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500 BCE
Pre-Aristotlelian Philosophers (BC 500~600)
Anaximenes: He thought that air was formed by motion. Insisted that there was a mixture of earth and water, which was combined when the sun's heat formed plants, animals and human beings.
Xenophanes: Searched about the origin of mankind. He too thought that spontaneous generation of sun's heat.
Empedocles: He accepted the spontaneous generation, but he insisted that there had to be trial of distinguishing successful combination.
Anaxagoras: He thought that the seeds of plants existed in the air. -
400 BCE
The History of Animals by Aristotle (BC 400)
Aristotle wrote a book about history or the animals. In his book, he explained that there were animals that came from parent animals by sexual reproduction, and the other animals that spontaneously from nonliving things because the nonliving material contained pneuma, or "vital heat". -
Period: 100 to
spontaneous generation timeline
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Oct 10, 1225
Acceptance of The Medieval Church
Aristotle, in Arabic translation, was reintroduced to Western Europe. During the 13th century, with the availability of Latin translations ,Saint Albertus Magnus and his student, Saint Thomas Aquinas,raised Aristotelianism to its importance. -
Spontaneous Generation in Renaissance
Spontaneous generation is discussed as a fact in literature well in the Renaissance. Shakespeare discussed snakes and crocodiles forming from the mud of the Nile. -
Francesco Redi's Experiment on Abiogenesis
An Italian scientist Francesco Redi wrote a book that refuted "spontaneous generation". In his experiment, he put meat in three jars. One of the jars was uncovered, and two of the jars were covered, one with cork and the other one with gauze. Maggots appeared in the uncovered jar. In the jar covered with gauze, maggots appeared on the gauze but didn't survived. Reid thought that if spontaneous generation was right, then maggots should appear in all three of the jars. So, he thought it was wrong. -
Fungi and spontaneous generation
Pier Antonio Micheli observed that when fungal spores were placed on slices of melon, the same type of fungi were produced that the spores came from. From this observation, he thought that fungi weren't made from spontaneous generation. -
Support of Spontaneous Generation Timeline
John Needham performed a series of experiments on boiled broths. He believed that boiling would kill all living things. He showed that when sealed right after boiling, the broths would cloud. It made to be able to believe that it was because of spontaneous generation. His peers agreed his studies. -
Refute to John Needham by Lazzaro Spallanzani
Lazzaro Spallanzani doubted John Needham's experiment. He thought germs went into the flank just when he sealed it. He did the same experiment again, and the result was different. There wasn't any bacteria at all. He proved that bacteria could be killed by boiling it. -
Appearance of Micro-organisms
Charles Cagniard de la Tour, a physicist, and Theodor Schwann, one of the founders of cell theory, published their independent discovery of yeast in alcoholic fermentation. They used the microscope to examine foam left over from the process of brewing beer. They observed yeast cells undergo cell division. This suggested that microorganisms, not spontaneous generation, was reliable. -
Conclusion by Louis Pasteur's swan-neck flask experiment
Louis Pasteur's experiment is widely known as one that settled the question of spontaneous generation. He boiled a meat broth in a flask that had a long neck that curved downward, like a goose. He invented a swan-neck flask that had bend in the neck so that sterile liquid could be exposed to air, but no outside things like dust could pass its neck. He proved that living things don't spontaneously come to exist. They had to come from some other living thing. -
John Tyndall's investigation
An Irish scientist named John Tundall, who was a great admirer of Louis Pasteur, did an experiment just as Louis Pasteur. He discovered that there were bacterial spores that could survive in boiling. This investigation could explain Needham's experiment.
