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Period: 300 to
Spontaneous Generation
Spontaneous Generation is the belief that life could come from non-moving things. it is the incorrect hypothesis that life can be produced from nonliving things. Example: mice from corn, maggots from rotting flesh -
340
Aristotle
*340 BC
The center of Aristotle's spontaneous generation theory was the idea of pneuma, or "vital heat". He believed that the pneuma contained in non-living materials had the power to generate life -thus leading to spontaneous generation. Aristotle's theory set the foundation for the theory of spontaneous generation. -
500
Anaximander
500 BC (Before Aristotle)
Anaximander was A Milesian (Turkish) philosopher. He wrote in the 6th and 5th centures (BC), and believed that everthing arose out of the elemental nature of the universe. In addition to this, he believed that humans were origionally fish. -
Jan 1, 1188
Spontaneous Generation in Christianity
Some believe that Christianity openly adopted the theory of spontaneous generation and that the ideas went unchallenged. An example would be from an extract from the bible “Let the waters bring forth abundantly the moving creature that hath life" (Genesis 1:20)” -
Jan Baptist van Helmont
Helmont used experimental techniques such as growing a willow for five years and showing it increased in mass while the soil showed a decrease in comparison to prove the existence of spontaneous generation. The results were believed because the process of photosynthesis was not understood. Helmont also described recipes for organisms such as mice (a piece of soild cloth plus wheat for 21 days). -
William Harvey
William Harvey's work predated the microscope. In his book "Exercitationes de Generation Animalium" he wrote about his belief in which life came from invisible eggs instead of "recipies" -
Francesco Redi
Redi challenged the idea that maggots arose spontaneously from rotting meat. He conducted an experiment where he placed meat in a variety of sealed, open, and partially covered containers. He found that maggots did not appear in the sealed containers, proving that decaying meat alone can not create maggots - they required the fly larvae laid directly on the meat by adult flies. -
John Needham
John Needham performed a series of experiments on boiled broths, he believed that boiling would kill all living things. After boiling the broth and sealing the container, the broth still continued to cloud - a clear indicator of life in the substance. This was a sign that spontaneous generation was occuring even after boiling. -
Lazzaro Spallanzani
Spallanzani modified Needham's experiment. He attempted to exclude the possibility of contamination between boiling and sealing. He hypothesized that after Needham boiled the broth, the substance became contaminated. After removing the air from the jar, no microbes grew within it. This was one of the earliest experiments to conclusively disprove spontaneous generation. However, Spontaneous Genration supporters Stated that he only proved that it couldn't occur without air. -
Louis Pasteur
Widely seen as having settled the question of spontaneous generation, Pasteur knew his experiment must show that a substance can be absent of all life, even when exposed to air. Pasteur heated the neck of a flask and bent it into an “S” shape, preventing any organisms to pass into the broth but allowing air to enter freely. The experiment showed that the microbial growth did not occur in the flask until the flask was turned so that particles could fall down the bends, proving the theory false.
