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400
Birth of the Spontaneous Generation
Aristotle was the first to believe in the idea of Spontaneous Generation. He believed that life could emerge from nonliving things. For example, mice from corn, maggots from rotting meat, and fish from the mud of dry lakes. Aristotle’s theory of Spontaneous Generation was mainly composed of the idea of pneuma or “vital heat.” He believed that the pneuma contained in nonliving things had the power to generate life. This set the foundation for the theory Spontaneous Generation. -
Period: 400 to
Spontaneous Generation
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Francisco Redi Experiment
In 1668, Francisco Redi designed an experiment to test the spontaneous creation of maggots by placing fresh meat in two jars. One jar was left open, and the other was covered with a cloth. Days later he noticed that the open jar had maggots inside, whereas the covered jar contained no maggots. By covering the decaying meat, and blocking access to flies, he proved that decaying meat alone would never produce maggots, and rather maggots were only produced when in contact with flies. -
Invention of the Microscope
The invention of the microscope by the Dutch scientist Antony Van Leeuwenhoek in the late 17th century allowed scientists to closely observe new forms of life such as yeast, fungi, and bacteria. No one was sure of where these small organisms came from or how they were created, and it seemed as if they spontaneously arose from nonliving things. -
John Needham Experiment
In 1745, John Needham challenged Redi’s findings by conducting a series of experiments using boiled broth. He believed that boiling the substance would kill any living organisms. After boiling the broth and sealing the container, the broth continued to cloud, causing him to believe that life had been created by nonlife. -
Lazzaro Spallanzani Experiment
In 1768, Lazarro Spallanzani reconstructed Needham’s experiment after concluding that perhaps Needham didn't heat the broth long enough to kill everything inside. In his experiment, he placed broth in two bottles, boiled the broth, then sealed one bottle and left the other open. Days later, the unsealed bottle contained small organisms. On the other hand, the sealed bottle showed no signs of life. -
Rudolf Virchow Introduced the Concept of Biogenesis
In 1858, Rudolf Virchow, a German scientist introduced the concept of biogenesis, stating that all living cells can arise from preexisting cells only. Essentially, he claimed that life could only come from life, which rebutted the Spontaneous Generation theory. -
Louis Pasteur and the End of the Spontaneous Generation Theory
In 1859, Louis Pasteur conducted an experiment disapproving the Spontaneous Generation theory in microscopic organisms. Pasteur boiled broth in a flask, heated the neck of the flask in a flame until it became soft enough to bend, and bent it into the shape of an S. Air could enter the flask, but airborne microorganisms could not – As Pasteur had expected, no microorganisms grew. After his experiment, he finally concluded that even if exposed to air, life cannot arise from nonliving things.
