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First westerner to believe in spontaneous generation was in around 611-547BCE, Anaximander, a philosopher from which is now called Turkey today. His belief was that all living things came from the elements.
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Aristotle believed that all the elements, earth, air, fire and water, blended in some combination together, would form life. Each element having its own recipe to form parts of the human body, as well as the soul. Different souls could be made, with humans having the ability to “reason” apart from other animals and soul types.
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Francesco Redi 1668 experiment, involving jars that contained a piece of meat. One glass jar was sealed, the other was left open. No maggots appeared from the sealed jar, and Redi believed that he had proved disapproved spontaneous generation.
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Back in the ancient Roman times, to around the 18th century, people believed that life forms were created from non-living matter. An example of a spontaneous generation recipe, would call for underwear and husks of wheat to be placed into a jar. After 21 days, mice would appear. It was assumed that the sweat from the underwear soaked into the wheat, creating mice
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In 1745, Englishmen John Needham made his own experiment attempting to prove the theory of spontaneous generation correct. It was common knowledge that heating something would kill all the microorganisms, therefor he boiled a flask of chicken broth, and then sealed it. Sure enough, living things began to emerge from the chicken broth. Needham believed that he proved spontaneous generation correct.
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Italian priest, by the name of Lazzaro Spallanzani did not agree with John Needham’s conclusion, and therefor sit about on his own experiment. Lazzaro proposed that the organisms appeared from the air before Needham sealed the flask. When he conducted his own experiment, he drew all the air out of the flask, and then boiled the broth. No microorganisms grew. However, people argued that this experiment only proved that spontaneous generation needed air to occur.
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Finally, in 1859, chemist named Louis Pasteur, proved that spontaneous generation did not exist. He changed the flask, creating the nozzle into a shape of an S. He then boiled the meat broth. Air could reach into the flask, going through the newly created nozzle, however organisms could not. They settled onto the bottom throughout the nozzle, because of gravity. No microorganisms were formed in the broth. Louis Pasteur proved that spontaneous generation did in fact not exist.
