BIOLOGY 2EE3 Lecture Notes - Lecture 16: Isotope Fractionation, Cambrian Explosion, Micropaleontology
15 Dec 2013
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Lecture 16: essential elements that make up the organic compounds: hydrogen, carbon, nitrogen, oxygen and phosphorous etc. upto iron. Carbon nitrogen and oxygen produced through nuclear fusion (cno cycle) and the others till iron were made from a nuclear fusion in the run. Others were generated through supernova (very high temperature explosion) creates heavier elements. living organisms need energy to sustain otherwise they would decay. Need a constant source of energy from the sun which is 6000 k degrees and emission of electromagnetic energy (heat) is what drives processes and gives us energy: water is required for all life forms on earth. 0-100 degrees celsius needed for liquid water. Evidence for ancient life on earth: stromatolites: rocky substances with many microbes growing inside them and cellular shape can be visualized under the microscope. Deposit of silicates and calcium carbonate within cells: microfossils: decayed microbial cells with distinct morphology filled with calcium carbonate/silicate.
