First Life

Conditions on Early Earth CO2, methane and other noxious gases in the atmosphere, extreme heat Methanogens Thermophiles Atmosphere is thick Sun cannot get through Oceans are olive green Caustic and uninhabitable

Heavy Bombardment Begins Oceans are vaporized, toxic rain Four molecules Carbon Nitrogen Hydrogen oxygen Amino acids Miller-Urey Experiment Pressure Theory

Miller-Urey Experiment H2O vapor, ammonia, methane, and hydrogen gases Electric current to simulate lightning Cooled gases, simulated rain, and collected everything in a flask Analyzed liquid and found amino acids, sugars, and other organic molecules

Pressure Theory Comets carried amino acids to earth The pressure of the comet hitting the earth did not cause all organic molecules to break down Instead, amino acids formed peptides, which can then form proteins

Amino Acids Amino acids form proteins DNA codes for proteins which allows the functions of the body to be carried out…that fact makes scientists’ think the formation of amino acids/proteins is relevant to the first events that formed life First life is Archaebacteria, which are extremophilic, like halophiles, methanogens, thermophiles

Heavy Bombardment Ceases The atmosphere begins to clear because there are no longer impacts throwing particles in the air Microbial life can begin Life most likely begins in the oceans or hydrothermal vents--protection from the sun Organisms would be anaerobic No oxygen available.