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Some definitions to keep in mind while reading this timeline:
Biogenesis: All life comes from living matter through some form of reproduction.
Abiogenesis (Spontaneous Generation): Life can appear spontaneously from nonliving matter. -
http://www.nndb.com/people/852/000103543/There is some debate about this year of birth as some sources state it was in 1577. Either way he was born in Brussels.
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During the 1620's van Helmont conducted his famous willow experiment. This experiment was conducted by first weighing the soil in a planter then a willow seed was added. After the willow was fully grown the soil was weighed again. The soil had not lost a significant amount of weight while the tree had gained over a hundred pounds in it's growth. From this it was determined that life came spontaneously from nonliving things.
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http://www.famousscientists.org/francesco-redi/Francesco was born in Arezzo, Italy.
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http://www.nndb.com/people/852/000103543/Van Helmont died for unspecified reasons in Vilvoorde, Belgium.
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While the experiment was conducted in the 1620's the details and hypothesis of this experiment was not published until 1648.
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William Harvey, an English physician, wrote a paper entitled, "On the Generation of Living Creatures." This paper claimed that life that did not grow from visible plants or animals grew from microscopic seeds. This is a biogenesis theory because it claims that all life comes from previous life.
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Francesco is most known for his maggot experiment which disproved the abiogenesis theory. The experiment was conducted by placing rotting meat in glass jars in a room with flies. The jars were covered in varying degrees and then monitored for the appearance of maggots. Maggots only appeared in the open or paritally covered jars. This experiment proved that the maggots came from eggs produced by flies rather than from the meat itself, which was the common belief at the time.
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At 71 years old, Francesco died in his sleep in Pisa, Italy.
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Needham was born in London, England.
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http://www.timetoast.com/timelines/abiogenesis-vs-biogenesis-research-project--4/edit He was born in Scandiano, Italy.
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http://science.jrank.org/pages/6408/Spontaneous-Generation.htmlNeedham boiled various broths. Once the broths had been boiled he poured them into flasks and then sealed them. Needham observed that once the broths had cooled microrganisms appeared. The microrganisms appeared to spontaneously appear, so Needham took this as proof of the Abiogenesis theory.
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http://www.daviddarling.info/encyclopedia/S/Spallanzani.html Spallanzani heated his samples longer than Needham and kept his samples sealed, instead of letting it cool before sealing. This technique stopped the samples from being contaminated so microrganisms didn't appear. People claimed that boiling killed 'vital energy' in the air that was needed for abiogenesis, so it wasn't taken as definitive proof of biogenesis.
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http://en.wikisource.org/wiki/Needham,John_Turberville%28DNB00%29Died in Brussles and is now buried in the vaults of the Abbey of Coudenberg.
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http://www.faqs.org/health/bios/39/Lazzaro-Spallanzani.html He died in Pavia, Italy.
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http://www.biography.com/people/louis-pasteur-9434402Louis Pasteur was born in Dole, France.
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http://www.brighthub.com/science/genetics/articles/21169.aspx</a> Pasteur proved that microorganisms exsisted in the air, but these organisms were not produced by the air itself. Pasteur proved microorganisms were not produced by air in an experiment similar to Spallanzani. Pasteur made a curved tube so that the air could escape, but microrganisms couldn't enter. Since air was entering and exiting but no microrganisms were found the organisms could not have been created by the air.
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http://www.biography.com/people/louis-pasteur-9434402In 1868 Pasteur suffered a brain stroke which led to partially paralysis. In 1895 this paralysis which is what ultimately led to his death.
