Randomness in Evolution: Valid and Invalid Usage

[jimbob]

And saying that chance wasn't involved, also misses a significant part of the story, especially as the odds of an individual cod fry reproducing are of the order of 500,000:1 against.

Uh no. Chance is just a way of describing your ignorance over which cod fry will survive but expressing your knowledge about how many are likely to be killed.

If all the predators were, for example, devastated by some disease your chance reproduction figures would become quite meaningless because they are not based on some fundamental property of the cod nor of the universe but on the avergage properties of the environment the cod find themselves in.

Uh no. Chance is just a way of describing your ignorance over which cod fry will survive but expressing your knowledge about how many are likely to be killed.

It is not just ignorance, but because of the influence of random events. The future history of an individual cod fry hasn't been determined at its hatching, because it will be affected by future random events:

An event is not a circumstance. An event is what arises from circumstances.

Once the event has occurred how it occured it irrelevant to its effects. I do not understand why you cannot understand this.

cyborg, read literally you're saying something totally empty - "if the events are the same, the events are the same". I think jimbob was trying to give you the benefit of the doubt and assume your statement wasn't tautological.

The issue at stake here is whether, given identical initial conditions, the outcome is the same. The answer is no - in standard interpretations of QM, at least. However this is indeed a red herring, since it is physically impossible to ever know whether the initial conditions are identical, and even in classical physics chaos means the uncertainties will grow exponentially, rendering some outcomes totally unpredictable even in principle.

ETA: If you were psychic, then that would be a different case.

 

[cyborg]

It is not just ignorance, but because of the influence of random events. The future history of an individual cod fry hasn't been determined at its hatching, because it will be affected by future random events:

So, to reiterate my previous statement:

if the QM argument is solid then I fail to see why it should be possible for me to give the label "deterministic" to any phenomena in this reality.

If your argument is "evolution is random because the cod fry's survival is at the whim of quantum mechanics," that is.

Which I find slightly preposterious - for some mad reason I kinda think it might be more helpful to consider the qualities of the environment such as the water, the existence of predators the raw materials availble for the biology of the fish and so forth. Not how any particular electron is going to behave.

ETA: Perhaps you'd like to demonstrate the relationship of the survival ratio of cod fry to an aspect of quantum determinance to bolster your case for its relevance?

 

[jimbob]

Did you see the comment about the difference between "weather" and "climate"?

Organisms will evolve in response to the climate, but individual selection events would be influenced by weather

 

[jimbob]

I'll ask this again:

Cyborg, how is your approach remotely useful?

It misrepresents how evolution works.

Of course you can creatte fundamentally incorrect models that explain evolutionary history (they are called stories and are popular on bad nature "documentaries"), just as pre-Copernican models described the movement of the planets. It desn't make it right, or any more useful than a simpler, accurate description.

 

[sol invictus]

If it sounds like a tautology then so be it but if the QM argument is solid then I fail to see why it should be possible for me to give the label "deterministic" to any phenomena in this reality.

But that is correct, of course. Classical determinism went out the window completely at the beginning of the 20th century.

Near the end of the 20th century, with the discovery of chaos, our understanding underwent another shift. The correct point of view now - in my opinion, at least - is that classical determinism is never a meaningful concept when applied to real systems, even if you ignore quantum mechanics.

Determinism is possible only in extremely simple and totally unrealistic mathematical models, like the two-body problem in Newtonian gravity.

 

[cyborg]

So what, exactly, has this argument got to do with evolution - at all?

Not a damn thing apparently - which makes any and all arguments that have been posited with respect to biology fallacious.

 

[articulett]

So what, exactly, has this argument got to do with evolution - at all?

Not a damn thing apparently - which makes any and all arguments that have been posited with respect to biology fallacious.

As well as utterly worthless and tangential to the OP.

 

[mijopaalmc]

So what, exactly, has this argument got to do with evolution - at all?

Not a damn thing apparently - which makes any and all arguments that have been posited with respect to biology fallacious.

Possibly that you made this statement:

The issue is that irrespective of the physicality of the situation it is always possible to create a deterministic model.

Deterministic models are not always reliable in terms of predictability, which is incredibly important when you are trying to make statements about physical systems.

 

[jimbob]

Back to the OP.

Mutation: Random and haphazard.

Natural slection: Probabilistic (due to chaotic systems) but not haphazard. (The "game" is played with loaded dice).

Evolutionary Direction: Stable for long periods of time, but affected by random events. Probabaly chaotic.

 

[articulett]

Whatever Jim-Bob... that's the mealy mouthed way you always have been promoting... no one's biting because it doesn't really describe natural selection... As I mentioned before, we don't tell people in genetic counseling that their chance of having a child with a certain disorder is probabilistic... because that doesn't convey information. We tell them what the probabilities are. And those probabilities are DETERMINED by multiple factors. It's as garbled as saying Poker is a game where the cards are dealt randomly, but the game is played probabilistically. No person who actually wanted to convey information to anyone would actually say that... though someone needing to define evolution as "random" might.

If you want to be taking seriously by those who understand and convey the topic to others, you might try communicating in the ways such experts do. If you are just trying to convince yourself that scientists somewhere think evolution is "random" (because it's probabilistic or whatever) then continue to argue this inane mealy mouthed definition that nobody but you (and maybe T'ai, Behe, and Mijo) are using. Try to convey what natural selection is with that garbled definition.

When you are explaining a model or a concept, it's important to be clear, don't you think?
It's not like you are wrong... it's just that you aren't really convey information in your muddledness and yet you are so sure you are. Why is it that you imagine you have expertise on this subject? Does anyone with expertise think you are making sense?

 

[cyborg]

Natural slection: Probabilistic (due to chaotic systems) but not haphazard. (The "game" is played with loaded dice).

Oh, so QM has got **** all to do with determining the survival ratio of cod fry has it now?

 

[jimbob]

Whatever Jim-Bob... that's the mealy mouthed way you always have been promoting... no one's biting because it doesn't really describe natural selection... As I mentioned before, we don't tell people in genetic counseling that their chance of having a child with a certain disorder is probabilistic... because that doesn't convey information. We tell them what the probabilities are. And those probabilities are DETERMINED by multiple factors. It's as garbled as saying Poker is a game where the cards are dealt randomly, but the game is played probabilistically. No person who actually wanted to convey information to anyone would actually say that... though someone needing to define evolution as "random" might.

As I mentioned before, we don't tell people in genetic counseling that their chance of having a child with a certain disorder is probabilistic... because that doesn't convey information.

Nor do I when describing natural selection.

I have even described it how I would convey information when discussing genetic disorders

within the spoiler for brevity:

So then it's random as to whether two carriers of sickle trait have a child with sickle cell anemia? And it's random as to whether you get an A on a test? And it's random as to whether seat belts save lives? -- and what passes through a sieve is random. If you have a royal flush, your chances of winning are random. That's just a piss-poor non-descriptive vague use of random. If you want to convey how order comes from randomness you better quit describing random as "any model that requires probability"... or provide at least one peer reviewed paper that describes random in that way.

So then it's random as to whether two carriers of sickle trait have a child with sickle cell anemia?

Essentially, yes. As you know the odds are 50% per child (assuming no screening), so the odds depend on the number of children.

If the family has 1 child the odds are 50% (1/2)
If the family has 2 children the odds are 25% (1/2)^2
If the family has 3 children the odds are 12.5% (1/2)^3

That none of the children will have sickle cell anaemia.
and so on.

How would you describe the chances of having a child with sickel cell anaemia


If only one parent was a carrier, then the odds are vanishingly that any child would have sickle cell anaemia. (The advantages of sexual reproduction and avoidance of inbreeding).

And a later correction to my sums:

I have just realised that I had stated the odds for all children being carriers, but without the full sickle cell trait.

The odds of two carriers having all their children without full sickle cell are

3/4 for 1 child
9/16 for two
27/64 for three

Anyway, articulett, would you tell the parents that any child they had would have a 25% chance of having sickle cell? Then discuss the implications of this.

Have you read my posts where I describe the probabilities and describe the probability distribution? For a stable population it could be described by a poisson distribution with a lambda of 1 reproducing offspring per parent. This tells you the probabilities; it also tells you the probabilities if a trait confered an x% reproductive advantage or disadvantage.

If you want to be taking seriously by those who understand and convey the topic to others, you might try communicating in the ways such experts do. If you are just trying to convince yourself that scientists somewhere think evolution is "random" (because it's probabilistic or whatever) then continue to argue this inane mealy mouthed definition that nobody but you (and maybe T'ai, Behe, and Mijo) are using. Try to convey what natural selection is with that garbled definition.

When you are explaining a model or a concept, it's important to be clear, don't you think?
It's not like you are wrong... it's just that you aren't really convey information in your muddledness and yet you are so sure you are. Why is it that you imagine you have expertise on this subject? Does anyone with expertise think you are making sense?

Why am I not conveying information? Here is my "insincere" question again (it isn't insincere, so would you please tell me

1) Why the questions are wrong?
2) Why it is wrong to approach them probabilistically?
3) How to answer such a question without using a probabilistic approach?
4) How is this unclear, garbled or muddled for a numerate audience?

I prefer talking about traits, because if the selection pressures are for smaller individuals (e.g. on an island with a reduced population) individuals with this trait have the advantage, and it it doesn't matter what gene is different, as long as the end result is a smaller organism.

In this case about half the population of offspring would have a smaller mature size than their parents, and thus the selective advantages work for a larger number than ifo one is talking about a single mutation.

In the case of a single advantageous mutation arising initially in one individual; the best (only) way of assessing how likely this mutation is to spread through the population is to perform a probabilistic analysis. It would be more advanced than my simple versions, but it needen't be by much.

Articulett,

In a stable population, a single advantageous mutation provides a 10% selective advantage, and arises in a single (asexually reproducing) organism.

The average brood size for this type of organism is 10.

1) At the birth of this organism, what is the probability of the mutation spreading through the population?

2) The organism makes it through to breed,

a) What is the probability of the mutation spreading now?

b) What is the probaility of the mutation remaining for 5 generations?

3) The mutation is now in 1% of a large popluation, now what is likely to happen?

I think these are usefull types of questions, and ones that can be only answered probabilistically, how would you answer such questions?

 

[jimbob]

Oh, so QM has got **** all to do with determining the survival ratio of cod fry has it now?

I thought you were more numerate than that.

I contend that an organism's survival is determined by many interacting chaotic systems, the weather being the first one to spring to mind.

The fundamental properties of chaotic systems mean that over large enough timescales they are (to simplify) random. The fundamental reason is because of nonlinear magnification of quantum uncertainties, however even without QM, the system would still be unpredictible. With QM it is also random. Far enough into the future, the weather is random, but we can still talk about the climate.

 

[cyborg]

I thought you were more numerate than that.

I've seen a distinct lack of numbers here but a lot of extrapolation well beyond that which is justifiable.

 

[jimbob]

I've seen a distinct lack of numbers here but a lot of extrapolation well beyond that which is justifiable.

This seems to be pretty well accepted by the vast majority of physicists:

It is a digression dogression, but chaotic systems are hypersentistive tio initial conditions so that a classical treatment requires accuracy that doesnt actually exist.

Here is a discussion about a very simple system (from the Israel physical society)

You can apply this rule to snooker balls as well as molecules. One knows from bitter experience that snooker or pool exhibits sensitive dependence on initial conditions: a slight miscue of the cue-ball produces a big miss! If the balls are bouncing around a frictionless snooker table in a perfect vacuum (otherwise they will just stop moving after one or two collisions) then we might typically have d=1 metre and r=3 cm, so our map is q_n+1 = 3q_n. The growth in recoil angle uncertainty in the trajectory of a ball as it bounces off other balls is therefore pretty dramatic. In fact, if you hit the ball as accurately as Heisenberg's quantum Uncertainty Principle allows any physical process to be determined by observation, then only about 12 collisions are needed to amplify this uncertainty up to more than 90 degrees!

Twenty-four collisions ahead, and there are twelve sets of collisons where the accuracy required would be beyind the uncertainty principle.

Why is it wrong to describe the behaviour of the snooker ball that far ahead as random? Not just unpredictible, but random.

You would be wrong to describe the behaviour three collisions ahead as random, but twenty four, or thirteen collisions ahead?

This is a simple system but it does involve classical mechanics in a chaotic system, and thus for far-enough ahead is random.

Weather systems, which affect individual organisms is similarly a chaotic system, so I cant see why this behaviour far enough ahead isn't truely random.

Indeed I can't see why any choatic system, far enough ahead, isn't random.

It was a simple deterministic system, which after a few (12) iterations became "random".

Biology contains many more complex chaotic systems interacting, and it is a fundamental property of chaotic systems that after a certain time they require accuracy at the quantum level, which is random.

 

[cyborg]

Biology contains many more complex chaotic systems interacting, and it is a fundamental property of chaotic systems that after a certain time they require accuracy at the quantum level, which is random.

So like any true Physicist your imposition of irrelevant details onto another scientific theory is simply that "it relies on physics".

So biology is a Red Herring.

 

[articulett]

Last I checked billiard balls on hypothetical pool tables aren't passing their DNA into the future based on how well they meet the rigors of the present...

genomes get more refined and honed and "complex" over time... a little different then what happens to snicker balls when struck by a cue, eh?

Natural Selection Jim. It is the de-randomizer... it makes evolution very unlike your billiard ball example. It allows for iteration of information over time--the opposite of increasing randomness... actually "increasing" refinement and complexity and reproductive efficacy.

How does your example compare to evolution... particularly the OP? To whom would this be useful or explanatory? In what way? How does this relate to natural selection... remember "natural selection" is like artificial selection... but over a much longer period of time with the environment "selecting" the winners--not human preference.

 

[jimbob]

But articulett, real ecosystems are messy. Natural selection is not 100% effective, although it is pretty close when it comes to removing even slight disadvantages. It is messy because of the chaotic interactions, and this leads to an element of randomness in natural selection.

Cyborg might argue that natural selection is deterministic and that you could hypothetically show this if your model had enough information, but chaotic systems don't work like that.

You can see how this affects the mechanism of natural selection with some simple observations and reasoning:

in the below post (link here) I have been assuming that most of the offspring resemble their parents so that on average chance mutations are equally likely to improve the reproductive chances of any owlet, as reduce them.

In other words, natural selction is very effective at culling disadvantageous traits, but pretty inneffective at preserving any individual advantageous ones.

Do you agree that the following example is situation where the probabilistic nature of natural selection is usefull in highlighting more about the implications than pretending that chance has no part in natural selection?

I think a valid analogy might be between weather and climate. The individual slection event might be "random" but the efffect over a large enough population means that some beneficial traits will propagate.

Doing the sums, I would conclude that most "beneficial" traits that arise probably don't survive more than one generation.

This is because the odds are against any individual organism reproducing, for virtually any species (possibly except our own currently). For example, the Barn Owl population is roughly stable, but it tends to have a clutch sizes of about 3-7 and sometimes breed twice a year, and live for 1-5 years in the wild (25 years in captivity). Of the total brood size over the lifetime of the pair, on average only two offspring will breed if the population is stable.

Say this equates to 5 clutches, of 4 birds. Then there is 90% chance of any individual not breeding, and a 10% chance of it breeding. To get an evens chance of a particular trait making it past the first individual, it would need to confer a 500% advantage compared to its peers...

However we are dealing with big numbers, and some (enough) advantageous traits will survive and get passed on...

Disadvantageous traits are almost certain to vanish very quickly. In the barn owl example, a neutral trait already has a 90% chance of not getting passed on.​

Malthusian reasoning also leads us to the conclusion that similar situations will occur most of the time in nature.

 

[cyborg]

Yawn

You're talking as if you're providing any new information. You're just not getting what is being said and I'm getting tired of explaining myself.

 

[Belz...]

They don't need to. The article explains quite well how the moments of a quantum mechanical distribution converge to the moments of a classical distribution.

So... let me get this straight. You say:

Quantum randomness has an orderly classical (or semiclassical) limit.

Whatever that means. So I ask "does it ?", to which you answer with a link that doesn't even mention randomness, and now you say it still supports your point ?

Would you mind citing the relevant passage, as I've already asked you ? Or will you just keep claiming that it says what you want it to say ?