Editing Microevolution (section)

==Origin and extended use of the term==

===Origin===
The term ''microevolution'' was first used by [[botanist]] [[Robert Greenleaf Leavitt]] in the journal ''Botanical Gazette'' in 1909, addressing what he called the "mystery" of how formlessness gives rise to form.<ref>{{cite journal |last1=Leavitt |first1=Robert Greenleaf |title=A Vegetative Mutant, and the Principle of Homoeosis in Plants |journal=Botanical Gazette |date=1909 |volume=47 |issue=1 |pages=30–68 |doi=10.1086/329802 |jstor=2466778 |s2cid=84038011 |doi-access=free }}</ref>
:''..The production of form from formlessness in the egg-derived individual, the multiplication of parts and the orderly creation of diversity among them, in an actual evolution, of which anyone may ascertain the facts, but of which no one has dissipated the mystery in any significant measure. This '''microevolution''' forms an integral part of the grand evolution problem and lies at the base of it, so that we shall have to understand the minor process before we can thoroughly comprehend the more general one...''

However, Leavitt was using the term to describe what we would now call [[developmental biology]]; it was not until Russian Entomologist [[Yuri Filipchenko]] used the terms "macroevolution" and "microevolution" in 1927 in his German language work, ''Variabilität und Variation'', that it attained its modern usage. The term was later brought into the English-speaking world by Filipchenko's student [[Theodosius Dobzhansky]] in his book [[Genetics and the Origin of Species]] (1937).<ref name="talkorigins"/>

===Use in creationism===
{{See also|Speciation}}

In [[young Earth creationism]] and [[baraminology]] a central tenet is that evolution can explain diversity in a limited number of [[created kind]]s which can interbreed (which they call "microevolution") while the formation of new "kinds" (which they call "macroevolution") is impossible.<ref name=escott>{{cite book|last1=edited by Scott|first1=Eugenie C.|title=Not in our classrooms : why intelligent design is wrong for our schools|year=2006|publisher=Beacon Press|location=Boston|isbn=978-0807032787|edition=1st|author2=Branch, Glenn|page=[https://archive.org/details/notinourclassroo00scot/page/n60 47]|url=https://archive.org/details/notinourclassroo00scot|url-access=registration}}</ref><ref>{{Cite web | title = Young Earth Creationism | url = http://ncse.com/creationism/general/young-earth-creationism | publisher = National Center for Science Education | date = 17 October 2008 |access-date=18 May 2012}}</ref> This acceptance of "microevolution" only within a "kind" is also typical of [[old Earth creationism]].<ref>{{Cite web | title = Old Earth Creationism | url = http://ncse.com/creationism/general/old-earth-creationism | publisher = National Center for Science Education | date = 17 October 2008 | access-date =18 May 2012 }}</ref>

Scientific organizations such as the [[American Association for the Advancement of Science]] describe microevolution as small scale change within species, and macroevolution as the formation of new species, but otherwise not being different from microevolution. In macroevolution, an accumulation of microevolutionary changes leads to speciation.<ref>[http://www.aaas.org/spp/dser/images_Doser/Publications/evol_dialogue_study_guide.pdf] {{Webarchive|url=https://web.archive.org/web/20120126203749/http://www.aaas.org/spp/dser/images_Doser/Publications/evol_dialogue_study_guide.pdf|date=26 January 2012}}, p. 12. [[American Association for the Advancement of Science]]</ref> The main difference between the two processes is that one occurs within a few generations, whilst the other takes place over thousands of years (i.e. a quantitative difference).<ref>[http://www.talkorigins.org/indexcc/CB/CB902.html Claim CB902: "Microevolution is distinct from macroevolution"], [[TalkOrigins Archive]]</ref> Essentially they describe the same process; although evolution beyond the species level results in beginning and ending generations which could not interbreed, the intermediate generations could.

Opponents to creationism argue that changes in the number of chromosomes can be accounted for by intermediate stages in which a single chromosome divides in generational stages, or multiple chromosomes fuse, and cite the chromosome difference between humans and the other great apes as an example.<ref>{{cite web |url=http://www.gate.net/~rwms/hum_ape_chrom.html |title=Human and Ape Chromosomes |access-date=2006-07-29 |url-status=dead |archive-url=https://web.archive.org/web/20110723050206/http://www.gate.net/~rwms/hum_ape_chrom.html |archive-date=23 July 2011 }}</ref> Creationists insist that since the actual divergence between the other great apes and humans was not observed, the evidence is circumstantial.

Describing the fundamental similarity between macro and microevolution in his authoritative textbook "Evolutionary Biology," biologist [[Douglas Futuyma]] writes,

{{blockquote|One of the most important tenets of the theory forged during the Evolutionary Synthesis of the 1930s and 1940s was that "macroevolutionary" differences among organisms - those that distinguish higher taxa - arise from the accumulation of the same kinds of genetic differences that are found within species. Opponents of this point of view believed that "macroevolution" is qualitatively different from "microevolution" within species, and is based on a totally different kind of genetic and developmental patterning... Genetic studies of species differences have decisively disproved [this] claim. ''Differences between species'' in morphology, behavior, and the processes that underlie reproductive isolation all ''have the same genetic properties as variation within species'': they occupy consistent chromosomal positions, they may be polygenic or based on few genes, they may display additive, dominant, or epistatic effects, and they can in some instances be traced to specifiable differences in proteins or DNA nucleotide sequences. ''The degree of reproductive isolation between populations,'' whether prezygotic or postzygotic, ''varies from little or none to complete''. Thus, ''reproductive isolation, like the divergence of any other character, evolves in most cases by the gradual substitution of alleles in populations''.|Douglas Futuyma, "Evolutionary Biology" (1998), pp.477-8<ref name=futu>{{cite book|first=Douglas|last=Futuyma|title=Evolutionary Biology|publisher=Sinauer Associates|year=1998}}</ref>}}

Contrary to the claims of some antievolution proponents, evolution of life forms beyond the species level (i.e. [[speciation]]) has indeed been observed and documented by scientists on numerous occasions.<ref>[http://www.talkorigins.org/faqs/faq-speciation.html Complete sourced list of observed instances of speciation, TalkOrigins Archive]</ref> In [[creation science]], creationists accepted speciation as occurring within a "created kind" or "baramin", but objected to what they called "third level-macroevolution" of a new [[genus]] or higher rank in [[taxonomy (biology)|taxonomy]]. There is ambiguity in the ideas as to where to draw a line on "species", "created kinds", and what events and lineages fall within the rubric of microevolution or macroevolution.<ref>{{cite web|last=Awbrey|first=Frank T.|title=Defining "Kinds" – Do Creationists Apply a Double Standard?|url=http://ncse.com/cej/2/3/defining-kinds-do-creationists-apply-double-standard|year=1981|publisher=National Center for Science Education}}</ref>