BIOL 1202 Lecture Notes - Lecture 4: Absolute Dating, Archaea, Autotroph
Document Summary
25. 1 conditions on early earth made the origin of life possible. Earth is about 4. 6 billion years (by) old. 01/30/2015: radiometric dating of meteorites and moon rocks. Life arose about 3. 8 by ago: chemical traces in rocks 3. 8 by, fossil bacteria in rocks 3. 5 by. No spontaneous generation now, but must have happened then. (cid:1) (cid:1) (cid:1) (cid:1) Atmosphere: co2, ch4, nh3, h2s, h2o, no free oxygen. Abundant energy to drive reactions: frequent storms with much lightening, frequent volcanic eruptions. o. Joining these molecules into polymers: small organic molecules polymerize when they are concentrated on hot sand or clay (lava or hot rocks in the early earth), lab experiments support this occurrence. First organic compounds may have been synthesized near hydrothermal vents. Now: dna rna protein, need proteins to synthesize more dna. Then: earliest cells used rna to store info, ribozymes to catalyze reactions.
