Neoteny

Neoteny (niˈɒtəni), also called juvenilization, is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compared to other primates. In progenesis or paedogenesis, sexual development is accelerated. Both neoteny and progenesis result in paedomorphism (as having the form typical of children) or paedomorphosis (changing towards forms typical of children), a type of heterochrony. It is the retention in adults of traits previously seen only in the young. Such retention is important in evolutionary biology, domestication and evolutionary developmental biology. Some authors define paedomorphism as the retention of larval traits, as seen in salamanders. The origins of the concept of neoteny have been traced to the Bible (as argued by Ashley Montagu) and to the poet William Wordsworth's "The Child is the father of the Man" (as argued by Barry Bogin). The term itself was invented in 1885 by Julius Kollmann as he described the axolotl's maturation while remaining in a tadpole-like aquatic stage complete with gills, unlike other adult amphibians like frogs and toads. The word neoteny is borrowed from the German Neotenie, the latter constructed by Kollmann from the Greek νέος (neos, "young") and τείνειν (teínein, "to stretch, to extend"). The adjective is either "neotenic" or "neotenous". For the opposite of "neotenic", different authorities use either "gerontomorphic" or "peramorphic". Bogin points out that Kollmann had intended the meaning to be "retaining youth", but had evidently confused the Greek teínein with the Latin tenere, which had the meaning he wanted, "to retain", so that the new word would mean "the retaining of youth (into adulthood)". In 1926, Louis Bolk described neoteny as the major process in humanization. In his 1977 book Ontogeny and Phylogeny, Stephen Jay Gould noted that Bolk's account constituted an attempted justification for "scientific" racism and sexism, but acknowledged that Bolk had been right in the core idea that humans differ from other primates in becoming sexually mature in an infantile stage of body development.