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Author
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Topic: Evolution - Survival of the Least Appetizing
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Irving
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Member # 535
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posted 11. January 2003 14:27
Frances,
I think Noel was looking for a real demonstration, not a simulation (do we really understand the complexities of life sufficiently to place substantial faith in human engineered simulations?). Plus the ev model has taken a number of criticisms for a variety of reasons. Perhaps a seperate thread? Since it looks like this is trending seriously off topic. SLAp
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rossum
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Member # 463
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posted 11. January 2003 19:37
Irving said:
quote:
Besides butterflys, there are also frogs that secrete poison. So it's is not something that can't appear in life. It just doesn't seem to appear enough.
IMHO poison is a lot less simple than simple distastefulness. Poison requires special efforts so that you are not killed by the poison. In the case of Monarch butterflies they have to both be immune to the poison and to develop ways to store it, rather than metabolise it -- rather more complex than developing a simple non-poisonous distasteful chemical. The frogs have both to produce the chemical themselves and not to be killed by it. Again more complex than just tasting nasty.
It is not at all clear that the poison based strategies are simpler than the alternatives. With a poison you have to avoid being killed by it yourself. For example, the problem for drug companies is not finding chemicals that kill bacteria; nitric acid will do nicely. The problem is finding chemicals that kill bacteria without doing too much damage to the patient in the process.
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Irving
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Member # 535
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posted 11. January 2003 21:53
quote:
IMHO poison is a lot less simple than simple distastefulness.
Okay, I can accept that. In a spectrum with dis-tastefulness at one end, and bio-mechanical mechanisms at the other, I'd put poison somewhere in between.
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Argon
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Member # 276
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posted 11. January 2003 22:58
Noel Rude wrote:
quote:
Well put! I think this thread illustrates the scientific futility of the Darwinian "just-so story", what with the IDists speaking facetiously and the methodological materialists trying to be serious. Imaginative story telling gets us nowhere.
Those who want Darwinism to be true must demonstrate that random incremental change and selection can increase information. Should they be able to do this, which is doubtful, it still does not follow that everyone would opt for their explanation. First we'd have to ask what kind of odds the materialists are up against, and then we'd want to weigh this against the fact that we already know that intelligence easily increases information (ex nihilo).
Thank you.
There is one thing I would like to clarify in the second paragraph. Most people -- evolutionists and ID-ists alike -- accept that selection can increase information. William Dembski has discussed this in his writings and even provided an extremely rough estimate of how much he thinks a selective event can contribute. I can't recall the exact term used... 'additive' or 'incremental' complexity, perhaps. Just recently, he posted some comments to this forum about the transfer of information from the environment to organisms via selection. So the question is not whether 'information' can be increased in an organism via selection, because it definitely happens. Instead, the question is 'how much' and 'what type' of information can accumulate. And that has been the subject of many previous discussions.
Personally, I suspect trying to reconstruct most of the past evolutionary steps in precise detail from the standpoints of either selection or ID is indeed futile. Most of the information necessary to evaluate detailed pathways is long gone and so reaching a conclusion either way is likely impossible. That is why I have advocated studying the most recently emerged systems -- These are the ones most likely to retain meaningful signals.
PS - One certainly hopes William Brookfield and Irving were not being facetious. That could incur the wrath of Moderator #1 who recently wrote the following warning to another Brainstorms participant about his facetious post here:
quote:
Your post is inappropriate to Brainstorms. You adopt a tone of mockery and ridicule rather than the careful, thoughtful analysis that is expected of participants.
You may well have a legitimate point, namely, that the appearance that biological systems are "designed for discovery" is an artifact of our discovery process. However, you method of bringing this point out is completely out of the spirit of Brainstorms.
So be careful, Noel, Moderator #1 is keeping a close eye on everyone. ![[Razz]](tongue.gif)
[ 11. January 2003, 23:00: Message edited by: Argon ]
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William Brookfield
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Member # 565
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posted 12. January 2003 00:26
Thank you *all* of you for your responses.
Frances quote:
There is nothing in Darwinian theory that should make an organism edible/tasty but there is nothing in Darwinian theory that prohibits this either.
But I *do* expect RM&NS to be bound by its probablistic formulation. If it is to be science then it must be thus bound.
Frances quote:
In fact I would argue that the common origins of life would suggest that from a nutritional perspective, organisms provide 'higher organisms' with the necessary nutrition.
This seems to miss the point. I am not talking about nutrition here I am talking about defense mechanisms that disguise, disrupt or otherwise defend the flesh (that is, of course, sought for its nutritional value). I also already realize the value of food tasting good from the predators' point of view.
Hello Argon
quote:
'Distastefulness' is probably easier to circumvent and doesn't really move an organism into another niche. The fact is, there are many potential 'solutions' to ecological arms races.
Can you help me out a bit here? How does the fox circumvent rabbits sudden distastefulness without de-selecting rabbits? Could you (or anyone out there) provide an alternate 'solution' that would keep distastefulness so suppressed in these cases?
Argon
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And remember, being eaten isn't the only pressure out there.
Nonetheless I consider “being eaten” to be a distinct survival disadvantage.
Argon
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Even if you aren't worried about being eaten (elephants are an example)
Elephants, (along with along with any other organisms not under such such selection pressure) are of course excused from any distastefulness.
Argon
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there is still competition in other arenas for limited resources.
I don't see why this would keep an incredibly valuable defense mechanism from becoming fixed in the population (due to its survival value).
Perhaps I can help a bit in explaining what I am looking for
My idea is to try predict the future evolution of a RM&NS system on the basis of its RM&NS formulation and constituent organisms and environment. Because randomness is random, by definition, it cannot provide a *weighted* probability map. This map *must* be provided by the structure of the organism and its environment. I have simply been looking for the most probable defense mechanism given the organisms existing structure(and env.)
The reason that I have put forward a Slap mechanism for prey organisms is because of its enormous SAI Survival Advantage Index (composite probability).
I have derived the "SA-Index" or "SA-quotient" directly from RM&NS.
The SAI represents the Darwinian equivalent of "bang per buck"-- I.E. survival "bang" per mutational step "buck."
Given a constant random sweep of a composite probability map, the target with the highest SAI (composite probabilty) always wins over the long haul.
Survival(reproductive) advantage PER/complexity(improbability) = SAI
or
SA/c = SAI
The SA (Survival Advantage) component represents the NS part of RM&NS whereas “c” (complexity) quantifies the probability of any given mechanism's selection by chance mutation -- the RM part of RM&NS.
What (SA/c) says, is that "If a given survival mechanism SM is both highly advantageous and highly probable (simple) then it has a very high SAI and it is bound (by mathematical probability) to appear more often than mechanisms that are lower in SA or more complex (more improbable)."
The kinds of counter-arguments that I am looking for therefore are those that impact upon the (SA/c) ratio.
For instance, if it turns out that anti-predator chemicals are for some reason difficult for DNA to produce then this would negatively affect Slap's SA/c ratio. This is because the complexity of a Slap mechanism would have to increase in order for it to reach those hard-to-get-at predator-repellent chemicals.
If it turns out that anti-predator chemicals for some reason *always* damage the survival or reproductive success of the prey then this would also negatively affect SLAp's SA/c ratio and subsequent SAI.
Without better evidence or information, I remain convinced of the enormous composite power of Slap type mechanisms. I know of no other Darwinian mechanism powerful enough to cause rabbits (or any species) to suddenly appear in the fossil record. I know of no other DE mechanism powerful enough to conceivable get all of your predators off your back in a single mutational step (thereby moving your species from zero or negative growth to maximum growth). Given my present information Slap mechanisms still seem to be the most powerful and probable Darwinian mechanisms in existence. I also see no reason why these concepts cannot be empiricaly tested.
I encourage anyone and everyone to submit a more powerful "bang per (mutational step) buck" Darwinian mechanism than Slap.
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Argon
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posted 12. January 2003 03:12
William Brookfield writes: [...]
quote:
Can you help me out a bit here? How does the fox circumvent rabbits sudden distastefulness without de-selecting rabbits? Could you (or anyone out there) provide an alternate 'solution' that would keep distastefulness so suppressed in these cases?
Foxes also experience mutation and selection. A fox which can eat the rabbits that other foxes cannot "wins" too. Basically, why would one expect that detoxification mechanisms are more difficult to acquire than those which produce "unpalatability"? Most organisms can field a quite broad and generic range of detoxification enzymes. Our livers are quite amazing in this regard. In fact, one of the roles of the liver is to detoxify many of the substances in our food that would otherwise be poisonous.
Then again, perhaps there are responses to other varying and more powerful pressures such as disease (viruses, bacteria and other parasites), changes in the local ecology, or even sexual selection that drive other mutations to dominance at the expense of "unpalatability". Population genetics and ecology textbooks are a good place to start reading about the complexity of selection on populations.
[...]
quote:
Given my present information Slap mechanisms still seem to be the most powerful and probable Darwinian mechanisms in existence. I also see no reason why these concepts cannot be empiricaly tested.
Perhaps they have been tested. Remember, just because an organism may have been intelligently designed does not mean that mutation and selection do not act on it. Rabbits and a large proportion of other prey organisms are still tasty despite perhaps hundreds of thousands of years of continued predation. This suggests that the SLap model is probably not adequate for predicting the relative frequency of "unpalatable" organisms. Either the actual likelihood of acquiring reliable repellent defenses is less than expected or the average strength of such mutations is not all that great in many cases. Perhaps "distastefulness" really isn't the most probable defense mechanism.
You suggest that SLap gives organisms the most 'survival "bang" per mutational step "buck."' Perhaps so. But I'd hope to see the biochemical evidence for that assertion because looking at current organisms such as rabbits and others that have been around long enough for such mechanisms to arise, that doesn't appear to be the case.
I know from working with bacteria that SLap type mutations (i.e. single mutations that drastically alter the 'survivability' of the bacterium in a particular medium) tend to only have a temporary and limited advantages before other mutations sweep through. See papers by Richard Lenski for examples of population dynamics in bacterial chemostats. That is; small, simple changes often have small, simple and short-term effects.
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yersinia
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Member # 324
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posted 12. January 2003 06:07
For the record, this is a very silly thread.*
However,
quote:
I encourage anyone and everyone to submit a more powerful "bang per (mutational step) buck" Darwinian mechanism than Slap.
Imitating the external appearence of another distasteful species, but cheaping out on producing the chemical yourself.
Producing a few million tiny offspring might also work.
* What is silly about this thread is the large number of reckless generalizations being made about what the "best adaptation" would be for biology in general, and then while admitting that while this particular adaptation is very common, it isn't "common enough". All without a smidgen of investigation to see if any biologists might have had a thought or two about how organisms in different ecological situations might adapt differently, or how the coevolution of predator and prey (an "arms race") might change one's expectations for what "should be" observed.
A brief check of PubMed reveals that there are rather a lot of articles on the topic of herb-herbivore arms races.
Just to emphasize that the situation *is* complex and that the kind of oversimplification proposed in this thread really is preposterous, check out this article:
quote:
Proc R Soc Lond B Biol Sci 2002 Jun 22;269(1497):1241-6
The evolution of tolerance to deer herbivory: modifications caused by the abundance of insect herbivores.
Stinchcombe JR, Rausher MD.
Ecology, Evolution and Organismal Biology Group, Biology Department, Duke University, Durham, NC 27708, USA. john_stinchcombe@brown.edu
Although recent evidence indicates that coevolutionary interactions between species often vary on a biogeographical scale, little consideration has been given to the processes responsible for producing this pattern. One potential explanation is that changes in the community composition alter the coevolutionary interactions between species, but little evidence exists regarding the occurrence of such changes. Here we present evidence that the pattern of natural selection on plant defence traits, and the probable response to that selection, are critically dependent on the composition of the biotic community. The evolutionary trajectory of defence traits against mammalian herbivory in the Ivyleaf morning glory (Ipomoea hederacea), and which defence traits are likely to respond to selection, are both dependent on the presence or absence of insect herbivores. These results indicate that variation in community composition may be a driving force in generating geographical mosaics.
link to this article and 97 related articles
[ 12. January 2003, 06:13: Message edited by: yersinia ]
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Irving
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Member # 535
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posted 12. January 2003 11:14
quote:
quote:
I encourage anyone and everyone to submit a more powerful "bang per (mutational step) buck" Darwinian mechanism than Slap.
Imitating the external appearence of another distasteful species, but cheaping out on producing the chemical yourself.
I would think mimicry has a much lower SAI that SLAp.
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Argon
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Member # 276
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posted 12. January 2003 11:49
Yersinia writes:
quote:
* What is silly about this thread is the large number of reckless generalizations being made about what the "best adaptation" would be for biology in general, and then while admitting that while this particular adaptation is very common, it isn't "common enough".(...)
Bingo.
Irving writes: "I would think mimicry has a much lower SAI that SLAp."
Perhaps. But try evaluating it in sufficient biochemical detail in a representative sampling of species so that a true determination can be made. That's going to be tough.
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Noel Rude
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posted 12. January 2003 12:31
Argon: quote:
Most people -- evolutionists and ID-ists alike -- accept that selection can increase information. William Dembski has discussed this in his writings and even provided an extremely rough estimate of how much he thinks a selective event can contribute.
Don't know what others have said, but please count me an unreformed skeptic. I do not believe for an instant that natural selection can add an iota of specified complexity. You cannot select for what is not already there. Water is designed to run into crevices and cracks and fill nooks and crannies precisely, but when it does I doubt that any more information has been added to the water -- to a mind observing it maybe -- but not to the water.
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Frances
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Member # 169
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posted 12. January 2003 13:07
Noel
quote:
Don't know what others have said, but please count me an unreformed skeptic. I do not believe for an instant that natural selection can add an iota of specified complexity. You cannot select for what is not already there.
An interesting strawman. I hope that Noel realizes that the theory has two components? Variation and selection? Variation has a variety of sources
There are some very good examples that show how these mechanisms can indeed increase complexity/information to the the genome.
Yersina, I agree that this is somewhat of a silly thread. I feel that someone is gathering Loki points at my expense.
[ 12. January 2003, 15:46: Message edited by: Frances ]
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Irving
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posted 12. January 2003 14:14
Argon, Yersinia
quote:
Yersinia writes:
quote:* What is silly about this thread is the large number of reckless generalizations being made about what the "best adaptation" would be for biology in general, and then while admitting that while this particular adaptation is very common, it isn't "common enough".(...)
Argon Writes: Bingo.
Irving writes: "I would think mimicry has a much lower SAI that SLAp."
Perhaps. But try evaluating it in sufficient biochemical detail in a representative sampling of species so that a true determination can be made. That's going to be tough.
Okay, maybe I'm way off here...What's the purpose of Brainstorms? In the continuim between rank speculation and fully funded & staffed research program, where does this forum participate?
[ 12. January 2003, 14:16: Message edited by: Irving ]
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Noel Rude
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posted 12. January 2003 15:34
Francis: quote:
An interesting strawman. I hope that Noel realizes that the theory has two components? Variation and selection?
I'm still a skeptic. Natural selection only suggests how a variation might spread through a population -- it says nothing about how the variation ("new information" in linguistic jargon) got there in the first place.
The materialist, of course, will argue that it is not just fortuna but the incremental, cumulative effects of selection that give rise to specified complexity. But I am a skeptic. Natural selection may be a good conservative mechanism, but absent hard evidence I'm not ready to concede that it has any power to add specified complexity.
[ 12. January 2003, 16:51: Message edited by: Noel Rude ]
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Argon
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posted 12. January 2003 20:40
Irving writes: [...]
"Okay, maybe I'm way off here...What's the purpose of Brainstorms? In the continuim between rank speculation and fully funded & staffed research program (Note 1, Argon) , where does this forum participate?"
There are some exceptions but for the most part, I believe it operates way too often in the 'rank speculation' zone. That wouldn't be so bad if it were rank *informed* speculation of the type that you'd find in the presence of beer and a smallish group of working scientists or serious amateurs ('amateurs' in the British sense of the word) with some familiarity of the field. But I think it would help greatly if participants would do some homework beforehand (2). Or at least say something like, "Yeah, maybe there are some problems with that idea of mine. Let me take some time off, do some reading, and tinker some more with the concept." That's what I try to do when I bounce ideas around.
I recognize that nothing halts the development of an idea into an experimental plan faster than over-analysis and second-guessing. Given enough time, one can always think of many more reasons why a proposal will not work than why it will. And that sort of pessimism can kill an otherwise worthwhile research project. But you've got to have some balance or else you will spend almost all your time on the poorer ideas.
To William Brookfield, I'd say: "Nice first effort! Now hit those books and keep plugging away. And it won't hurt to sit in on a few biology classes at a local college to get some good feedback on your ideas."
Anyway, I'm off for probably quite a while. Have fun and thanks a lot for the discussions.
Notes:
(1) Fully funded and staffed research programs don't exist. Anywhere. I think that is Dilbert's First Law of R&D.
(2) I have developed a very rough way of predicting which threads are most likely to have soundly developed topics. That is, for any particular thread, sum the number of replies from Mike Gene and Francis. Add a few more points for working engineers and biologists participating. And also add up the number of journal references. Subtract points for URL references. Subtract points for replies less than twenty-five lines. That seems to provide a rough index for reasonable scientific content.
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