Sorry Buddy, I’m rushing through these replies and forgot to answer the actual question you asked. I don’t know any more about it but I would be interested to hear if anyone else has.
Jorolat
Specifically a homeostatic internal mechanism. If organisms are integrated then imagine for a moment there is a center to that integration, an apex to the homeostatic hierarchy in the form of a localized area of natural equilibrium. In post notochord organisms, such as man, this would be located in the older (in evolutionary terms) structures of the brain. In these regions physiological homeostasis is often defined by “set points” such as temperature: If the temperature rises about the homeostatic mean then initiate co-ordinated responses to reduce it. If the temperature begins to fail to meet the set point then initiate physiological processes in order to maintain it. In principle a homeostatic evolutionary mechanism would operate in exactly the same way only in this instance the “set point” would be the current genome in the germ cells. A fuller explanation can be found at the URL in my signature (nb the purpose of the evolutionary changes would be to restore equilibrium in the next generation(s) - no “direction” is involved beyond this).
Jorolat
ps If you do visit the page then “The Bacterial Model” explains why I feel the phenomena of Stationary Phase Mutations may be connected to an internal mechanism.
I’ve just answered half a dozen posts and now have to go so I’ll take the easy way out and suggest you look at the method of testing appropriate to the possible mechanism that I’m interested in:
http://members.aol.com/jorolat/mot.html
Organisms are integrated, steroid hormones enter directly into the nucleus of germ cells (see earlier post, I would answer more fully but I have to rush, if necessary I’ll come back to it)
Jorolat
Read some of your site, jorolat.
Interesting thoughts; but I’d have to see a LOT of rigorously-defended, peer-reviewed testing before I believed it.
One easier way I can imagine that external pressures could affect genetic material:
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High levels of environmental stress cause an increase in the production of stress hormones, etc., in the body
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The high levels of stress hormones increase chances of genetic mutations in the germ cells (not too far-fetched, if stress is indeed a factor in causing cancer; perhaps such things increase mutations in other cells, leading to runaway cell division…)
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Such mutations cause a burst of genetic diversity in the species, resulting in some creatures that are better adapted to the new environment than the norm (and some that are less well-adapted)
So I can see how you could increase the rate of mutation, but not how you could increase the rate of “beneficial” mutations.
jorolat wrote:
Well, I’ve got plenty of objections to the ‘testing’ page just cited. Not least of which is that doing a Web search for “willow moth caterpillar” or +“frederick griffiths” +rats turns up only pages written by you. Given that your premise appears to be over 100 years old, I guess I shouldn’t find this surprising.
A more specific objection turns on the caterpillar results: obviously, using the side of a leaf was a behaviour these organisms already had, otherwise the first generation all would have died on leaves lacking tips. The results must then be interpreted solely upon measurements of what percentage of caterpillars “preferred” using the tips of leaves before and after this generation presented with the snipped tips. 19 whole caterpillars? Far too small a sample size to be considered at all conclusive, or even highly suggestive.
Hormones enter the nucleus? Sure. Are they capable of inducing a process whereby the genetic code is actually modified? That is the mechanism you appear to be promoting, and I think we would have found it in the last forty years or so if it exists.
Besides which, I don’t personally see any reason to believe that any sort of homeostatic mechanism other than natural selection is necessary, except, perhaps, to explain the rats (if such an experiment returns repeatable results).
Am I the only one who’s remembers seeing refrence to stress induced mutation here on the boards?
I meant Stress-induced Gene Expression
"Okay, Firx, that’s a hypothetical ‘body plan’ many steps away from the root fo the tree. And the G&L quote from jorolat has them talking about basic body plans, from which I gather that turning a hand into a foot is pretty much a superficial change. Whereas turning a hand into, say, a second working head would be much more drastic, and definitely a change in body plan.
As far as “integrated organisms” go, it seems that G&L are speaking of such as a way of thinking about an organism (as opposed to ‘atomization’), and not as any definite point in a species’ evolution. I mean, there’s no way a foot will survive without being ‘integrated’ into the rest of an organism, no matter how closely it functions as a hand, so I’m not sure that your use of “integrated” is the same as G&L’s." -DaveW
Fair objections, DaveW. I only made the foot remark to illustrate that structures which are functionally analogous may not be related from an evolutionary standpoint. As a different example I might cite the platypus, which, if I remember correctly, was the subject of much confusion when first discovered. Just because it lays eggs doesn’t mean that it’s related to birds. As for beeing “many steps away from the foot of the tree”, the vast majority of organisms [are/i] far from the foot of the tree. How does it help us to get too general? All vertebrates are similar in that they have backbones, but there are lots of other differences that come into play after that.
I’m sorry about the ‘integrated organism’ bit. I think you are right about G and L meaning it as a way of thinking about organisms. I would add, though, that they mean it as a way of explaining that not every part of an organism is the direct result of natural selection, and that there are limitations in the way an organism can change imposed by the entire body (i.e. some changes are precluded by other elements of the bodyplan). (What I originally meant was that saying an organism has a “foot” doesn’t say anything useful because many organisms have feet, and the term “foot” doesn’t mean anything more than ‘something to walk on’; it doesn’t describe the organism’s foot or say anything about how the foot is related to the rest of the body. True, I still say, but not what we are talking about.) I apologize for not being clear.
Jorolat:
Originally posted by Jorolat:
quote:
Originally posted by Firx
“Populations are made up of non-evolving individuals and an internal mechanism, whereby evolutionary changes would appear in succeeding generations, contains no direct contradiction to “Populations evolve…(etc.)”. I’m just trying to see whether there’s anything I’m missing concerning this objection.” -Jorolat
What do you mean by “…internal mechanism, whereby evolutionary changes would appear in succeeding generations…”? Isn’t the method by which net changes (in allele frequency) appear over time known as “natural selection”, and the net result of many (usually small) changes known as “evolution”?
Also, what exactly is your aim here? are you trying to suggest that there is a process seperate from natural selection working to order body plans?
At first glance the geocentric theory would appear quite different from the earlier belief that the world was flat. They do share one characteristic though - they are both egocentric.
It’s a question of whether one wants an intellectually satisfying explanation of a reality or whether one wants to discover the true nature of that reality - hence the reference to how well the geocentric theory explained the known facts and yet was completely wrong. Outside of the human intellect there are only individual organisms, lotsa 'em, and so I do feel there is something else: an internal evolutionary mechanism.
My aim here, however, remains the same - to find out what objections there may be to an internal mechanism that I’m not aware of.
Reading your post again, and in case I haven’t made it clear, I don’t feel the mutations that occur in the germ cells are entirely random but I would stress that neither do I feel they are directed.
Jorolat
I agree that both the ‘flat earth theory’ and the ‘geocentric theory’ were egocentric, but I don’t understand why you are making this point. Your first reference to geocentric theory was a comparison between it and natural selection:
“Natural Selection is an explanation a la geocentric theory and you can’t test it. I am suggesting that there is a mechanism rather than a process.” -Jorolat
A comparison which I hope you have abandoned. Incidentally, geocentrism wasn’t intellectually satisfying because it didn’t accurately explain what was happening. Notice that it was abandoned for a theory that fit the facts better?
Now for a direct answer to your question:
What does it matter whether the mutations in the germ cells are entirely random? Let’s just assume that they aren’t - that they are influenced by the hormones an organism produces, for example. Natural selection will just ‘select’ the most appropriate mutation anyway. The way I see it, the only way influencing the germ cells would be meaningful is if you could a) somehow be able to cause mutations that have specific consequences (a BIG if) and b) anticipate environmental changes in such a way that you would be able to mutate beforehand and thus be ‘selected’ ( another big if).
I suppose that if you could cause an unusual number of mutations in the right places you would get more variety in a number of traits, but that hardly counts as “ordering” or “directing” the bodyplan.
By the way, if there is an internal factor to evolution how do you explain the evolution-free Hardy-Weinberg Equilibrium, a place without “outside evolutionary forces”? It would seem that if all outside forces were removed evolution would continue due to the “internal mechanism”.
Not at all, the possible mechanism I’m interested in is indirect
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This is taken from one of my web pages (http://members.aol.com/jorolat/spmah.html) but obviously you could look up “Stationary Phase Mutations” on any search engeine:
- N.B. The following sections are extracts from another article (referenced in the Conclusion) and refer to a technique [3] where an initial mutation is engineered in a strain of bacteria which then necessitates their being supplied with the “product” they have become dysfunctional for. An experiment would then begin, for example, when this product was removed.
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Origin of the “Directed Mutation” hypothesis [Return to Index]
An experiment representative of those that Cairns conducted was performed on a strain of bacteria (e. coli) that were unable to utilize the sugar lactose [4]. First the bacteria were deprived of all sugars for a few days, during which time they entered a starvation or “stationary-phase” state and ceased replicating, and then they were provided with lactose as the only source of nutrition.
Once the lactose was added the number of bacteria that subsequently mutated enabling them to utilize it while not replicating far exceeded the number that conventional theory could account for. It was this appearance of the mutations being specifically directed to the presence of the sugar that contributed to the forming of the “Directed Mutation” hypothesis.
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“Stationary-Phase Mutations”
Seeking to disprove the hypothesis Mittler & Lenski [5][6], and separately, Sniegowski [6] performed their own experiments and each concluded that the mutations observed while their bacteria were in the stationary-phase state weren’t “directed” at all but were instead attributable to the “non-specific stresses of starvation” (my italics).
The two points of significance concerning these particular experiments are i) the strains of bacteria used had different mutations to those employed by Cairns and ii) the number of mutations still exceeded what conventional theory could account for (the number of observed mutations varies, in the appended references, from between 100 to 100 million times greater than expected).
Taking these and the results of other experiments into account has led to the phenomena becoming more commonly known as “Stationary-Phase Mutations”. The change in terminology has also lessened controversy although in 1997 a researcher in this field continued to describe it as “the mutation whose name one dare not speak” [7].*
The nature of the resistance once shown to the heliocentric theory (“It’s absurd!”) indicates the intellect can have difficulty accepting a reality contrary to what has previously been taught.
For the mechanism I’m interested in it would become easier
I sometimes feel that Einstein was being polite.
Jorolat
Anything that is currently unknown can be termed “strange” in the same way as it can be called “mystical” but these words only reflect reaction to the novelty of the concept and not that any reality would have these attributes.
An internal mechanism doesn’t have to be directional. Outa time again but I’ll be back later.
Jorolat
ps I should have made it clearer in the earlier post that the URL was in the signature.
Too… many… posts… overwhelmed.
Must… write… like… straining… Captain… Kirk.
Jorolat, please see this BBQ Pit Thread
This is still described from the intellect viewpoint.
Sorry about the brevity but there are a number of posts to catch up on.
Somehow you’ve managed to *reverse[/] what G and L actually say:
“But the important steps of evolution, the construction of the Bauplan itself and the transition between Baupläne, must involve some other unknown, and perhaps “internal,” mechanism.” (my emphasis)
In other words Natural Selection can’t account for formation of the bauplan in the first place, Natural Selection’s role is secondary.
Jorolat
Could what we perceive to be stress actually be an upset to equilibrium (in the older structures of the brain)? In addition, though I don’t know enough to specifically say hormones are the means of communication an internal mechanism would use (should one exist), their release is generally initiated by the areas of the brain in which I’m interested.
Jorolat
I had the same trouble trying to locate any further information regarding the caterpillars despite starting a thread here, talk origins, and other places. On the other hand I’m sure many other examples are available, its just a question of tracking suitable candidates down.
The implication in the secondary source was that the willow moth caterpillars always used the tips (else there would be no cause for comment). Its the potential significance of the results that interests me and from this perspective the sample size, in terms of numbers, isn’t important but the percentage exhibiting the change is.
Despite the subsequent controversy I can’t remember anyone dismissing “Mitochondrial Eve” simply because, as only one member of a population, she was statistically insignificant.
It’s not a question of believing in an internal mechanism it’s a question of the fact that if one exists it would be testable. Natural Selection does not exist outside of the human intellect, there are only individual organisms.
If such a mechanism exists part of the reason it hasn’t been found is because of the conditioned response “Internal Mechanism? Oh you mean Lamarck - nawwww!”. It was only twenty years ago that Gould and Lewontin were arguing that organisms should be analyzed as integrated wholes! Part of what I’m saying is if organisms are integrated wholes then when you look at the nature of that integration you’ll find it is homeostatic.
Jorolat
ps The experiment on the rats was appalling but once again no specific mechanism was being tested for, it was a shot in the dark that appears to have been lucky - wish I could get my hands on the original source!
Originally poster by Jorolat:
Sorry about the brevity but there are a number of posts to catch up on.
quote:
I think the “weak” form says something more like ‘once the entire body plan is put together no really large changes can occur, and the process by which the body plan forms is guided by natural selection’. This would seem to be consistent with many of the ideas Gould expressed in “Wonderful life: The Burgess Shale and the Nature of History”.
Somehow you’ve managed to reverse[/] what G and L actually say:
“But the important steps of evolution, the construction of the Bauplan itself and the transition between Baupläne, must involve some other unknown, and perhaps “internal,” mechanism.” (my emphasis)
In other words Natural Selection can’t account for formation of the bauplan in the first place, Natural Selection’s role is secondary.
Jorolat
I don’t have my copy on hand, so I can’t quote right now, but (correct me if I’m wrong; or better still, put the passage up here for us to see) isn’t Gould referring to the Cambrian Explosion here? If so, and if that is what you have been talking about the entire time, then I agree with you. The sudden appearance of complex multicellular life at the beginning of the cambrian does seem to need an explaination besides natural selection, and the subsequent extinction of many of the bodyplans found in the Burgess Shale certainly does. In fact, Gould goes on to form the argument that natural selection had nothing at all to do with the survival or destruction of those bodyplans, that they survived or died due to random chance. No matter how you cut it, the beginning of life as we know it is far from clear.
Furthermore, I’m pretty sure that Gould states that each subsequent change (after the cambrian body type is selected, according to him by chance) limits the changes, to some degree, that can reasonably occur later. Thus, I think, the integrated organism: one in which all aspects of anatomy and physiology are taken into account for the purposes of looking at evolutionary change. A trait doesn’t have to be selected in order to influence the organism.
I would be interested in reading this thread if anyone knows anything more about it. A search using “stress induced mutations” got zero hits on this message board.
Jorolat
The point in mentioning the geocentric theory was that “Natural Selection” is our perception of what happens whereas an internal mechanism may be the reason it happens. Natural Selection only exists in the intellect whereas an internal mechanisms may exist in all the organisms outside of the intellect.
The nature of the resistance once shown to the heliocentric theory indicates the intellect can have difficulty accepting a reality if it is contary to what has been previously taught. I would argue that the geocentric theory was once very intellectually/emotionally satisfying else why did they place Galileo under house arrest for the rest of his life?
I would also argue that this punishment, no matter how rationalized, was clearly psychological in origin and due to the upset to the conditioning Galileo’s peers had received in being taught to believe in the Bible. After all, Galileo had a natural right to life equal to that of his peers.
A homeostatic mechanism would be indirect and if no upset to equilibrium exceeded, or failed to meet, existing thresholds then no evolutionary changes would occur (eg the shark)
Jorolat
I think you’re attacking too many things at once here.
Seems to me that your major complaint with N.S. is that it doesn’t have a single, neatly wrapped cause. As in, “Oh, look, here’s chromosome 12, with the well-known ‘natural selection’ gene. If we remove it from the nucleus, then the organism’s offspring will never evolve.”
N.S. has zillions of causes–more than we can usually predict (like trying to forecast the weather). It’s really more of a mathematical sorting than anything else–but that doesn’t mean it only exists in our heads. Just because it doesn’t rest entirely within the organism doesn’t mean it’s not real. Lemme see if I can think of an analogy…
There’s no “mechanism” inside an individual snowflake that causes an avalanche to crush a town in the Alps. There are a ton of different factors involved that say whether that town gets squished or another one does or none do. (Not great, but the best I can think up right now.)
I understand your logic. Perhaps you’re right, though I personally doubt it.
This is two separate issues–(1) organisms are integrated wholes (2) said integrated wholes are homeostatic–each of which is debatable.
I would agree that (1) is a fair assumption, although the degree to which you seem to want to carry it (that the genetic material of said integrated whole can be unconsciously altered by the life experience of the rest of the whole so that the offspring receive advantageous adaptations…) is more tenuous, IMO.
And (2) does not really follow from (1), at least not by anything I’ve seen you post here or on your site.
Perhaps this thread?. Around the second or third page IIRC.