Talk:Unit of selection

Marcosantezana (talk • contribs)
This article has serious POV inspired errors: JeffBurdges 11:28, 3 April 2006 (UTC)
 * 1) There is virtually no such things as a right-wing evolutionary biologist, almost all are left wing.  Scientists, including  evolutionary biologist, usually end up being wrong when they let their politics get involved.
 * 2) Right wing people who speak in favor of natural selection make the exact same group selectionist mistake as left wing people, like Gould.  Group selection probably does exist, but its a very minor force, much dominated by other units of selection.
 * 3) Gene level selection had the only workable mathematical models for altruism, or much of anything, for most of the last 30 years.  Its only recently that quite sophisticated multi-level selection models have begun to displace it.
 * 4) Individual level selection seems incorrectly described here so as to make it only a semantic diffrence from gene level selection.
 * 5) Much modern modeling work doesn't really need to specify the unit of selection, as much general understanding derived from the gene level model has percolated through the community and sidelined the debate in favor of more practical matters.  So, while this is an extremely important topic for historical reasons, the current work directly related to units of selection is now quite theoretical; while applied work simply uses the tools provided by the gene level model.  Just because they discovered quantum mechanics doesn't mean calculous is wrong.


 * Yes, has a problem with representing NPOV, hence Requests for arbitration/Marcosantezana. This should be mentioned there. &mdash; Dunc|&#9786; 13:46, 3 April 2006 (UTC)


 * Interesting, glad to know a fundamental issue will be worked out. However, I'm not an involved party, nor have I attempted other resolutions with Marcosantezana, so I'm not sure its appropriate for me to be involved in the case.  I'm not sure the arbitors want to hear about every editorial problem the user has caused.  Is a "Statments by Uninvolved Parties" section an acceptable feature of an arbitration page?  JeffBurdges 15:03, 3 April 2006 (UTC)

For now, I recommend reverting to this version, which has much more minor and easily correctable errors: specifically it assigns credit to Dawkins for work he merely popularized. Agreed? JeffBurdges 15:03, 3 April 2006 (UTC)


 * Alright, its done & improved. JeffBurdges 17:41, 3 April 2006 (UTC)

I agree that this simpler version is better for now. We need to eventually include a discussion of each level of selection, at the gene, cell, individual, group, and higher taxa level. (link to macroevolution?)  Safay 23:35, 4 April 2006 (UTC)
 * There are several people who are so fed up with his ownership mentality that they do not edit anything. Untill the arbitration case is finished, I refrain from editing. KimvdLinde 01:47, 5 April 2006 (UTC)
 * I'm not sure this is the right place to put this comment; this is my first exposure to this arbitration process and indeed this peculiar behavior of a user. I have dealt with creationists in other contexts, but this is downright weird.  It is obvious that Marco has a keen grasp of the material and has something constructive to contribute, yet remains totally unwilling to work within the Wikipedia community.  I wonder if there are any psychologists or sociologists specifically studying behavioral pathologies on wikipedia. Safay 23:38, 5 April 2006 (UTC)

Who defined a unit of selection?
"....A unit of selection is a biological entity within the hierarchy of biological organisation (e.g. genes, cells, individuals, groups, species) that is subject to natural selection..." -- Who is the person that formally established this? Scientific theories are always formally established. —Preceding unsigned comment added by 41.17.51.103 (talk) 20:22, 7 September 2009 (UTC)


 * Who defined species? Who is the person who formally established this? Scientific terms are not always formally established. To this day, people still argue about what exact species means, but that does not stop us from using this term meaningfully in discussions on biology. Fred Hsu (talk) 22:43, 7 September 2009 (UTC)

Restructure
I quickly tried to add some structure and for the intro pared down the convoluted prose. Maybe this will help guide it into a more coherent whole. It is still far from being readable but with time and help we can all pull it together. Safay 00:57, 6 April 2006 (UTC)

Suggestion about a merge or split
You'll all notice that there is quite a bit of info at both Group selection and Gene-centered view of evolution. I believe this brings up the question of how we should handle the page as a whole. I assume if you're working on this page that you at least are willing to entertain the idea of there being a hierarchy of selection. I think there are two possibilities: I strongly prefer this second option. Any other opinions out there? Safay 01:01, 11 April 2006 (UTC)
 * 1) We can include all the other information on those other pages into this page, merging them into one big page on multilevel selection.
 * 2) The other possibility is to split them all up - have a different page for each level of selection (which now would just require adding cell and species level selection pages) and then one page uniting them. Aside from being a portal to these other pages, this one page uniting them could also have a discussion of all the various philisophical points of view, Sober, Gould, Dawkins, Williams, Buss, etc., whomever else...

A split is better. Evolution topics currently have ongoing POV wars. So damage will be minimized by keeping articles specific. JeffBurdges 13:03, 11 April 2006 (UTC)

Yes, I also favour the split. - User:Samsara (talk • contribs) 23:29, 12 April 2006 (UTC)

Cool. Interesting "damage control" observation, Jeff. I'll start working on a more complete section for Leo Buss' work on selection at the level of the cell. BTW, the Gould book is great for all this stuff, pp. 644-714 or thereabouts, if you happen to have it. I myself have to look up that Sober reference. Another interesting one is the book by Maynard-Smith and Szmarthy (sp?) "The Major Transitions in Evolution," which deals loosely with this subject. Safay 02:12, 13 April 2006 (UTC)


 * I am still undecided about splitting. KimvdLinde 02:19, 13 April 2006 (UTC)

I've reverted the last set of changes because they seemed to introduce some anthropomorphisms. For example "He argues that genes are "selfish" because they manipulate the characteristics of individuals" No, I don't believe that Dawkins would never say anything quite so crass. There are similar problems later. Gleng 20:54, 17 May 2006 (UTC) On deeper reading I see that this article is in deep trouble. I run awayGleng 21:10, 17 May 2006 (UTC)


 * True, Dawkins isn't that crass: it is a metaphor as explained in The Selfish Gene...
 * We must temporarily abandon our metaphor of the gene as a conscious agent, because in this context it becomes positively misleading. We must translate it back into respectable if more longwinded terms. Albino genes do not really 'want' to survive or to help other albino genes. But if the albino gene just happened to cause its bodies to behave altruistically it would tend to become more numerous in the gene pool.
 * — Axel147 03:24, 2 August 2006 (UTC)

I decided to look at this article. I think the Marcos version is a big improvement on what was there before. But it does contain some pro-Sober anti-Dawkins bias which ought to be corrected? And those are not the only two positions. I've looked around on this and I think there are 7 different views on what it means for an entity to be a 'unit of selection'.  Entity which reproduces Entity which interacts directly with environment Entity whose properties cause differential reproduction (at any level) Entity which can be preserved (by replication) Entity which does the adapting Entity which 'benefits' from evolution/adaptations (by increasing its representation or propagation of its properties) Entity which responds to selective forces as a unit  This gives us a problem with the opening line! — Axel147 03:11, 2 August 2006 (UTC)

Individual selection part
Marcos seems to have expressed a different point from Sober here, or if he is expressing Sober's point I don't find it clear enough. This is the sentence I have issue with: The description of the causation chain in this case of selection can be stopped at the individual level because the generation of fitness differences is supervenient to the (various possible) causes below the individual level (i.e. differences in speed were necessary and sufficient in this case of selection).

If an event has multiple causes I don't think Sober is giving us any basis for choosing between them. The individual gazelle is the unit of selection in the example because the gazelle is the entity whose property (speed) is the cause of selection. For high speed to be a cause of selection in Sober's sense it must
 * 1) Increase gazelles' reproductive success in at least one case and reduce it in none.
 * 2) Identify a single (or similar sorts of) causal process

Sober says p94,  'disjunctive properties will appear to be causally efficacious only to the degree that their disjuncts strike us a resembling similar sorts of causal processes' . On the other hand supervenient properties, such as (overall) fitness, are not causally efficacious. Sober uses supervenience of fitness to argue p96  'the overall fitness of a trait does not cause survival and reproduction' . So I have removed the sentence for now. — Axel147 02:07, 4 August 2006 (UTC)

Structure of article
I've restored the previous structure but kept text changes. Hope that's ok with Safay. I think it's clearer to distinguish the debate about what it means to be a unit of selection from examples given the multi-level approach. — Axel147 01:24, 15 August 2006 (UTC)


 * I understand your desire to move "The Debate" to be the focus of the article. This is indeed a contentious subject, something that some biologists have very strong feelings about one way or the other.  But the idea of multi-level selection is what this article is about, so I think we should unabashedly present it up-front.  Does this violate NPOV? :Safay 07:44, 26 August 2006 (UTC)


 * Possibly. If this article was called 'multi-level selection' I think I would agree that 'the debate' should be more of a footnote. But the way I was looking at it was the article should begin by answering the question 'what is a unit of selection?' And since not everyone agrees we have to mention the debate? — Axel147 19:49, 30 August 2006 (UTC)


 * In my edit I was also trying to make this article more "encyclopedic," that is, accessable to someone coming to find out what multi-level selection is about. Yes, of course the history of the idea is important to understanding it.  But I feel like starting off with "The Debate" is a circuitous way to get to the main idea: selection can happen at different levels of biological organization.  Perhaps most importantly, this stuff is covered elsewhere more exhaustively (Williams & Dawkins already at Gene-centered view of evolution, also Group selection).


 * Can we have some others weigh in on this organizational issue?


 * Safay 07:44, 26 August 2006 (UTC)

Differential Reproduction
* "Artificial Selection" only used once by Darwin and did not appear before his publication. * "Survival of the fittest" was invented by Darwin and occurs 16 times. * reproductive success, differential appears nowhere in Origin of Species * Artificial Selection was never defined by Darwin. * Only attempts to define Natural Selection once in the entire book. * Natural Selection is repeated over 300 times. * Micro and Macro Evolution were not used by Darwin, only Evolution.

Differential reproduction can be rephrased as unsimilar reproduction. 99.99% organisms reproduce not clone carbon copies of themselves and thus differential is superfluous. If there are 0.01% that actually produce exact clones of themselves would somebody inform me? In trying to get a conceptual grip on what a Unit of Selection is many posters have used this phrase reproductin success. We can't define the concept Unit of Selection before we define phrases that are used to formally establish the concept. Who has formally defined or established what reproductive success means? A Wikipedia entry gets a redirect to Natural Selection. Are the two concepts related, who has formally established that they are one and the same thing, published where? And if beavers were ment to produce A-frames then their present structures can't be described as a "success". For something to be a success, one needs to specify some sort of goal. TongueSpeaker 20:57, 23 March 2007 (UTC)

Unreferenced
tag added. Every section of the article contains unreferenced information. Shayno 11:27, 14 April 2007 (UTC)

Levels of Organization
Would it be appropriate to organize this article around the functional levels of organization? 
 * Perhaps something like:
 * 1) Level of the gene
 * 2) Level of the cell
 * 3) Level of the tissue
 * 4) Level of the organ
 * 5) Level of the organ system
 * 6) Level of the individual
 * 7) Level of the population
 * 8) Level of the group
 * 9) Level of the species
 * 10) Level of the community


 * Or perhaps:

Just some thoughts... EPM 23:25, 31 May 2007 (UTC)
 * 1) Individual level and below
 * 2) Level of the gene
 * 3) Level of the cell
 * 4) Level of the tissue
 * 5) Level of the organ
 * 6) Level of the organ system
 * 7) Level of the individual
 * 8) Group level
 * 9) Level of the population
 * 10) Level of the species
 * 11) Level of the community

Removal of Zig-Zag Argument
I have removed the zig-zag argument for 2 main reasons 1) it appears to suffer from a bit of bias not clearly representing the original source 2) it is a negative argument: there is no positive proposal as to what a unit of selection should be.

Of course the zig-zagging occurs and is in one sense 'invisible' when the gene rather than the genotype is used as a unit of selection. But this 'invisibility' is a symptom of the fact that fitness and evolution are typically defined in terms of frequencies of genes, genotypes or traits. If ones looks at both frequencies and distributions within other entities the zig-zag can be modelled perfectly well while maintaining the gene as a unit of selection.

'The concept of selection as a force and as a cause of evolution' is only lost if a unit of selection is something that causes selection (where cause is defined in a certain way) rather than somethings that simply gets selected. This is a definitional issue. The criticism that the gene is not in general a cause has already been made in the article. — Axel147 21:57, 19 September 2007 (UTC)

The gene isn't the unit of selection.
The idea is outdated and has fallen out of favor. As explained by Mayr:

" The idea that a few people have about the gene being the target of selection is completely impractical; a gene is never visible to natural selection, and in the genotype, it is always in the context with other genes, and the interaction with those other genes make a particular gene either more favorable or less favorable. In fact, Dobzhanksy, for instance, worked quite a bit on so-called lethal chromosomes which are highly successful in one combination, and lethal in another. Therefore people like Dawkins in England who still think the gene is the target of selection are evidently wrong. In the 30's and 40's, it was widely accepted that genes were the target of selection, because that was the only way they could be made accessible to mathematics, but now we know that it is really the whole genotype of the individual, not the gene. Except for that slight revision, the basic Darwinian theory hasn't changed in the last 50 years. "

Mayr again:

"On one occasion Dawkins (ref. 13, point 7) himself admits that the gene is not an object of selection: “. . . genetic replicators are selected not directly, but by proxy . . . [by] their phenotypic effects.” Precisely! Nor are combinations of genes, as for instance chromosomes, independent objects of selection; only their carriers are. "



How can you reconcile these facts about chromosomes with the gene being the unit of selection?

Mayr should be noted here. He is much more important to evolutionary theory than Dawkins.

Savagedjeff (talk) 01:24, 30 August 2009 (UTC)
 * The debate is noted at the start of the article. For the purposes of the article we only need to know that some (significant) people believe in gene-level selection. Shayno (talk) 16:57, 31 August 2009 (UTC)

Needed citations...
I believe the rabbit/virus example in "Selection at the level of the group" is from Lewontin's 1970 paper - however, it's not a direct quote - is it a paraphrase from a different source? Chgrs (talk) 19:38, 2 December 2010 (UTC)