What concept did Pasteur’s experiment with the swan-necked flasks disprove?
a. germ theory b. aseptic technique c. vaccination d. spontaneous generation e. cell theory
The correct answer and explanation is:
The correct answer is d. spontaneous generation.
Explanation:
Louis Pasteur’s famous experiment with swan-necked flasks played a crucial role in disproving the theory of spontaneous generation, which was the idea that living organisms could arise spontaneously from non-living matter. Before Pasteur’s time, many scientists believed that microbes, like bacteria, could emerge from decaying matter without any prior living source. This belief had been long-standing and was especially widespread in relation to the origins of diseases.
In Pasteur’s experiment, he used a flask with a long, curved neck that was bent in the shape of a swan’s neck. He boiled broth inside the flask to kill any pre-existing microbes. The design of the flask allowed air to enter but prevented dust particles and microorganisms from contaminating the broth. The neck of the flask trapped airborne particles, and thus, the broth remained free of microbial growth for a long time, despite being exposed to air. However, if the flask was tilted, allowing the broth to come into contact with particles trapped in the neck, microbial life began to appear. This clearly demonstrated that life did not arise spontaneously from the broth but instead from microorganisms in the air.
This experiment was a significant turning point in the development of microbiology. It provided strong evidence supporting the idea that life comes only from pre-existing life, a principle known as biogenesis. Pasteur’s work laid the foundation for the modern germ theory of disease, which asserts that many diseases are caused by microorganisms, and it also contributed to the development of techniques like sterilization and aseptic techniques that are vital in medicine and microbiology today.
Therefore, Pasteur’s experiment helped eliminate spontaneous generation from scientific thought, leading to an understanding of how life is propagated and how infectious diseases are spread.