Talk:Natural selection/Archive 5

message: Kim van der Linde and Gleng have developed a updated version of the Natural selection article at User:KimvdLinde/Natural selection. At the talk page there:
:This page shows a proposed new version of the article on Natural Selection. This has been developed using parts of the existing version by Kim van der Linde and Gleng, following the discussions on the Natural selection talk page. We have tried to produce an article that will be both clear and rigorously accurate. If there is general agreement that this version is an improvement over the existing version, then we will replace it. Please put any comments and criticisms about this proposed new version on this Talk page, and in particular please indicate your support for, or opposition to, replacement of the existing version. Please do not edit this version except for any minor corrections at this stage.
Kim van der Linde at venus 05:16, 13 May 2006 (UTC)
thread_title:  New version of Natural selection 

message: "A well-known example of natural selection is the development of antibiotic resistance in microorganisms."
let's dissect the very first sentence above: "an example of selection is the development of antibiotic resistance..."
kim, i thought you agreed that selection is not evolution !?  now the whole new article is full of such high-school-level imprecisions and sloppy formulations.
and, possibly more serious, the new article is mainly about evolution !
everybody should welcome additions and revisions to the existing article as long they are done orderly and carefully.
but one must correct any imprecisions, and one must refocus back to selection any additions that focus mainly on evolution.
note that i am an evolutionary biologist but i couldn't care less about selection for scientific reasons that are not simple.
however, the article about selection must be about selection, i.e. about the generation of fitness differences.
Marcosantezana 04:23, 16 May 2006 (UTC)
replies: text: See User_talk:KimvdLinde/Natural_selection#what_is_born_out_of_spite... for responses. Kim van der Linde at venus 20:46, 19 May 2006 (UTC)
thread_title:  what is born out of spite... 

message: Yo! Can we dump the history and sociology stuff from this article? It heavily retreads stuff that happens in evolution, and I think, as a secondary page, it doesn't really belong here. Brief mention of it and reference to better, secondary articles on the subject are in order, but not the 4-5 odd pages we've got here. I humbly submit. Anyone concur? Graft 23:24, 21 May 2006 (UTC)
replies: text: Well dumping it completely no, but cutting out significant sections, fine with me. That are oieces that are left of the old article, I did not want to rewrite everything at once. Kim van der Linde at venus 01:16, 22 May 2006 (UTC)
replies: text: Looking at the History and Impact sections here and in evolution I would say they are generally focussed on Natural selection here and on evolution there. There are two issues - the impact of the idea of Descent of species (covered in evolution - and the impact of the explanatory power of the mechanism, covered here. I don't know that an article on Natural selection can avoid either the history or discussing the very broad impact beyond biologyGleng 08:37, 22 May 2006 (UTC)
thread_title:  HIStory 

message: I want to thank all the people who have been active on this article over the past couple of weeks - I am commenting on the process, not the article itself - I think this has been a model of collaboration for writing Wikipedia articles.  bravo! Slrubenstein   |  Talk 11:01, 22 May 2006 (UTC)
thread_title:  general comment 

message: "this can lead to adaptation" - I think this needs explanations.  Most non-scientists think adaptation is an intentional act; I think in evolutionary biology it is an effect, not an act.  "Adapt" is a verb and it is hard to think of it as anything other than an act, the act of the creature thad adapts (i.e. not the act of "nature"). Slrubenstein   |  Talk 11:04, 22 May 2006 (UTC)
replies: text: I tweaked it a bit, and I think it is clearer now. Kim van der Linde at venus 11:21, 22 May 2006 (UTC)

text: The way you have added it is actually causing more cinfusion, as this implies that adaptaitons are behaviour, which they are not perse. I will undo it for the moment, and add something to clarify it there as well later when I am back from workKim van der Linde at venus 13:02, 22 May 2006 (UTC)

text: I think I will add a sentense making explicite what adaptation is in this context, more like a defining sentence. Or something like that. It is perfect clear what you want to say, and it is indeed one of those little nifty things that need to be addressed.-- Kim van der Linde at venus 13:09, 22 May 2006 (UTC)

text: I tweaked it, let me now if it is clear enough now. -- Kim van der Linde at venus 13:27, 22 May 2006 (UTC)

text: If I am correct, the question you ask is about the scope of the article. I do not think that this article should detail speciation for example, there are a whole series of other articles about that on wikipedia. In the end, Natural selection perse is pretty dull. It is the embedding in the wider context that makes it so radical. Darwins idea was so radical because he explained evolution by means of natural selection. And maybe that is what we need, a seperate article about Evolution by means of Natural Selection (which might be actually already covered enough in Darwinism and evolution).  What I question to a degree is how far we have to go in making each and every article creationist proof (it actually annoys me at times to see that some American controversies creep into every possible article that is even slightly related to it). Maybe we can do a littlebit here and there to clarify and point towards the appropriate articles, but in the end, I think we should keep the article as much as possible on the topic, and leave all the social controversies out of it. Just my 0.02 Euro cents. -- Kim van der Linde at venus 14:30, 22 May 2006 (UTC)

text: I understand Slrubenstein's concern, but I think it's difficult to avoid using the word 'adapt' in some form or another. I can't think of anything better than Kim's wording at the moment. I think like Kim we could go too far in making the article creationist proof, but equally we could go too far in making it read like a science text. The audience for an encyclopedia no doubt includes many lay people particularly for an article with such great general interest as this. Ensuring the article accessible to non-scientists is surely a worthy goal if it can be done without compromising it. Hopefully that should also help in making it creationist proof. — Axel147 18:22, 22 May 2006 (UTC)
thread_title:  adaptation 

message: I uploaded a slightly cleaner version of the image (anti-aliased, looks a bit nicer). Let me know if font sizes, line thicknesses, or the text need changing. It's PD, so use at will! - Samsara (talk • contribs) 18:54, 24 May 2006 (UTC)
replies: text: It is better, except that the color difference between two most resistant versions is pretty much invisible. -- Kim van der Linde at venus 19:02, 24 May 2006 (UTC)
replies: text: I tweaked the colours. Take another look! :) Samsara (talk • contribs) 12:08, 26 May 2006 (UTC)
replies: text: On my computer, it is somewhat better, but I still have a problemto see thatbthe resistant ones are actualy two different colors. Sorry :-(  -- Kim van der Linde at venus 16:06, 26 May 2006 (UTC)

text: I like it! -- Kim van der Linde at venus 16:06, 26 May 2006 (UTC)
thread_title:  Top image 

message: I've made a picture! probably easier than the spaghetti of this thread. Above is what I was tring to say — Axel147 19:36, 25 May 2006 (UTC)
replies: text: It is wider than my screen, so not easy to see. -- Kim van der Linde at venus 20:22, 25 May 2006 (UTC)
thread_title: Diagram of different definitions of NS

message: Do we have to worry that nontechnical readers of this article might read "outward form of an individual" to exclude vascular systems, organs, behavior, and the such? Ted 22:39, 26 May 2006 (UTC)
replies: text: As a "nontechnical reader" of the article, my interpretation of that phrase is physical appearance and possibly behavior - internal organs and such are presumably excluded when you say outward. Moulder 02:32, 27 May 2006 (UTC)
replies: text: I agree, it might not be the best way to say it, as it would include everything. Maybe TedE has a good proposal, I will also think about how to reword it. -- Kim van der Linde at venus 02:37, 27 May 2006 (UTC)
replies: text: I changed it, hopefully, it is clearer in this way. -- Kim van der Linde at venus 02:41, 27 May 2006 (UTC)
thread_title:  Outward form of an individual 

message: The article uses the heading "Genetical theory of natural selection", which sounds odd to me.  The -al difference (e.g. historic and historical) generally comes down to personal preference, but is there a difference (perceived or real) between genetic and genetical? I'm curious to know. Moulder 02:30, 27 May 2006 (UTC)
replies: text: I used it as Futuyama Used it, in his standard work for biology students (Evolution). I have no preference. Is one or the other more linked to British or American english?-- Kim van der Linde at venus 02:36, 27 May 2006 (UTC)
replies: text: It's possible Americans prefer genetic and Britons prefer genetical. My preference comes from familiarity with epigenetic theory, but English has no real rules at times. I thought there might be a distinction in academic circles, otherwise I wouldn't bother bringing it up. :) Moulder 02:58, 27 May 2006 (UTC)
replies: text: I understand. As I said, I have no preferences. If there are no good reasons, I think we might want to stick with Futuyama, who is at least a recognized scholar in the field. -- Kim van der Linde at venus 03:01, 27 May 2006 (UTC)
replies: text: See: The Genetical Theory of Natural Selection (1930) by R.A. Fisher, one of the cornerstones to the area by one of the Titans. Ted 04:27, 27 May 2006 (UTC)

text: R.A. Fisher's The Genetical Theory of Natural Selection is the foundation book of the modern synthesis, and where Futuyama is paying homage by using the phrase. Pete.Hurd 04:38, 27 May 2006 (UTC)

text: Based on what's at Modern evolutionary synthesis a reasonable candidate for first would be The Correlation Between Relatives on the Supposition of Mendelian Inheritance... sort of... ish... Cheers, Pete.Hurd 05:59, 27 May 2006 (UTC)
thread_title:  Not to be pedantic but... 

message: :Just a note, to watch out for usage of some words in a way that is peculiar to the field. The frequency of an allele is something WE understand as the frequency in a population - but it is potentially ambiguous or misleading to lay readers. Prevalence might be a better word here, or incidence. As the article (rightly) gets into more technical detail, it is particularly important to watch out to be both rigorous scientifically, but also rigorous in the use of language as it will be understood by a lay reader. (I think I count myself as lay here).:)Gleng 21:03, 27 May 2006 (UTC)
replies: text: I think this is a good idea - maybe a short glossary in a text box, so as not to break the flow of reading? and especially for words whose technical use might conflict with common use? Gleng 13:13, 28 May 2006 (UTC)

text: I think that a good article is self explanatory, and we have dealt with several terms by just explaing them. I do not think we should do that in the lead, which the previous discussion kind of circled around. I had the impression that Gleng comment was primarily based on the genetic sweep sections and such that use more jargon. I actually think we have to copy and past some of that information to seperate articles, after which we can condense the stuff to a more resonable proportion of the full text. -- Kim van der Linde at venus 17:12, 28 May 2006 (UTC)

text: Anything that is potentially ambiguous, should have a link to an article of its own or a Wiktionary entry.  I think jargon should have a brief explanation, but once allele frequency is linked, the reader has access to a definition of the term.  Guettarda 17:58, 28 May 2006 (UTC)
replies: text: I would be completely with you, but I try to keep in mind that the topic of this page is also atrackting a lot of people who really start from the basics, so I think it is warranted to explian slightly ore than in many other articles. Just my 0.02 Euro cents -- Kim van der Linde at venus 18:08, 28 May 2006 (UTC)

text: I am fine with parentheses, explanatory sentences, or whatever is needed to make it clear. I would prefer for the lead to have it self-explanatory, without parentheses, but if needed, fine. What I am more concerned about is the general line of the article, but it slowly becomes clear to me that I should back of from this article and spend my time with other articles. -- Kim van der Linde at venus 16:00, 29 May 2006 (UTC)
thread_title: Jargon usage

message: Kim's characterisation above of my concerns is correct, I was worried about jargon "creep" into the later sections. RA Fisher I know better as a statistician, and there's a passage of his that I often use, where he argues against argument from authority: Of statistical tests, he says "the questions involved can be dissociated from all that is strictly technical in the statistician's craft, and, when so detached, are questions only of the right use of human reasoning powers, with which all intelligent people, who hope to be intelligible, are equally concerned, and on which the statistician as such speaks with no special authority"
To me this expresses the ideal of what we should be trying to do here, to explain natural selection, and the logic and power of the arguments, in ways that all intelligent people can follow without specialised knowledge. I'm not suggesting "dumbing down" or that sophistications should not be introduced, but only that we should be careful to write for the intelligent reader who comes to the article with no specialised knowledge. (For this reader especially we must be careful e.g. not to use 'allele' and 'gene' as though they were interchangeable, or talk of the phenotype of a gene when we've defined it as the property of an individual)
In any generation, only some individuals will leave progeny. We can think of this as being a process of "natural selection" of individuals to reproduce. Individuals with certain traits are more likely to be 'selected' in this sense than individuals with other traits. When such traits have a heritable component, they will become more common in the next generation. 
It seems to me that this is the core, the beginning of a logical progression that anyone can follow.Gleng 10:34, 29 May 2006 (UTC)
thread_title: Who are we writing for?

message: This section was deleted by me (the author) due to lack of interest in the process. Ted 01:27, 4 June 2006 (UTC)
thread_title:  Another try for a definition (deleted due to lack of interest) 

message: I posted this at TedE's talkpage, but I think the rest might want to know as well:
:Ted, thanks for the invitation for the renewed definition discussion at NatSel. I think however that it is wiser that I let it in your hands and refrain from participating. There is still a lot of work that needs to be done at other important article that I for the moment prefer to concentrate on those instead of spending my energy on a renewed definition discussion. Best -- Kim van der Linde at venus 19:08, 30 May 2006 (UTC)
replies: text: Fine with me. -- Kim van der Linde at venus 12:42, 31 May 2006 (UTC)

text: Fine with me! — Axel147 13:40, 31 May 2006 (UTC)

text: How does balancing selection fit into the first paragraph? Ted 18:06, 31 May 2006 (UTC)
replies: text: True, but "they will become more common in the next generation" isn't true when they are at equilibrium. Ted 19:47, 31 May 2006 (UTC)

text: This statement has too much of the feel of design.  It is as if there is something physical (or, metaphysical) that is evaluating individuals and deciding to keep or reject based on their phenotype.  I don't think this is what you want to say. Ted 18:10, 31 May 2006 (UTC)

text: Maybe we should add a 'tends to' and 'in the absence of other evolutionary forces' to be clearer — Axel147 21:54, 31 May 2006 (UTC)
replies: text: Good catch Ted, potentially good solution Axel or replace 'in the absence of...' with '(but see balancing selection for exceptions).  "When those traits have a heritable component, they will tend to become more common in the next generation (though not always, for one exapmle, see balancing selection for exceptions)."??
Anyway, I'm tied up for a bit now with exam boards so it's up to you guys. Axel, if you're willing and able to make the improvements to the definition section I think there's consensus that we have an improved version; perfection is beyond any or all of us (it will evolve).Gleng 10:49, 1 June 2006 (UTC)
thread_title:  Posted at TedE's talk page 

message: I'm just passing by this article, and certainly don't feel any ownership, where it goes it goes. I thought this was something important for WP though because of another space - the search space. This article will get a lot of hits from lay people, high school students, some attracted by creationist controversies, some by popular science articles etc etc. It's a quite different audience to those who will search for say population genetics. So it seems to me that this page is inevitably a portal, and we mustn't scare anyone off, or try to dazzle them with either authority or sophistication too fast, but be clear, interesting, and get the essence of the  important ideas across in an accurate way and make the arguments internally consistent. I don't think that the intention was ever not to characterise different usages, or to "prioritise" one except for the important purposes of internal consistency for logic and clarity.
Ted is raising interesting issues here,  - you have to think carefully through how statements about the gene/individual/group as the unit of selection fare for instance. I am far from sure whether it is possible to find a definition that can be applied consistently across levels, and would be very interested in following a discussion. My reservation is not about the value of this - only about whether this article is the right place. 
Like I suspect everyone here feels, there are no fundamental scientific differences here, just different perspectives from different backgrounds. The rght answer depends on who's asking the question; it's the same answer I hope, but couched differently. So here, who are we writing for? Or rather you, because like Kim I should really move alongGleng 20:12, 30 May 2006 (UTC)
replies: text: Fine with me. -- Kim van der Linde at venus 12:42, 31 May 2006 (UTC)

text: Fine with me! — Axel147 13:40, 31 May 2006 (UTC)

text: How does balancing selection fit into the first paragraph? Ted 18:06, 31 May 2006 (UTC)
replies: text: True, but "they will become more common in the next generation" isn't true when they are at equilibrium. Ted 19:47, 31 May 2006 (UTC)

text: This statement has too much of the feel of design.  It is as if there is something physical (or, metaphysical) that is evaluating individuals and deciding to keep or reject based on their phenotype.  I don't think this is what you want to say. Ted 18:10, 31 May 2006 (UTC)

text: Maybe we should add a 'tends to' and 'in the absence of other evolutionary forces' to be clearer — Axel147 21:54, 31 May 2006 (UTC)
replies: text: Good catch Ted, potentially good solution Axel or replace 'in the absence of...' with '(but see balancing selection for exceptions).  "When those traits have a heritable component, they will tend to become more common in the next generation (though not always, for one exapmle, see balancing selection for exceptions)."??
Anyway, I'm tied up for a bit now with exam boards so it's up to you guys. Axel, if you're willing and able to make the improvements to the definition section I think there's consensus that we have an improved version; perfection is beyond any or all of us (it will evolve).Gleng 10:49, 1 June 2006 (UTC)
thread_title: who are we writing for exactly?

message: I looked in my local library last night and 7 out of 7 dictionaries and encyclopedias of biology did not use the phenotypic def. so against my better judgement I will only I agree to using it as a lead if we are absolutely neutral about both definitions in the definition section. It's proabably useful to say terms such as 'principle of natural selection', 'theory of natural selection' tend to be historic and now most people prefer to describe NatSel as a process/mechansim. In terms of neutrality. For the phenotypic defintion it's important we have no pejorative suggestions that it is
# Only part of the whole story
# Close to being reducible to tautology
For the wider definition we need no suggestion it's:
# Not mechanistic
# Not current (even though I think it was preferred historically)
# Equal to the outcome 'Evol by NatSel'
# Loose/imprecise
# Not scientific mainstream
Also no general suggestion that separating mechanism from outcome is a new thing. I think also we should explicity use the word inheritance/heredity/heritability rather than ducking it.
Please see Endler Talk:Natural_selection/Archive_003#Endler_-_Thankyou!.  
I propose, I mean request Gleng does a tweak bearing some of this in mind to keep us all happy. — Axel147 08:55, 31 May 2006 (UTC)
replies: text: Fine with me. -- Kim van der Linde at venus 12:42, 31 May 2006 (UTC)

text: Fine with me! — Axel147 13:40, 31 May 2006 (UTC)

text: How does balancing selection fit into the first paragraph? Ted 18:06, 31 May 2006 (UTC)
replies: text: True, but "they will become more common in the next generation" isn't true when they are at equilibrium. Ted 19:47, 31 May 2006 (UTC)

text: This statement has too much of the feel of design.  It is as if there is something physical (or, metaphysical) that is evaluating individuals and deciding to keep or reject based on their phenotype.  I don't think this is what you want to say. Ted 18:10, 31 May 2006 (UTC)

text: Maybe we should add a 'tends to' and 'in the absence of other evolutionary forces' to be clearer — Axel147 21:54, 31 May 2006 (UTC)
replies: text: Good catch Ted, potentially good solution Axel or replace 'in the absence of...' with '(but see balancing selection for exceptions).  "When those traits have a heritable component, they will tend to become more common in the next generation (though not always, for one exapmle, see balancing selection for exceptions)."??
Anyway, I'm tied up for a bit now with exam boards so it's up to you guys. Axel, if you're willing and able to make the improvements to the definition section I think there's consensus that we have an improved version; perfection is beyond any or all of us (it will evolve).Gleng 10:49, 1 June 2006 (UTC)
thread_title: Not quite happy. Just a tweak to get there...

message: What do you mean by "passive process?"  I presume it is a pre-emptive strike against Intelligent Design, but I'm not sure it really fits.  Is selection a passive process to the organism?  The individuals are certainly part of the selection process, particularly when you study behavior.  Selection is a random stochastic process, based on the inherent properties of the individuals.  That doesn't seem passive to me. Ted 18:25, 31 May 2006 (UTC)
replies: text: Kim put in the word "passive" in response to a concern I raised.  I am not committed to the word "passive" but I do think my concern remains valid and should be addressed in the article.  Most people - even some biologists, but I mean most if not all lay-people - believe that the verb "adapt" revers to an intentional act.  Moreover, I believe most believe that "adapting" is akin to "learning."  Thus, many people assume that "adaptations" are usually learned behaviors, the result of the intentional act of adapting.  Now, it seems to me that even in Darwin, certainly in the modern synthesis, adaptations are (1) non-intentional and (2) inherited rather than learned.  I believe that the article communicates this, but I believe it communicates this in a way that is evident to anyone with a decent science education - but in a way that many if not most lay-people (and most people have a pretty bad science education, at least in the English-speaking world) will not really appreciate.  For this reason, I felt that these differences (between how evolutionary scientists use the words "adapt" and "adaptation" and how lay-people colloquially use the words) need to be highlighted in this article.  I suspect there are a number of ways of doing this.  My own way would be to have a paranthetical saying "(in evolutionary science, adaptations are inherited rather than learned, and unintentional)" or something like that.  What do you guys thing? Please come up with something very explicit, because I think that this really needs to be highlighted the first time "adapt" or some variant of the word is used, at least in the body of the article (if not in the lead) Slrubenstein   |  Talk 10:02, 1 June 2006 (UTC)
thread_title:  Passive process 

message: What types of selection do you consider to be part of Natural Selection?
*viability selection
*fertility selection
*fecundity selection
*gametic selection
*mate selection
*truncation selection
*gametic selection
*hybrid dysgenesis
*sexual selection
*kin selection
*group selection
*clonal selection
*balancing selection
*stabilizing selection
*altruism
*reciprocal altruism
*density dependent selection
Ted 18:25, 31 May 2006 (UTC)
replies: text: I was tempted to try the quiz but got stuck. I think they are mainly sub-mechanisms too. They generally identify either a different property being selected which is a subset of fitness, or a different object being selected i.e. a different level of selection. Providing there are phenotypic differences (of any object at any level) that cause differential reproduction we have a form of natural selection. (Ought to qualify by saying while this true it is also possible to have competing selection that cancels iself out and therefore does not result in diffferential reproduction. So maybe I should withdraw that one-liner!!??!!). Brainstorming all types of selection is interesting but seems more useful if we are creating something new. But as natural selection exists already I think maybe we can define that first using other reference points and then see where the other terms fit in?? (And add this in the specialist section for the non layman!) But as a matter of interest do you have the anwsers.... — Axel147 21:45, 31 May 2006 (UTC)
replies: text: The "quiz" was not meant to have a specific set of right answers.  Instead, it is a gauge about how people view selection.  Some population geneticists would include all forms of selection as natural selection, preferring to think only of natural vs artificial selection.  Others would only include those forms where the individual is the unit of selection (excluding Hamilton's altruism, Williams' sexual selection, Trivers' reverse altruism, Wilson's group selection, etc).  That, of course introduces problems, such as with bacteria where the selection is clonal (or "infection-al").  It is, instead, a test to see if you are a clumper or a divider.  (PS.  My apologies for actually referencing someone who is not quite dead yet.  I know it is out of character.) Ted 17:27, 1 June 2006 (UTC)

text: If you want it to be a portal, then I suspect you would want to take a more inclusive view of natural selection, plus trying to spin off most of the material to other articles. Ted 17:27, 1 June 2006 (UTC)
thread_title:  What selection is natural selection? 

message: Not to put any additional pressure, but "For the planned paper Wikipedia 1.0, one recommendation is that the paper version of articles will be the lead section of the web version. Summary style and news style can help create a concise intro that works as a stand-alone article." (WP:LEAD). Ted 20:24, 31 May 2006 (UTC)
thread_title:  Lead section 

message: I've added the change to the definition section for which there was more or less agreement. I left out balancing selection.
If we'd claimed natural selection resulted in adaptive evolution I agree balancing selection would be an exception. But we didn't say this. We only considered one generation. As I understand it for a given generation at a given context it is still fair to say 'beneficial traits tend to become more common'. What is beneficial may differ from generation to generation as the frequency changes but for I single genration I think it's still valid. —  Axel147 22:08, 1 June 2006 (UTC)
replies: text: Axel, natural selection in general does not result in adaptive evolution, it can do it, but in general it results in balancing selection keeping things nicely as it is, keeping gene-frequencies etc nicely as they are. That is why it is so important to keep evolution and adaptation seperate from Natural selection. -- Kim van der Linde at venus 23:34, 1 June 2006 (UTC)
replies: text: True I'm not disagreeing with you. In fact for the wider definition I was emphasising this point. For me it is wrong to say Darwin's 'preservation of favourable characteristics' is synonymous with 'evolution by natural selection' for exactly this reason. When looked at over a single generation or a few generations, preservation of favourable characteristics is compatible with both balancing and stabilising selection. It does not need to result in adaptive evolution. Just to be absolutely clear it is because Darwin is saying it is a principle not a 'must have' outcome. Of course even the outcome 'evolution by natural selection' need not be adaptive either. — Axel147 07:08, 2 June 2006 (UTC)

text: Do you mean stabilizing selection?  Balancing selection seems to be rather rare, unless you look at multiple niches.  Isn't stablilizing selection also adaptive?  I don't think you have to restrict adaptive evolution to directional selection. Ted 02:29, 2 June 2006 (UTC)
thread_title: Change to defintion section put in