Question

The spontaneous generation theory was disproved by __________.

• A. Esther Lederberg
• B. Edward Jenner
• C. Sergei Winogradsky
• D. Lazzaro Spallanzani

Hint:

Spallanzani boiled and hermetically sealed broths to prove microbes come from air, which was a crucial early experiment disproving Spontaneous Generation.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The theory of Spontaneous Generation (Abiogenesis) held that living organisms could arise spontaneously from non-living matter (such as microbes arising from decaying broth).
Several historical scientific experiments were designed to disprove this theory, establishing the principle of Biogenesis (life arises only from pre-existing life).

Step 2: Detailed Explanation:
While Louis Pasteur is universally credited with the definitive blow to spontaneous generation with his swan-neck flask experiments in 1859, several early pioneers laid the groundwork by disproving it in the 18th century.
Among the choices provided:
- Lazzaro Spallanzani (D): An Italian Catholic priest and biologist who, in 1768, performed elegant experiments by boiling meat broth in sealed glass flasks.
He demonstrated that boiled broth remained completely sterile and free of microbes indefinitely as long as the flask was hermetically sealed, whereas flasks that were left open or poorly sealed grew microbes rapidly.
His experiments successfully countered John Needham's claims of spontaneous generation and proved that microbes enter from the air.
Let us review the other options:
1. Esther Lederberg: Discovered the bacteriophage lambda and developed the replica plating technique.
2. Edward Jenner: Developed the first successful vaccine (for smallpox) in 1796.
3. Sergei Winogradsky: A pioneer of soil microbiology who discovered chemoautotrophy and nitrification.

Step 3: Final Answer:
Therefore, the spontaneous generation theory was disproved by Lazzaro Spallanzani among the choices.