Talk:Punctuated equilibrium/Archive 1

Can we have some specifics on the trout research, please? A citation, specifically. --Dmerrill

Section on simulations

I have removed the following section:

==Simulations==

Recently, computer simulations have provided some insight into how punctuated evolution may work: The equilibrium periods show a gradual accumulation of neutral mutations, and the jump occurs when some beneficial combination of them reaches a certain threshold percentage.

While certainly interesting, the phenomenon demonstrated seems akin to saltation, not punctuated equilibrium. If this isn't so, then a better explanation is needed, as well as references.--Johnstone 02:43, 21 Dec 2004 (UTC)

Links

Why is an antievolution site being linked concerning PE? (Re: the ISCID Encyclopedia entry) That essay is inept in any case, failing even once to correctly label the alternative to PE as *phyletic* gradualism. If it is being retained as an example of the hash that antievolutionists make of the concept, that should be indicated in the description of the link. --Wesley R. Elsberry

"punctuated equilibria" vs. "punctuated equilibrium"

I moved this back because:

1. It is not inline with the naming conventions (don't use plurals).
2. Punctuated equilibrium gets more Google hits (70,000) than Punctuated equilibria (52,000)
3. It is widely taught in evolutionary biology courses using the singular form.

--Lexor|Talk 13:58, Dec 31, 2004 (UTC)

Reply:

1. This isn't a valid application of the rule for article titles. While "punctuated equilibria" is plural in grammatical construction, it is singular in concept. Think Great Lakes, New York Yankees, or Federalist Papers.
2. If it was a complete misnomer (but it's not, see item 3), the number of Google hits wouldn't matter. It would still be wrong to use it. For example, if a majority of people thought that "nucular power" was correct, should that term be used for the article nuclear power?
3. Gould originally used "equilibria", and continued to use it for several years, but appears to have switched over to "equilibrium". He may have bowed to popular usage: people are much more familiar with the word "equilibrium," and possibly mistakenly used it rather than the correct "equilibria." I seem to remember reading something once where he discussed this issue, but haven't been able to find it using Google. Anyone? If more definite information on this can be found, it should be reflected in the article. Other biologists (including Mayr) continue to use "equilibria." Not that it matters for the sake of the article content (i.e., if an inaccurate term is the generally accepted term, then so be it), but to me, "punctuated equilibrium" seems to be an oxymoron per the theory: When an equilibrium is punctuated, it returns to a different equilibrium, so it's at least two equilibria.

--Johnstone 23:38, 3 Jan 2005 (UTC)

I'm not saying Google is the ultimate arbiter, but basically both are correct, and while punctuated equilibria as you point out is probably more technically correct, punctuated equilibrium is also correct (and certainly not incorrect, so we are not in the situation where we are propagating an incorrect title). However, I maintain that since punctuated equilibrium is widely accepted (even by Gould towards the end of his life) and widely introduced under that title in textbooks, and it wins the "popularity contest" that that should trump the minor extra amount of technical correctness. --Lexor|Talk 11:34, Jan 4, 2005 (UTC)

Agreed. I wasn't arguing against "equilibrium," just making a few comments. Your reverting the article to "equilibrium" was the right move. (Again, this whole topic of the two names should to be reflected in the article, once comments by Gould about the usage of "equilibrium" are found.)--Johnstone 01:36, 5 Jan 2005 (UTC)

But is there some change that could be made anyway? I found the name 'punctuated equilibrium' to be confusing; I didn't know what it meant. At best, it was a short, sharp equilibrium between two times of change: But apart from being nonsense, that's the complete opposite of what's meant. Punctuated equilibria, OTOH, makes sense. We should make sense and be correct. A redirect can take people who are popular to the sensible one. Felix the Cassowary 08:15, 20 Feb 2005 (UTC)

( (The "two times of change", equilibrium before, equilibrium after, is ignoring this: The two things occurring are —(little short events of Punct. equil. are adding up to what appears to be just "One", geologic-time-scale--"Punctuated equilibrium point" ): 1--the speciation changes(they are actually just a 'pressure', because they have to sustain long enough to go(spread) through the population, (as Darwin knew) ), 2--and the change in the External environment; the "time elapsed" may have the ext. environment change, then change back to original, or all sorts of variations of this theme; But the two events changing are the " Internal Speciation ", and the " External environment ", which if nothing really changes (in the external), then at least: time has passed, (rain has fallen, geology has changed, the continents have moved a little, all data facts) ) ).6.3.55.1 18:26, 1 December 2005 (UTC)

( (It is fine to discuss this "plurality" dilemma; However, If one has read Darwin, seen the various "sub-components" of Evolution, 1—the Cosmic catastrophe events, 2— the astronomical 3-cycle systems (that eventually line up full-axis tilt, orbital variation, and the 3rd (?)(these have the Ice age,Glaciation implications) ), 1B—the Impacts that cause a chemical change in the ocean-continent system, 3—the continental drift, tectonic event that causes an ocean gyre to be removed, globally, (a Paleoclimatology problem), 4— the huge "array" of speciation, or inter-speciation events going on,... all just a list of "Changes globally", or 'almost' globally,...however, if one doesn't understand, the creation of a " New term ", specifically "Punctuated equilibrium", covers the same ideas talked about, even before Darwin (the Ocean explorers, observed some of this)(the Greek-Darwin, others?). So, the creation of "new terms" are an attempt to incorporate more data into the equation. If one cannot guess that Punctuated equilibrium/bria concerns Evolution, then it is also like saying: "How does Cladistics help understand speciation?" Cladistics-study, of an organism(within a species), looking internally (and functionally) inside of a species, and sees parts of the body. The "family trees" are perfected, elucidated through "cladistics". But this was noticed in the 1800's and earlier, by the term "convergent evolution" (As in the dolphin is shaped like the Fossil "Ichthyosaur"). Cladistics is just more precise, technical, and from one bone shape/function, the door of knowledge is opened. ...So, if one cannot guess what the Law of superposition, or the Law of faunal succession refers to, better to send the 'students' into another line of study. In Bold, or Highlight: Evolution is a study of 'Knowledge'; Evolution is not a study of Truth. [ Another term that is possibly unknown, is that after the "Impact", the "Catastrophe", ...there are the [Sweepstake winners (biology)] (could be made into a wiki study (if not already)); our Human species is part of the Winners group, incidentally. ] ) ) 6.3.55.1 18:26, 1 December 2005 (UTC)

Although the singular form is pretty common, I agree with Felix that the plural form is to be preferred. --Wesley R. Elsberry

"Equilibria" sounds weird; after all, we don't speak of quanta theory, strings theory, computers science, plants protection, etc. --isidora 06:23, 13 October 2005 (UTC)

Ernst Mayr's understanding of punctuated equilibrium.

The article, at the time of my writing, says: "Punctuated equilibrium is often confused with quantum evolution, saltationism, catastrophism, and with the phenomenon of mass extinction, and is therefore mistakenly thought to oppose the concept of gradualism."

It might be noteworthy to add that Mayr in his book "The Growth of Biological Thought : Diversity, Evolution, and Inheritance" (1982), notes that he believes Gould & Eldredge theory is more accurately described as saltationism than his own, which he considers different. While he might have changed his views, it is hard to forget this comment. --Thomi 02:16, 23 March 2006 (UTC)

If you read Mayr more carfuly (which I had to do many times) he actually considers it both gradual and saltational—all in in the same breath! First as a gradual account, when it properly employs his mode of peripatric and allopatric speciation. And then in the saltational mode, which Mayr (wrongly) interpreted from a poor reading of Gould's Natural History essay "The Return of Hopeful Monsters." For his proof Mayr quotes Gould as saying "Macroevolution proceeds by the rare success of these hopeful monsters, not by an accumulation of small changes within populations." But if you look at the essay it is as clear as day that Gould was articulating Goldschmidt's views, not his own. Furthermore this paper was never related—directly or indirectly—to punctuated equlibrium, but rather, as an attempt to open theoretical space to the idea, long disposed, that "small changes early in embryology accumulate through growth to yield profound differences among adults." Gould did play with a moderate form of saltationism, but not in the essay Mayr quotes. This is to be found in the 1980 paper listed in the bibliography. But as before, it had nothing to do with punctuated equilibrium. Best, Miguel Chavez 18:04, 8 June 2006 (UTC)

And you're right, he has since changed his views. Best, Miguel Chavez 18:14, 8 June 2006 (UTC)

addes stuff about evidence

hi guys!

i added a bit about evidence, this stuff is well proven and it would be a shame if it did not reflect on the article besides from the mechainsm i mentioned there are anothers (at least one that i dont remember right now)

bye!

(sorry for my poor english)

I think that the bit you added, is not quite about PE, i.e., stasis and periods of quicker evolution, but rather about genetic and developmental mechanisms for quick evolution, which are not part of PE per se, even though they can be. But are not more PE than phyletic gradualism or punctuated gradualism, never the less. --Extremophile 00:53, 14 May 2006 (UTC)

dawkins quotes that might be added

I think that the mentioned opposition of Dawkins is problematic area. I do not think that he has a problem with punctuated equilibrium, but more with the way it used to be divulged:

• What needs to be said now, loud and clear, is the truth: that the theory of punctuated equilibrium lies firmly within the neo-Darwinian synthesis. It always did. It will take time to undo the damage wrought by overblown rhetoric, but it will be undone. [251]"

• ... it is all too easy to confuse gradualism (the belief, held by modern punctuationists as well as Darwin, that there are no sudden leaps between one generation and the next) with 'constant evolutionary speedism' (opposed by punctuationists and allegedly, though not actually, held by Darwin). They are not the same thing at all. [242-243]

From the "Blind Watchmaker" book http://www.simonyi.ox.ac.uk/dawkins/WorldOfDawkins-archive/Dawkins/Work/Books/blind.shtml

--Extremophile 16:25, 5 June 2006 (UTC)

Alternative interpretations

Please do not impose a particular view of punctuated equilibrium on this article when the newer scientific literature supports alternatives. Wikipedia articles are supposed to have an NPOV.--StN 02:36, 6 June 2006 (UTC)

I don't disagree with you changing the section header, but I'm not sure what you mean with the above. There are all sorts of alternatives to Punctuated Equilibrium, it is only one amongst numerous macroevolutionary theories. On the other hand, the only 'particular view' that really matters is that of E+G, as put forward in their original paper with subsequent papers by them clarifying and expanding their original intent, and perhaps that of their supporters who add evidence or further clarification within the avowed framework of PE. I'm not sure if one can have an alternative view of a particular scientific theory; one either believes that it's true or that it is not. A better word for 'an alternative view' would be 'a new theory', i.e. Einstein had an alternative view of the workings of gravity to Newton. Badgerpatrol 03:01, 6 June 2006 (UTC)

"Alternative interpretations," in this context, is meant to indicate that "PE is a form of gradualism" is not the only way of understanding how the pattern discerned by E+G arose. There are other possibilities, as I have indicated in the additions. So this is not an alternative to PE, but an alternative to the assumption that everything in evolution has to be gradualistic, even when it doesn't look that way.--StN 03:11, 6 June 2006 (UTC)

Poor example in Alternative interpretations

The example ends with the sentence: "It is therefore reasonable to conclude that if the limb size in our hypothetical population evolved in the most conservative manner, it need only increase at a rate of 0.005 cm per generation (= 50 cm/10,000), despite its abrupt appearance in the geological record."

I find it incredible that anyone would take such an explanation seriously. So called "random" mutations of the same type must occur 10,000 times in a row. Not only that, natural selection must act on a variation in length that is about the size of a bacterium. This is not science. Please remove that example and give one that is as least a believable explanation of a possible mechanism for PE. OFG 03:20, 8 June 2006 (UTC)

I think you're misreading the example. Its point is that even tiny changes generation to generation can still amount to apparently instantaneous change in the fossil record, let alone selection operating on much larger differences (which would appear even more instantaneous; were that possible). It's not meant to be read absolutely literally, it's hypothetical. This isn't to say that it's not possible; differences only need to confer advantage on a statistical basis for them to be selected and lead to longer term change. The magnitude of an "advantage" depends on lots of factors (including things like population size; whether a species is r/K selected, etc.), many of which are difficult for an external observer to quantitatively discern.

Regarding PE, the point this example is making is simply that apparent "jumps" in the fossil record can simply be caused by steady selection - PE might not be happening at all. So this isn't an example of PE at all (which instead would suggest that something "interesting" has been happening on top of steady selection). Does this help? Cheers, --Plumbago 10:03, 8 June 2006 (UTC)

Yes, it isn't an example of PE and doesn't really seem to me to be relevent. Obviously, it is oversimplified (no reversals, constant incremental non-adaptive change, makes a mockery of population genetics and intra-population variation etc etc) but that is perhaps reasonable in a teaching example. But surely the key point it is missing is that the reason the effect will be observed as saltational rather than gradual is because of time averaging the poor resolution of the fossil record. To my mind, this is the opposite intent to that of PE, which (effectively) posits that there is actually not too much wrong with the fossil record as an index of evolutionary trends, and the staccato pattern of evolution observed is actually faithfully relating a genuine underlying process. The example given doesn't to my mind explain anything useful about PE at all. Badgerpatrol 12:40, 8 June 2006 (UTC)

I disagree. It's just making a very simple point that is entirely pertinent to PE, but not an example of it. All that is being said is that even very gradual change can stack up sufficiently that it looks like a PE event in the fossil record. Although it's hypothetical, it serves to underscore that boring old gradual change can be responsible for an impressive "jump" in fossil history rather than positing a special mechanism, like PE, to "speed up" evolution. I believe the idea was originally suggest by Stebbins (1982) then re-used (spun to address PE) by Dawkins (1986) in The Blind Watchmaker. Cheers, --Plumbago 13:17, 8 June 2006 (UTC)

It says nothing about PE because it doesn't mention why such change would appear to be sudden in the fossil record, i.e. because there are naturally large temporal jumps between horizons due to incompleteness. There is no context. Whilst this might be obvious to a palaeontologist, it is not explicitly layed out for an interested untrained reader. All it is currently is a rather oversimplified (misleading?) example of simple gradualism. There is a problem here discriminating data (=the fossil record of an organism often seems to be made up of large and sudden morphological jumps) and the interpretative theory (=punctuated equilibrium). The idea that deficiencies in the fossil record are causing large macroevolutionary jumps to be perceived when the actual underlying process is gradualistic pre-dates 1982 by a long way; it has been floating around since Chuck Darwin at least. Badgerpatrol 13:34, 8 June 2006 (UTC)

You're right about the clarity of the explanation. The article (at best) only implies the connection between the short timescales and fossil record incompleteness. It would certainly help to have this made more explicit. If this is added, I think the example makes more sense. Regarding the age of the idea, yes, you're correct of course, it isn't new. I should have said that the specific example of animal/limb size is one used by Stebbins (and repeated by Dawkins in a discussion of PE). Anyway, with these qualifications, I think the example could remain, but if you can think of a better way to rewrite this objection to PE that might be best. Actually, re-reading the paragraph, I find the earlier portion, "... though evolutionary change aggregates "quickly" between geological sediments ...", even more opaque. So perhaps a complete rewrite is in order? Cheers, --Plumbago 16:18, 8 June 2006 (UTC)

No, it doesn't have to happen a 10,000 times in a row, in a progressive manner. I believe that you are picturing evolution from one generation to the next, to the next, to the next, and so on. Evolution doesn't work that way. Evolution takes genes from the entire population and sorts them through natural selection and other mechanisms. Natural selection has an entire pool of genetic variation to work from. Populations evolve, not individuals, and not single lines of generations. But this is a very common misunderstanding. Lastly, Badgerpatrol has questioned the general usefulness of this paragraph. And I have questioned it too, but I agree with Plumbago that it helps by eliminating some of the confusion that PE relies on some sort of "alternative" mechanism. It doesn't. As anyone remotely familiar with the literature knows, it never has. (For those in the know, but who would question this, Gould's 1977 and 1980 papers were not about PE). I think who ever wrote it got the idea from Dawkins chapter in The Blind Watchmaker, which makes a similar argument. --Miguel Chavez 17:18, 8 June 2006 (UTC)

I understand quite well how evolution is supposed to work. I understand the capriciousness and contingencies in the workings of evolution. It is the paragraph in question, especially the example in that paragraph, which distorts the workings of evolution. The phrase “it need only increase at a rate of 0.005 cm per generation (= 50 cm/10,000)” easily gives the impression of progressive linear change. The anthropocentric notions of directionality and purpose often (I assume inadvertently) find their way into the writings of specialists who attempt to explain various forms of Darwinian evolution. From these I have often read how evolution “invents” various forms and functions. Carl Sagan, in my opinion one of the worst offenders in these matters, injected anthropocentric notions on a massive scale so as to justify his idea of a million highly advanced technological civilizations in the Galaxy. I read your paragraph as suffering from the same notions of directionality. --OFG 15:35, 9 June 2006 (UTC)

I see how it can be read that way, but when evolutionists speak of generations, they are speaking from the point of view of the population, not the individual. It's not the paragraphs fault, it's simply the only word we have. (And it is not my paragraph, but I think it has been somewhat helpful.) If you believe you can improve upon it, please, by all means, do. Best, Miguel Chavez 16:22, 9 June 2006 (UTC)

About the example, why do not substitute for something more real rather than something purely abstract and problematic? For example, the Grant's sudies with Finches had shown that three species of the genus Geospiza will evolve gradually in a few generations, as they witnessed; but at the same time, island conditions and short lifespan of the birds made impossible to the graduality of this evolution to be recorded in fossil. However, despite of not leaving the impression that what is happening is a fictitious hypergradual orthogenetic evolution, it still not is a example of PE, but I think it still is needed to explain how PE can be gradual.

Other idea I think that might be good would be a explanatory table or simple scheme of some kind, with the real oppositions and short explanations... "phyletic gradualism" vs "punctuated equilibrium" (maybe with punctuated gradualism in between) and "gradualism" vs "saltationism" --Extremophile 03:42, 18 June 2006 (UTC)

As I think I mentioned above, a distinction should be made between theory and observation. Punctuated equilibrium is a theory to describe the (disputed) observation that new species tend to occur suddenly in the geological record. Any example (and forgive me if I'm misreading what you are trying to say) that seeks to posit the idea that this observation may be an artefact of incomplete preservation of gradually evolving species is by definition an alternative to PE, not an example of it. Badgerpatrol 03:50, 18 June 2006 (UTC)

I was referring to the example "It is therefore reasonable to conclude that if the limb size in our hypothetical population evolved in the most conservative manner, it need only increase at a rate of 0.005 cm per generation (= 50 cm/10,000), despite its abrupt appearance in the geological record.". Which attempts to make clear that although a new species can occur suddenly in the fossil record, it does not necessarely indicates saltation. Since this example has some problems, as discussed above, I suggested a real occurrence of how evolution can be quick without these problems. Just happens that this specific case is also an example of how something could evolve in a non-PE way and yet would more likely look as if it were in the fossil record, but what causes this evolution to be quick can occur in a PE instance too, by no means implies that there is no PE at all. --Extremophile 20:21, 18 June 2006 (UTC)

Non-NPOV edits

Punctuated equilibrium describes the tempo and mode of evoluionary change as determined from the paleontological record. It implies nothing about the underlying mechanism for this or whether the "jumps" are apparent or real. Gould took a more saltationist position early in his career but eventually went over to the gradualist side. The purpose of this article is not to track SJG's intellectual peregrinations, but to explore the content, history, and scientific reception of the PE concept. Shifting the neo-saltationist interpretations arising from some recent EvoDevo work to a separate article is to sweep thes ideas under the rug so as leave this article comfortably within the neo-Darwinian paradigm. If the editors who keep removing the EvoDevo/tissue morphodynamics material cannot come up with a good justification for doing so over the next few days I will replace it. If they continue to remove it without good reason I will seek to have a non-neutrality advisory tag placed on the article.--StN 17:13, 8 June 2006 (UTC)

I'm sorry, but you're mistaken. Punctuated equilibrium is a specific theory of how cladogenesis—in particular peripatric and allopatric speciation—aggregates itself in the geological record. It is not a universal theory of rapid evolutionary change. And it's not proper to employ any mechanism of your liking as a substitute for the one outlined in their original 1972 paper, and subsequent papers. Eldredge and Gould have publicly complained about this numerous times, and a careful reading of their papers agrees with this interpretation. I moved your contributions elsewhere because if we keep it here it will continue to misinform people about what punctuated equilibrium is trying to say about the nature of the paleontological data and evolutionary theory. I don't want to short-shrift your contributions, but I have to protect the integrity of the article above all else. If people are going to make changes, they have to know what they're talking about. For example someone wrote that Hugh Falconer anticipated Mayr, Eldredge and Gould, but Falconer ideas were related to the tempo of evolution and had absolutely nothing to do with peripatric and allopatric speciation. Stasis is as old as paleontology. Best, Miguel Chavez 17:49, 8 June 2006 (UTC)

I appreciate your explaining your rationale, and will defer to your views for the time being, since you have clearly invested a lot in this article. However, my reading of the the original PE papers is a bit different. Gould was one of the major initiators of the contemporary EvoDevo field, particularly with his book "Ontogeny and Phylogeny," which discussed the evolutionary effects of the reorganization of body plans. Mechanisms such as neoteny and paedomorphosis can lead to extensive correlated morphological change with little genetic change. When considered in this context, the discussion on p. 114 of the 1972 Eldredge and Gould paper on the role of individual developmental homeostasis in maintaining species identity supports my view. In particular, the breach of developmental homeostasis (e.g., by the developmental alterations described in O&P and by the morphodynamic mechanisms I referred to in my original contribution) is precisely a mechanism of allopatric speciation. I think in your assertion that PE is a specific theory of cladogenesis, based on ideas like allopatric speciation, you are neglecting the fact that allopatric speciation is actually a descriptive phenomenon that itself *requires* a mechanism.

One more thing: if the idea that PE opposes the concept of phyletic gradualism is a "common misconception," as the article currently states, and if PE is actually a form of gradualism, then why is the 1972 article titled "Punctuated Equilibria: An Alternative to Phyletic Gradualism"?--StN 18:56, 8 June 2006 (UTC)

I see where you're coming from, but I still disagree. Re-reading the original Eldredge and Gould paper I find that their use of development is tied specifically to the morphological stability of species (i.e. stasis), not to rapid evolution caused by key mutations affecting development and timing (the punctuations). As for allopatric speciation, this is still caused by standard population dynamics, namely reproductive barriers, population size, the "alien [peripheral] environment," and natural selection. What Eldredge and Gould are saying here is that these mechanisms are fighting against more than simple gene flow (as Mayr and others assume), but developmental homeostasis as well (as suggested by Lerner and Ehrlich and Raven). On this reading, however, I would recommend that we include this aspect into the article to reflect that there be more to stasis than gene flow.

Lastly there are two kinds of gradualism: phyletic gradualism (the slow transformation of whole lineages through the succession of geological time) and populational gradualism (that genetic change from one generation to the next is incremental). Eldredge and Gould were speaking of the former. See Ernst Mayr's One Long Argument or his "Speciational Evolution or Punctuated Equilibria" for further detail and elaboration. Best, Miguel Chavez 19:09, 8 June 2006 (UTC)

Here's what I got from a quick search of Gould's texts. Hope this helps.

• "In this crucial sense, the theory of punctuated equilibrium adopts a very conservative position. The theory asserts no novel claim about modes or mechanisms of speciation; punctuated equilibrium merely takes a standard microevolutionary model and elucidates its expected expression when properly scaled into geological time. S. J. Gould The Structure of Evolutionary Theory. Cambridge MA: Harvard University Press. 2002. p. 778.

• "Ordinary speciation remains fully adequate to explain the causes and phenomenology of punctuation." ibid. p. 1001.

• "I did speak extensively—often quite critically—about the reviled work of Richard Goldschmidt, particularly about aspects of his thought that might merit a rehearing. This material has often been confused with punctuated equlibrium by people who miss the crucial issue of scaling, and therefore regard all statements about rapidity at any level as necessarily unitary, and necessarily flowing from punctuated equilibrium. In fact, as the long treatment in Chapter 5 of this book should make clear, my interest in Goldschmidt resides in issues bearing little relationship with punctuated equilibrium, but invested instead in developmental questions that prompted my first book, Ontogeny and Phylogeny. The two subjects, after all, are quite separate, and rooted in different scales of rapidity—hopeful monsters in genuine saltation, and punctuated equilibrium in macroevolutionary puntuation (produced by ordinary allopatric speciation)." ibid. p. 1005.

• "Finally, the claim that we equated punctuated equilibrium with saltation makes no sense within the logical structure of our theory—so, unless we are fools, how could we ever have asserted such a proposition? Our theory holds, as a defining statement, that ordinary allopatric speciation, unfolding gradually at microevolutionary scales, translates to punctuation in geological time." ibid. p. 1009[1]

• "Punctuated equilibrium is not a theory of macromutation…it is not a theory of any genetic process…It is a theory about larger-scale patterns—the geometry of speciation in geological time. As with ecologically rapid modes of speciation, punctuated equilibrium welcomes macromutation as a source for the initiation of species: the faster the better. But punctuated equilibrium clearly does not require or imply macromutation, since it was formulated as the expected geological consequence of Mayrian allopatry." S. J. Gould, "The meaning of punctuated equilibrium and its role in validating a hierarchical approach to macroevolution." In R. Milkman, ed., Perspectives on Evolution. Sunderland MA: Sinauer Associates, 1982. p. 83.

• "Punctuated equilibrium is a specific claim about speciation and its deployment in geological time; it should not be used as a synonym for any theory of rapid evolutionary change at any scale . . . Punctuated equilibrium holds that accumulated speciation is the root of most major evolutionary change, and that what we have called anagenesis is usually no more than repeated cladogenesis (branching) filtered through the net of differential success at the species level." ibid. 84-85.

• "First, simple misunderstanding of basic content was distressingly common, even among professional evolutionists. Many colleagues thought that we had raised the old anti-Darwinian specter of macromutationism, or truly sudden speciation in a single generation by a large and incredibly lucky mutation. I do not know why this happened; I think that all our articles and public statements were clear in separating human from geological rapidity." S. J. Gould "Opus 200" Natural History 100 (August 1991): 16.

• "Punctuated equilibrium was not a grandiose theory of the nature of change, a Marxist plot, a cladistical cabal, an attempt to sneak the hopeful monster back into evolution, or a tortuous assault on the concept of adaptation. It was at first, and has always been: (1) A well-defined, testable theory about the origin of species and their geological deployment (not a general rubric for any old idea about rapidity at any scale, and specifically not a notion about saltation, the origin of new Baupläne, or mass extinction). (2) A theory based on the recognition that events judged as glacially slow in ecological time might appear instantaneous in geological resolution (the conversion of the peripheral isolate into species, in particular). Some neontologists, misconstruing punctuated equilibrium as a theory of saltation, have charged that we made a disabling error in not recognizing the difference in scale between ecology and geology and in thinking that geological abruptness demanded some notion of true discontinuity. Quite the reverse: Punctuated equilibrium is not a theory of saltation, and its anchor lies in this appreciation of scaling—particularly, in recognizing how an ecological "slow" event like allopatric speciation must translate into the geological record." S. J. Gould "Punctuated equilibrium in fact and theory." In Albert Somit and Steven Peterson, The Dynamics of Evolution. New York: Cornell University Press, p. 57.

— Miguel Chavez 21:15, 10 June 2006 (UTC)

I never claimed (in my original addition to the article, which you removed) that punctuated equilibrium was equivalent to saltationism. I said it was consistent with, and possibly explained by, saltationism. That is, I changed the section title from Common Misconceptions to Alternative Interpretations, so as to make the point that although there are gradualist interpretations of PE, there are also saltationist ones, and modern EvoDevo provides a basis for them. As you quote Gould as saying in 1982: "As with ecologically rapid modes of speciation, punctuated equilibrium welcomes macromutation as a source for the initiation of species: the faster the better." It couldn't be clearer that the original conception of PE was consistent with rapid morphological change. That it does not require saltation is irrelevant. I did not claim it did. I just presented it as an alternative interpretation (without removing the gradualist one, by the way). This brings a more neutral point of view to the article. If you insist on calling the possible saltationist interpretation of PE a common misconception (one that Gould held in 1982), then this undermines the usefulness of the article. The fact that Gould threw in the towel on this in his later writings is also irrelevant. He did not keep up with the recent developments in EvoDevo toward the end of his life and was unable to defend rapid evolution scenarios (which he was clearly attracted to, continually revisiting Goldschmidt, D'Arcy Thompson - more than 30 pages in his final book - and even Lamarck) against his neo-Darwinist critics. But recent findings provide developmental mechanisms for rapid evolution, and Gould's original instincts were on target.--StN 05:20, 11 June 2006 (UTC)

Of course you are right—saltation is consistent with punctuated equilibrium. After all, how could it be otherwise? And I know you didn't make the obvious error in saying that punctuated equilibrium equates with, or even suggest, saltation. That was never my issue. However, as Gould rightly emphasizes, the issue of special developmental mechanisms involved in rapid (or instantaneous) speciation is a completely separate theoretical problem (and one that cannot be resolved by a careful analysis of the fossil record). And here we have the fundamental issue. Punctuated equilibrium takes a specific account of speciation—one that is (for the better part) standard, conventional, and well studied—and extrapolates it through the immensity of geological time. In a nutshell, punctuated equilibrium is the geological rendering of Mayrian cladogenesis. If anything, Eldredge and Gould have been meticulously steadfast in limiting their theory to this strict and testable mode. There is no alternative interpretation to be made, so therefore no metaphorical towel to be thrown. Other mechanisms, even conventional ones (such as habitat-tracking), may reproduce patterns of geological stability and rapid displacement, but they are supplemental theories, not subsidiary mechanisms in some grand overextended theory of punctuational change. Punctuated equilibrium does not subsume all theories of evolutionary rapidity, as the many quotations I've given, I think, make clear. And lastly, I don't want you to think that I'm hostile to your ideas, or your contributions. In fact, I feel strongly sympathetic. All I ask is that we respect the proper boundaries of an idea. Words have meaning. And robust scientific theories must be strict in their scope, and must be well defined. Punctuated equilibrium has more than just a few times been criticized for being a "moving target." And from my reading, I don't think this criticism has been at all fair. And I don't want to play into it. If people have trouble understanding punctuated equilibrium, it is because they have not read carefully, or misunderstood the problems punctuated equilibrium was intended to solve. I am willing to give an inch however, and will be happy to re-include your contributions myself, so long as it's made clear that these are not a part of punctuated equilibrium, but are consistent with the general pattern. Although, if not explained well enough, it may be misleading. (Perhaps I moved to quick to remove the text, rather than to take the time to rework it.) Miguel Chavez 06:05, 12 June 2006 (UTC)

I think this is a very fair assessment and proposal. I will leave it to you to work in a version of the text I supplied in a way you consider appropriate to the article.--StN 15:00, 12 June 2006 (UTC)

Punctuated Equilibrium - God of gaps?

How is this theory really a science? It's really hard to accept it as science, if this is what science is all about:

  1. Make observations.
  2. Form a testable, unifying hypothesis to explain these observations.
  3. Deduce predictions from the hypothesis.
  4. Search for confirmations of the predictions;
     if the predictions are contradicted by empirical observation, go back to step (2).

TalkOrigins. It seems like it's a poor exuse to fill in the gaps for unexplained theory of transitional steps of macroevolution. This is pure hypocrisy due to the fact that most deniers of creation, trying to poke fun of ID (intelligent design), say that ID theory is based on a belief in this so called God of Gaps (who is a supernatural being). Well, punctuated equilibrium theory is one strong claim, however without any evidence to back it up? (or to be more scientific, why don't we observe this happen today), so we can predict it as having occured in the past? And please don't use such statements as "it must have happened, therefore it did".Lyotchyk 10:47, 27 June 2006 (UTC)

• Quickly, because wikipedia is not a discussion forum. Punk eek predicts that there would be longer periods of relatively stasis, punctuated with relatively quicker episodes of evolution ocurring in small populations. It is consistent with populational genetics (see for example, hardy-weinberg equilibrium and founder effect). It does not claim that the evidence is lack of transitionals between species. It says that those will be less likely to found, and, when those are found, they will be in shorter distributions in space and time, rather than the whole species, over all their territorial distribution, gradually changing over time. There are findings that go according with this, I think that in the very talk origins website there is a section on PE. Besides all that, it does not proposes to fill major gaps on macroevolution, in the same way ID proponents say that ID tryes to; the more important evolutionary change is still driven by natural selection, and do not occur in single episodes of macroevolution (I.e, speciation), but gradually across a longer phyletic distance. Speciation itself is not such a big deal. Most of the difference between closely related species is not different from the type of difference found between dog breeds, plus gradual degrees of sterility and inviability (sometimes can be less gradual). Gould himself pointed a few times, that there are plenty of transitional forms between higher taxa, which are much more relevant than transitional forms between species. Now, I suggest that if there is yet anything you want to discuss, to do it in a discussion forum, such as EvC forums, SciForums.com, or even at Talk.origins --Extremophile 05:04, 28 June 2006 (UTC)

species substitution

I'm not an expert but I think that species substitution has much to do with TE, like being almost half of it, doesn't it? But the article doesn't even mentions it. --Extremophile 00:58, 12 August 2006 (UTC)

Criticism of punctuated equilibrium has even appeared from non-biologists.

So What? Theres plenty of other people with no relivant qualifications who argue against somthing, for all sorts or irrlivant reasons. The wording is just terrible "has even" "non-biologists" you will find people who oppose everything in every field.

--Biebersbro (talk) 11:20, 12 July 2011 (UTC)

In the article http://en.wikipedia.org/wiki/Punctuated_equilibrium#Criticism The section starts with

“Richard Dawkins believes that the apparent gaps represented in the fossil record document migratory events rather than evolutionary events.”

Could it be possible that around the period of Punctuated Equilibrium there were storms that lifted species from one location and deposited them in another?

Are there any archeological tests to show if storms may have occurred in that given period? Ghislain Marie (talk) 11:23, 25 August 2012 (UTC)

Jerks and creeps

This addition:

evolution by 'jerks and creeps'? is this vandalism or is it really what biologists refer to it as?

by 58.28.156.83, (the latest adddition), Totally addressess my complaints, about "Punctuated equilibrium"(The Article (in wikipedia)) --22:10, 6 December 2006 (UTC)

1. "Jerks and creeps" –Just a historical part of the definition (?), and is probably pretty much a "skewed" way of analyzing or interpreting this very important concept (of rapid movements of change), (analagous to another concept of: Saltation, recently split by wikipedians, but missing the whole darn point of what satltation implies: a steady–state condition immediately (in a short time) ending at a different steady-state condition.)
2. Just because the historical part of how this term: Puntuated Equilibrium arose, fits into some new thinkings, or definings of our world, doesn't mean that "We" have it accurate, ... or that it actually is defined well (defined well= defined Not-poorly).
3. When even looking at the articles-(and the associated articles like Darwin's finches, or Charles Darwin Research Station) for the Galápagos Islands in wikipedia, they mention seeing the "evolution", the changes right in front of them, It pretty much shows that the "time-frames", and that reference-points to time changes, (w/ envionmental condition changes), are all only surmised, or guessed. When I first heard of the term "punctuated equilibrium", I knew finally that the correct term had finally been found. Having studied, or having seen data, on so many interesting "natural selection" species, types, etc., I was so glad that a "correct-term", more appropriate term had been found.
4. for the above short reasons, (and confer with the concept: Saltation), understand that we can have an article that helps define "Punctuated equilbrium", but even the first sentence in the article may be poor, (or even incorrect in its statement). (I believe the first sentence has "Mis-statements")

So lets just continue on, (and please bypass the puns about the "jerks and creeps", and sometimes notes by the ....people who have another idea). Comments from the ArizonaDesert...--Mmcannis 22:10, 6 December 2006 (UTC)

"Evolution by Jerks". the 'creeps' who coined this phrase never considered the Harm they could do, to trying to understand the the Mechanisms of Evolution. Every, all changes both rapidly and slowly, only the Timeframe is the lens that determines which change is quick, (snap of the finger) of Slow, (Glacial-ly slow). Any way, i personally have always been offended by the Phrase, because it Belittles how difficult it is to organize how changes actually do occur in All Scientific fields over the Time Changes. As for Biology: Thank goodness for Cladistics. (from the SonoranDesert ofArizona-) -Mmcannis 15:59, 27 January 2007 (UTC)

Archiving. Also, the article is too wordy.

Just cleaning up and archiving here. *swings his feather duster around gaudily*

By the way, the depth of understanding that this article assumes varies, but worse off, the average knowledge on the subject assumed is too deep itself. There are plenty of people out there who want to know what Punctuated Equilibrium is who haven't taken ecology courses, or took their last one a few decades ago. Most people don't know what sympatric, allopatric, and destabilising selection (forget if that's what you call it) are. And they don't want to have to read through 80 links to be "qualified" to read this article, so the solution isn't to put up more links.

This article needs to be put in plain English, boys.

Anyone here who knows the basics of ecology: break down some of the scary words into layman's English. Easy up the language. If you think this current bookish version is too educative to dumb down, move parts of it to the ecology wikibook before you dumb the article. But it does need to be dumbed down in some places (specifically the first three sections.. it seems to get a little easier after that).

Don't forget, your audience is a bunch of people who barely understand what evolution is. You don't need to cater to the ignorant (you don't need to re-explain evolution here), but at least allow them to eat at the table with you (make it so they can follow along).

-Monk of the highest order 06:28, 16 November 2006 (UTC)

Depends on whether people consider this an encyclopaedia for grown ups, or a Jack and Jill site for ill-educated creationists.

Acquiescence?

Under "Punctuated Equilibrium's History," is "acquiescence" the correct word or should it be "acceptance" or something else?
Monado 11:32, 27 July 2007 (UTC)

relation to darwinism

I think that this section is somewhat misleading, or at least incomplete. Despite of the Darwin quote stressing the importance of the large areas, and demining somewhat the importance of isolation, "darwinism" as it is known didn't stop with Darwin (which barely knew mendelian genetics, and probably (my guess) haven't taken it into consideration at all), and with the modern synthesis (by 1930, about 40 years before PE), the aggregation of populational genetics with neodarwinism, the importance of peripheral isolates is at least implied, but was even stressed by some, such as Sewall Wright with his shifting balance theory of evolution, and Ernst Mayr emphasized the importance of allopatric speciation, isolation implied.

But also, the quotation in that context constrasts somewhat artificially Darwin's views with PE and its precursors. Much of what he is saying in the quotes, could be recontextualized and seen as an example of how he anticipated not only peripheral isolation as important for species formation, and also the species substitution (and species selection) of PE, to which, I think, isolation is also a hinderance. --Extremophile 06:17, 7 September 2006 (UTC)

FYI addition to Influenzavirus A

Researchers from the National Institutes of Health used data from the Influenza Genome Sequencing Project and concluded that during the ten-year period examined most of the time the hemagglutinin gene in H3N2 showed no significant excess of mutations in the antigenic regions while an increasing variety of strains accumulated. This resulted in one of the variants eventually achieving higher fitness, becoming dominant, and in a brief interval of rapid Darwinian evolution rapidly sweeping through the human population and eliminatimg most other variants.

WAS 4.250 22:58, 27 October 2006 (UTC)

Biased article - More Criticism of Punctuated equilibria position needed

I believe if the material below were incorporated in the article it would make it less biased.

First, I found the following quote: "Although uncertainty exists about just how recently the pairs of species diverged and about the relation between range and population size, Anderson and Evenson's data does not support Eldredge and Gould's claim that speciating populations are very small." —*Mark Ridley, "Evolution and Gaps in the Fossil Record," in Nature 286(5772):444-445 (1980). *Anderson and *Evenson did a 1978 study on geographic ranges of North American species which are supposed to have diverged recently.] [2]

I also found this material criticizing punctuated equilibrium: "But why do proponents of the punctuated equilibrium theory insist so much on the concept of restricted populations? The reason is clear: Their aim is provide an explanation for the absence of intermediate forms in the fossil record.

However, scientific experiments and observations carried out in recent years have revealed that being in a restricted population is not an advantage from the genetic point of view, but rather a disadvantage. Far from developing in such a way as to give rise to new species, small populations give rise to serious genetic defects. The reason for this is that in restricted populations individuals must continually mate within a narrow genetic pool. For this reason, normally heterozygous individuals become increasingly homozygous. This means that defective genes which are normally recessive become dominant, with the result that genetic defects and sickness increase within the population.178

In order to examine this matter, a 35-year study of a small, inbred population of chickens was carried out. It was found that the individual chickens became progressively weaker from the genetic point of view over time. Their egg production fell from 100 to 80 percent of individuals, and their fertility declined from 93 to 74 percent. But when chickens from other regions were added to the population, this trend toward genetic weakening was halted and even reversed. With the infusion of new genes from outside the restricted group, eventually the indicators of the health of the population returned to normal.179" [3] ken 11:35, 19 November 2006 (UTC)kdbuffalo

• Will you please stop spamming ridiculous POV tags. The article is fine at its core, and the two sources you cite fail WP:RS with blazing colors. *Spark* 14:33, 19 November 2006 (UTC)

Removed tag. Just because your creationist POV doesn't fit the article does not mean the article has a problem. POV trolling is the problem. Vsmith 15:46, 19 November 2006 (UTC)

Are Nature and Science forbidden journals to allude to. Because that is what was alluded to here. Putting back POV tag. ken 17:35, 19 November 2006 (UTC)kdbuffalo

You didn't cite Nature and Science. You cited second hand creationists who cite Nature and Science. We've been over this before. They aren't WP:RS and that isn't acceptable. And once again the sources are way out of date. In this case at 26 and 28 years out old they are even more out of date than the ones you wanted to put on the Dawkins page. Now stop, this is getting to be disruptive. JoshuaZ 18:18, 19 November 2006 (UTC)

Disruptive to what? Disruptive to your desire to have biased articles that are propaganda pieces for the evolutionary position? Articles should be NPOV. ken 18:26, 19 November 2006 (UTC)kdbuffalo

Regarding the issue of small population - this illustrates the problem with quote mining quote miners. To begin with, the article was about prairie chickens, not chickens. It appears that the author of "darwinism refuted" doesn't realise that there's a difference between the two. If you actually look at the article, Illinois populations declined from "possibly several million prairie chickens statewide in the mid-19th century" to 2000 birds in 179 populations, to 46 birds in two populations in 1994. So this isn't an article about small populations, it's an article about precipitously declining populations. And that makes a huge difference. Large populations can tolerate fairly large genetic loads. However, when individuals are moved from large populations to small populations, you now have a much higher probability of deleterious alleles coming together (see inbreeding depression). This isn't the case in populations which were small to begin with (or which declined gradually). In cases like that, the genetic load is lower to begin with, so they are more tolerant of inbreeding. Taking one of the most extreme examples (millions to dozens in a century) and trying to generalise it to small populations in general is dishonest. Which, again, leads back to the issue of why you should not quote second hand sources. Guettarda 13:32, 20 November 2006 (UTC)

Regarding the Ridley reference - I don't see how Ridley's statement, from a quarter century ago, which says that Anderson and Evenson's data did not support punctuated equilibrium somehow makes this article non-neutral. The intro to the article contrasts PE with gradualism, and even a cursory glance down the article shows a criticism by Dawkins. So what about the article is non-neutral? Eldridge and Gould proposed to idea to explain trilobites. Anderson and Evenson, according to your source, looked at species which diverged recently. While I don't have a context for what Ridely said, I suppose given that there was still a fairly polarised debate regarding PE back in 1980, it may have been worth pointing out. But, to the best of my knowledge, no one is saying that PE applies in all cases, but rather than it may apply in some cases. Anyway, I still don't understand what any of this has to do with NPOV. Guettarda 13:52, 20 November 2006 (UTC)

The following critique of the punctuated equilibrium hypothesis should be incorporated in the article

I think the following article clarifies matters further: Punctuated equilibrium: come of age? by Dr Don Batten 136.183.146.158 00:50, 26 November 2006 (UTC)

Can you stop spamming AiG links? I'm failing to see how a "Creationist Agricultural Scientist" can be taken seriously in any meaningful scientific context. *Spark* 02:50, 26 November 2006 (UTC)

I thought the article was quite informative and would give some needed balance to the Wikipedia article. 136.183.146.158 03:00, 26 November 2006 (UTC)

Well Ken, you're wrong. The article is basically balanced as it is, and input from someone who has no business commenting in a scientific article is not warranted. *Spark* 03:23, 26 November 2006 (UTC)

(reset indet) For others reading this and wonder where the heck "Ken" came from, we're suspicious that the IP address 136.183.146.158 is being used by someone called ken/kdbuffalo. See http://en.wikipedia.org/wiki/Wikipedia:Requests_for_comment/Kdbuffalo_2#Evidence_of_disputed_behavior for more and make your own mind up. Pity really as I thought we had someone new, with new ideas and not just the same old stuff. Ttiotsw 05:34, 26 November 2006 (UTC)

GA Re-Review and In-line citations

Members of the Wikipedia:WikiProject Good articles are in the process of doing a re-review of current Good Article listings to ensure compliance with the standards of the Good Article Criteria. (Discussion of the changes and re-review can be found here). A significant change to the GA criteria is the mandatory use of some sort of in-line citation (In accordance to WP:CITE) to be used in order for an article to pass the verification and reference criteria. Currently this article does not include in-line citations. It is recommended that the article's editors take a look at the inclusion of in-line citations as well as how the article stacks up against the rest of the Good Article criteria. GA reviewers will give you at least a week's time from the date of this notice to work on the in-line citations before doing a full re-review and deciding if the article still merits being considered a Good Article or would need to be de-listed. If you have any questions, please don't hesitate to contact us on the Good Article project talk page or you may contact me personally. On behalf of the Good Articles Project, I want to thank you for all the time and effort that you have put into working on this article and improving the overall quality of the Wikipedia project. LuciferMorgan 02:21, 16 December 2006 (UTC)

Result of the GAR

Punctuated equilibrium

result:No consensus (leaning toward keep) 3-3

Warned by me 5 weeks ago regarding lack of inline citations. Delist. LuciferMorgan 02:17, 25 January 2007 (UTC)

• Delist, no inline cits. Kyriakos 03:01, 25 January 2007 (UTC)
• Keep , this is silly, the Wikipedia:Harvard referencing is completely acceptable on Wikipedia. / Fred-Chess 13:12, 26 January 2007 (UTC)
• Comment The referencing doesn't even state what it's specifically referencing. Also, WP:WIAGA requires some form of inline citation. LuciferMorgan 14:48, 26 January 2007 (UTC)

• I'm sorry, but I don't understand what the problem with the article is... / Fred-Chess 09:53, 27 January 2007 (UTC)

• Keep I'm not claiming this is a perfect article content-wise, but to delist it because it uses Harvard referencing - which is a form of inline citation - would be silly. Opabinia regalis 05:16, 28 January 2007 (UTC)
• Keep per Opabinia regalis. Could possibly use some diagrams. - Malkinann 06:16, 29 January 2007 (UTC)
• Can't someone convert the Harvard referencing then? LuciferMorgan 03:20, 30 January 2007 (UTC)
  • Why does it need converting? (And what to?) Harvard referencing is a perfectly acceptable form of inline referencing on Wikipedia. Converting the article's referencing system without the consensus of the editors of the article is also discouraged in WP:CITE. - Malkinann 04:24, 30 January 2007 (UTC)
    • Convert to cite.php. Or at least have the Wikipedia templates for Harvard referencing, like {{ref}} and {{note}}. Hbdragon88 22:49, 31 January 2007 (UTC)

Conversion to Cite.php would be a lot of work, especially as Harvard referencing is a perfectly acceptable form of inline referencing on Wikipedia. I've put a proposal up on the associated wikiproject to change the method of citation from plain Harvard to Harvard with templates, as seen in Charles Darwin. But without consensus on this change from the wikiproject, I am reluctant to do so myself, as I've previously had very little to do with this article. -Malkinann 23:37, 31 January 2007 (UTC)

Hold on a minute, "Awaiting consensus"? Many GA reviews end with no consensus at all, and this looks like a 3 to 2 vote. Homestarmy 20:39, 7 February 2007 (UTC)

I count 3-3. - Malkinann 08:29, 8 February 2007 (UTC)

• Delist External jumps, the 3 inline references aren't formatted correctly, does not conform with WP:MOS. M3tal H3ad 08:46, 8 February 2007 (UTC)
• Delist Per above (reference formatting, lack of conformity). I can't support an article when someone who wishes to keep it says "I'm not claiming this is a perfect article content-wise". If it's not better than the average article, why make it good? A little work on the article and they can easily re-nominate it. Nja247 (talk • contribs) 00:14, 9 February 2007 (UTC)

It is better than the average article. Two years ago, it was checked by the Nature journal and found to be a pretty good article, with no glaring omissions. Isn't there no such thing as a perfect article, anyway? -Malkinann 07:34, 9 February 2007 (UTC)

• First of all, it should be noted that footnotes can not necessarily be replaced by Harvard references, because footnotes are not always references. However, in this article I do think that the inline citations can all be converted to the harvard references. Why not convert all to Harvard references if you think it is too much work to convert them to cite.php? / Fred-Chess 12:29, 10 February 2007 (UTC)

Ok, I'll give it a go. :) -Malkinann 04:39, 11 February 2007 (UTC)

I've been bold and changed the footnotes to Harvard citation.-Malkinann 06:23, 11 February 2007 (UTC)

Just a quick question!!

I don't want to sound like I'm stupid or something but could someone clear it up for me... if like a bird hatched from a lizard egg or something and flew off happily ever after, what would it mate with to, erm, make more birds? Thanks!! hope I didn't sound entirely naive or anything LOL 24.231.209.204 23:26, 21 February 2007 (UTC)

Could you guys answer real quick i have a paper to write -- 24.231.209.204

Wikipedia talk pages are not the place to ask questions about the subjects of their associated articles. That being said, the process you described is called saltation, and it doesn't actually happen. Every offspring is the same species as its parent, and they turn into different species slowly over many generations. Consider reading the TalkOrigins article "Introduction to Evolutionary Biology" before writing about the subject, and please don't use Wikipedia talk pages for this purpose. -- Schaefer (talk) 04:53, 28 February 2007 (UTC)

My apologies, then. 24.231.209.204 19:36, 15 March 2007 (UTC)

Controversy

I will start by saying that I am a supporter of the Modern evolutionary synthesis and an opponent of Intelligent design. However, I believe that the theory of punctuated equilibrium is deeply flawed. Daniel Dennet (well-known as a supporter of Darwinian evolution and atheism) gives a harsh criticique of punctuated equilibrium in Chapter 10 of Darwin's Dangerous Idea. I was surprised that there is no discussion of the controversy in this Wikipedia article. See Dennett's book for further references.--Pdturney 00:48, 2 March 2007 (UTC)

Daniel Dennet's criticism amounts to "what's the big deal?" I imagine it would be difficult to incorporate this "argument" into the body of the article. Miguel Chavez 06:59, 6 April 2007 (UTC)

Your summary of Dennet is accurate but simplistic. "What's the big deal?" is a valid question. And it's a question that Gould was unable to answer. --Pdturney 02:38, 7 April 2007 (UTC)

Of course. But there is a curious aspect of evolution called tempo. For those who study evolution, they are very curious as to how the tempo of evolution behaves. Does it behave uniformly, or on multiple levels? Is it slow, or fast, and is it gradual or sporadic? Paleontologists who study this phenomenon have wondered about the tempo of change even before Darwin published his Origin of Species, and for them--and really for anyone who has an honest curiosity about the nature of evolution--they wonder about such things. Eldredge and Gould proposed a novel answer to this problem (by combining several theories, and applying new statistical techniques to the empiric's of paleontology). They challenged their colleagues to look at their data in a completely inverted way. So for some, this idea might be worthy of some attention. But if you don't care about such things, and all you care about is adaptation, I can see why you might throw your hands up and say "what's the big deal?" Miguel Chavez 07:17, 7 April 2007 (UTC)

I think that Dennet and Dawkins would agree that the issue of tempo is interesting, but argue that Eldredge and Gould do not shed light on the issue; rather, they confuse the issue. --Pdturney 14:41, 7 April 2007 (UTC)

Regarding your latter statement, Dawkins has said just the opposite in The Extended Phenotype (p. 101), and Dennet (I'm not quite sure what particular statement you're referring to) is not remotely qualified to offer an opinion one way or another. He simply has no grasp of the paleontological literature. Best, Miguel Chavez 15:43, 7 April 2007 (UTC)

"What needs to be said now, loud and clear, is the truth: that the theory of punctuated equilibrium lies firmly within the neo-Darwinian synthesis. It always did. It will take time to undo the damage wrought by the overblown rhetoric, but it will be undone." (Dawkins 1986)--Pdturney 21:13, 7 April 2007 (UTC)

Well I agree with Dawkins, but so does Gould. The problem arises when people like Dennet run their mouth and haven't a clue to what they're talking about. When Gould says punctuated equilibrium challenges neo-Darwinism, he means its commitment to gradualistic modes of change. Even Dawkins admits that stasis was unexpected (p. 243). If this article has a problem, and it has many, it stems from a lack of disscussion of the "species as individuals" hypothesis, variable speciation rates, and its implication for a hierarchical theory of selection, etc. If I were you, I would read Gould's original papers, as many as you can, read some of the major reviews (Mayr, Ruse, etc.) and then, and only then, make up your mind. I too started with Dennet and had to work my way out. Best, Miguel Chavez 01:29, 9 April 2007 (UTC)

I've read several of Gould's books (Ontogeny and Phylogeny, Ever Since Darwin, The Panda's Thumb, Wonderful Life, Full House, The Structure of Evolutionary Theory) and several reviews of Gould (Dawkins, Dennet, Papineau, Tooby and Cosmides, Wright, Ruse, Alcock). I agree completely with Dennet's conclusions about Gould in Darwin's Dangerous Idea. It's clear that you and I are not going to agree on Gould, but I think we can agree that this article needs to discuss the controversy in more detail. --Pdturney 15:12, 9 April 2007 (UTC)

Gould's books are a great start, but I meant his original technical papers. And by reviews, I meant both sides of the controversy, and those written by professionals who know what they're talking about. For example, a list of competent critics would include names like Maynard Smith, Stebbins, Gingerich, and Ridley; not Dennet. Best, Miguel Chavez 04:26, 10 April 2007 (UTC)

Lastly, I agree with you on the need to expand on the controversies section, but I don't have the time right now to go through the literature and write up summaries. If you wish I can help you incorporate some of the arguments into the article, in fact, I would be more than happy to do this, but I need to know what criticisms you have in mind (short of Dennet's antipathy). Best, Miguel Chavez 15:27, 10 April 2007 (UTC)

On your advice I incorporated a detailed summary of Dawkins' critique, as expressed in his Blind Watchmaker. There will be more will come as time permits me. Miguel Chavez 02:58, 18 April 2007 (UTC)

Good summary! --Pdturney 12:45, 18 April 2007 (UTC)

Thanks! Miguel Chavez 17:28, 20 April 2007 (UTC)

After having gone back and reread Dennett, I now regret my remarks (with regards to Dan's section on punctuated equilibrium). His analysis is actually quite reasonable, and it is obvious to me that he has taken his time to read the original papers carefully. My apologies, I was brash and unfair. But I think you overestimate Dennett's arguments here. He actually holds a very moderate opinion on the whole issue of Punc Eq. It is far less extreme than the rest of Dennett's book. Best, Miguel Chavez 05:24, 27 April 2007 (UTC).

This part of the criticism section seems odd to me: "Another pervasive misunderstanding of punctuated equilibrium was that it invoked large-scale mutations, the sort invoked by Richard Goldschmidt in The Material Basis of Evolution...." The criticism section immediately follows the misconception section. If this is a "pervasive misunderstanding", shouldn't it be in the "common misconception" section? Placing it here with that framing sentence seems to imply that the other criticisms are invalid, or also simply common misconceptions. Also, may be of interest; Niles Eldridge is the curator of a page on PE at Scholarpedia, could be a good source of info for editors: http://www.scholarpedia.org/article/Punctuated_equilibria --Beetlesteve (talk) 19:49, 20 November 2008 (UTC)

I noticed that too. I took parts of some paragraphs in the Controversy section that belonged in the Misconceptions section and placed them there, keeping other parts of the paragraph in the Controversy section. --76.93.130.28 (talk) 01:32, 9 December 2008 (UTC)

Research results published in 2000 indicate that punctuated equilibrium doesn't work. Theoretical work by University of Oregon scientists shows that the essential processes making up punctuated equilibrium’s mechanism lead to extinction, not evolution. These scientists demonstrated that risk of extinction significantly increases for a species when its population becomes disconnected. Moreover, environmental changes and habitat fragmentation exacerbate a disconnected population’s susceptibility to extinction. Population and habitat fragmentation, along with an altered environment, stand at the center of punctuated equilibrium’s mechanism.

Investigators from Washington University in St. Louis produced field work confirming the work done by the scientists from the University of Oregon. Studying collared lizards in the Missouri Ozarks, the Washington University scientists showed that habitat fragmentation doesn’t drive speciation; rather it leads to extinction. —Preceding unsigned comment added by 96.40.106.195 (talk) 01:32, 22 April 2010 (UTC)

Whoever you are, you copied and pasted this from a creationist web site and inserted it into the article at least six times without any discussion in the talk page, only to have it reverted every time because you're misrepresenting the sources and drawing your own conclusions about the material (WP:OR,WP:SYN). One paper cited is [Templeton et al. 2001], which you claim shows that habitat fragmentation leads to extinction. The actual abstract says "... population genetic theory and experiments predict that most fragmentation events caused by human activities will facilitate not speciation, but local extinction. Founder events have played an important role in the macroevolution of certain groups, but only when ecological opportunities are expanding rather than contracting. The general impact of human activities on genetic diversity disrupts or diminishes the capacity for adaptation, speciation, and macroevolutionary change." (emphasis mine). The other paper cited, Higgins and Lynch 2000, is almost entirely irrelevant to the claims made for it. That paper says that a metapopulation composed of multiple small, poorly connected populations is subject to a high mutational load, and at risk of extinction; the authors' point is that such metapopulations are as vulnerable as single small populations. As with the other paper, there's no claim that this means that all small populations must necessarily go extinct, nor that punctuated equilibrium "doesn't work". Agathman (talk) 11:45, 11 April 2010 (UTC)

RTB is a science based organization which thousands of qualified scientists, researchers, and educators around the world work closely with and, as such, are qualified to offer criticism where applicable. Censuring the interpretations of reputable published scientists simply because they believe the best fit for the aggregate of human understanding leads to a progressive creation understanding rather than strict atheistic naturalism shouldn't occur on wikipedia but it does. The evidence from the above studies fits neatly into the RTB model, a scientifically testable model that makes specific predictions. Punctuated Equilibrium was meant to address the emergence of different Orders of life forms (above Genus and species) in macroevolutionary theory. Gradualism could not explain the sudden appearance of different Genus and species that leads to new Orders, so Gould and Eldridge postulated that small groups of organisms of a specific species would become isolated from their main group. These organisms, now isolated, would evolve as they adapted to the new niche they occupied much more quickly than those they left behind. What the studies are showing is that the opposite occurs.

Your objection that if human activity causes the isolation, rather than a natural sequence of events, this must result in an environment devoid of resources for punctuated equilibrium to work in should be disregarded. Punctuated equilibrium posits that rapid evolution occurs when a small subpopulation of a species becomes isolated from the general population where environmental and predatory pressures found in the periphery differ significantly from those found in the species’ typical geographical range. This mismatch supposedly provides the driving force for rapid evolutionary change. In fact, adequate environmental resources and the conditions necessary for the driving force behind the punctuated equilibrium hypothesis to be tested certainly are present in a multitude of instances of isolation both naturally occuring and also as a result of human activity right now in this world. Locusts, deer populations on islands, lemming populations, rat overpopulation, and lizards all have populations in an environment that fit the conditions for punctuated equilibrium to occur on this planet right now. Not in all cases but in specific cases. In all of these cases, changes in behavior were noted by scientists, but no permanent physical change ever resulted. We never see punctuated equilibrium occur. In fact, to date, there is no evidence proving a mechanism of secondary causes that makes such sudden advances even possible. This despite biologists like Read and Shapiro asserting that life has the capacity to make rapid innovations in the face of stress or opportunity. Still no punctuated equilibrium.

What we do see though is extinction and an excuse offered that we cannot find punctuated equilibrium in the world because too many humans are in it which amounts to little more than a loophole so that punctuated equilibrium never has to actually be proven. Population and habitat fragmentation, along with an altered environment, stand at the center of the naturalist's assertion of punctuated equilibrium hypothesis. This study provides evidence that it is not occurring. Your failure to allow this valid scientific criticism from a reputable scientist (published in Nature and many other scholarly journals) because of fallacious reasoning and the fact that the information itself is already published is untenable in the extreme. The fact that you wrote all of this off as "evangelism" shows your strong bias against any scientist's interpretation of evidence that doesn't align with atheistic naturalism. This bias guides your decision, and others like you, to actively suppress any scientific criticism of punctuated equilibrium, no matter how valid, from ever being presented resulting in a distorted view of reality.

Outlining

This article lacks a proper and coherent outline. I've cleaned it up a little, but I was thinking of something along the lines of:

• Introduction
• Brief History
• Mechanisms
• Tempo and Mode Before 1972

• Pre-Darwin
• Charles Darwin
• 1859-1930s
• Neo-Darwinian Synthesis

• Summary of 1972 Paper
• Reception

• Summary

• Positive Reception

• Detailed list of supporters (possibly in an endnote)

• Critical Responses

• Richard Dawkins
• John Maynard Smith
• Francisco Ayala
• Daniel Dennett
• Philip Gingerich
• Detailed list of detractors (possibly in an endnote)
• The Tri-fold history

• Popular Press
• Creationists

• Alternative Support

• Neo-saltationism
• Complexity theory
• Species as individuals

• Michael Ghiselin and David Hull
• Gould and hierarchy

Any suggestions would be more than welcome. This list, if implemented, will demand much more work from contributors. Best, Miguel Chavez 03:17, 18 April 2007 (UTC)

Intro

Most of you who edit this article and such probably already knew what it was so it might be hard to tell. But to someone like me who has no clue what it's about and is just reading it to understand a term from Science class the introduction is very confusing. A lot of terms in that intro that I don't understand, maybe links to an article that explains what they mean would help while a few of the sentences aren't that clear. Just some suggestions. Thanks! Deflagro ^C/_T 01:47, 20 September 2007 (UTC)

I think Deflagro is onto something. The first sentence of the intro is not the right lead for the section. I don't trust my own editiorial powers in this subject area, but I may take a run at it. This should be viewed as a threat because I might botch it. DCDuring 03:11, 20 September 2007 (UTC)

While I hope I've made a small improvement, the lede could be further improved. Verisimilus T 10:09, 20 September 2007 (UTC)

Imported from User_talk:Verisimilus Verisimilus, I like most of your changes to the intro to the article on Punctuated Equilibrium but I wanted you to reconsider one in particular. I am not a bilogist but more of a social scientist so I might be interpreting your changes incorrectly but when the original text described evolution as taking place "in rapid bursts, separated by long periods of stasis, in which little change occurs," I thought that it communicated very well the idea that change happens but not in a progressive way. On the other hand, your new text seems to imply, directly, that punctuated equilibrium states that no change happens, period. I am interpreting this correctly? Do we need to go back to the previous text? Jsarmi 15:04, 16 October 2007 (UTC)

I hope to have addressed this point. Verisimilus T 17:23, 16 October 2007 (UTC)

Gersicks

Would anyone object to the insertion of a paragraph on gersick punctuated equilibrium model of group development into the social theory section. Its explained pretty well on http://www.misrc.umn.edu/workshops/2006/spring/alan.pdf if anyone want to have a look. So let me know, an addition to this article or a seperate article?

Oops, I didn't see this note when I added the paragraph under "applications to social theory". See if you like it. Based on the PDF maybe a bit more detail might be good but I wanted to stay away from a in-depth discussion because I thought that the article should be accessible enough for people to grasp the general biological idea and some of the applications outside of biology/evolution. Jsarmi 15:38, 16 October 2007 (UTC)

Be bold! Go ahead and get stuck in! You can edit where you like and let the bureaucrats worry about the best place to put it later. Verisimilus T 18:29, 16 October 2007 (UTC)

Question on diagram description

The comments with the diagram at the top of the article has the tag "verification needed." The tag raises the question "Doesn't genetic change count?"

Of course genetic change counts -- I suppose there could be only little morphological change without genetic change. But, didn't the idea for Punctuated Equilibrium come from looking at the fossil record? It is notoriously hard to obtain genetic information from a fossil.

Also, the ideas for taxonomy, the relationships of species, the "tree of life" predate our ability to analyze genetics. SlowJog (talk) 02:09, 15 February 2008 (UTC)

I think the question I was trying to raise was whether punctuated equilibrium was a consequence of long periods of underlying genetic change, expressed in a sudden burst of morphological variation - as the image caption implies - or whether both genes and mophology undergo a rapid change at once, as I understand the hypothesis to suggest. The hypothesis can be (and I think has been) tested in recent groups for which DNA is available, although the details desert me. Verisimilus T 11:11, 15 February 2008 (UTC)

I didn't interpret the diagram & caption to imply anything -- one way or another -- about the underlying genetics. I simply see the intent of the diagram's creator to illustrate in a simple manner the difference between phyletic gradualism and punctuated equilibrium. SlowJog (talk) 17:28, 16 February 2008 (UTC)

It would be interesting if someone were to add more information about the underlying genetics in the article, though. SlowJog (talk) 17:33, 16 February 2008 (UTC)

Theory or hypothesis

Punctuated equilibrium is referred to in the lead as a hypothesis, and elsewhere as a theory. Which is it? Theory has very specific requirements. Has punctuated equilibrium met those requirements (and can we have a citation for that) or are we just using the word casually? I've seen it listed as a theory, hypothesis, observation, etc. WDavis1911 (talk) 22:21, 16 December 2008 (UTC)

Given that PE has been tested and the literature widely refers to it as a "theory" I think theory is the most suitable term. Best, Miguel Chavez (talk) 09:33, 3 January 2009 (UTC)

Punctuated equilibrium is not a theory. How could it possibly be one? It is a hypothesis (see Futuyma. Evolutionary biology, p. 137.) If gradualism is referred to as a hypothesis in Wikipedia, then so should punctuated equilibrium. mezzaninelounge (talk) 22:59, 15 January 2011 (UTC)

Separate page for hopeful monsters

Isn't really necessary. I'm no paleontologist or biologist, but punctuated equilibrium is the same essential idea, except that hopeful monsters is now a term used by creationists in the hope that people hearing it will think it's stupid without knowing anything about it. Wannabe rockstar (talk) 00:12, 9 January 2009 (UTC)

Not even close. Different mechanisms, different rate of change, different agency, and the latter says nothing of stasis. Best, Miguel Chavez (talk) 21:52, 5 July 2009 (UTC)

Missing argument

One argument I've seen against punctuated equilibrium is that it overlooks changes which occur which are not preserved in the fossil record, but are preserved in the genetic code. Basically, things which aren't preserved in the fossil record occur as well (things like behaviorial changes, changes in soft organs which aren't preserved, ect), and as such Gould underestimates the true continuity of evolution. Titanium Dragon (talk) 01:45, 8 July 2009 (UTC)

You're right, that should be included as well. However Gould has addressed that argument many times. His response is that there is no reason to think that sibling species evolve any differently than morphological species, therefore you can deduce the former by examining the latter. Therefore if morphological species evolve by fits and starts, sibling species should as well. In the case of molecular evolution, Gould has always allowed for its continual presence through geological time. He and other punctuationists fully accept the tenets of gradual molecular evolution, especially with regard to neutral evolution. But as Gould points out, punctuated equilibrium is not about molecular changes, it is about the emergence and deployment of species through time. Best, Miguel Chavez (talk) 19:42, 13 July 2009 (UTC)

Too much Dawkins/Neo-Darwinism

I'm not the person to do it well, but this article cites Dawkins far too much to be fair to PE. The evaluation given here, both in marginalizing the differences between PE and Neo-Darwinism and in marginalizing the value of PE in general, are adjudged faulty in Sterelny's book (which is generally overly-generous to Dawkins and itself overly attempting to play down the differences or the problems each theory sets for the other). There is nothing like this from Gould's side on the Phyletic gradualism page. Also, giving the scathing back and forth in the New York Review of Book letters, it seems extremely disingenuous to suggest so strongly that PE is squarely within even the Modern evolutionary synthesis given its emphases (if not its mechanism or timelines). Finally, some discussion of the many important results or at least strains of thought justifying the viewpoint against the type of Neo-Darwinism held by most MES adherents is in order given all the criticism. At least some mention of genetic disparity, the problems of extrapolationism, the Cambrian explosion, and the more recent supportive evidence in Burgess Shale, Chengjiang, and Sirius Passet. 67.166.176.181 (talk) 16:34, 31 December 2009 (UTC)

I agree, though in a different way. Neo-Darwinism (or rather, Dawkins et. al.) does not represent Darwinism as a whole (I think of it as the New Age counterpart to science or... like pop rock music... I guess... but that's a bit of bias from me), I'd still like to see criticisms that aren't "Richard Dawkins says *enter text here.*" It's bland really and it makes me wonder what OTHER people think, seeing as I see his name on very science article I read on Wikipedia... which is odd because I thought he was just a popular evolutionary biologist. 98.198.83.12 (talk) 07:37, 15 January 2010 (UTC)

Questionable statement about stasis of large populations

"Allopatric speciation suggests that species which are composed of large central populations are stabilized by their large volume and the genetic process of gene flow. New and even beneficial mutations are diluted by the population's size and are unable to reach fixation due to factors such as constantly changing environments."

I find this statement really questionable and am wondering what the source for it is. Based on computer simulated population models I learned, beneficial mutations (that is, those that increase fitness) will proportionally increase in a population over generations. This will be slower in a larger population than a small one, but also more steady and constant in its growth rate. Conversely, in a smaller population, a beneficial mutation is likely to increase quite rapidly, but is also more subject to the vagaries of genetic drift. In an absolute sense, complete fixation (that is, reaching 100% of the population and elimination of polymorphism) of a more fit allele takes place much more slowly, but nevertheless, the distribution of alleles in the population overall most certainly does change. Peter G Werner (talk) 21:42, 1 January 2010 (UTC)

I believe it stems from a statement from Gould, who wrote:

"The modern theory of evolution does not require gradual change. It in fact, the operation of Darwinian processes should yield exactly what we see in the fossil record. It is gradualism that we must reject, not Darwinism. […] Eldredge and I believe that speciation is responsible for almost all evolutionary change. Moreover, the way in which it occurs virtually guarantees that sudden appearance and stasis shall dominate the fossil record. All major theories of speciation maintain that splitting takes place rapidly in very small populations. The theory of geographic, or allopatric, speciation is preferred by most evolutionists for most situations (allopatric means ‘in another place’). A new species can arise when a small segment of the ancestral population is isolated at the periphery of the ancestral range. Large, stable central populations exert a strong homogenizing influence. New and favorable mutations are diluted by the sheer bulk of the population through which they must spread. They may build slowly in frequency, but changing environments usually cancel their selective value long before they reach fixation. Thus, phyletic transformation in large populations should be very rare—as the fossil record proclaims. But small, peripherally isolated groups are cut off from their parental stock. They live as tiny populations in geographic corners of the ancestral range. Selective pressures are usually intense because peripheries mark the edge of ecological tolerance for ancestral forms. Favorable variations spread quickly. Small peripheral isolates are a laboratory of evolutionary change.

"What should the fossil record include if most evolution occurs by speciation in peripheral isolates? Species should be static through their range because our fossils are the remains of large central populations. In any local area inhabited by ancestors, a descendant species should appear suddenly by migration from the peripheral region in which it evolved. In the peripheral region itself, we might find direct evidence of speciation, but such good fortune would be rare indeed because the event occurs so rapidly in such a small population. Thus, the fossil record is a faithful rendering of what evolutionary theory predicts, not a pitiful vestige of a once bountiful tale." (Gould, S. J. "The Episodic Nature of Evolutionary Change," The Panda's Thumb, New York: W. W. Norton, 1980, pp. 182-184.) Best, Miguel Chavez (talk) 23:19, 23 January 2010 (UTC)

Reverted passage critiquing punctuated equilibrium

I just reverted an edit quoting "Dr Fazale Rana, executive vice president of research at RTB" and citing two PNAS abstracts. The editor claims that punctuated equilibrium "doesn't work". One abstract cited was [Templeton et al. 2001], which was misquoted as saying "habitat fragmentation doesn’t drive speciation; rather it leads to extinction." The actual abstract says "... population genetic theory and experiments predict that most fragmentation events caused by human activities will facilitate not speciation, but local extinction. Founder events have played an important role in the macroevolution of certain groups, but only when ecological opportunities are expanding rather than contracting. The general impact of human activities on genetic diversity disrupts or diminishes the capacity for adaptation, speciation, and macroevolutionary change." The other paper cited, Higgins and Lynch 2000, is almost entirely irrelevant to the claims made for it. That paper says that a metapopulation composed of multiple small, poorly connected populations is subject to a high mutational load, and at risk of extinction; the authors' point is that such metapopulations are as vulnerable as single small populations. As with the other paper, there's no claim that this means that all small populations must necessarily go extinct, nor that punctuated equilibrium "doesn't work". Agathman (talk) 11:45, 11 April 2010 (UTC)

And now the material was put back in without discussion on this talk page. I removed it again. Agathman (talk) 17:51, 11 April 2010 (UTC)

And now it's back again. I'm not going to get involved in an edit war here. Maybe someone else would like to take a look at the passage in question. Agathman (talk) 18:22, 11 April 2010 (UTC)

Removed and blocked anon for edit warring. Vsmith (talk) 23:58, 11 April 2010 (UTC)

The temporary block expired, and the same material was promptly added from the same IP again. Agathman (talk) 17:46, 13 April 2010 (UTC)

Picture

I understand what the image is trying to say. However, strictly speaking, the branches would represent changes, thus the representation of the squarish graph versus a smooth, gradual one does not accurately depict what is going on. The gradual representation should look the same as the punctuated one with the exception that it has more branching over time. —Preceding unsigned comment added by 192.168.1.99 (talk • contribs)

Branching represents "speciation," not morphological change. Change is represented by lateral movement across the hoizontal plane. Moreover a key aspect of punctuated equilibrium is that evolution is generally limmited to key moments of speciation, so if the figure has a flaw, it is that the gradual representation should have less branching, as it is often associated with anagenesis. Best, Miguel Chavez (talk) 05:29, 24 September 2010 (UTC)

some stuff

in the first sentence: "little evolutionary change" should be changed to "little net evolutionary change". Evolution occurs at the time-scale of the generation (maybe a couple or a few more generations max), much quicker than the time-scale that PE operates at (1000s of generations).

again in the first sentence: "most sexually reproducing organisms". I don't understand why the same principles can't be applied to asexually reproducing organisms?

start of second sentence: "when evolution occurs". Perhaps this could be reworded; as written it is not part of the PE hypothesis (see first comment above). Perhaps something like; "under PE, large net change away from the mean phenotype is a rare event"...etc.

Suggesting that PE and phyletic gradualism are considered opposing is misleading. If this is to be included I think a small section should follow that explains that PE and phyletic gradualism are not necessarily opposing. They are indeed phenomena that describe different scales of change in evolution. PE in many cases can describe observations of macro-evolution, while PG in many cases can describe observations of micro-evolution. Therefore, proving one does not disprove the other; in fact there's is very good evidene for PG, but that does not in any way weaken PE.

Finally, I think it would help people to understand PE if it is additionally explained as "the hypothesis that rates of ['morphological' is more accurate, but in sticking with the article 'evolutionary' could be substituted here] change are bimodally distributed across time." (the inclusion of a diagram of this concept would also be beneficial, and they exist). This is where a comparison to phyletic gradualism may be appropriate, as it can be defined as "the hypothesis that rates of evolutionary change are unimodally distributed across time." Obviously, the disclaimer, that these phenomena actually describe different scales of change in evolution, would follow. —Preceding unsigned comment added by 81.191.92.230 (talk) 04:24, 14 November 2010 (UTC)

OK, i'm just going to go ahead and change "little evolutionary change" and "when evolution occurs.

I'll wait for discussion on my other points. —Preceding unsigned comment added by 81.191.92.230 (talk) 14:36, 19 November 2010 (UTC)

I just noticed that someone has reverted my change regarding 'net evolutionary change', without discussion. I'm adding it back in. stasis does not refer to a process of 'little evolutionary change', it refers to a process of 'little net evolutionary change' (or, more accurately, 'little net morphological change'). As I said already, evolutionary change generally occurs from one generation to the next; therefore, if the original statement made about stasis was correct then PE would be false (but we know it is not). In reality, stasis describes little variation in the mean phenotype (very different to the 'little evolutionary change'that was claimed). This means that evolution need not cease (unlike in the original statement about stasis that would lead one to believe that it did); instead, it is change in the mean phenotype that varies over evolutionary time.

Found the edit -- 06:42, 23 May 2011 Mchavez(talk | contribs) (38,015 bytes) (Clarified a few points) (undo) — Preceding unsigned comment added by 118.210.234.99 (talk)

Here's the problem, you're making the lead way too difficult to understand. The lead should be as utterly simple as possible, without sacrificing content or mischaracterizing the subject. Even I have difficulty following your description of punctuated equilibrium, and I'm reasonably familiar with it. The point about change vs. net change is a valid one. However it is a subtle point which needs to be stressed in the body of the article, not the introduction (as the article does, in the section on stasis). My main worry is that we are overloading the lead with far too much minutia, and it's going to get in the way of clarity. It needs to be written in such a way that someone with almost no familiarity with the subject can digest it and understand the topic. This point has been brought up by other contributors and I am very sensitive to it. Best, Miguel Chavez (talk) 10:07, 3 July 2011 (UTC)

Further Reading

Would it be appropriate to include Greg Bear's sci fi book Darwin's Radio as a work of fiction which uses Punctuated Equilibrium as one of the plot points? —Preceding unsigned comment added by 173.48.79.49 (talk) 04:23, 13 December 2010 (UTC)

Hypothesis vs. Theory

Choosing to classify a scientific idea as either a hypothesis or theory can be somewhat subjective, and may depend on how scientists understand the two terms. Generally philosophers and historians of science have identified two principal properties of a scientific theory. First, that it is a general explanation which incorporates other hypotheses to explain a series of broad observations. Second, that it has withstood critical testing and scrutiny, and thereby functions as a plausible explanation by professionals in the scientific community. By such a definition punctuated equilibrium surely meets the minimum requirement for a scientific theory.

While practitioners in the fields of paleontology and evolutionary biology use both terms to describe the model of evolution proposed by Eldredge and Gould, the term most often used in the professional literature today is the word "theory."

Notable evolutionists who favor the word theory include Ernst Mayr, who was among the greatest evolutionists of the 20th century. And although Mayr began as a critic of punctuated equilibrium, he became a strong devotee as time went on. The eminent evolutionist John Maynard Smith disagreed with Gould about the tempo of evolution, but he nevertheless saw fit to describe PE as a theory, which if true was saying something very significant about the character of evolutionary change. Richard Dawkins—perhaps the best known evolutionist today—devoted an entire chapter to PE in his book The Blind Watchmaker, and while critical, designates PE with the word "theory," in this book and others. Philosopher of biology, and outspoken critic of Gould, Michael Ruse also describes PE not only as a theory but a genuine scientific paradigm. Mark Ridley, another critic of Gould and former student of Richard Dawkins, wrote a definitive textbook on evolution titled Evolution. Throughout the text Ridley also prefers to use the word theory. Other prominent scientists include George C. Williams, G. Ledyard Stebbins, Michael T. Ghiselin, Francisco J. Ayala, Richard Lewontin, Richard Levins, Steven Rose, Sean B. Carroll, Steven Pinker, Norman D. Newell, Jerry Coyne, Brian Charlesworth, William Provine, John Turner, Stuart Kauffman, paleoanthropologists such as C. Loring Brace, Richard Leakey, Tim White, Ian Tattersall, and historians of science Peter J. Bowler, Frank Sulloway, Michael Shermer, and Frank Rhodes. Then of course there are the numerous writings of Stephen Jay Gould and Niles Eldredge.

After the publication of Eldredge and Gould's 1972 paper, numerous paleontologists sought to investigate their claims, and have contributed greatly to the understanding of evolutionary tempo. Paleontologists who describe PE as a theory rather than hypothesis include David Raup, David Sepkoski, Richard Fortey, Peter Ward, J. William Schopf, Robert L. Carroll Elisabeth Vrba, Donald Prothero, Tim Flannery, Douglas Erwin, Warren D. Allmon, Robert T. Bakker, John R. Horner, Michael McKinney, Bruce Lieberman, Mark McMenamin, Patricia Princehouse, David Fastovsky, John Huss, Richard Bambach, Anthony Hallam, Arthur Boucot, John Alroy, David Norman, D. B. Lazarus, Richard Kerr, and many, many others.

To justify the preference for the designation "hypothesis" we our provided with Douglas Futuyma's seminal textbook Evolutionary Biology. While both Futuyma and his textbook are very well respected in the field of evolutionary biology, Futuyma's practice of dubbing punctuated equilibrium a hypothesis is: first, unrepresentative of most biologists; second, frequently inconsistent; and third a reflection of Futuyma's conservative employment of the word theory. For example, in his book Science on Trial Futuyma goes as far as to say, "Every scientific claim is a hypothesis, however well supported it may be." This point is further elaborated upon in the opening pages of his textbook Evolutionary Biology. There he states his preference to restrict his use of the word "theory" to describe a "complex of statements" which are composed of a large "body of hypotheses" which "does not stand or fall on the basis of a single critical test." Futuyma thereby limits the word theory to such things as "atomic theory, quantum theory, and the theory of plate tectonics," but not others theories like allopatric speciation, the idea that hemoglobin carries oxygen in our blood, or the "hypothesis that smoking causes cancer." Futuyma also makes a distinction between the "pattern of punctuated equilibrium" and the "hypothesis of punctuated equilibrium." The pattern represents the empirics of the theory, and hypothesis represents the causal agency. Yet in other places he uses the word "theory" to identify the whole structure of punctuated equilibrium. With these facts in mind, Futuyma should hardly be considered the definitive word on the matter.

The words: tempo, mode, pattern, model, hypothesis, theory, thesis, idea, concept, and paradigm have all been used to describe punctuated equilibrium in the literature (and they are often used interchangeably). In fact Stephen Jay Gould and Niles Eldredge made it a point to use the more neutral word "picture" in their 1972 paper to avoid what they called a "tedious debate" about what to label their new idea. However as they began to develop PE over the years you see a notable shift in their language. They switch to the word model, and eventually move to the word theory.

Lastly, just as an experiment I ran the phrases "hypothesis of punctuated equilibrium" and "theory of punctuated equilibrium" through Google's digitized book search engine. The phrase with the word theory returned 2,080 results, whereas hypothesis only returned 119. [As of 4/22/2015, the disparity has grown even more skewed, 13,8000:375.] The same pattern resulted using Google Scholar, with the word theory returning 1,010 results and the word hypothesis only returning 60.

Today it is obvious that the word theory dominates the professional literature with the highest relative frequency. As such it should be used in this article. Best, Miguel Chavez (talk) 03:21, 30 January 2011 (UTC)

Literature cited

^{The following more suitable template has been substituted for {{Reflist ...}} by Jerzy•t 02:33, 4 November 2012 (UTC)}

References

Article could use a new section

The article has some information about what drives punctuated equilibrium, but it is scattered and incomplete. It would be beneficial to have a section that only addresses the causes/forces behind punctuated equilibrium. To be complete the "causes of punctuated equilibrium" section should include the hypothesis and the who proposed it.

Thanks! — Preceding unsigned comment added by 98.237.112.57 (talk) 02:52, 14 August 2014 (UTC)