Register | Sign In


Understanding through Discussion


EvC Forum active members: 49 (9179 total)
3 online now:
Newest Member: Jorge Parker
Post Volume: Total: 918,225 Year: 5,482/9,624 Month: 507/323 Week: 4/143 Day: 4/13 Hour: 1/1


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Criticizing neo-Darwinism
extremophile
Member (Idle past 5709 days)
Posts: 53
Joined: 08-23-2003


Message 90 of 309 (303560)
04-12-2006 2:11 PM
Reply to: Message 60 by nwr
03-25-2006 9:50 AM


Re: Why prejudge?
I've read almost the entire thread right now (I'm reading backwards, to the beginning), and there’s a statement I did not understand quite well:
The biology shows how complex structures can arise, but the gradualism of the neo-Darwinist model seems to argue against it.
How come "biology" explains complexity apart from neodarwinism? It is supposed to mean embryologic development?

This message is a reply to:
 Message 60 by nwr, posted 03-25-2006 9:50 AM nwr has replied

Replies to this message:
 Message 93 by nwr, posted 04-13-2006 7:42 PM extremophile has replied

  
extremophile
Member (Idle past 5709 days)
Posts: 53
Joined: 08-23-2003


Message 91 of 309 (303576)
04-12-2006 3:04 PM
Reply to: Message 45 by nwr
03-23-2006 11:24 PM


Re: gould vs dawkins *ding ding*
nwr writes:
My disagreement with the last Dawkins paragraph was particularly disagreement with:
Dawkins writes:
It will take time to undo the damage wrought by overblown rhetoric, but it will be undone. The theory of punctuated equilibrium will come to be seen in proportion, as an interesting but minor wrinkle on the surface of neo-Darwinian theory.
I agree (with Dawkins). Since PE incorporates or is icorporated by ND, and the ND part is which really explains the origin of adaptations and novelties. What PE says is more or less how and why it would be found in the fossil record.
The fact that species can exist as a sort of unit of selection, that may have been (I don’t know) proposed in PE, does not help much, or anything, in explaining the ultimate origin of adaptations.
Contingencies aside, it says that when two species adapted to the same niche, if inhabiting the same habitat, one is likely to go extinct (or else, less likely but yet possible, don' know if predicted by PE, but predictable anyway, one could divert adaptatively to another niche in same habitat).
Is more or less like comparing the day-by-day training of a pugilist, and the actual tournments, as an explanation for their fitness. The main cause of their fitness condition and abilities is not the real decisive fights (analogue to species selection), but the training, the workouts, which are analogue to evolution by NS / neodarwinism.
Maybe a better example would be the breeding of fighting dogs. Which are bred in two isolated populations, and eventually put into a fight. The fight itself did nothing for originating the traits of the winner/survivor, it only defined the survivor. The origin of the traits took place in the selection done within the populations.
And PE has yet more problems with contingencies than ND, when it comes to explain adaptation. While in ND, there is a large number of individuals being selected over generations, thus compensating for eventual lesser adapted individuals that got lucky, and for better adapted individuals that did not reprodue or reproduced less because of bad luck, with species selection is more like a single event, more prone to the disturbs of contingencies. If of two horse-like species, one survived in one habitat, it was not necessarely because the survival had the best adaptation for the niche, but could be that it brought a new disese to which the "residents" did not have resistance, while the invasors had more time to develop in their original habitat.
Not to mention that PE alone (somehow... because I do not think it can possibly be proposed anyway) would require much more time to develop a adaptation such as the camera-like eye.
So I think that it’s a matter of what one sees as major and minor points of evolution. I do see the origin of adaptation as a major point than distribution of species along the fossil record, transitionals and etc.
This message has been edited by extremophile, 04-12-2006 06:16 PM

"Science comits suicide when it adopts a creed."
Thomas H. Huxley

This message is a reply to:
 Message 45 by nwr, posted 03-23-2006 11:24 PM nwr has replied

Replies to this message:
 Message 92 by Brad McFall, posted 04-13-2006 7:14 AM extremophile has replied
 Message 94 by nwr, posted 04-13-2006 7:47 PM extremophile has not replied

  
extremophile
Member (Idle past 5709 days)
Posts: 53
Joined: 08-23-2003


Message 96 of 309 (304109)
04-14-2006 1:07 AM
Reply to: Message 93 by nwr
04-13-2006 7:42 PM


nwr writes:
I am using "neodarwinism" to refer to a mathematical theory of change in population genetics. You can, in principle, see what is predicted in this theory without having to refer back to what is observed.
I am not sure if I understood it. By this phrase solely, seems a bit that you mean that you are basically okay with natural selection being responsible for adaptations; but does not feel so secure about the mathematical description...?
But guessing a bit further (partly based on what I (may) remember from your posts in this thread), you are okay with the evolution of the traits per se (maybe by natural selection) but at the same time you have the impression that something entirely new is needed sometimes, rather than the more visible action of natural selection, that is the tuning of what is already there?
I have not been suggesting group selection (species selection). I'm a bit surprised to see you suggest that group selection is part of PE.
I do not suggested that you suggested or anything, I just mentioned because someone briefly mentioned something about species possibly being units of selection.
Now again I am not really sure, but I think that group selection and species selection are distinct types of selection, even though a species is a "group". Group/ selection, AFAIK, refers to smaller groups of more closely related individuals, with a distinction a bit blurred with kin selection. It can occur within species, among groups, more or less continuously. Species selection would be when one of two two distinct species, not even necessarily closely related, but adapted to a same niche, face extinction when they met in the same habitat.
Group selection is a lot more powerful to explain adaptation, because the selection of groups within a species probably is far more frequent than the extinction of a species resulting from the encounter of two species adaptad to the same niche in the same habitat.
Evolution - A-Z - Species selection
This brief definition does not says quite what I said, but mentions at least that species selection should not be confused with group selection... if I understood what is there and other stuff I quickly searched to be sure that I was not confusing things, species selections also have to do with how a species is highly specialized or generalist; generalist ones tend to be "selected" over time. Which may be a bit different from what I said, I guess, since there’s no emphasis on the adaptation to a niche, unless it was implied but I did not get... but also may be the just the consequence of sucessive episodes like those I described...
I don't understand that comment at all.
I mean, the is much more likely to a adaptation (specially the complex ones) to evolve by the selection of individual traits than of species’ traits because all that takes to the gradual change and fixation of a trait within a population happens much more quickly than the extinction of species, that may not even be related to a very specific adaptation, but to the overall adaptation and eventualities such as population size.
In other words, the eyes are much more likely to have evolved due to differences in the proto-eye structures and what it represented for the fitness of individuals within a population or among sub-populations of the same species; rather than evolving because successive extinctions of species with less effective proto eye structures "against" species with a more effective structures, all the way to a actual eye.
Species selection seems to me that just says that the overall adaption of species will make those exist for more time, or that the more adapted species in the overall will be the parent species of lots of species with minor variations... but not explains how the specific adaptations of species evolved.
Moreover, I don't consider the mammalian eye to be camera-like.
It is not just the mammalian eye, but the vertebrate eye in general; and I think that is not a matter of individual opinion, but of consensual similarity of the structures that work very in the same way; light coming from the environment through a slit or small hole, projecting a image of that environment at a certain distance of that entrance; that is what "camera" means in this context, it’s a basically a eye made of a "chamber", but in some versions also presents even other similarities with photographic cameras.
This message has been edited by extremophile, 04-14-2006 03:09 AM

"Science comits suicide when it adopts a creed."
Thomas H. Huxley

This message is a reply to:
 Message 93 by nwr, posted 04-13-2006 7:42 PM nwr has replied

Replies to this message:
 Message 98 by nwr, posted 04-14-2006 8:17 PM extremophile has replied

  
extremophile
Member (Idle past 5709 days)
Posts: 53
Joined: 08-23-2003


Message 97 of 309 (304127)
04-14-2006 2:34 AM
Reply to: Message 92 by Brad McFall
04-13-2006 7:14 AM


Re: gould vs dawkins *ding ding*
...
I’m sorry, but I understood infinitesimally close to nothing, if anything.
I think that if I try to "slice" your post and comment every slice it would look like if I was trying to make fun or something, because it would be successions of things like "I don’t know what you are talking about and how it have anything to do with what I said or relates with the topic at all"
The only part that I think I (supposedly) could grasp a bit was that:
[...]Now I doubt the "wrinkle" is a propostion of any form[...]
I did not divagated as much as you apparently did on what he meant by wrinckle... I just supposed it immediatelly as that PE is a minor detail, not something that really needs a revision of the basic mechanisms of natural selection... (but maybe I was inattentive and there was some context that would change it)
So, differently from what you apparently suggested (or maybe not), I think that PE does not brings any hierarchical or whatsoever difficult to NS. It complements the general aspects of evolution, but hardly has anything to do with the specific of how adaptations evolve, which is what NS at "classical" levels intends to explain.
The point of critcism of neo-Darwinism is that Darwinism by failing to heed the diversity of shapes themselves, failed to not class possible embryological changes, that were observed first and continue to be from looking at tissue and levels higher, no matter what the molecular evidence also brings forward.
I think (if I really understand that part; now I more safely I guess so) that it is not really a "failure" of the mathematical description of natural selection, even though I accept that it can not do it. I think it do not need to, and I profoundly doubt that could exist some general theory that would describe evolution in such entireness of information. It does not mean that this information above the simple mathematical concerns with frequencies of genes is worthless, I just think that it deals with to many possible specifics to be adressed in a general mathematical theory of evolution.
However, may be possible to insert this data, of a specific context, and study it within the mathematical framework of ND (or more properly modern synthesis, for sake of pedantic correctness).
I think that the "problem" of the simple notion of genetic frequencies varying due to selection does not gives us any immediate sense of how the specifics of a adaptation evolved "in the real world". For that we need to create some specific visual aids, or even "mini theories" dealing with what comes after the gene, what really "propels" these changes genetic frequencies.
This message has been edited by extremophile, 04-14-2006 04:36 AM

"Science comits suicide when it adopts a creed."
Thomas H. Huxley

This message is a reply to:
 Message 92 by Brad McFall, posted 04-13-2006 7:14 AM Brad McFall has replied

Replies to this message:
 Message 99 by Brad McFall, posted 04-15-2006 7:00 PM extremophile has not replied
 Message 104 by fallacycop, posted 08-29-2006 7:16 AM extremophile has not replied

  
extremophile
Member (Idle past 5709 days)
Posts: 53
Joined: 08-23-2003


Message 100 of 309 (304496)
04-15-2006 7:55 PM
Reply to: Message 98 by nwr
04-14-2006 8:17 PM


nwr writes:
Actually, I am critical of what I consider an over-emphasis on natural selection (sometime described as pan-selectionism).
Ah, okay. I am also critical of that, which I think that is in most of time something resulting from bad media coverage of science, or even sloppy and hurry assumptions of some scientists (when speaking to media)...
I'm okay with evolving of new traits. But I think neo-Darwinism doesn't adequately explain it.
...mmm from what I remember of the whole thread I can’t figure exactly what would be the problem yet... I’ll reread it eventually...
There are several published articles that claim to debunk the idea of group selection.
Probably there are, and there are those who defend it too. However, I was not deffending the existence of GS in this sentence, but was more in the sense that if it works, would be more significative to the generation of adaptations than species selection.
I'm not sure why you see PE as involving the selection of "species' traits". It is my impression that PE advocates tend to downplay the role of selection, and instead look to the importance of environmental contingencies.
Actually I do not know much about PE, except that is the opposition to phyletic gradualism. I started mentioning species selection in relation with PE because someone did it earlier; my point was supposed to be that PE is still compatible with natural selection in levels below of the species, and those are far more reasonable to produce adaptation. So there’s no reason to make case of PE against natural selection or neodarwinism. Does not make sense putting PE against conventional NS because is this what would create the adaptations even in PE; and does not make sense opposing PE with neodarwinism because they’re not quite opposites in a specific aspect; modern synthesis itself is already "against" neodarwinism (as MS acknowledges drift and etc), even if PE is not taken in consideration.
Yes, I should have said "vertebrate eye".[...]
Okay, I was speaking of camera-like in a much less strict viewt than this.
This message has been edited by extremophile, 04-15-2006 09:58 PM

"Science comits suicide when it adopts a creed."
Thomas H. Huxley

This message is a reply to:
 Message 98 by nwr, posted 04-14-2006 8:17 PM nwr has seen this message but not replied

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2023 by EvC Forum, All Rights Reserved

™ Version 4.2
Innovative software from Qwixotic © 2024