adapted bacteria.
