Editing Punctuated equilibrium (section)

==Common misconceptions==
Much confusion has arisen over what proponents of punctuated equilibrium actually argued, what mechanisms they advocated, how fast the punctuations were, what taxonomic scale their theory applied to, how revolutionary their claims were intended to be, and how punctuated equilibrium related to other ideas like [[Saltation (biology)|saltationism]], [[quantum evolution]], and [[mass extinction]].<ref name="gould_pe-fact-theory">[[Stephen Jay Gould|S. J. Gould]] (1992) [http://systematicbiology.co.nf/Gould_1989_PunctuatedEquilibriumFactTheory.pdf "Punctuated equilibrium in fact and theory."] {{Webarchive|url=https://web.archive.org/web/20180126071002/http://systematicbiology.co.nf/Gould_1989_PunctuatedEquilibriumFactTheory.pdf |date=2018-01-26 }} In Albert Somit and Steven Peterson ''The Dynamics of Evolution''. New York: Cornell University Press. pp.&nbsp;54–84.</ref>

===Saltationism===
[[File:Punctuated Equilibrium.svg|thumb|upright=1.5|Alternative explanations for the punctuated pattern of evolution observed in the fossil record. Both [[macromutation]] and seemingly "rapid" episodes of gradual evolution could give the appearance of instantaneous change, since 10,000&nbsp;years seldom registers in the geological record.]]

The punctuational nature of punctuated equilibrium has engendered perhaps the most confusion over Eldredge and Gould's theory. Gould's sympathetic treatment of [[Richard Goldschmidt]],<ref>{{cite magazine |author-link=Stephen Jay Gould |first=S.J. |last=Gould |date=June–July 1976 |url=http://www.stephenjaygould.org/library/gould_hopeful-monsters.html |title=The return of hopeful monsters |magazine=[[Natural History (magazine)|Natural History]] |volume=86 |pages=22–30}}</ref> the controversial [[geneticist]] who advocated the idea of "[[hopeful monster]]s," led some biologists to conclude that Gould's punctuations were occurring in single-generation jumps.<ref>{{cite book |author=Mayr, Ernst |year=1982 |title=Growth of Biological Thought |publisher=Harvard University Press |page=[http://www.stephenjaygould.org/library/mayr_macroevolutionary-diversity.pdf 617] |url=http://www.stephenjaygould.org/library/mayr_macroevolutionary-diversity.pdf |archive-url=https://web.archive.org/web/20160623211259/http://www.stephenjaygould.org/library/mayr_macroevolutionary-diversity.pdf |archive-date=2016-06-23}}</ref><ref>{{cite journal |author-link=John Maynard Smith |last=Maynard Smith |first=J. |year=1983 |title=The genetics of stasis and punctuations |journal=Annual Review of Genetics |volume=17 |page=12 |url=http://teosinte.wisc.edu/gen677_pdfs/Maynard_Smith.pdf |archive-url=https://web.archive.org/web/20101206232444/http://teosinte.wisc.edu/gen677_pdfs/Maynard_Smith.pdf |archive-date=2010-12-06}}</ref><ref>{{cite book |author=Ruse, Michael |year=1985 |title=Sociobiology, Sense or Nonsense? |place=New York, NY |publisher=Springer |page=[https://books.google.com/books?id=LdSgNlQgdlkC&pg=PA216 216]}}</ref><ref>''For reply see'':
* {{cite book |author-link=Stephen Jay Gould |first=S.J. |last=Gould |title=Structure |year=2002 |pages=765, 778, 1001, 1005, 1009}}
* {{cite book |first=R. |last=Dawkins |author-link=Richard Dawkins |title=The Blind Watchmaker |year=1996 |pages=[https://books.google.com/books?id=sPpaZnZMDG0C&pg=PA231 230-236] |publisher=W. W. Norton & Company |isbn=9780393315707 |url=https://books.google.com/books?id=sPpaZnZMDG0C&pg=PA231 |via=Google Books}}
* {{cite book |first=D. |last=Dennett |title=Darwin's Dangerous Idea |year=1996 |pages=[https://books.google.com/books?id=FvRqtnpVotwC&pg=PA288 288–289] |publisher=Simon and Schuster |isbn=9780684824710 |url=https://books.google.com/books?id=FvRqtnpVotwC&pg=PA288 |via=Google Books}}</ref> This interpretation has frequently been used by [[creationism|creationists]] to characterize the weakness of the [[Paleontology|paleontological]] record, and to portray contemporary evolutionary biology as advancing neo-saltationism.<ref>{{cite book |author-link=Hank Hanegraaff |author=Hanegraaff, H. |year=1998 |title=The Face that Demonstrates the Farce of Evolution |place=Nashville, TN |publisher=Word Publishing |pages=[https://books.google.com/books?id=Ta-qOuhtGkAC&pg=PA40 40-45] |isbn=9781418515096 |url=https://books.google.com/books?id=Ta-qOuhtGkAC&pg=PA40 |via=Google Books}}</ref>

In an often quoted remark, Gould stated,
: "Since we proposed punctuated equilibria to explain trends, it is infuriating to be quoted again and again by creationists – whether through design or stupidity, I do not know – as admitting that the fossil record includes no [[Transitional fossil|transitional forms]]. Transitional forms are generally lacking at the species level, but they are [[List of transitional fossils|abundant between larger groups]]."<ref>{{cite magazine |author-link=Stephen Jay Gould |first=S.J. |last=Gould |date=May 1981 |title=Evolution as fact and theory |magazine=[[Discover (magazine)|Discover]] |volume=2 |pages=34–37 |url=http://www.stephenjaygould.org/library/gould_fact-and-theory.html}}</ref>

Although there exist some debate over how long the punctuations last, supporters of punctuated equilibrium generally place the figure between 50,000 and 100,000&nbsp;years.<ref>{{cite journal |last1=Ayala |first1=F. |date=2005 |title=The structure of evolutionary theory |journal=Theology and Science |volume=3 |issue=1 |page=104 |doi=10.1080/14746700500039800 |s2cid=4293004 |url=http://www.stephenjaygould.org/reviews/ayala_structure.pdf |url-status=dead |access-date=2007-04-22 |archive-url=https://web.archive.org/web/20180923235159/http://www.stephenjaygould.org/reviews/ayala_structure.pdf |archive-date=2018-09-23}}</ref>

===Quantum evolution===

[[Quantum evolution]] was a controversial hypothesis advanced by [[Columbia University]] paleontologist [[George Gaylord Simpson]], regarded by Gould as "the greatest and most biologically astute paleontologist of the twentieth century."<ref>[[Stephen Jay Gould|S. J. Gould]] (2007) ''Punctuated equilibrium''. Cambridge MA: Harvard University Press, p. 26.</ref> Simpson's conjecture was that according to the geological record, on very rare occasions evolution would proceed very rapidly to form entirely new [[Family (biology)|families]], [[Order (biology)|orders]], and [[Class (biology)|classes]] of organisms.<ref name=Simpson1944>Simpson, G. G. (1944). ''[[Tempo and Mode in Evolution]]''. New York: Columbia Univ. Press, p. 206</ref><ref>Fitch, W. J. and F. J. Ayala (1995) [https://download.nap.edu/cart/download.cgi?record_id=4910 ''Tempo and mode in evolution: genetics and paleontology 50 years after Simpson''.] Washington, D.C.: National Academy Press.</ref> This hypothesis differs from punctuated equilibrium in several respects. First, punctuated equilibrium was more modest in scope, in that it was addressing evolution specifically at the [[species]] level.<ref name=Gould&Eldredge1977/> Simpson's idea was principally concerned with evolution at higher taxonomic groups.<ref name=Simpson1944/> Second, Eldredge and Gould relied upon a different mechanism. Where Simpson relied upon a [[Synergy|synergistic]] interaction between [[genetic drift]] and a shift in the [[fitness landscape|adaptive fitness landscape]],<ref>Simpson, G. G. (1953). [http://www.stephenjaygould.org/library/simpson_evolutionary-rates.html ''The Major Features of Evolution''] {{Webarchive|url=https://web.archive.org/web/20190421001618/http://www.stephenjaygould.org/library/simpson_evolutionary-rates.html |date=2019-04-21 }}. New York: Columbia Univ. Press, p. 390.</ref> Eldredge and Gould relied upon ordinary speciation, particularly Ernst Mayr's concept of allopatric speciation. Lastly, and perhaps most significantly, quantum evolution took no position on the issue of stasis. Although Simpson acknowledged the existence of stasis in what he called the bradytelic mode, he considered it (along with rapid evolution) to be unimportant in the larger scope of evolution.<ref name="Simpson1944p206">Simpson, G. G. (1944). ''[[Tempo and Mode in Evolution]]''. New York: Columbia Univ. Press, [https://books.google.com/books?id=f5qucNebo-kC&pg=PA205 pp. 205-206.]</ref> In his ''Major Features of Evolution'' Simpson stated, "Evolutionary change is so nearly the universal rule that a state of motion is, figuratively, normal in evolving populations. The state of rest, as in bradytely, is the exception and it seems that some restraint or force must be required to maintain it." Despite such differences between the two models, earlier critiques—from such eminent commentators as [[Sewall Wright]] as well as Simpson himself—have argued that punctuated equilibrium is little more than quantum evolution relabeled.<ref>{{cite journal |last=Wright |first=Sewall |date=1982 |title=Character change, speciation, and the higher taxa |journal=Evolution |doi=10.2307/2408092 |volume=56 |issue=3 |pages=427–443 |url=http://stewardshipofcreationenabler.giving.officelive.com/Documents/21_Wright1982.pdf |url-status=dead |archive-url=https://web.archive.org/web/20110828022050/http://stewardshipofcreationenabler.giving.officelive.com/Documents/21_Wright1982.pdf |archive-date=2011-08-28 |jstor=2408092 |pmid=28568042 }}</ref><ref>Simpson, G. G. (1984) ''Tempo and Mode in Evolution''. Reprint. Columbia University Press, p. xxv.</ref>

===Multiple meanings of gradualism===
Punctuated equilibrium is often portrayed to oppose the concept of [[Gradualism#Geology and biology|gradualism]], when it is actually a form of gradualism.<ref name="Dawkins, Richard 1996 p. 224-252">[[Richard Dawkins|Dawkins, Richard]] (1996). ''[[The Blind Watchmaker]]''. New York: W. W. Norton & Co., Chapter 9. (p. 224-252)</ref> This is because even though evolutionary change appears instantaneous between geological sedimentary layers, change is still occurring incrementally, with no great change from one generation to the next. To this end, Gould later commented that "Most of our [[paleontology|paleontological colleagues]] missed this insight because they had not studied evolutionary theory and either did not know about [[allopatric speciation]] or had not considered its translation to geological time. Our [[Population genetics|evolutionary colleagues]] also failed to grasp the implication(s), primarily because they did not think at geological scales".<ref name=Opus200/>

[[Richard Dawkins]] dedicates a chapter in ''[[The Blind Watchmaker]]'' to correcting, in his view, the wide confusion regarding ''rates of change''. His first point is to argue that [[phyletic gradualism]]—understood in the sense that evolution proceeds at a single uniform speed, called "constant speedism" by Dawkins—is a "caricature of Darwinism"<ref>Dawkins, Richard (1996). ''[[The Blind Watchmaker]]''. New York: W. W. Norton & Co., p. 227.</ref> and "does not really exist".<ref>[[Richard Dawkins|Dawkins, Richard]]  (1996). The Blind Watchmaker, p. 228. Dawkins' exception to this rule is the non-adaptive evolution observed in molecular evolution.</ref> His second argument, which follows from the first, is that once the caricature of "constant speedism" is dismissed, we are left with one logical alternative, which Dawkins terms "variable speedism". Variable speedism may also be distinguished one of two ways: "''discrete variable'' speedism" and "''continuously variable'' speedism". Eldredge and Gould, proposing that evolution jumps between stability and relative rapidity, are described as "discrete variable speedists", and "in this respect they are genuinely radical."<ref>[[Richard Dawkins|Dawkins, Richard]] (1996) ''[[The Blind Watchmaker]]'', p. 245.</ref> They assert that evolution generally proceeds in bursts, or not at all. "Continuously variable speedists", on the other hand, advance that "evolutionary rates fluctuate continuously from very fast to very slow and stop, with all intermediates. They see no particular reason to emphasize certain speeds more than others. In particular, stasis, to them, is just an extreme case of ultra-slow evolution. To a punctuationist, there is something very special about stasis."<ref>Dawkins, Richard (1996). The Blind Watchmaker, p. 245-246.</ref>