Description
Spontaneous generation refers both to the supposed processes in which different types of life might repeatedly emerge from specific sources other than seeds, eggs or parents, and also to the theoretical principles which were presented in support of any such phenomena. Such hypothetical processes sometimes are referred to as abiogenesis, in which life routinely emerges from non-living matter on a time scale of anything from minutes to weeks, or perhaps a season or so. An example would be the supposed seasonal generation of mice and other animals from the mud of the Nile. Such ideas have no operative principles in common with the modern hypothesis of abiogenesis, in which life emerged in the early ages of the planet, over a time span of at least millions of years, and subsequently diversified without evidence that there ever has been any subsequent repetition of the event.
Another version of spontaneous generation is variously termed univocal generation, heterogenesis or xenogenesis, in which one form of life has been supposed to arise from a different form, such as tapeworms from the bodies of their hosts.
In the decades following the 1859 publication of On the Origin of Species, the term "spontaneous generation" fell into increasing disfavor. Experimentalists used a variety of terms for the study of the origin of life from non-living materials. Heterogenesis was applied to once-living materials such as boiled broths, and Henry Charlton Bastian proposed the term archebiosis for life originating from inorganic materials. The two were lumped together as "spontaneous generation", but disliking the term as sounding too random, Bastian proposed biogenesis. In an 1870 address titled, "Spontaneous Generation", Thomas Henry Huxley defined biogenesis as life originating from other life and coined the negative of the term, abiogenesis, which was the term that became dominant.
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