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Author Topic:   Mimicry: Please help me understand how
Wounded King
Member (Idle past 2438 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 25 of 241 (414193)
08-03-2007 6:45 AM
Reply to: Message 23 by MartinV
08-03-2007 5:21 AM


Re: mimicry isn't the problem, then
In the described process natural selection plays no role.

Well the described process covers several different levels only at some of which we might expect to see natural selection operating.

Once again you seem to assume that century old research on a topic is the definitive study, even when such research predates virtually the whole of modern genetics.

The progression from stripes to tails and the posterior sounds very reminiscent of the research into patterning as a Turing reaction-diffusion system. It would be interesting to see how the variations in pattern end points which Eimer noticed in Lacerta muralis correspond to the variations of proportions in the body and tail of Lacerta muralis which Alfred Russel Wallace discussed in his book 'Darwinism'(1889).

No one is saying that there aren't mathematical or physical principles which govern the way forms are generated. But to ignore such patterns basis in the genetic complement of the organism and the subsequent implication of evolutionary mechanisms in their maintenance and development is to throw out the patently obvious genetic baby with your own ideological bath water.

TTFN,

WK


This message is a reply to:
 Message 23 by MartinV, posted 08-03-2007 5:21 AM MartinV has responded

Replies to this message:
 Message 27 by MartinV, posted 08-03-2007 11:23 AM Wounded King has responded

  
Wounded King
Member (Idle past 2438 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 28 of 241 (414212)
08-03-2007 12:12 PM
Reply to: Message 27 by MartinV
08-03-2007 11:23 AM


You aren't saying anything, just throwing up random references.
Anyway I am not sure - as we discussed before - that genetical background can explain mimetism.

You have never given any coherent reason why however. All you seem to do is stick your fingers in your ears and ignore any genetic research, except when trying to quote mine it to fit your preconcieved ideas.

I don't quite see why you expect Nijhout to reference every study of colour patterning in butterflies the paper wasn't a historical review but novel genetic research.

Mimetism is therefore pure chance of being on the same transformation level during development. It is indepent from selection

This makes no sense unless you are claiming that the patterning is not heritable, which itself makes no sense. The fact that there may not be an infinite number of possible patterns of wing colouration and that some patterns reoccur partially by chance, is in no way inconsistent with modern developmental genetics. When we discussed this previously I referencd research showing distinct genetic origins for the same pattern in two different species of Heliconius (Naisbit et al, 2003).

All you really seem to be saying is that the origin of the traits is independent from natural selection and geography, which would of course be entirely consistent with modern evolutionary theory in the same way that the de novo occurence of a mutation is independent from natural selection and (with some possible exceptions for changes in rate) geography.

TTFN,

WK


This message is a reply to:
 Message 27 by MartinV, posted 08-03-2007 11:23 AM MartinV has responded

Replies to this message:
 Message 29 by MartinV, posted 08-03-2007 1:18 PM Wounded King has responded

  
Wounded King
Member (Idle past 2438 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 31 of 241 (414326)
08-03-2007 8:13 PM
Reply to: Message 29 by MartinV
08-03-2007 1:18 PM


Re: You aren't saying anything, just throwing up random references.
In such cases genes might have play no signifficant role.

Completely unsupported assertion based on ignorance. You seem once again to be unaware of the wealth of research in the field, in this case that which looks into the relationship between cold shock and heat shock and their effects on gene expression. Its strange since your reference directly discusses several examples.

Just for a record. "Genetic research" do not explain deep secrets of life sometimes.

http://8e.devbio.com/article.php?id=213

What? That link is to an explicit discussion of how genetic research can help explain 'deep secrets of life', if you have to be melodramatic about it.

You seem to have totally failed to pick up the point of the article, which is that the different phenotypes are the result of the interaction of the environment and the genotype.

Waddington's 'Genetic Assimilation' posits that since there is the capacity for variation on the basis of environmental factors then when there is a consistent environmental factor affecting the phenotype that phenotype will be selected for on the basis of the genetic complement which has the correct interaction with the environment to produce it. The alternative form of 'Genetic assimilation' is when the re is a genetic component for the development of an environmentally stimulated characteristic, the example given in the article you link to is callus development, elements in the pathway of that environmental response can be altered so the characteristic manifests in the absence of the environmental cue.

all you seem to have just done is illustrate my point, just giving references is pointless if you haven't read and understood them, and if reading that Gilbert article lead you to believe it was discussing the limits of developmental genetics then you have severe reading comprehension problems.

TTFN,

WK

P.S. That is a great article, one of the clearest explanations of genetic assimilation I have come across.


This message is a reply to:
 Message 29 by MartinV, posted 08-03-2007 1:18 PM MartinV has responded

Replies to this message:
 Message 32 by MartinV, posted 08-05-2007 3:18 PM Wounded King has responded

  
Wounded King
Member (Idle past 2438 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 33 of 241 (414675)
08-05-2007 5:10 PM
Reply to: Message 32 by MartinV
08-05-2007 3:18 PM


Re: You aren't saying anything, just throwing up random references.
Just re-read the last paragraph.

Genetic assimilation can function by genetically fixing traits that had a phenotypic plasticity or it can genetically fix a phenocopy. For a phenocopy to be fixed, the population must be exposed to environmental conditions that repeatedly induce the phenocopy and there must be selective pressure such that the phenocopy is advantageous (produces higher fitness) in that environment (Rachootin and Thomson 1981). In this way, advantageous traits may be selected and incorporated into a population at a higher frequency that would be expected by random chance. As Waddington (1961) pointed out, a combination of orthodox Darwinism and orthodox embryology can give the results that look like the inheritance of acquired characteristics.

Clearly the fixation of the phenocopy is also considered a form of genetic assimilation, although it is 'converse' in its acquirement to the initial example, the callus which Waddington. I addressed the fixation of the phenocopy first in my post before the callus example.

One form is the change of the underlying genetic developmental mechanisms to stabilise a previously transitory environmental response, the other is the selection of a genetic background which maintains a particular phenotype, resembling the phenotype of some other species, in the presence of a constant environmental factor.

Neither of these phenomena does anything to undercut the importance of genetics, they simply emphasise that the genetics must be studied in the context of their interactions with an organisms environment, a perfectly neodarwinian approach.

So I don´t see reason for your enthusiam that those three great scientists with their experiments should support your neodarwinistic views.

Well I didn't say that, I said that the article doesn't present anything which doesn't support my neodarwinistic views, certainly not the experiments it discusses.

You can read - "converse of genetic assimilation".

One single phrase doesn't counter my point, that would actually require some reasoned argument. Why don't you try that instead of appealing to authority? I don't require Waddington, Goldschmidt and Schmalhausen to agree with me, I don't even require Darwin to agree with me. I have the benefit of a wealth of experimental evidence and genetic evidence which none of those scientists had so I can draw my own conclusions.

TTFN,

WK


This message is a reply to:
 Message 32 by MartinV, posted 08-05-2007 3:18 PM MartinV has not yet responded

  
Wounded King
Member (Idle past 2438 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 48 of 241 (419438)
09-02-2007 6:39 PM
Reply to: Message 46 by MartinV
09-02-2007 3:11 AM


Re: See neodarwinism mimicry everywhere?
In the previous article authors and scientists saw "imperfect" wasp-mimics almost everywhere - that's probably why it's explanation was so messy.

You haven't really explained what was messy about Gilbert's explanation, assuming that is the article you mean, it may interest you that he has authored a more recent paper on imperfect mimics focusing on the preferences of pigeons (Bain et al., 2007).

I did find the final part of Gilbert's 2004 paper to be particularly amusing...

More untested theories are not really a priority. Ideas about mimicry have been produced for at least 130 years, and the debris from them lie all around in the literature. Mimicry suffers more than most fields from a surfeit of armchair theorizing, often completely divorced from reality, even in those who castigate such theorizing

In the previous article authors and scientists saw "imperfect" wasp-mimics almost everywhere - that's probably why it's explanation was so messy.

I agree that there can be cases of misattribution, I would certainly be hesitant to state that every one of the 600 species in the Sessidae family were close enough wasp/hornet mimics to gain a selecitve advantage, but then Wikipedia is hardly known for its circumspection and reserve.

Probabaly in many cases we are facing only the fact of covergence and chance.

Those would be exactly the factors which neodarwinism would consider to be responsible. The chance would be the mutational basis of the pattern variation and the convergence a result of common selective pressures on the mimic and target species. What basis would you, or Heikertinger, ascribe the convergence or the element of chance to.

Darwinism often support it's view by presenting "stunning" examples of mimics. One of them is "wasp-mimic" Trochilium apiforme

Care to support this, say with an example of some modern paper describing Trochilium apiforme as "stunning", or are the quotation marks just for effect?

So the outcome should be this one - the range, extent of different colors of Sessidae is so great that Trochylium apiforme would exists in the same coloration and shape even if there were no wasps on the Earth.

Based on what? Your wishful thinking? You single out Trochilium but the Synathedon species on the wikipedia page looks pretty similar in terms of its markings at least. We seem to have nothing but your armchair speculation that Trochilium is the only wasp mimic, although since you don't believe in mimicry you are presumably claiming it is just the only one that resembles a wasp.

Your theorising about what might exist in a world without wasps seems pretty divorced from reality.

TTFN,

WK


This message is a reply to:
 Message 46 by MartinV, posted 09-02-2007 3:11 AM MartinV has not yet responded

  
Wounded King
Member (Idle past 2438 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 79 of 241 (424119)
09-25-2007 5:20 PM
Reply to: Message 78 by MartinV
09-25-2007 3:24 PM


Re: Mimicry
How many times does the same point have to be made before you get it. The 'unpalatability' does not need to extend to every potential predator of the organism in order for it to represent a selective advantage. Half a dozen* people seem to have pointed this out already.

TTFN,

WK

*This statement may have employed some hyperbole.


This message is a reply to:
 Message 78 by MartinV, posted 09-25-2007 3:24 PM MartinV has responded

Replies to this message:
 Message 80 by MartinV, posted 09-26-2007 12:24 AM Wounded King has not yet responded

  
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