Randomness in Evolution: Valid and Invalid Usage

[jimbob]

According to wik: pluto's chaotic orbit means that it is unpredictible over tens of millions of years. Maybe some ateroids are in a chaotic NEO, then over 3.8 Gyr of life on earth their orbits would have been unpredictible, as the accuracy required for the initial measurements should be comfortably below the qunantum level.

Discussing weather systems, as they are faster than millions of years...


Even if we had measurements down to the quantum level, we would be limited as to how far into the future we could forcast the weather, because beyond this time, we would need more accurate measures. Beyond this timescale why isn't it random? (I am rusty with many aspects of physics, but was under the impression that it still was the case that beyond a certain time, events at the quantum level are significant). Tens of milllions of years for one chaotic orbit (pluto), but we are talking about a period of 3.8 billion years...

 

[cyborg]

Beyond this timescale why isn't it random?

Why isn't what? Why isn't anything?

You find nothing odd about the fact you are arguing about the orbital path of Pluto in a discussion about evolution? Just how much don't you want to admit to yourself that you're completely lost on irrelevancies?

 

[Reality Check]

According to wik: pluto's chaotic orbit means that it is unpredictible over tens of millions of years. Maybe some ateroids are in a chaotic NEO, then over 3.8 Gyr of life on earth their orbits would have been unpredictible, as the accuracy required for the initial measurements should be comfortably below the qunantum level.

Discussing weather systems, as they are faster than millions of years...

Even if we had measurements down to the quantum level, we would be limited as to how far into the future we could forcast the weather, because beyond this time, we would need more accurate measures. Beyond this timescale why isn't it random? (I am rusty with many aspects of physics, but was under the impression that it still was the case that beyond a certain time, events at the quantum level are significant). Tens of milllions of years for one chaotic orbit (pluto), but we are talking about a period of 3.8 billion years...

Note that the chaotic behaviour of orbits are solutions of Newtonian mechanics, i.e. have nothing to do with quantum mechanics.

Quantum effects do not affect the weather. Weather forecasters just need to include classical mechanics.

Quantum effects are subject to quantum decoherence (the interaction of the quantum system with its environment). This quickly turns quantum effects into classical effects. Quantum computing needs the decoherence to be as small as possible and research is ongoing on methods to do this. But this does not happen in nature.

We can see quantum effects in molecules such as bucky-balls (carbon-60) where a 2-slit experiment shows interference fringes. Anything much larger than this is a classical object exhibiting classical effects.

 

[articulett]

See, isn't it weird... --he's not interested in describing evolution clearly--he's interested in calling evolution "random".

 

[Reality Check]

What factors were important in the evoluiton of unicellular life into a T Rex? This needs an acceptance that random events have been important.

1. Variability in inheritance.
2. Natural selection.

This is of course evolution. There are some random events in the variability in inheritance. This is overwhelmed by the non-randomness of natural selection.

 

[mijopaalmc]

See, isn't it weird... --he's not interested in describing evolution clearly--he's interested in calling evolution "random".

The same could be said about describing evolution as non-random even though all of its component has the possibility of being random. Orderly adaptation to the environment does not imply that natural selection or evolution is non-random.

 

[cyborg]

The same could be said about describing X as non-random even though all of its component has the possibility of being random.

Please give an X where this does not apply in mijo world. You know, as you've been asked to do so repeatedly.

 

[articulett]

1. Variability in inheritance.
2. Natural selection.

This is of course evolution. There are some random events in the variability in inheritance. This is overwhelmed by the non-randomness of natural selection.

He and Mijo have been told as much for well over a year... and gotten the best quotes from peer reviewed experts on the topic. But they think they are smarter than the experts... and they absolutely must have the last word and the last word must be that "evolution is random" or if they are feeling generous "evolution is not nonrandom". It's bizarre, but unchangeable. They would rather believe that scientists think that evolution is random than to be clear.

And they will reward you with insults for your careful replies. They have no interest on current understanding on this topic... their only interest is proving themselves right in their head. If you engage them, keep all expectations low... and be prepared to find them maddeningly nonsensical.

 

[Earthborn]

Quantum effects do not affect the weather. Weather forecasters just need to include classical mechanics.

Weather forecasters just need to include classical mechanics to model the weather for up to few days into the future, but you may have noticed that Jimbob is talking about extremely long timeframes. Timeframes that are so long that they cannot be accurately modelled as they become chaotic. Smaller and smaller factors start to interfere with the results. In medium timeframes things like butterflies flapping their wings start would need to be considered if you want to make the model predict the weather to any degree of accuracy, which of course makes the model too complex to handle. In truly long timeframes, lets say trying to predict the weather for a specific day a million years in the future, taking all the butterflies into consideration will not be enough. Would quantum fluctuations need to be considered as well? I would think so.

 

[Earthborn]

I wanted to reiterate what articulett said: Those who write the most scientifically accepted books about evolution, tend not to describe evolution as random, at all.

Articulett also claims that by doing so, they are more effective at explaining evolutionary theory to people who have no prior understanding or belief in it. Perhaps this is true, but I have not heard an argument that convinces me that it is.

And, sometimes, they take great pains to show how it is not random. Dawkins' book The Blind Watchmaker is one, for example. Here is an excerpt from its preface:

I agree with Dawkins that it is a mistaken idea to conceptualise evolution as having "nothing other than random chance" and I also agree that Darwinism is not a theory of chance. I just don't think it is unfair to look at the entire history of the evolution of life and say that it has been influenced in many ways by random events, great and small.

It is perfectly possible to describe every aspect of Evolution with other words besides "random".

Perhaps, but I don't think "unconsciously indifferent" is it. "Probabilistic" or "stochastic" are probably better, but have the additional problem that the average layperson probably has no understanding of those words at all.

 

[Dancing David]

According to wik: pluto's chaotic orbit means that it is unpredictible over tens of millions of years.

That is a really long time, why does it matter? You can be accurate enough to send a probe there is a human life time. Causal and detrministics does not mean, set upon a rail track moving at a constant rate and speed.

So a system may not be predictable, a chaotic system is causal and deterministic, it is not random.

Oganisms and the genome can not predict the future. So what traits will have benefit in which future enviromenets is unknown, that does not mean that the process that leads to reproductive success is random. That means the setting and players are somewhat unpredictable.

Why is the ability to predict the future important? It is not what science means when it says predict the behavior of a system. In fact it is acceptable to say "It will fall within this area."

Predictability doesn't matter to reproductive success. It isn't going somewhere it is just going.

Maybe some ateroids are in a chaotic NEO, then over 3.8 Gyr of life on earth their orbits would have been unpredictible, as the accuracy required for the initial measurements should be comfortably below the qunantum level.

You really don't get it do you?

It has nothing to do with QM, the orbits are effected by gravitation, and that is a gross scale event.
It is causal, deterministic and chaotic (within limits), it is not random. Unpredictable does not mean random.

Discussing weather systems, as they are faster than millions of years...


Even if we had measurements down to the quantum level, we would be limited as to how far into the future we could forcast the weather, because beyond this time, we would need more accurate measures. Beyond this timescale why isn't it random?

Because it is deterministic, just because we can't accurately model the parameters does not sudenly *poofo* make it random.

It makes it beyond our ability to model.

Omniscence is for made up creatures beyond the real world.

(I am rusty with many aspects of physics, but was under the impression that it still was the case that beyond a certain time, events at the quantum level are significant).

Nope, that is just not tue, the radiation from the sun comes in photons, but the energy does not sudenly jump to the other side of the planet. The weather is a gross system, QM pertains to very small events.

Tens of milllions of years for one chaotic orbit (pluto), but we are talking about a period of 3.8 billion years...

So you have 50 significant gravitational forces, it only takes three bodies to make a chaotic system.

Chaotic systemsn are detrministic and causal they are not random.

 

[Reality Check]

Weather forecasters just need to include classical mechanics to model the weather for up to few days into the future, but you may have noticed that Jimbob is talking about extremely long timeframes. Timeframes that are so long that they cannot be accurately modelled as they become chaotic. Smaller and smaller factors start to interfere with the results. In medium timeframes things like butterflies flapping their wings start would need to be considered if you want to make the model predict the weather to any degree of accuracy, which of course makes the model too complex to handle. In truly long timeframes, lets say trying to predict the weather for a specific day a million years in the future, taking all the butterflies into consideration will not be enough. Would quantum fluctuations need to be considered as well? I would think so.

Actually no - the chaotic solutions come out of classical mechanics, not quantum mechanics. Just ask yourself whether geologists who often work on scales of 100's of millions of years have to consider quantum mechanics?

 

[Dancing David]

Weather forecasters just need to include classical mechanics to model the weather for up to few days into the future, but you may have noticed that Jimbob is talking about extremely long timeframes. Timeframes that are so long that they cannot be accurately modelled as they become chaotic. Smaller and smaller factors start to interfere with the results. In medium timeframes things like butterflies flapping their wings start would need to be considered if you want to make the model predict the weather to any degree of accuracy, which of course makes the model too complex to handle. In truly long timeframes, lets say trying to predict the weather for a specific day a million years in the future, taking all the butterflies into consideration will not be enough. Would quantum fluctuations need to be considered as well? I would think so.

I don't know EB, those things might matter but when the huge amount of energy from the sun hits the soild ground, plants or ocean and creates updrafts or evaporation, then the flap of a butterfly, will just sort of not matter.

There is no mathematical proof of the butterfly effect. It is an allusion. ( I love butterflies, but I see them sail in the wind. It is what they do. They don't make the wind. Not even if you got them all together, then you would have a brownian motion thing.
(I love watching butterflys stall glide, especialy the monarchs in the fall when they rise up way high in the sky.)

 

[Dancing David]

I just don't think it is unfair to look at the entire history of the evolution of life and say that it has been influenced in many ways by random events, great and small.

Yes, the history of evolution. That is not the same as the process of evolution, the fall of a mountain is the history of gravity. It is not the process we call gravity?

 

[quixotecoyote]

Yes, the history of evolution. That is not the same as the process of evolution, the fall of a mountain is the history of gravity. It is not the process we call gravity?

That would be more plate tectonics/vulcanology than gravity. Analogy fails.

 

[Wowbagger]

Perhaps, but I don't think "unconsciously indifferent" is it. "Probabilistic" or "stochastic" are probably better, but have the additional problem that the average layperson probably has no understanding of those words at all.

How about "directionless"? I think someone suggested that substitute, at some point.

 

[jimbob]

It is a 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.

 

[mijopaalmc]

jimbob-

If I may be so bold to speculate, I seems that the most common response to your questions about chaos and randomness would be "your description makes everything random". While that is not necessarily my opinion, I would like to point out that your focus on the divergence in chaotic system obscure an important characteristic of evolution and of random system, namely their convergence to optima over long periods of time. I am not saying that chaotic systems cannot describe evolution, but it is not at all clear how the phenomenology of evolution emerges from your descriptions of chaotic systems

 

[Reality Check]

It is a 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)
...snip...
Indeed I can't see why any choatic system, far enough ahead, isn't random.

Look further on in the article that you cite:

Chaotic systems can have stable, predictable, long-term, average behaviours. However, it is often very difficult to predict when they will. You usually just have to explore and discover whether they do or not.

I suggest that you read the Wikipedia article on chaos theory:

Chaotic behavior has been observed in the laboratory in a variety of systems including electrical circuits, lasers, oscillating chemical reactions, fluid dynamics, and mechanical and magneto-mechanical devices. Observations of chaotic behaviour in nature include the dynamics of satellites in the solar system, the time evolution of the magnetic field of celestial bodies, population growth in ecology, the dynamics of the action potentials in neurons, and molecular vibrations. Everyday examples of chaotic systems include weather and climate. There is some controversy over the existence of chaotic dynamics in the plate tectonics and in economics.

Systems that exhibit mathematical chaos are deterministic and thus orderly in some sense; this technical use of the word chaos is at odds with common parlance, which suggests complete disorder. A related field of physics called quantum chaos theory studies systems that follow the laws of quantum mechanics. Recently, another field, called relativistic chaos, has emerged to describe systems that follow the laws of general relativity.

As well as being orderly in the sense of being deterministic, chaotic systems usually have well defined statistics. For example, the Lorenz system pictured is chaotic, but has a clearly defined structure. Bounded chaos is a useful term for describing models of disorder.

 

[sol invictus]

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

First of all, you are correct that quantum fluctuations can have large effects on chaotic systems. ANY fluctuation, no matter how small, can have a large effect on a chaotic system - that's by definition of chaos. So forget about QM, it's irrelevant - chaotic systems are fundamentally unpredictable, and it is pointless to differentiate between "true randomness" and unpredictability (except as an intellectual exercise). The distinction has no operational meaning.

I introduced these ideas weeks (months?) ago into these threads. My point was that since the world is quantum and chaotic, and since all systems in the world are coupled, everything is random and unpredictable if your definition of those terms is too rigid (like mijo's before we changed his mind). But even though the earth may be destroyed by a giant asteroid tomorrow, we still (correctly) regard many things in our lives as predictable.

Weather is chaotic, but it's always warmer in summer than winter. Evolution took place in a chaotic environment, but it predictably lead from prokaryotes to more complex and diverse life. Flames are chaotic, but they always burn you. Smoke detectors rely directly on random decays, but they are very reliable.