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In the opening of the article it's stated that the theory has "lost importance". This is vague and overly general and worded as opinion. Yes, newer theories have expanded or reformed r/k (actually, most have just said the same thing while changing the name because r/k was labelled "racist" via EO and Rushton). As of May 2012 we are still learning r/k selection in the UC system in California - arguably the top public university system in the world, especially in the biological sciences. Surely there's a better way to explain that expansions of earlier r/k selection theory have appeared rather than calling it "unimportant". It's still one of the foundational topics in organismal biology. — Preceding unsigned comment added by 207.233.120.5 ( talk) 23:45, 22 May 2012 (UTC)
I agree. r/K is a foundational concept of biology, the same as supply and demand is in economics. There may well have been more elaborate theories advanced, and thought might have moved beyond r/K, but r/K has not "lost importance" as this article seems to strongly suggest. [[[User:Issue313|Issue313]] ( talk) 17:22, 15 December 2013 (UTC)
I agree too. As much as I am not a fan, the theory is still very actively and explicitly used in ecology. Kyle MoJo ( talk) 05:16, 14 December 2018 (UTC)
Just wondering if we need to mention Rushton here? While I can see that it's important for his article to link to this one, it's not obvious that the reverse is necessary. Especially as his work is described as pseudoscience here. Anyway, just thought that it might be better not to burden a science page with not-entirely-appropriate links. Anyone care to comment? -- Plumbago 18:16, 9 January 2006 (UTC)
Rather than have two separate forums for discussion, can we stick to Talk:R-K Life History Theory? I've started things off there. Cheers, -- Plumbago 15:41, 24 February 2006 (UTC)
Rushton's work is very much outside the mainstream, and to present it without presenting the opposing view is tantamount to endorsing a POV. His theories, and the counter arguments, are well presented elsewhere. An uncritical presentation of his views here does not add to the understanding of r/K selection, and is intellectual dishonesty. Pete.Hurd 19:08, 6 May 2006 (UTC)
Related to this: editors may wish to note that I nominated Rushton's ordering of the human races for deletion for reasons explained on the article's AFD notice. Pete.Hurd 14:57, 8 May 2006 (UTC)
I've removed the following from the article (but copied it here, and over at Adaptive Capacity). I'm not convinced that it helps articulate the general r/K theory. It seems to me that the concepts of r/K are used in Adaptive Capacity analogously to how they are used in ecology. Certainly the text below is unclear and confusing (and needs copyediting). I've moved adaptive capacity to a "See also" point. Not least because explaining the relevance of r/K for adaptive capacity might be best done there.
Of course, I could just be being dense, and haven't understood the relevance of the above! Cheers, -- Plumbago 17:33, 9 November 2006 (UTC)
Plumbago, r and K phases are important in the work of the resiliance alliance, and are being widely applied throughout the Applied Environmental Assessment and Monitoring (AEAM) field at present. For this reason I added the section on Adaptive Capacity. I feel it should be included. John D. Croft ( talk) 18:38, 23 March 2009 (UTC)
Should we remove the no citations label now. In fact I find it reasonably well referenced/ John D. Croft ( talk) 18:38, 23 March 2009 (UTC)
I failed in my search for exactly this page when I entered "r/k". It wasn't in the first ten pages of results, presumably because the search engine ignores forward slashes. I found this page later by accident (while reading about semelparity on the reproduction page). The page should havebeen in the results, can you think of anything that can be done about that? -seth 189.162.17.16 05:12, 20 July 2007 (UTC)
I've removed the following statement from the article:
Firstly, it's too human-specific - the purported r/K-strategist traits of men/women apply equally to other organisms (furthermore, since stable reproductive pairs of child-rearing humans are not uncommon, humans may not be a good example). Secondly, r/K is usually viewed as interspecific rather than intergender, but if there's a reliable source (scientific literature) to back this use that'd be great. Certainly, there's something to the idea that different strategies suit different genders, but my feeling is that we need good sources before inserting potentially contentious about human psychology into an article on ecology (c.f. J. Philippe Rushton). If it's original research, while it shouldn't be here, it might well make for a interesting paper! :-) Cheers, -- Plumbago 16:33, 26 July 2007 (UTC)
This article seems to me misleading. r/K selection became highly controversial as early as the 1970's, and was long ago abandoned by most of those doing research in the evolution of life histories. If nothing else, see the review by Stearns in Ann. Rev. Ecol. Syst.
There's certainly nothing wrong with discussing the theory, but since this is a work that will mainly be consulted by those outside of research in evolutionary biology, I don't think it's a good idea to represent the theory as one that's generally agreed upon. That's just not the case.
I've noticed that lately discussions of r/K selection have begun to appear in places like this, or in textbooks. Obviously you needn't agree with the many criticisms of the theory, but I do think it's misleading not to mention them. An interesting and useful article might address the history of the idea -- its life, death, and recent resurrection outside the research arena -- and reasons for that.
Gafox1 01:55, 24 October 2007 (UTC)
Here's the Stearns cite: Stearns, S. C. Evolution of life-history traits - critique of theory and a review of data. Ann. Rev. Ecol. Syst. 8: 145-171. This paper was very influential for 10 or 15 yrs -- for some time it was *the* standard reference for much about life history theory. That's not to say that it was the definitive work -- just that it was widely read and cited.
In addition to Stearns' criticism, it's worth asking two things about r/K theory. First, the theory was derived from logistic growth models, but a moment's thought will tell you that the derivative of the logistic equation with respect to both r and K is positive. In other words, there's no necessary trade-off in that model -- one must add other assumptions, usually ad hoc. Second, is r/K theory actually testable? If you go to look inside a population and study its evolution, how could you test it?
I've heard it said before by marine ecologists that marine ecology tends to be light on theory. Maybe it's true -- I don't get wet in my work, so can't say. All I'll say is that if you look at leading journals on ideas in evolutionary biology -- say, Evolution and Am. Nat., or others if you like -- you'll find that r/K theory hasn't inspired substantial work in a long time. It seems to have been resurrected lately because, well, it's a simple explanation for something that's complicated -- so it's made a reappearance in places like textbooks. My own view is that this is a bad thing: the theory doesn't work logically and it led to a real mess empirically; there are good reasons to discuss it as part of the history of science, but not as a currently viable theory.
By the way, you might also look at Derek Roff's book on life histories and their evolution. I don't recall what he says about r/K theory, but that's just the point -- it plays little role.
Cheers, Gordon Gafox1 00:28, 25 October 2007 (UTC)
Hey Gordon,
As a professor who teaches about r/K selection in my courses, I was a little surprised to find that the first line of this entry states that R/K theory has been largely discredited. As I work primarily on empirical population genetics, I thought that perhaps I had simply not kept up with the literature in this arena. However, after doing a little digging, I'm not sure the evidence supports you.
I did go and read Stearns' article, which it is worth pointing out is itself rather old -1977. The current editions of both Futuyma's "Evolution" (the standard textbook for Evolutionary Biology) and Ricklefs' "Ecology" (the premier textbook in population ecology) both discuss r/K selection in some detail, and both of these textbooks were revised within the last ten years.
I noted in your talk post (above) your disdain for textbooks as sources (perhaps a reasonable position), so I did some searches on Web of Science. I find that there have been 43 paper published in the last 20 years that have the term "r/K selection" in the abstract or the keywords and that are in journals relevant to ecology and evolution. You mention Evolution and American Naturalist as your gold standard for journals in evolutionary biology (having recently published in both, I would agree that these are the best journals out there! ;)). Here are two articles about r/K selection, one from each of these journals, one of which is quite recent:
Title: Shift in colonial reproductive strategy associated with a tropical-temperate gradient in Rhytidoponera ants Author(s): Molet M, Van Baalen M, Peeters C. Source: AMERICAN NATURALIST Volume: 172 Issue: 1 Pages: 75-87 Published: JUL 2008
Title: Laboratory evolution of life-history traits in the bean weevil (Acanthoscelides obtectus): The effects of density-dependent and age-specific selection Author(s): Tucic N, Stojkovic O, Gliksman I, et al. Source: EVOLUTION Volume: 51 Issue: 6 Pages: 1896-1909 Published: DEC 1997
Lastly, I'm not sure that I agree that simply because there is no clear trade-off between reproduction and competition visible in the logistic equation itself should tell us that there is not a biological reality to r and k strategies. It merely tells us that if r/K trade-offs exist, they are not captured in a vastly oversimplified equation. The logistic equation does not account for the effects of age structure either... would you therefore contend that Lewis Leslie Matrix Models should be abandoned? More seriously, we see that there are good physiological reasons to expect that there is a trade-off between producing fewer, more vigorous offspring, and producing more, lower quality offspring. This expectations is supported by numerous empirical studies.
I'm not saying you're wrong, and I hope this post doesn't seem like a flame... I honestly am not a good student of life history evolution, so I don't pretend to be an expert here. All that I am saying is that to me - as a quasi independent observer - it doesn't look like this theory has been debunked.
Lastly, to strike a perhaps more conciliatory tone, although I have not read Derek Roff's book, which you suggest as further reading on this issue, Roff is quoted in the current edition of Ricklefs. The full passage reads as follows:
"To summarize, the concept of r- and K- selection has been useful in helping to formalize the definition of fitness in density-regulated populations, but attempts to transfer the concept to actual populations without regard to the realities of the complexities in life history have probably been detrimental rather than helpful"
Although clearly not a ringing endorsement of r/K selection, neither does Roff seem to indicate that the whole idea has been abandoned.
Your thoughts?
Moneilema. —Preceding unsigned comment added by Moneilema ( talk • contribs) 16:35, 15 April 2009 (UTC)
April 15, 2008
Ok, So I went and looked at Roff's book. In fact what he says is that r/K theory is applicable only when considering density dependency within species, and calls for studies that specifically quantify selection acting on reproductive strategies when populations are either near their carrying capacity, or below K/2. Roff also identifies a recent (at the time that he was writing) study which he considers to be an excellent example of how r/K selection should be explored: Density-dependent natural selection in Drosophila: evolution of pupation height. LD Mueller, VF Sweet - Evolution, 1986.--
Moneilema (
talk)
17:24, 18 April 2009 (UTC)
It is true that Roff only spends about a page talking about r/K theory, but that seems to be primarily because the models he explores do not consider density dependency.
Given that, in fact there seems to be a rich literature on r/K selection in the last ten years (see previous post, including papers from Evolution and American Naturalist), particularly in the areas of genome evolution, and given that Stearns' article is more than 30 years old, I do not think it is appropriate to label r/K selection as discredited. On this basis, I have removed the label on the first line indicating that r/K selection has been discredited. I have retained the "status of the theory" section at the end of the article.
Feel free to undo my edit if it seems I am overreaching.
Moneilema.
-- Moneilema ( talk) 17:24, 18 April 2009 (UTC)
I was updating my class notes on the topic. Several references incorporate the terms opportunistic population and equilibrium populations into the general descriptions. I didn't see any reference to those terms here. It shows up in Campbell/Reese as well with those descriptors. Is anyone still invested in this article that wishes to work it in? -- JimmyButler ( talk) 00:23, 7 April 2008 (UTC) Here is an excellent reference if it needs a citation.
Two basic types of life strategies have been distinguished in eukaryotes. Populations that are subject to disturbances and thus grow in regular or erratic bursts are called opportunistic populations, whereas those which exist at more stable densities are termed equilibrium populations. Opportunistic populations typically grow fast, whereas equilibrium populations have a high competitive ability. http://en.wikipedia.org/skins-1.5/common/images/button_sig.png Your signature with timestamp
User:Ksyrie is going across articles on multiple Wikipedias adding seealso links between this article and one-child policy (see, for example, this). As far as I can tell, the connection is tangential at best, and original research. I don't see any reason for inclusion of this seealso. rʨanaɢ talk/ contribs 04:29, 8 May 2009 (UTC)
Rushton's definition of "race" does not agree with the accepted biological definition "race = subspecies". See any university-level biology textbook that discusses the question. By the standards of Dd2, any flat-earther could complain about not being given due attention on WP. WP:VERIFY does not change a shred about the fact that in the sciences we have something called falsification, and that WP:UNDUE stands above all policies designed (like WP:VERIFY) to avoid disputes of opinion: Earth is not flat, and while anyone can redefine "gravity" to "prove" a flat Earth, pseudoscience is still pseudoscience, and similarly Rushton's "races" are a complete and utter fiction.
Speaking from my professional training in ecology, the life history differences between any two human populations are not large enough to differentiate on the r/K spectrum, because Homo sapiens is a K strategist to the extreme, the same league as whales and elephants. r vs K strategists, we're talking about the life-history differences between elephants and mice here. r strategists typically having one batch of dozens or even thousands of offspring and not living to reproduce a second time, and such things. r/K selection, furthermore, is something that changes within geological time, not in the few puny millennia since the start of civilization. Rushton has as much understanding of biology as Robert Mugabe has about economy; or perhaps less considering Zimbabwe's economy is a farce, but at least exists.
Sources:
(FWIW, the Sentinelese qualify as a distinct human race more than almost anyone else. And for a fictrional example where that what Rushton proposes does hold true, see the differences between Middle-earth Common Men and Elves - though biologically, Elrond and Elros nonwithstanding, they are "species" not "races", and of course ) Dysmorodrepanis ( talk) 13:48, 11 August 2009 (UTC)
Why are trees listed as an example K-selection? They are sometimes big, yes, but they invest less in their offspring than most reptiles, produce sometimes hundreds of thoudands of seeds per season (virtually none of which will survive to sexual maturity or even germinate) and distribute them over vast ranges. Seems to me they are classic r. —Preceding unsigned comment added by 220.233.36.78 ( talk) 05:30, 8 November 2010 (UTC)
The physical characteristics of trees are irrelevant, plant life takes place on a different scale, and r/K are evolutionary strategies. Plumbago, are you the one who decided to use a book on minding children as the citation for declaring trees, the classic r, to be K?
This is probably my favourite wikipedia article, it's hilarious how badly you people have messed it up. [[[User:Issue313|Issue313]] ( talk) 16:07, 15 December 2013 (UTC)
What's the relationship of k-strategists and r-strategists to the differential equation presented? N converges to K regardless of where you start or what r is. I can sort of see how high-r (some kind of "intrinsic growth rate) is high fecundity while high-K is offspring quality (efficient use of existing resources or something) but both kinds of species exhibit stable dynamics so what's the discussion about "unstable environments" have to do with this? At very least this is very unclear. Volunteer Marek ( talk) 06:34, 5 April 2011 (UTC)
In r/K selection theory, selective pressures are hypothesised to drive evolution in one of two generalized directions: r- or K-selection. These terms, r and K, are derived from standard ecological algebra, as illustrated in the highly simplified Verhulst equation of population dynamics:
where r is the growth rate of the population (N), and K is the carrying capacity of its local environmental setting. As the name implies, r-selected species are those that place an emphasis on a high growth rate (high r, low K), and typically exploit less-crowded ecological niches and produce many offspring, each of which has a relatively low probability of surviving to adulthood. By contrast, K-selected species display traits associated with living at densities close to carrying capacity (low r, high K), and typically are strong competitors in such crowded niches that invest more heavily in fewer offspring, each of which has a relatively high probability of surviving to adulthood. In the scientific literature, r-selected species are occasionally referred to as "opportunistic", while K-selected species are described as "equilibrium".
Ah, ok, looked some stuff up. So r can be negative - in which case the only stable level of population is 0, while there is also an unstable equilibrium at K. Just putting that in would help clarify things. Of course r<0 has some very unrealistic implications if N(0)>K.
Question - is there some maximization of fitness going on here which determines {r,K} - the wording of the text sort of implies it? Volunteer Marek ( talk) 08:46, 5 April 2011 (UTC)
Answering myself So r can be negative - in which case the only stable level of population is 0, while there is also an unstable equilibrium at K. - but even this confuses cause and effect. r<0 CAUSES instability rather than vice versa. It sounds like what it's trying to say is that in environments with lots (or is it "large"?) of stochastic shocks (to what?) a higher r/lower K is better (for what?) but in environments with few (or is it "small"?) stochastic shocks lower r/higher K is better (again, for what?). So there's some confusion going on between the idea of mathematical stability of a dynamic system and frequency (or magnitude?) of shocks. Volunteer Marek ( talk) 08:54, 5 April 2011 (UTC)
Two 1992 books are hardly evidence for current status. Also, that authors may criticize a theory does not prove conclusively that the theory is falsified. Miradre ( talk) 18:28, 13 April 2011 (UTC)
While the general use and application of the theory in biology is a legitimate topic, the fact that some racists have hijacked the theory to push their agenda is neither here nor there. Racist organizations have usurped all kinds of bits and pieces from all kinds of fields in order to "dress up" their ideas in pseudo-scientific garb. There's no reason why Wikipedia needs to serve as a forum for this kind of disinformation. At most a short statement that some racists "researchers" have tried to exploit the theory, and misapplied and misunderstood it in the process, in order to further their racist ideology would be sufficient. So the Rushton's section goes. Volunteer Marek ( talk) 21:22, 13 April 2011 (UTC)
As for Stearns and Graves empirical evidence falsifying the theory has been given as well as evidence that it was gradually abandoned. I have searched databases myself and have barely found any reference to it. EgalitarianJay ( talk) 03:01, 14 April 2011 (UTC)
Do we know where the name "r/K" comes from? I've seen it speculated (but would be loath to add to the article without substantiation) that it's a reference to the different breeding strategies of the rat and Kangaroo... DS ( talk) 12:19, 13 August 2011 (UTC)
I almost understand it, but "d" and "t" are not defined. There are no links to other pages that might explain. The purpose of Wikipedia is to teach. I want to learn. Formulae that are not fully defined and not linked are like a brick wall impeding my progress. Just give me some links to follow people. Thanks. — Preceding unsigned comment added by 70.41.216.250 ( talk) 19:30, 12 March 2012 (UTC)
I think it is appropriate to include a note about Rushton, with appropriate links to pro and anti Rushton sites. Rushton's analysis is one of the things that has made R/K selection theory notable (see all previous posts and the warnings at the top of this page!!). You can't just remove it.. This Wikipedia article is where people will come when they hear about the theory, so I think a paragraph or two can be justified. I don't think it's UNDUE. It would be undue if nobody had heard of Rushton. Like it or not many have.
Let's look a similar things such as global warming the holocaust criticism of Islam and evolution, to see how these things are handled. They are not handled by removing all references to the counter arguments altogether, or by peppering most of the account with the "minority theory" but are dealt with by a paragraph in the main article, and a link to another article. I think this is what should be done here. Mike Young ( talk) 06:25, 13 April 2012 (UTC)
Rushton's work on r/K selection was heavily relied upon by Herstein and Murray in
The Bell Curve.
Dmcw127 (
talk)
23:10, 12 November 2013 (UTC)
-- Sgmanohar ( talk) 17:27, 3 May 2012 (UTC)
Isn't being nidicolous the same as being K selected? FunkMonk ( talk) 05:03, 10 July 2012 (UTC)
What do r and k actually stand for? I get that r might mean reproduction or am i wrong? Difficultly north ( talk) - Simply south alt. 13:12, 9 May 2013 (UTC)
This edit removed sourced content with an edit summary stating that it's "still the dominant theory in college biology textbooks". Be that as it may, textbooks are lagging indicators, and general biology textbooks are especially bad. A sourced qualification might be helpful, but simple deletion isn't a good solution. Guettarda ( talk) 16:15, 9 August 2013 (UTC)
You may find it helpful while reading or editing articles to look at a bibliography of Intelligence Citations, posted for the use of all Wikipedians who have occasion to edit articles on human intelligence and related issues. I happen to have circulating access to a huge academic research library at a university with an active research program in these issues (and to another library that is one of the ten largest public library systems in the United States) and have been researching these issues since 1989. You are welcome to use these citations for your own research. You can help other Wikipedians by suggesting new sources through comments on that page. It will be extremely helpful for articles on human intelligence to edit them according to the Wikipedia standards for reliable sources for medicine-related articles, as it is important to get these issues as well verified as possible. -- WeijiBaikeBianji ( talk, how I edit) 16:00, 28 August 2013 (UTC)
I'd like to request that someone produce a 3-dimensional graph to add to the "Overview" section, showing the relationship between dN⁄dt (z-axis, or height of the graph) and the values of r (x-axis) and N (y-axis). z increases as r increases, and also increases as N decreases, producing a curved (linear in the x direction but hyperbolically curved in the y direction) surface. Any takers? — Loadmaster ( talk) 02:24, 21 September 2014 (UTC)
Hello, I'm new to WP editing, so I'm just going to post this and hope someone else takes it up. The "mouse" picture on this page is most definitely a picture of a rat. It's still a perfectly good example, just mislabeled in the caption and in the source file name. 89.204.139.90 ( talk) 04:39, 30 October 2014 (UTC)
Seems about right.. ! That mouse is a rat. ParanoidLemmings ( talk) 23:53, 29 December 2014 (UTC)
I have made a translation of this article on the danish wikipedia, and became somewhat unsure about that point. Sure r/K-selection is not used widely anymore on its own, but Life history theory incorporate most of the model. Saying the model have been replaced might misrepresent that point. ParanoidLemmings ( talk) 10:18, 26 February 2015 (UTC)
Furthermore, what about rK-selection in human races? ParanoidLemmings ( talk) 10:36, 26 February 2015 (UTC)
Okay, wont add anything about it in the danish wikipedia then. thx. ParanoidLemmings ( talk) 17:54, 26 February 2015 (UTC)
r/K theory is a forerunner of life history theory. Life history theory is broader. Now r/K theory can be considered a subset of life history theory. Some prefer to use the terms fast versus slow life history instead of r versus K reproductive strategy, but it is basically the same. The r/K theory is mainly used for describing differences between species, and rarely between individuals. The theory of human r/K differences should probably have a separate wiki page as it has developed into a separate research tradition dealing with individual differences in behavior. Agnerf ( talk) 07:19, 9 April 2022 (UTC)
I get that it's intellectually pleasant to argue that claim in opposition with the previous paragraph, but can it be backed up, if not just false? [I'm really no expert, but I get that K-selection doesn't work well in unstable environments. But isn't saying they predominate in stable environments pushing it?] — Preceding unsigned comment added by Seub ( talk • contribs) 08:45, 15 March 2015 (UTC)
Well can you give an example of K-species that lives in an unstable environment? ParanoidLemmings ( talk) 08:55, 30 March 2015 (UTC)
Currently we have "A typical K reproducer is the orchid, or members of the Orchis genus.[citation needed]" I was tempted to just remove it, because it makes no sense to me. Orchids have many small seeds, that have almost no provisioning. That's why they're such a pain to propagate from seed- they need their fungal buddies.
In plants, K selection usually means fewer, larger seeds, with more provisioning. From Orchidaceae "The seeds are generally almost microscopic and very numerous, in some species over a million per capsule. After ripening, they blow off like dust particles or spores. They lack endosperm and must enter symbiotic relationships with various mycorrhizal basidiomyceteous fungi that provide them the necessary nutrients to germinate, so all orchid species are mycoheterotrophic during germination and reliant upon fungi to complete their lifecycles."
So, unless someone can give me a good citation for orchids as k-selected, I'm going to remove that soon, and put in a more canonical example (probably animal, because people can easily tell the difference between a million fish eggs and a few infant apes). SemanticMantis ( talk) 22:14, 14 June 2016 (UTC)
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![]() | The contentious topics procedure applies to this page. This page is related to the intersection of race/ethnicity and human abilities and behaviour, which is a contentious topic. Please consult the procedures and edit carefully. |
![]() | Arbitration Ruling on Race and Intelligence The article R/K selection theory, along with other articles relating to the area of conflict (namely, the intersection of race/ethnicity and human abilities and behaviour, broadly construed), is currently subject to active arbitration remedies, described in a 2010 Arbitration Committee case where the articulated principles included:
If you are a new editor, or an editor unfamiliar with the situation, please follow the above guidelines. You may also wish to review the full arbitration case page. If you are unsure if your edit is appropriate, discuss it here on this talk page first. |
This article was the subject of a Wiki Education Foundation-supported course assignment, between 31 August 2020 and 18 December 2020. Further details are available
on the course page. Student editor(s):
Liliapearljackson. Peer reviewers:
Mcox19,
Spectral099.
Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT ( talk) 07:39, 17 January 2022 (UTC)
In the opening of the article it's stated that the theory has "lost importance". This is vague and overly general and worded as opinion. Yes, newer theories have expanded or reformed r/k (actually, most have just said the same thing while changing the name because r/k was labelled "racist" via EO and Rushton). As of May 2012 we are still learning r/k selection in the UC system in California - arguably the top public university system in the world, especially in the biological sciences. Surely there's a better way to explain that expansions of earlier r/k selection theory have appeared rather than calling it "unimportant". It's still one of the foundational topics in organismal biology. — Preceding unsigned comment added by 207.233.120.5 ( talk) 23:45, 22 May 2012 (UTC)
I agree. r/K is a foundational concept of biology, the same as supply and demand is in economics. There may well have been more elaborate theories advanced, and thought might have moved beyond r/K, but r/K has not "lost importance" as this article seems to strongly suggest. [[[User:Issue313|Issue313]] ( talk) 17:22, 15 December 2013 (UTC)
I agree too. As much as I am not a fan, the theory is still very actively and explicitly used in ecology. Kyle MoJo ( talk) 05:16, 14 December 2018 (UTC)
Just wondering if we need to mention Rushton here? While I can see that it's important for his article to link to this one, it's not obvious that the reverse is necessary. Especially as his work is described as pseudoscience here. Anyway, just thought that it might be better not to burden a science page with not-entirely-appropriate links. Anyone care to comment? -- Plumbago 18:16, 9 January 2006 (UTC)
Rather than have two separate forums for discussion, can we stick to Talk:R-K Life History Theory? I've started things off there. Cheers, -- Plumbago 15:41, 24 February 2006 (UTC)
Rushton's work is very much outside the mainstream, and to present it without presenting the opposing view is tantamount to endorsing a POV. His theories, and the counter arguments, are well presented elsewhere. An uncritical presentation of his views here does not add to the understanding of r/K selection, and is intellectual dishonesty. Pete.Hurd 19:08, 6 May 2006 (UTC)
Related to this: editors may wish to note that I nominated Rushton's ordering of the human races for deletion for reasons explained on the article's AFD notice. Pete.Hurd 14:57, 8 May 2006 (UTC)
I've removed the following from the article (but copied it here, and over at Adaptive Capacity). I'm not convinced that it helps articulate the general r/K theory. It seems to me that the concepts of r/K are used in Adaptive Capacity analogously to how they are used in ecology. Certainly the text below is unclear and confusing (and needs copyediting). I've moved adaptive capacity to a "See also" point. Not least because explaining the relevance of r/K for adaptive capacity might be best done there.
Of course, I could just be being dense, and haven't understood the relevance of the above! Cheers, -- Plumbago 17:33, 9 November 2006 (UTC)
Plumbago, r and K phases are important in the work of the resiliance alliance, and are being widely applied throughout the Applied Environmental Assessment and Monitoring (AEAM) field at present. For this reason I added the section on Adaptive Capacity. I feel it should be included. John D. Croft ( talk) 18:38, 23 March 2009 (UTC)
Should we remove the no citations label now. In fact I find it reasonably well referenced/ John D. Croft ( talk) 18:38, 23 March 2009 (UTC)
I failed in my search for exactly this page when I entered "r/k". It wasn't in the first ten pages of results, presumably because the search engine ignores forward slashes. I found this page later by accident (while reading about semelparity on the reproduction page). The page should havebeen in the results, can you think of anything that can be done about that? -seth 189.162.17.16 05:12, 20 July 2007 (UTC)
I've removed the following statement from the article:
Firstly, it's too human-specific - the purported r/K-strategist traits of men/women apply equally to other organisms (furthermore, since stable reproductive pairs of child-rearing humans are not uncommon, humans may not be a good example). Secondly, r/K is usually viewed as interspecific rather than intergender, but if there's a reliable source (scientific literature) to back this use that'd be great. Certainly, there's something to the idea that different strategies suit different genders, but my feeling is that we need good sources before inserting potentially contentious about human psychology into an article on ecology (c.f. J. Philippe Rushton). If it's original research, while it shouldn't be here, it might well make for a interesting paper! :-) Cheers, -- Plumbago 16:33, 26 July 2007 (UTC)
This article seems to me misleading. r/K selection became highly controversial as early as the 1970's, and was long ago abandoned by most of those doing research in the evolution of life histories. If nothing else, see the review by Stearns in Ann. Rev. Ecol. Syst.
There's certainly nothing wrong with discussing the theory, but since this is a work that will mainly be consulted by those outside of research in evolutionary biology, I don't think it's a good idea to represent the theory as one that's generally agreed upon. That's just not the case.
I've noticed that lately discussions of r/K selection have begun to appear in places like this, or in textbooks. Obviously you needn't agree with the many criticisms of the theory, but I do think it's misleading not to mention them. An interesting and useful article might address the history of the idea -- its life, death, and recent resurrection outside the research arena -- and reasons for that.
Gafox1 01:55, 24 October 2007 (UTC)
Here's the Stearns cite: Stearns, S. C. Evolution of life-history traits - critique of theory and a review of data. Ann. Rev. Ecol. Syst. 8: 145-171. This paper was very influential for 10 or 15 yrs -- for some time it was *the* standard reference for much about life history theory. That's not to say that it was the definitive work -- just that it was widely read and cited.
In addition to Stearns' criticism, it's worth asking two things about r/K theory. First, the theory was derived from logistic growth models, but a moment's thought will tell you that the derivative of the logistic equation with respect to both r and K is positive. In other words, there's no necessary trade-off in that model -- one must add other assumptions, usually ad hoc. Second, is r/K theory actually testable? If you go to look inside a population and study its evolution, how could you test it?
I've heard it said before by marine ecologists that marine ecology tends to be light on theory. Maybe it's true -- I don't get wet in my work, so can't say. All I'll say is that if you look at leading journals on ideas in evolutionary biology -- say, Evolution and Am. Nat., or others if you like -- you'll find that r/K theory hasn't inspired substantial work in a long time. It seems to have been resurrected lately because, well, it's a simple explanation for something that's complicated -- so it's made a reappearance in places like textbooks. My own view is that this is a bad thing: the theory doesn't work logically and it led to a real mess empirically; there are good reasons to discuss it as part of the history of science, but not as a currently viable theory.
By the way, you might also look at Derek Roff's book on life histories and their evolution. I don't recall what he says about r/K theory, but that's just the point -- it plays little role.
Cheers, Gordon Gafox1 00:28, 25 October 2007 (UTC)
Hey Gordon,
As a professor who teaches about r/K selection in my courses, I was a little surprised to find that the first line of this entry states that R/K theory has been largely discredited. As I work primarily on empirical population genetics, I thought that perhaps I had simply not kept up with the literature in this arena. However, after doing a little digging, I'm not sure the evidence supports you.
I did go and read Stearns' article, which it is worth pointing out is itself rather old -1977. The current editions of both Futuyma's "Evolution" (the standard textbook for Evolutionary Biology) and Ricklefs' "Ecology" (the premier textbook in population ecology) both discuss r/K selection in some detail, and both of these textbooks were revised within the last ten years.
I noted in your talk post (above) your disdain for textbooks as sources (perhaps a reasonable position), so I did some searches on Web of Science. I find that there have been 43 paper published in the last 20 years that have the term "r/K selection" in the abstract or the keywords and that are in journals relevant to ecology and evolution. You mention Evolution and American Naturalist as your gold standard for journals in evolutionary biology (having recently published in both, I would agree that these are the best journals out there! ;)). Here are two articles about r/K selection, one from each of these journals, one of which is quite recent:
Title: Shift in colonial reproductive strategy associated with a tropical-temperate gradient in Rhytidoponera ants Author(s): Molet M, Van Baalen M, Peeters C. Source: AMERICAN NATURALIST Volume: 172 Issue: 1 Pages: 75-87 Published: JUL 2008
Title: Laboratory evolution of life-history traits in the bean weevil (Acanthoscelides obtectus): The effects of density-dependent and age-specific selection Author(s): Tucic N, Stojkovic O, Gliksman I, et al. Source: EVOLUTION Volume: 51 Issue: 6 Pages: 1896-1909 Published: DEC 1997
Lastly, I'm not sure that I agree that simply because there is no clear trade-off between reproduction and competition visible in the logistic equation itself should tell us that there is not a biological reality to r and k strategies. It merely tells us that if r/K trade-offs exist, they are not captured in a vastly oversimplified equation. The logistic equation does not account for the effects of age structure either... would you therefore contend that Lewis Leslie Matrix Models should be abandoned? More seriously, we see that there are good physiological reasons to expect that there is a trade-off between producing fewer, more vigorous offspring, and producing more, lower quality offspring. This expectations is supported by numerous empirical studies.
I'm not saying you're wrong, and I hope this post doesn't seem like a flame... I honestly am not a good student of life history evolution, so I don't pretend to be an expert here. All that I am saying is that to me - as a quasi independent observer - it doesn't look like this theory has been debunked.
Lastly, to strike a perhaps more conciliatory tone, although I have not read Derek Roff's book, which you suggest as further reading on this issue, Roff is quoted in the current edition of Ricklefs. The full passage reads as follows:
"To summarize, the concept of r- and K- selection has been useful in helping to formalize the definition of fitness in density-regulated populations, but attempts to transfer the concept to actual populations without regard to the realities of the complexities in life history have probably been detrimental rather than helpful"
Although clearly not a ringing endorsement of r/K selection, neither does Roff seem to indicate that the whole idea has been abandoned.
Your thoughts?
Moneilema. —Preceding unsigned comment added by Moneilema ( talk • contribs) 16:35, 15 April 2009 (UTC)
April 15, 2008
Ok, So I went and looked at Roff's book. In fact what he says is that r/K theory is applicable only when considering density dependency within species, and calls for studies that specifically quantify selection acting on reproductive strategies when populations are either near their carrying capacity, or below K/2. Roff also identifies a recent (at the time that he was writing) study which he considers to be an excellent example of how r/K selection should be explored: Density-dependent natural selection in Drosophila: evolution of pupation height. LD Mueller, VF Sweet - Evolution, 1986.--
Moneilema (
talk)
17:24, 18 April 2009 (UTC)
It is true that Roff only spends about a page talking about r/K theory, but that seems to be primarily because the models he explores do not consider density dependency.
Given that, in fact there seems to be a rich literature on r/K selection in the last ten years (see previous post, including papers from Evolution and American Naturalist), particularly in the areas of genome evolution, and given that Stearns' article is more than 30 years old, I do not think it is appropriate to label r/K selection as discredited. On this basis, I have removed the label on the first line indicating that r/K selection has been discredited. I have retained the "status of the theory" section at the end of the article.
Feel free to undo my edit if it seems I am overreaching.
Moneilema.
-- Moneilema ( talk) 17:24, 18 April 2009 (UTC)
I was updating my class notes on the topic. Several references incorporate the terms opportunistic population and equilibrium populations into the general descriptions. I didn't see any reference to those terms here. It shows up in Campbell/Reese as well with those descriptors. Is anyone still invested in this article that wishes to work it in? -- JimmyButler ( talk) 00:23, 7 April 2008 (UTC) Here is an excellent reference if it needs a citation.
Two basic types of life strategies have been distinguished in eukaryotes. Populations that are subject to disturbances and thus grow in regular or erratic bursts are called opportunistic populations, whereas those which exist at more stable densities are termed equilibrium populations. Opportunistic populations typically grow fast, whereas equilibrium populations have a high competitive ability. http://en.wikipedia.org/skins-1.5/common/images/button_sig.png Your signature with timestamp
User:Ksyrie is going across articles on multiple Wikipedias adding seealso links between this article and one-child policy (see, for example, this). As far as I can tell, the connection is tangential at best, and original research. I don't see any reason for inclusion of this seealso. rʨanaɢ talk/ contribs 04:29, 8 May 2009 (UTC)
Rushton's definition of "race" does not agree with the accepted biological definition "race = subspecies". See any university-level biology textbook that discusses the question. By the standards of Dd2, any flat-earther could complain about not being given due attention on WP. WP:VERIFY does not change a shred about the fact that in the sciences we have something called falsification, and that WP:UNDUE stands above all policies designed (like WP:VERIFY) to avoid disputes of opinion: Earth is not flat, and while anyone can redefine "gravity" to "prove" a flat Earth, pseudoscience is still pseudoscience, and similarly Rushton's "races" are a complete and utter fiction.
Speaking from my professional training in ecology, the life history differences between any two human populations are not large enough to differentiate on the r/K spectrum, because Homo sapiens is a K strategist to the extreme, the same league as whales and elephants. r vs K strategists, we're talking about the life-history differences between elephants and mice here. r strategists typically having one batch of dozens or even thousands of offspring and not living to reproduce a second time, and such things. r/K selection, furthermore, is something that changes within geological time, not in the few puny millennia since the start of civilization. Rushton has as much understanding of biology as Robert Mugabe has about economy; or perhaps less considering Zimbabwe's economy is a farce, but at least exists.
Sources:
(FWIW, the Sentinelese qualify as a distinct human race more than almost anyone else. And for a fictrional example where that what Rushton proposes does hold true, see the differences between Middle-earth Common Men and Elves - though biologically, Elrond and Elros nonwithstanding, they are "species" not "races", and of course ) Dysmorodrepanis ( talk) 13:48, 11 August 2009 (UTC)
Why are trees listed as an example K-selection? They are sometimes big, yes, but they invest less in their offspring than most reptiles, produce sometimes hundreds of thoudands of seeds per season (virtually none of which will survive to sexual maturity or even germinate) and distribute them over vast ranges. Seems to me they are classic r. —Preceding unsigned comment added by 220.233.36.78 ( talk) 05:30, 8 November 2010 (UTC)
The physical characteristics of trees are irrelevant, plant life takes place on a different scale, and r/K are evolutionary strategies. Plumbago, are you the one who decided to use a book on minding children as the citation for declaring trees, the classic r, to be K?
This is probably my favourite wikipedia article, it's hilarious how badly you people have messed it up. [[[User:Issue313|Issue313]] ( talk) 16:07, 15 December 2013 (UTC)
What's the relationship of k-strategists and r-strategists to the differential equation presented? N converges to K regardless of where you start or what r is. I can sort of see how high-r (some kind of "intrinsic growth rate) is high fecundity while high-K is offspring quality (efficient use of existing resources or something) but both kinds of species exhibit stable dynamics so what's the discussion about "unstable environments" have to do with this? At very least this is very unclear. Volunteer Marek ( talk) 06:34, 5 April 2011 (UTC)
In r/K selection theory, selective pressures are hypothesised to drive evolution in one of two generalized directions: r- or K-selection. These terms, r and K, are derived from standard ecological algebra, as illustrated in the highly simplified Verhulst equation of population dynamics:
where r is the growth rate of the population (N), and K is the carrying capacity of its local environmental setting. As the name implies, r-selected species are those that place an emphasis on a high growth rate (high r, low K), and typically exploit less-crowded ecological niches and produce many offspring, each of which has a relatively low probability of surviving to adulthood. By contrast, K-selected species display traits associated with living at densities close to carrying capacity (low r, high K), and typically are strong competitors in such crowded niches that invest more heavily in fewer offspring, each of which has a relatively high probability of surviving to adulthood. In the scientific literature, r-selected species are occasionally referred to as "opportunistic", while K-selected species are described as "equilibrium".
Ah, ok, looked some stuff up. So r can be negative - in which case the only stable level of population is 0, while there is also an unstable equilibrium at K. Just putting that in would help clarify things. Of course r<0 has some very unrealistic implications if N(0)>K.
Question - is there some maximization of fitness going on here which determines {r,K} - the wording of the text sort of implies it? Volunteer Marek ( talk) 08:46, 5 April 2011 (UTC)
Answering myself So r can be negative - in which case the only stable level of population is 0, while there is also an unstable equilibrium at K. - but even this confuses cause and effect. r<0 CAUSES instability rather than vice versa. It sounds like what it's trying to say is that in environments with lots (or is it "large"?) of stochastic shocks (to what?) a higher r/lower K is better (for what?) but in environments with few (or is it "small"?) stochastic shocks lower r/higher K is better (again, for what?). So there's some confusion going on between the idea of mathematical stability of a dynamic system and frequency (or magnitude?) of shocks. Volunteer Marek ( talk) 08:54, 5 April 2011 (UTC)
Two 1992 books are hardly evidence for current status. Also, that authors may criticize a theory does not prove conclusively that the theory is falsified. Miradre ( talk) 18:28, 13 April 2011 (UTC)
While the general use and application of the theory in biology is a legitimate topic, the fact that some racists have hijacked the theory to push their agenda is neither here nor there. Racist organizations have usurped all kinds of bits and pieces from all kinds of fields in order to "dress up" their ideas in pseudo-scientific garb. There's no reason why Wikipedia needs to serve as a forum for this kind of disinformation. At most a short statement that some racists "researchers" have tried to exploit the theory, and misapplied and misunderstood it in the process, in order to further their racist ideology would be sufficient. So the Rushton's section goes. Volunteer Marek ( talk) 21:22, 13 April 2011 (UTC)
As for Stearns and Graves empirical evidence falsifying the theory has been given as well as evidence that it was gradually abandoned. I have searched databases myself and have barely found any reference to it. EgalitarianJay ( talk) 03:01, 14 April 2011 (UTC)
Do we know where the name "r/K" comes from? I've seen it speculated (but would be loath to add to the article without substantiation) that it's a reference to the different breeding strategies of the rat and Kangaroo... DS ( talk) 12:19, 13 August 2011 (UTC)
I almost understand it, but "d" and "t" are not defined. There are no links to other pages that might explain. The purpose of Wikipedia is to teach. I want to learn. Formulae that are not fully defined and not linked are like a brick wall impeding my progress. Just give me some links to follow people. Thanks. — Preceding unsigned comment added by 70.41.216.250 ( talk) 19:30, 12 March 2012 (UTC)
I think it is appropriate to include a note about Rushton, with appropriate links to pro and anti Rushton sites. Rushton's analysis is one of the things that has made R/K selection theory notable (see all previous posts and the warnings at the top of this page!!). You can't just remove it.. This Wikipedia article is where people will come when they hear about the theory, so I think a paragraph or two can be justified. I don't think it's UNDUE. It would be undue if nobody had heard of Rushton. Like it or not many have.
Let's look a similar things such as global warming the holocaust criticism of Islam and evolution, to see how these things are handled. They are not handled by removing all references to the counter arguments altogether, or by peppering most of the account with the "minority theory" but are dealt with by a paragraph in the main article, and a link to another article. I think this is what should be done here. Mike Young ( talk) 06:25, 13 April 2012 (UTC)
Rushton's work on r/K selection was heavily relied upon by Herstein and Murray in
The Bell Curve.
Dmcw127 (
talk)
23:10, 12 November 2013 (UTC)
-- Sgmanohar ( talk) 17:27, 3 May 2012 (UTC)
Isn't being nidicolous the same as being K selected? FunkMonk ( talk) 05:03, 10 July 2012 (UTC)
What do r and k actually stand for? I get that r might mean reproduction or am i wrong? Difficultly north ( talk) - Simply south alt. 13:12, 9 May 2013 (UTC)
This edit removed sourced content with an edit summary stating that it's "still the dominant theory in college biology textbooks". Be that as it may, textbooks are lagging indicators, and general biology textbooks are especially bad. A sourced qualification might be helpful, but simple deletion isn't a good solution. Guettarda ( talk) 16:15, 9 August 2013 (UTC)
You may find it helpful while reading or editing articles to look at a bibliography of Intelligence Citations, posted for the use of all Wikipedians who have occasion to edit articles on human intelligence and related issues. I happen to have circulating access to a huge academic research library at a university with an active research program in these issues (and to another library that is one of the ten largest public library systems in the United States) and have been researching these issues since 1989. You are welcome to use these citations for your own research. You can help other Wikipedians by suggesting new sources through comments on that page. It will be extremely helpful for articles on human intelligence to edit them according to the Wikipedia standards for reliable sources for medicine-related articles, as it is important to get these issues as well verified as possible. -- WeijiBaikeBianji ( talk, how I edit) 16:00, 28 August 2013 (UTC)
I'd like to request that someone produce a 3-dimensional graph to add to the "Overview" section, showing the relationship between dN⁄dt (z-axis, or height of the graph) and the values of r (x-axis) and N (y-axis). z increases as r increases, and also increases as N decreases, producing a curved (linear in the x direction but hyperbolically curved in the y direction) surface. Any takers? — Loadmaster ( talk) 02:24, 21 September 2014 (UTC)
Hello, I'm new to WP editing, so I'm just going to post this and hope someone else takes it up. The "mouse" picture on this page is most definitely a picture of a rat. It's still a perfectly good example, just mislabeled in the caption and in the source file name. 89.204.139.90 ( talk) 04:39, 30 October 2014 (UTC)
Seems about right.. ! That mouse is a rat. ParanoidLemmings ( talk) 23:53, 29 December 2014 (UTC)
I have made a translation of this article on the danish wikipedia, and became somewhat unsure about that point. Sure r/K-selection is not used widely anymore on its own, but Life history theory incorporate most of the model. Saying the model have been replaced might misrepresent that point. ParanoidLemmings ( talk) 10:18, 26 February 2015 (UTC)
Furthermore, what about rK-selection in human races? ParanoidLemmings ( talk) 10:36, 26 February 2015 (UTC)
Okay, wont add anything about it in the danish wikipedia then. thx. ParanoidLemmings ( talk) 17:54, 26 February 2015 (UTC)
r/K theory is a forerunner of life history theory. Life history theory is broader. Now r/K theory can be considered a subset of life history theory. Some prefer to use the terms fast versus slow life history instead of r versus K reproductive strategy, but it is basically the same. The r/K theory is mainly used for describing differences between species, and rarely between individuals. The theory of human r/K differences should probably have a separate wiki page as it has developed into a separate research tradition dealing with individual differences in behavior. Agnerf ( talk) 07:19, 9 April 2022 (UTC)
I get that it's intellectually pleasant to argue that claim in opposition with the previous paragraph, but can it be backed up, if not just false? [I'm really no expert, but I get that K-selection doesn't work well in unstable environments. But isn't saying they predominate in stable environments pushing it?] — Preceding unsigned comment added by Seub ( talk • contribs) 08:45, 15 March 2015 (UTC)
Well can you give an example of K-species that lives in an unstable environment? ParanoidLemmings ( talk) 08:55, 30 March 2015 (UTC)
Currently we have "A typical K reproducer is the orchid, or members of the Orchis genus.[citation needed]" I was tempted to just remove it, because it makes no sense to me. Orchids have many small seeds, that have almost no provisioning. That's why they're such a pain to propagate from seed- they need their fungal buddies.
In plants, K selection usually means fewer, larger seeds, with more provisioning. From Orchidaceae "The seeds are generally almost microscopic and very numerous, in some species over a million per capsule. After ripening, they blow off like dust particles or spores. They lack endosperm and must enter symbiotic relationships with various mycorrhizal basidiomyceteous fungi that provide them the necessary nutrients to germinate, so all orchid species are mycoheterotrophic during germination and reliant upon fungi to complete their lifecycles."
So, unless someone can give me a good citation for orchids as k-selected, I'm going to remove that soon, and put in a more canonical example (probably animal, because people can easily tell the difference between a million fish eggs and a few infant apes). SemanticMantis ( talk) 22:14, 14 June 2016 (UTC)