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Author Topic: Why doesn't ecological instability rapidly wipe out lots of important species?  (Read 11853 times)

Offline Martin J Sallberg

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While simple computer simulations appeared to support the Gaia hypothesis (self-stabilizing ecosystems), adding more complexity to the simulations did not support the theory at all. But scaling up to the even greater complexity of real life, that instability should lead to wiping out of lots of species all the time. Just like if every species in existence was recently arrived and invasive. This shows that evolution must be driven by something that cannot be explained by maximization of the amount of offspring.

But what is it? I have read about even amoebas and slime molds learning from their mistakes. Can that be the solution to the problem?
« Last Edit: 13/05/2013 16:47:26 by chris »


 

Offline JimBob

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please define "Quickly"  days years meillenia??
 

Offline JimBob

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This  is a math question, not a question on evolutionary science.
 

Offline damocles

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This is a widely recognised problem with computer simulations. If you attempt to make a computer simulation more complex, eventually you will come to a point where chaos will reign. This does not mean that chaos will reign in the real system -- rather it points to a problem with the stability of modelling as you try to incorporate more complexity into the model. It is essentially a matter of tractability.

A case in point is with the modelling of photochemical smog. Unfortunately I no longer can find a reference to it, but there was an article that reported an attempt to simulate a "smog box" experiment with about 200 chemical processes taken into account. The authors found that the concentration of one species that they input was not matching the concentration they had used at short times. Further investigation showed that a radical explosion was occurring in the first few seconds. This does not mean that smoggy air is likely to explode, but rather that their attempt to simulate its behaviour had become critically unstable.
 

Offline CliffordK

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No doubt there have been many hard learned lessons in nature.  Any organism that eats all of its food will DIE.

One thing I have wondered is why few plants are good at absorbing Nitrogen from the air.  Yet, perhaps absorbing too much nitrogen could seriously destabilize the whole planet. 

It is quite possible that there are many planets like Earth scattered around the Universe.  One might say that Earth succeeded to the point that humans evolved.  But, many planets might have failed, and human-like organisms would never have had a chance to evolve.
 

Offline damocles

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from CliffordK:
Quote
One thing I have wondered is why few plants are good at absorbing Nitrogen from the air.  Yet, perhaps absorbing too much nitrogen could seriously destabilize the whole planet.

There is a much simpler reason -- no energy is available for the process! Any plant that wants to convert atmospheric nitrogen into protein is facing an uphill battle on an energy scale for little return. Therefore it is only in a very few cases that plants have entered symbiotic arrangements with micro÷rganisms where the plant provides the energy while the micro÷rganism provides the protein.

The best known of these symbiotic arrangements involves micro÷rganisms that live in nodules on the roots of legumes. Grain protein contains few residues of arginine or lysine, while pulse protein (peas, beans, & lentils) contains these residues in abundance, and the plants even make a bit of cyanide (which should be soaked off before use).
« Last Edit: 28/04/2013 22:57:55 by damocles »
 

Offline damocles

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This question is one perplexing current research. A good (but heavy) review can be found at
http://www.santafe.edu/media/workingpapers/04-07-021.pdf
 

Offline yor_on

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Yes, that sounds plausible Martin. Life needs being adaptive, and that should counteract chaos. But it must also be a question of the timescale something has to adapt on. As JimBob pointed out, nature uses millenia, and centuries, but decades I don't really expect to be enough for this adaptability, and then years? We have spores driven by the winds, held inside clouds, and inside birds stomachs. So there is all sorts of mechanisms for transporting them though? I think we will find out, at some time in the future, if it was.
 

Offline CliffordK

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Of course, Humans may be the exception to the rule.
Eventually eating all the food on the planet till we starve.
And, using all the resources till there is nothing left.
And, of course, the only species that can do this on land, in the oceans, and from the arctic to the equator.
 

Offline Martin J Sallberg

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By "wiping out lots of important species quickly" I mean at the same timescales as implanted cats on islands wiped out small burrowing flightless birds there. And the kind of adaptation I am referring to is qualitatively different from anything that selfish gene-style reproductive success evolution can possibly produce. Life must learn to stop overproducing offspring before stocks terminally collapse. So I am really talking about learning from mistakes, learning in the sense of active self-change, and not differential reproductive success style change over generations. Even amoebas have been shown to learn from their mistakes, and any form of associative learning inevitably produces foresight (if you associate something with something else, you of course anticipate one when the other is present).
 

Offline yor_on

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You are going out from a human preconception there, based on what we refer to as IQ :)

Earth doesn't use IQ, instead it use just what you refer to as 'over population, and that is imprinted in all genes existing. Why else would people feel so 'attacked' when suggesting we could limit our population on a voluntary basis? we blame that on all sorts of things but deep down I expect it to be a genetic imperative.

Earth does not see us as the 'kings and queens' of this planet, and do not deem us as 'irreplaceables' either. She use another time scale than humans, and have still time left to try some other way.
 

Offline Martin J Sallberg

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You are going out from a human preconception there, based on what we refer to as IQ :)

Earth doesn't use IQ, instead it use just what you refer to as 'over population, and that is imprinted in all genes existing. Why else would people feel so 'attacked' when suggesting we could limit our population on a voluntary basis? we blame that on all sorts of things but deep down I expect it to be a genetic imperative.

Earth does not see us as the 'kings and queens' of this planet, and do not deem us as 'irreplaceables' either. She use another time scale than humans, and have still time left to try some other way.

I was not talking about IQ tests. I was talking about the fact that all associative learning inevitably creates some form of foresight, and that learning from mistakes have even been documented in amoebas.

If life was driven by selfish genes, we would all be dead from intergenomic conflict between cellular nuclei and mitochondria. Cellular nuclei and mitochondria are not closely related, so why are there no intergenomic conflict between them within our cells?

Simple unmotivated bans always create resistance. Population management is by no means unique in that regard. See my thread "Poisonous justification" under "Medicine".

And the whole main point of what I was saying is that the destroyers (be it humans or whatever) not only wipe themselves out, they also wipe others out, and that includes a great risk of wiping out many ecosystemically important key species. And I never claimed that there was any unified "mind of Nature", i do not even believe in such a thing. What I claimed was (and is) that living organisms learn from their mistakes in a way qualitatively different from anything achievable by "selfish genes" and that just such learning from mistakes plays an important role in decreasing the frequency of serious ecological collapses. I never even claimed or thought that it was infallable. It obviously is not. But if it did not exist at all, the frequency of mass extinction events would have been impossibly high and no life would have been able to survive.
 

Offline yor_on

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I think one have to differ life from Nature. Life is based on surviving, but Earth itself is just a platform for it. Life will adapt, if we in it contain all living organisms, oxygen based or otherwise. I think Earth adapt to what circumstances defining it, but it does not put any special value to any of its life forms, including fauna. so yeah, I should really stop referring to Earth as 'she' :)

One might want to think of life as a 'competition for survival', not by the fittest, but by the most adaptive. And there we're one of those species that know pretty well how to adapt. The problem is that instead of adapting we've made the last two three centuries more into some sort of terraforming, not planned either, as I see it. It's just a result of personal greed and the idea of infinite resources. And we're receiving the pay back, starting about now. I don't expect genes to change by such though, that would demand some sort of reasoning and logic I don't expect them to have. Although I think that we, as conscious logic humans, can change our ways, that is if we want too? And no genetic imperatives can stop it, if there is will or need, enough.

That's what I mean by IQ.
 

Offline yor_on

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And life is also a chaotic expression to me, open ended reacting to inputs, species growing and declining depending on other species, and all sorts of things really, like access to water,  the climate and local weather, humans moving in terraforming landscapes for their use, etc. Tricky thing humans :)

It's all non linear, to me at last. And the way it balance up is dynamically, although you can find more static balances too, as on some isolated island. Genes want to live one might say :) So they make sure we reproduce.
=

Hmm? Are you discussing http://en.wikipedia.org/wiki/The_Selfish_Gene ?
Don't know if it is 'selfish' to want to live? If it is, sure, all genes are selfish. But that I would call a archetype, human made. Genes have a way of finding new adaptions though, and there what climate Earth has will play a role for what adaption that works. It's give and take sort of, as I see it. But I think it's not as fast as a human time scale, today that is. We think in decades I would say, practically seen, although I suspect we would like to think that we're planning for centuries :) Or millenniums.
=

But it depends, think there are two competing ideas there. One that speaks of sudden genetic diversification, adapting 'on a whim' sort of, using some studies, relative the the slower definition of evolution we have historically. Maybe both can exist side by side?
« Last Edit: 29/04/2013 21:06:00 by yor_on »
 

Offline Martin J Sallberg

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Granted, an *isolated* DNA molecule cannot think. However, DNA molecules in living beings (as opposed to in some laboratories) are not isolated. They are integrated parts of organisms. There are lots of enzymes involved in processing DNA. This means that DNA is not protected from change caused by learning from mistakes. Life is not made up of one chief molecule and its servants at all. It is an interconnected thing. The whole division into "intrinsic value" and "instrumental value" is a purely cultural construct.
 

Offline yor_on

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Yes, that's true, saw a piece some time ago writing about 'intelligent microbes'? I think it was? Accentuating your way of reasoning there. It depends on what you find to be a 'intelligent behavior'. But to me all those are effects of evolution, not individually made choices. If we define a mistake as something detrimental to living, then all genes learn from their mistakes. Because the ones not surviving shouldn't be there to reproduce, alternatively only exist in a dormant position, just for that possible need. It's a little like war stories, the only stories you ever will hear is from those surviving, and their story's has to be biased :) just due to their surviving it.
 

Offline yor_on

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Sorry, it was bacterias.
http://www.thenakedscientists.com/forum/index.php?topic=39253.0

still, same type of reasoning. You could also state that 'life' itself seems intelligent, from such a reasoning, and to draw it a step further, assume that if it all is a pattern evolving in time, then state that the pattern indeed shows a 'intelligence'. But intelligence is in fact our definition, proudly social as well as hopefully logical, with evolution being the one more appropriate for life, as it seems to me?
 

Offline CliffordK

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One thing that occurs is that many plants and animals have a narrow niche where they can survive.  And there is always something to fill in any niche that is opened up. 

So, consider the koala.  If it ate all of the eucalyptus plants, it would not just move onto another food source, it would die off until the plants recovered. 

Yet, if you tried to feed a polar bear the same eucalyptus plants, it would starve.  And, of course, various plants are adapted to different environments.

Humans are perhaps the biggest exception to the rule.  We live EVERYWHERE.  And, if a certain crop doesn't suit us, we tear it out and plant what we like better.
 

Offline Martin J Sallberg

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There is evidence that microbes have changed their behavior in response to individual experience, as well as flexible problem solving. and once again, assuming that a hardwired reproduction maximizer was even possible, it would have had time to terminally kill its food stocks off BEFORE starving to death itself. And if all life was that way, all ecosystems would have collapsed into total mass extinction in a very short period of time.
 

Offline yor_on

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Martin, you're making me curious. Can you link your evidence so I can see what you're talking about?
 

Offline Martin J Sallberg

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Martin, you're making me curious. Can you link your evidence so I can see what you're talking about?

Yes, there is "Amoebas Anticipate Climate Change" (on Physics News Update's archive), showing that something that can functionally only be described as learning to predict the future, actually "evolved" in a single generation, without cell divisions. Sorry I could not find an URL link, but it is googleable.
 

Offline damocles

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Facts:
(1) Models that attempt to simulate real ecosystems are unstable.
(2) 2-dimensional models (predator/prey) are quite stable and account well for observations.

Possible explanations:
(1) Additional factors are operating in the real systems (like the one that the OP suggested).
(2) Something is going wrong with the modelling when the number of dimensions is increased.

Against  explanation (1): it would appear to involve new science that would not be comfortable fitting into the body of existing knowledge.
In favour of explanation (2): although there is an implication of instability and chaos, there remains the possibility of the system finding a steady state:

https://en.wikipedia.org/wiki/Attractor

Similar things -- models of systems that are stable in a few dimensions becoming unstable when the number of dimensions is increased -- are found and recognised in other areas of science.
 

Offline Martin J Sallberg

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The fact that introduced species often do seriously upset ecosystems in ways that causes extinctions proves that "flaws in the computer simulations" are not an adequate explanation. And if the theory of flawed computer simulations is taken seriously, it is the same as supporting the Gaia hypothesis, and are you really willing to do that? I doubt so. Furthermore, the whole gene-centered theory of how life behaves predicts that there should be "intergenomic conflict" between the cellular nuclei and the mitochondria in our cells, and a three-side standoff with chloroplasts in plant cells (cellular nuclei, mitochondria and chloroplasts all have their own genomes and are not closely related at all). So why are there no such conflicts?
 

Offline yor_on

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Stupid of me. Don't know why I forgot that one Damocles? You're perfectly right, and that one needs to be included, although it somehow makes us (life) out as a expression of some possible constants, aka Feigenbaum. at least when it comes to population pressures. But I think there exist some formulas for describing it from chaos? Think I read about some Australian example, or if it was New Zealand? In where they had some population disappearing, and what was possible to do about it, or not possible would probably be the correcter, ahem, definition.

As for "the fact that introduced species often do seriously upset ecosystems in ways that causes extinctions proves that "flaws in the computer simulations" are not an adequate explanation." Martin. I would say that if you define it from chaos mathematics you will get effects not easily foreseen, but still explainable from it.
« Last Edit: 02/05/2013 19:05:02 by yor_on »
 

Offline yor_on

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But I will also need to look your link up Martin :)
And hopefully see what you're thinking of there.
 

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