Experiments using swan-necked flasks were conducted by which scientist to disprove spontaneous generation?

Experiments using swan-necked flasks were conducted by which scientist to disprove spontaneous generation?

• A. Louis Pasteur
• B. Aristotle
• C. Alexander Fleming
• D. Christian Gram

Answer: (A)

Biogenesis versus spontaneous generation is about whether life can arise from nonliving matter or only from existing life. Louis Pasteur used swan-neck flasks that let air in but trapped dust and microorganisms in the curved neck. After boiling the broth, nothing grew in these necked flasks because microbes from the air were blocked, showing that microbial life comes from preexisting organisms in the environment, not from the broth itself. Growth only appeared if the neck was broken or contaminated air could reach the broth, proving that spontaneous generation does not occur under these conditions and supporting the germ theory of disease. Historically, Aristotle argued for spontaneous generation, while Fleming and Gram are known for other contributions (penicillin and Gram staining), not swan-neck flask experiments.

Biogenesis versus spontaneous generation is about whether life can arise from nonliving matter or only from existing life. Louis Pasteur used swan-neck flasks that let air in but trapped dust and microorganisms in the curved neck. After boiling the broth, nothing grew in these necked flasks because microbes from the air were blocked, showing that microbial life comes from preexisting organisms in the environment, not from the broth itself. Growth only appeared if the neck was broken or contaminated air could reach the broth, proving that spontaneous generation does not occur under these conditions and supporting the germ theory of disease. Historically, Aristotle argued for spontaneous generation, while Fleming and Gram are known for other contributions (penicillin and Gram staining), not swan-neck flask experiments.