Randomness in Evolution: Valid and Invalid Usage

[sol invictus]

Yes or no, mijo?

 

[sol invictus]

If nothing else, I appreciate the delicious irony, sol.

Yeah - it really doesn't get much better than that...

 

[zosima]

Yeah - it really doesn't get much better than that...

This thread just exploded with funny today.

 

[Belz...]

Do you actually have any evidence of individuals of a certain group of phenotypes all surviving while all individuals of the other group of phenotypes don't?

Err... aren't you arguing for a strong bias in evolution, now ? Doesn't that kinda make it non-random ??

 

[Belz...]

Here's a geneticist, Jerry Coyne, discussing Behe's book--the ambiguity of "random"--the need to distinguish--and the fact that what we see in various species did not come about "randomly"...

On the basis of much evidence, scientists have concluded that mutations occur randomly. The term "random" here has a specific meaning that is often misunderstood, even by biologists. What we mean is that mutations occur irrespective of whether they would be useful to the organism. Mutations are simply errors in DNA replication. Most of them are harmful or neutral, but a few of them can turn out to be useful. And there is no known biological mechanism for jacking up the probability that a mutation will meet the current adaptive needs of the organism. Bears adapting to snowy terrain will not enjoy a higher probability of getting mutations producing lighter coats than will bears inhabiting non-snowy terrain.

What we do not mean by "random" is that all genes are equally likely to mutate (some are more mutable than others) or that all mutations are equally likely (some types of DNA change are more common than others). It is more accurate, then, to call mutations "indifferent" rather than "random": the chance of a mutation happening is indifferent to whether it would be helpful or harmful. Evolution by selection, then, is a combination of two steps: a "random" (or indifferent) step--mutation--that generates a panoply of genetic variants, both good and bad (in our example, a variety of new coat colors); and then a deterministic step--natural selection--that orders this variation, keeping the good and winnowing the bad (the retention of light-color genes at the expense of dark-color ones).

It is important to clarify these two steps because of the widespread misconception, promoted by creationists, that in evolution "everything happens by chance." Creationists equate the chance that evolution could produce a complex organism to the infinitesimal chance that a hurricane could sweep through a junkyard and randomly assemble the junk into a Boeing 747. But this analogy is specious. Evolution is manifestly not a chance process because of the order produced by natural selection--order that can, over vast periods of time, result in complex organisms looking as if they were designed to fit their environment. Humans, the product of non-random natural selection, are the biological equivalent of a 747, and in some ways they are even more complex. The explanation of seeming design by solely materialistic processes was Darwin's greatest achievement, and a major source of discomfort for those holding the view that nature was designed by God.

http://richarddawkins.net/article,12...e-New-Republic

Excellent link, Articulett. Bravo!

 

[Belz...]

Natural selection is arguably the most momentous idea ever to occur to a human mind, because it — alone as far as we know — explains the elegant illusion of design that pervades the living kingdoms and explains, in passing, us. [/I]

And the idea even explains the spread of all other forms of information, as we discussed in the Intelligent Evolution thread.

 

[Belz...]

False dichotomy. It's order operation arises from random processes.

 

[Dancing David]

But that doesn't mean that evolution by natural selection is not fundamentally random.

Random is some respects but contrained by enviroment and contingent history.

 

[mijopaalmc]

I don't see the problem with my saying that the fundamental operation of a process is random but its overall behavior is orderly. If this weren't the case, inferential statistics would be meaningless and you would have to poll a whole population to find out its demographic information. In essence, the description of a system as "random" or "non-random" depends on its micro-level behavior and not its macro-level behavior.

 

[Ichneumonwasp]

I don't see the problem with my saying that the fundamental operation of a process is random but its overall behavior is orderly. If this weren't the case, inferential statistics would be meaningless and you would have to poll a whole population to find out its demographic information. In essence, the description of a system as "random" or "non-random" depends on its micro-level behavior and not its macro-level behavior.

Then why don't you just say that a smoke detector is fundamentally random?

You do see the parallel/relationship with evolution do you not?

You do realize that you have just called Boyle's law fundamentally random?

 

[jimbob]

have just realised that you have completely misunderstrood me.

Random, but not haphazard.

I think I understand you. Your view of evolution is not uncommon in the mainstream. I wasn't really imagining that you think it is haphazard. What I and articulett are trying to tell you, is that the evidence and the math does not bear your argument out, that no evolutionary biologists would agree with what you are saying. What I find funny is that articulett favors quoting dawkins, while I favor gould. Two separate schools of evolution, who come to the same conclusion regarding randomness, by different means.

I would beg to differ on your interpretation of Gould's work.

Wasn't his point in Wonderful Life that chance played a large part in altering the course of evolution? A slightly different subset of organisms surviving, and a different set of parent species leading to a completely different ecology, and inhabitants of that ecology. I realise that since the publication of this book, osme of the fossil evidence has been re-interpreted, but I would say that the original point is still valid.

Not everything.

Quantum events might conceivably affect the Earth's orbit, but not significantly (or even measurably). A slight change in the wind direction due to a difference at the quantum level several weeks earlier could very easily affect the survival or otherwise of a particular trait.

I'm suspicious that it could even change the direction of the wind in a way that would be significant. Just because someone can generate a "butterfly flapping its wings" argument to show that small effects can be significant doesn't mean that they ever are. There are always significant stabilizing effects. While wind may appear complex that is no reason to automatically assume that its behavior hinges upon the behavior of quarks and leptons.

I'd imagine that it woldn't have taken much to alter the evolutionary history of Darwin's Finches. A slightly differnt wind direction, and the founder population doesn't make it to the Galaopgos

The reason quantum physics is a modern theory, why scientists for many many years thought that the universe was a very ordered and regular place, is because on all scales that effect processes above the atomic level it is very very regular. The discovery of quantum physics does not invalidate those results.

I've noticed that it is not uncommon for the wooish arguments to hinge on the infinitesimally improbably, so imo this line of reasoning seriously undermines your argument. As I've stated before, it also makes it very different to talk about the science.

My point was that it seems that chaotic systems are truly random, as opposed to merely unpredictable, far enough in the future. Non-chaotic systems aren't. Several people have been arguing that natural selection is not random, whilst I would say it is better to think of it as a bent dice game - over time the winnerr will be fixed, but by how much isn't determined, and can still lose in the short term.

The feedback loops I am talking about is because an organism alters the fitness landscape for other organisms in its ecosystem. Which mutation occurs first in which organism would help define the fitness lancdscape for the other organisms.

I dispute that it is trivial. When discussing with other people, most would consider it to be a significant difference whether anything was filling our ecological niche. In fac, given our effect on the evolution of other organisms, this is probably true.

Mamoths, passenger pigeons, dodos, moas, rats, TB, would all have had different evolutionary histories without mankind.

If this depended on random events, as well as nonrandom but unpredictable events, then I can see it is valid to talk about randomness in evolution. It is also valid to talk about inevitibility in evolution too, for example the loss of flight in birds on isolated islands with no predators.

You can dispute it. I think I've laid out my argument in excruciating detail. Your argument either reduces to the claim that history is random or is very wrong. Either way you aren't talking about evolution. But as I've stated several times, the argument I'm making is based in large part on the evidence, and I've recommended you go to the primary sources. So if you choose to dispute it without examining those sources, you chose to dispute it via ignorance* not argument.

With that I'm out.

*p.s. I'm not trying to be rude, by saying that it is an ignorant position, I'm trying to impress upon you the importance of reading some of the work in the field, before you assert that it is false.

Yes, I do think that history is affected by random events. So is evolution.

I am syaing that there are situations especially over long enough timescales, or rapidly changing environments when random events play important roles in the course of evolution. On other occasions it is more predictable.

Convergent evolution happens on occasion, because some sets of outcomes are likley. Others are not. Given that large mammals existed for at least 30-odd million years before the arising of humanity, anfd that large animals had been around for far longer, would provide circumstantil evidence that humanity's niche is one that is not as likely to be filled as that of a large plains-dwelling hearding herbivore.

Humanity is probably the species that has had the biggest effect on the evolution of other organisms. If it wasn't inevitable that humanity or anything like it evolved, then that is another significant difference on many species evolutions. In fact humanity is a classic example of a species that arises and a;ters the fitness landscape for surrounding organisms.

When these happen, and how, is random.

 

[Paul C. Anagnostopoulos]

But I have never done that or advocated doing that.

Then you should word your responses more carefully, because you've convinced pretty much everyone here that you are calling evolution "random."

I think this conversation would be a lot clearer if people would use "nonrandom with respect to ..." alot more often.

I don't see the problem with my saying that the fundamental operation of a process is random but its overall behavior is orderly. If this weren't the case, inferential statistics would be meaningless and you would have to poll a whole population to find out its demographic information. In essence, the description of a system as "random" or "non-random" depends on its micro-level behavior and not its macro-level behavior.

I think we'd be okay if you said mutations are fundamentally random. But there's too much to evolution that is nonrandom to countenance saying that evolution as a whole is fundamentally random.

~~ Paul

 

[mijopaalmc]

Then you should word your responses more carefully, because you've convinced pretty much everyone here that you are calling evolution "random."

I think this conversation would be a lot clearer if people would use "nonrandom with respect to ..." alot more often.


I think we'd be okay if you said mutations are fundamentally random. But there's too much to evolution that is nonrandom to countenance saying that evolution as a whole is fundamentally random.

The problem is that no-one has presented evidence that evolution by natural selection is "nonrandom with respect to (blank)". The fact that a given phenotype is more likely to reproduce than others because individuals who possess it can access resources in the environment more efficiently as others does not make it nonrandom with respect to the environment (which is what I think your are referring to when you say that "there's too much to evolution that is nonrandom to countenance saying that evolution as a whole is fundamentally random").

 

[Paul C. Anagnostopoulos]

The problem is that no-one has presented evidence that evolution by natural selection is "nonrandom with respect to (blank)".

I think it goes without saying that selection is nonrandom with respect to the current environment, by the very definition of the word selection.

The fact that a given phenotype is more likely to reproduce than others because individuals who possess it can access resources in the environment more efficiently as others does not make it nonrandom with respect to the environment

Please explain how you come to this conclusion.

~~ Paul

 

[Ichneumonwasp]

The problem is that no-one has presented evidence that evolution by natural selection is "nonrandom with respect to (blank)". The fact that a given phenotype is more likely to reproduce than others because individuals who possess it can access resources in the environment more efficiently as others does not make it nonrandom with respect to the environment (which is what I think your are referring to when you say that "there's too much to evolution that is nonrandom to countenance saying that evolution as a whole is fundamentally random").

Yes, we have presented such evidence, more than once. Paul has specifically stated -- more than once -- that evolution by natural selection is non-random with respect to the environment. When the entire system is considered, as has been mentioned more than once, it is clear that adaptation to the environment is what falls out. That is non-random in the same way that pressure is non-random when volume, heat, and the amount of a gas are considered. One of the problems is that too many folks are concentrating on the details of evolution, on the organisms themselves -- which is analagous to the molecules in a container, not the system as a whole.

So, let's look at natural selection. It is random which organisms survive. It is not random that not all organisms will survive given limited resources. It is random what sorts of variations will appear. It is not random that variations will appear. It is random what types of traits will survive. It is not random that certain traits will survive and be passed along.

That is what people mean when they say that evolution is not random.


ETA:
Dang, Paul already said it again.

 

[mijopaalmc]

Paul C. Anagnostopoulos and Ichneumonwasp-

The way I define "random" requires that individuals with identical phenotype always all reproduce or never reproduce at all. If some individuals with identical phenotypes reproduce while others don't, the process is by definition random.

jimbob has presented evidence to this effect here.

 

[Reality Check]

The problem is that no-one has presented evidence that evolution by natural selection is "nonrandom with respect to (blank)". The fact that a given phenotype is more likely to reproduce than others because individuals who possess it can access resources in the environment more efficiently as others does not make it nonrandom with respect to the environment (which is what I think your are referring to when you say that "there's too much to evolution that is nonrandom to countenance saying that evolution as a whole is fundamentally random").

My 2 cents worth: Evolution by natural selection is nonrandom because similar inputs give similar results. Remember that we are talking about the entire process of evolution where the effects of natural selection dominate the effects of variation.

A few examples from my small knowledge of biology:

• If you put bacteria in an environment containing antibiotics then the bacteria will develop resistance to the antibiotics. The species of the bacteria does not matter so long as the antibotic affects it.
• If you add a predator to an environment then its prey will develop strategies to avoid predation, e.g. speed. See cicadas.
• If you add a parasite to an envronment then its hosts will develop strategies to cope with the parasite.
• If there is an extinction event that removes animals from environments then other animals will evolve to fit the environments.

However if your definition of random process is any process where the same inputs give outputs that are not identical then by that definition evolution by natural selection is random. But this definition does not stop evolution from being predictable since the outputs are a small subset of all possible outputs.
That defintion has problems in other areas, e.g. it makes statistical thermodynamics and quantum mechanics "random".

 

[Ichneumonwasp]

I went back to see how this whole conversation began. And like most internet arguments it began in equivocation.

It started in Meadmaker's thread about "The God Delusion". He chastised Dawkins for arguing against "chance" in evolution. But Dawkins didn't do so in the way it is being taken here.

I hadn't read the book until just recently -- right now actually. Today I happened on the chapter in question -- chapter 4. In it, Dawkins argues against the idea that evolution happened by "chance" because he was examining a tract put out by the JWs in which they repeatedly stated that the intense beauty and complexity of organisms "couldn't have happened by chance." The Watchtower piece clearly uses the word "chance" in its colloquial sense, and Dawkins continues to use it in that way.

Meadmaker introduced the mathematical sense of 'random' into this conversation -- as a way to criticize Dawkins. But Dawkins makes it very clear that he does not speak of 'chance' in that way. He maintains a single use of the word -- the colloquial use -- throughout the chapter. And he clearly encodes the idea that evolution contains random elements and that it is random in the technical sense of the term.

Let's look at what he actually does say:

"What is it that makes natural selection succeed as a solution to the problem of improbability, where chance and design both fail at the starting gate? The answer is that natural selection is a cumulative process, which breaks the problem up into small pieces. Each of the small pieces is slightly improbable, but not prohibitively so. When large numbers of these slightly improbable events are stacked up in series, the end product of the accumulation is very very improbable indeed, improbable enough to be far beyond the reach of chance. It is these end products that form the subjects of the creationist's wearisomely recycled argument. The creationist completely misses the point, because he (women should for once not mind being excluded by the pronoun) insists on treating the genesis of statistical improbability as a single, one-off event. He doesn't understand the power of accumulation."

Dawkins clearly uses the idea of 'random' as has been proposed here -- described by a probability distribution -- so the entire original chain of posts was based on a mischaracterization of his position from the get-go.

While all of the little steps that lead to the formation of new organisms may be random -- random mutations (not complete chance, mind you, because crossing over occurs in particularly prone areas and copying errors tend to be more likely in certain stretches of DNA, etc.) and the historical contingencies that result in natural selection -- the process will lead to changes over time. That is not in doubt. Those changes that leave behind more offspring will tautologically leave behind more offspring. That is not random.

 

[Ichneumonwasp]

Paul C. Anagnostopoulos and Ichneumonwasp-

The way I define "random" requires that individuals with identical phenotype always all reproduce or never reproduce at all. If some individuals with identical phenotypes reproduce while others don't, the process is by definition random.

jimbob has presented evidence to this effect here.

Stop looking at molecules. From that vantage everything is random. Look at the whole container with all the molecules. That is how, where, and why the process is non-random. No one argues that we can predict the course of molecules in a balloon, only that we can reliably measure the pressure of the system, given certain inputs.

 

[articulett]

But Mijo HAS to prove to himself that it makes sense to say evolution is random. And he can only do this if you let him have the last word... otherwise this thread will go on forever. He has a need to use that word-- no matter how vague or misinforming it may be. He will use it, no matter how many actual experts say it's misleading... he will insist it makes sense no matter how he is told that it is the number one ways that intelligent cdesign proponentists obfuscate understanding of natural selection-- the core teaching of evolution. He will use it and must use it because, to mijo, it can't be right to call evolution nonrandom. Dawkins must be wrong. He must be "right".

To mijo, anything (except apparently a smoke alarm) that has randomness IS random--especially evolution which is "fundamentally" random.

It's the craziest thing... but he's just so predictable. As are his few cohorts on this thread. Why does anyone "need" evolution to be "random"? Why do people who can't convey information to the people on this forum imagine that they are so much smarter than those who teach the subject to many? Your hypothesis is as good as mine.