Final answer:
The theory of spontaneous generation, which posits life can arise from nonliving matter, was refuted by experiments conducted by Francesco Redi, Lazzaro Spallanzani, and finally, Louis Pasteur, whose swan-neck flask experiment conclusively debunked the theory.
Step-by-step explanation:
Spontaneous Generation Theory
The theory of spontaneous generation is an ancient concept that posits life can emerge from nonliving matter. Greek philosopher Aristotle was a notable proponent of this idea, citing examples such as fish appearing in new puddles as evidence. The theory was widely accepted until the scientific community began to rigorously test its validity.
Challenges to Spontaneous Generation
Francesco Redi's experiments in the 17th century were among the first to challenge the theory by demonstrating that maggots on meat came from flies, not the meat itself. Later, Lazzaro Spallanzani refuted the concept further by showing that sealed flasks of broth did not generate life. However, Louis Pasteur's renowned swan-neck flask experiment delivered the final blow to spontaneous generation, proving through meticulous scientific methods that life comes only from preexisting life (Omne vivum ex vivo).