Editing Quantum evolution (section)

==Quantum evolution in plants==

Usage of the phrase "quantum evolution" in plants was apparently first articulated by [[Verne Grant]] in 1963 (pp. 458-459).<ref>{{cite book|last1=Grant|first1=Verne|title=The Origin of Adaptations|url=https://archive.org/details/originofadaptati0000gran|url-access=registration|date=1963|publisher=Columbia University Press|location=New York and London|pages=[https://archive.org/details/originofadaptati0000gran/page/606 606]}}</ref>  He cited an earlier 1958 paper by Harlan Lewis  and [[Peter H. Raven]],<ref name ="Cates">{{cite journal|last1=Lewis|first1=Harlan|last2=Raven|first2=Peter H.|title=Rapid Evolution in Clarkia|journal=Evolution|date=1958|volume=12|issue=3|pages=319–336|doi=10.1111/j.1558-5646.1958.tb02962.x|s2cid=88373329|doi-access=free}}</ref> wherein Grant asserted that Lewis and Raven gave a "parallel" definition of quantum evolution as defined by Simpson.   Lewis and Raven postulated that species in the Genus [[Clarkia]] had a mode of speciation that resulted <blockquote>...as a consequence of a rapid reorganization of the chromosomes due to the presence, at some time, of a genotype conducive to extensive chromosome breakage. A similar mode of origin by rapid reorganization of the chromosomes is suggested for the derivation of other species of [[Clarkia]]. In all of these examples the derivative populations grow adjacent to the parental species, which they resemble closely in morphology, but from which they are reproductively isolated because of multiple structural differences in their chromosomes. The spatial relationship of each parental species and its derivative suggests that differentiation has been recent. The repeated occurrence of the same pattern of differentiation in Clarkia suggests that a rapid reorganization of chromosomes has been an important mode of evolution in the genus. This rapid reorganization of the chromosomes is comparable to the systemic mutations proposed by [[Richard Goldschmidt|Goldschmidt]] as a mechanism of [[macroevolution]]. In [[Clarkia]], we have not observed marked changes in physiology and pattern of development that could be described as macroevolution. Reorganization of the genomes may, however, set the stage for subsequent evolution along a very different course from that of the ancestral populations<ref name ="Cates"/></blockquote>

[[Harlan Lewis]] refined this concept in a 1962 paper<ref>{{cite journal|last1=Lewis|first1=Harlan|title=Catastrophic Selection as a Factor in Speciation|journal=Evolution|date=1962|volume=16|issue=3|pages=257–271|doi=10.1111/j.1558-5646.1962.tb03218.x|s2cid=88311196|doi-access=free}}</ref> where he coined the term  "Catastrophic Speciation" to describe this mode of speciation, since he theorized that the reductions in population size and consequent inbreeding that led to chromosomal rearrangements occurred in small populations that were subject to severe drought.

[[Leslie D. Gottlieb]] in his 2003 summary of the subject in plants stated<ref name= "Rethink" >{{cite journal|last1=Gottlieb|first1=L.D.|title=Rethinking classic examples of recent speciation in plants|journal=New Phytologist|date=2003|volume=161|pages=71–82|doi=10.1046/j.1469-8137.2003.00922.x|doi-access=free}}</ref>  <blockquote>we can define quantum speciation as the budding off of a new and very different daughter species from a semi-isolated peripheral population of the ancestral species in a cross-fertilizing organism...as compared with geographical speciation, which is a gradual and conservative process, quantum speciation is rapid and radical in its phenotypic or genotypic effects or both.</blockquote>   Gottlieb did not believe that sympatric speciation required [[disruptive selection]] to form a reproductive isolating barrier, as defined by Grant, and in fact Gottlieb stated that requiring disruptive selection was "unnecessarily restrictive"<ref name= "AmJBot" >{{cite journal|last1=Gottlieb|first1=L.D.|title=Genetic Differentiation, Sympatric Speciation, and the Origin of a Diploid Species of Stephanomeria|journal=American Journal of Botany|date=1973|volume=60|issue=6|pages=545–553|doi=10.2307/2441378|jstor=2441378}}</ref> in identifying cases of sympatric speciation. In this 2003 paper Gottlieb summarized instances of quantum evolution in the plant species [[Clarkia]], [[Layia]], and [[Stephanomeria]].