Definition of "polygenesis"

polygenesis

/ˌpɒlɪˈd͡ʒɛnəsɪs/

noun
usually uncountable, plural polygeneses
1. The genesis of a species from more than one ancestor.
  Quotations
  After polygenesis was soundly rejected by theologians, it was taken up with enthusiasm by many scientists. Thomas Henry Huxley published Evidence as to Man's Place in Nature in 1863, applying Darwin's evolutionary theory to human origins. […] Evolutionary polygenesis, of course, did away with belief in Adam and Eve, and instead asserted that humans arose as a population.
  2019, S. Joshua Swamidass, The Genealogical Adam and Eve: The Surprising Science of Universal Ancestry, InterVarsity Press, page 125
2. (biology) The theory that living organisms originate in cells or embryos of different kinds, instead of coming from a single cell; as opposed to monogenesis.
3. (linguistics) The theory that languages developed independently in different places at different periods, as opposed to originating from a single source.
  Quotations
  The alternative to monogenesis for the origin of language is polygenesis, i.e. that language originated in human evolution at a number of distinct points. If polygenesis is assumed, then the different protolanguages would have developed independently and lead over millennia to the diversity of the descendant languages found at the present day.
  1994, Jan Wind, Abraham Jonker, Robin Allott, Leonard Rolfe, editors, Studies in Language Origins, volume 3, John Benjamins Publishing, page 131
4. The emergence from multiple causes or origins.
  Quotations
  The contrasting theory of polygenesis assumes that resemblances among tales can be attributed to independent invention in places unconnected by trade routes or travel.
  2003, Maria Tatar, The Hard Facts of the Grimms' Fairy Tales, Princeton University Press, page 64