Life continually arises spontaneously. A widespread belief from the time of the ancient Romans through and beyond the Middle Ages was that organic life routinely generates from non-life, such as when rats emerge from a heap of trash, amphibians appear each spring from swampy mud, or maggots swarm from rotting meat. This standard folklore is known as abiogenesis, or the origin of life via spontaneous generation.
abiogenesis; proliferation
Life continually arises spontaneously. A widespread belief from the time of the ancient Romans through and beyond the Middle Ages was that organic life routinely generates from non-life, such as when rats emerge from a heap of trash, amphibians appear each spring from swampy mud, or maggots swarm from rotting meat. This standard folklore is known as abiogenesis, or the origin of life via spontaneous generation.
The revised worldview is that only life normally begets life. The “disproof” of spontaneous generation traditionally is ascribed to the French chemist and microbiologist Louis Pasteur, who in 1861 conducted a critical laboratory experiment showing that sterilized broth cultures do not regrow microorganisms unless exposed to suitable inocula containing other microbes. Apparently, the microbes were proliferating rather than arising spontaneously.
Pasteur’s experiments – important though they were – were not entirely novel in concept, because two centuries earlier the Italian physician Francesco Redi similarly had disproved the maggots-from-meat hypothesis simply by keeping adult flies (and thus their eggs) away from rotting meat. Thus, Pasteur merely extended doubts about spontaneous generation into the microbial realm. Also, Pasteur’s work gets only a modest PS-score because, by hard criteria, his experiments did not prove that life has never arisen from inorganic materials, but rather that any such spontaneous process apparently does not happen routinely, even in the microbial world. Nearly a century later, other kinds of experiments (see Chapter 27) would suggest that organic life has indeed arisen from inorganic substrates on at least one occasion in the Earth’s long geological history.
1. Levine R, Evers C. The Slow Death of Spontaneous Generation (1668–1859) Washington, DC: National Health Museum; 1999.