What evidence is there for evolution being non-random?

[articulett]

I also have to comment on mijo's request that we point to a peer reviewed scientific article showing that evolution is not random. To me, that is like asking could you point to a peer reviewed article that shows that there really are invisible things called germs. It implies a sort of ignorance that doesn't seem amenable to be addressed much less "understood" by actual peer reviewed articles.

This just sounds like his vague request about "discontinuity in the fossil record" of which he found all the answers absolutely unhelpful. When you ask a creationist question...all the answers are bound to be unhelpful--because the question, itself, shows that you don't want to understand the answer, doesn't it.

I think science is way beyond proving germs exist...and I think it's way beyond proving that evolution isn't "random"--. The concept is simple; unless you have a vested interest in believing a particular faith.

 

[Taffer]

This seems to be an argument with an expected outcome on your part.

You wish to argue some divine plan into an observed random situation.

Nope.

Asteroid paths can be predicted, but not to the degree where their impact (pardon the unintended pun (yes, it really was unintended)) can be predicted on the evolutionary cycle of the planet. Gravitational forces, solar winds, and collisions from other spatial bodies contribute to the trajectories of these objects and cannot be predicted far beyond a few years at best.

This may be true, but does it change the fact that selection is not random?

The orbits of many comets have been plotted with considerable accuracy, but even then, the exact path cannot be determined with enough precision to determine if it will impact with a solar body beyond one orbital period.

So to say that evolutionary changes can be predeterminantly linked to solar system events is quite the stretch and leads to a deitistic belief system. But then, this is probably the conclusion to which you are trying to force the debate to arrive at.

Good luck.

Given my lack of belief in a deity, I think that would not be easy.

Evolutionary changes are based on a number of related and unrelated factors. The process of evolution will introduce environmental changes which cannot be predicted and whose effects will often require millions of years to assert themselves.

The ecosystem is a dynamic entity and can take sudden turns when confronted with major geologic activity, such as caldera eruptions.

The resulting dust clouds can kill off species of algae and plants, causing a ripple effect throughout the life structure. The volcanic eruptions cannot be predicted, and therefore the effects they have on the evolutionary process cannot be predicted and, ipso facto, the resultant ecosystem cannot be predicted.

Does this change the fact that selection is not random?

Mutations are random, and their effect on other existing lifeforms cannot be predicted.

Of course.

At best, life is a fractal pattern. There are some possibilities which are excluded from the matrix. The part-monkey-part-crocodile-part-penguin creature will never evolve, but there will be a variety of new finches, probably including a few species with bright orange, red, green and blue feathers at some time.

Indeed.

You are entirely welcome to your belief in intelligent design.

Just realize that you can't prove the intelligence that exists behind it.

Given that I am an evolutionary geneticist grad student, I'm fairly sure I realise this already.

Dr. A is right, I think you missed the point of my post.

 

[Taffer]

I also have to comment on mijo's request that we point to a peer reviewed scientific article showing that evolution is not random. To me, that is like asking could you point to a peer reviewed article that shows that there really are invisible things called germs. It implies a sort of ignorance that doesn't seem amenable to be addressed much less "understood" by actual peer reviewed articles.

This just sounds like his vague request about "discontinuity in the fossil record" of which he found all the answers absolutely unhelpful. When you ask a creationist question...all the answers are bound to be unhelpful--because the question, itself, shows that you don't want to understand the answer, doesn't it.

I think science is way beyond proving germs exist...and I think it's way beyond proving that evolution isn't "random"--. The concept is simple; unless you have a vested interest in believing a particular faith.

Exactly. It is unfortunate that many creationists hear the "random" of "random mutation and natural selection", and think that completely describes evolution.

I will make a bold statement: Even if we grant that, by most definitions, evolution is a random process, this does not remove the fact that selection is not random. Sure, genetic drift may drive allele frequences one way or another, but that is not selection. Selection, as a 'force', is not random. It always acts the same way every time.

 

[mijopaalmc]

I notice he didn't answer. I still contend that he's a creationist though he denies it. I predict that this thread will be like his fossil thread where people bend over backwards to explain and illustrate a somewhat simple concept with multiple links and examples which he'll ignore and dismiss and then tell everyone that they didn't answer his question, and so evolution is really random and he'llo just ask his biologist friend to explain it better.

It's simple if you aren't a creationist.

Mutations are "random" (more or less)--
Selection is not (more or less)--the specifics (more are less) are not important until you get the basics. There are trillions of experiments going on all the time. Only a very small percentage of life lives long to reproduce the another generation--some more successfully than others.

The dogs we have we breed from a very small group of wolves--bred for traits we humans like--over about 12000 years. We aided the survival and reproductive success of the dog creatures we valued the most...or at least the ones that irritated us the least were allowed to feast upon our historical leftovers...where their more timid or aggressive kin might not have been allowed the privilege.

Nature does the same kind of thing--but it takes a lot longer. The results are all the fabulously cobbled together creatures and genomes you see before you.

Mijo seems to purposefully obfuscate things to keep himself from understanding this simple notion as far as I can tell.

And once again, we are back to articulett calling me a creationist because I don't agree with her. This is a personal attack (given that "creationist" is a smear term") and I am surprised that people with actual evidence would employ it if they could refute the argument with that evidence. I have once again offered definitions of "random", "stochastic", and "probabilistic" and explained why I think that evolution fits those definitions. I have also offered evidence that it is highly improbable that evolution is deterministic (i.e., a process where all organisms with a given fitness complement either "survive" or don't) if fitness is interpreted as a probability of "survival" of a given fitness complement rather than the raw data of whether an individual "survives" or not. No-one has yet pointed to a resource that say that it isn't random. Instead, by articulett's own admission, it is claimed that it is impossible to do such a thing, and evolution is simply "understood" to be non-random. It seems that people are trying to evade the issue by appealing to some vague "understanding" rather than a concrete explanation or published evidence.

 

[Schneibster]

OK, "random" and "stochastic" mean the same thing; the former has a colloquial meaning that is less precise, so it is preferable in a formal setting to use the latter.

Taffer, the beauty of physics (and IMO biology) is how order emerges from stochastic processes. Just a very few simple rules, imposed on top of random phenomena, yields order at the high level, but stochasm remains at the low levels. The thermodynamics of gases is an excellent example of this.

Maxwell-Boltzmann statistics model the atoms of a gas as tiny classical particles. These particles are modeled as bouncing around randomly, with random speeds in random directions. However, the average velocity is zero- and the average speed is dependent upon the temperature, by a very simple equation:
E_K = kT
and the pressure outward of the gas is equal in all directions, dependent upon the volume, temperature, and number of molecules, and is defined by:
PV = NkT

These extremely simple (and very accurate) equations are derived from the underlying stochastic behavior of the component molecules. And from this behavior is garnered the three laws of thermodynamics, and a great deal of other physics. Slight corrections have proven necessary, as with many such theories; but the kinetic theory of gases stands as an achievement as impressive and enduring as Newton's deceptively simple laws of motion, or Kekule's realization of the only possible form of the benzene ring.

And the point is, they emerge from randomness, with only a very few very simple rules added. Just as evolution by natural selection does. This appears to be a general characteristic of the most powerful and descriptive scientific theories: the emergence of order at the high level from chaos at the low.

I think that both sides here are right, and both are wrong. Right, in that evolution represents chaos, in the environment and the production of novel characteristics; and in that overall, high level order emerges from the chaotic underpinnings and can be clearly observed in the world around us. Wrong, in that each says the other's order or chaos is somehow not so.

What is NOT correct is the creationists' claims that order cannot emerge from chaos. We encounter examples of order emerging from chaos all the time; they are all around us. To claim that goddidit for evolution is tantamount to maintaining that goddidit for the laws of thermodynamics and is manipulating all those molecules to make the pressure come out uniform at the macroscopic level. We have math that says that the underlying chaos is necessary for it to come out that way in thermodynamics; and that same type of math says it is also necessary for evolution to work the way it does. Anyone with any sort of scientific training at all has to cringe every time they hear the creationists twist math and logic the way they do.

So stop arguing, you guys. It's senseless. It's random, and it's orderly. That's how the universe is. If you wanna say God did that, well, I can't prove you wrong. Yet. But we're getting close.

 

[Walter Wayne]

Can you list any of these points which do not apply to evolution by artificial selection?

Artificial selection as it is presently is still random. However, some traits will converge very rapidly.

If I am breeding for a certain trait, long noses, I can choose the most extreme cases from each generation. Additional, with some animals I can be especially protective of them so that the long nosed ones don't die an untimely death for an unrelated reason.

Think of dog breeding. The animals are handed food, protected from predators and get to see a vet. As such my long nosed dogs all make it to maturity, even if they have other undesired traits. If you look at pure bred dogs they do get the traits they are bred for. Seems rather non-random. But at the same time, look at how many pure breeds have high incidence of genetic disorder. Different breeds are linked more commonly to certain disorders. Which disorder is a case of which one is associated with the original small breeding stock.

As such while the evolution of some traits in selectively bred animals becomes highly predictable, you get with it some disorder that it happens to be associated with. As such artificial breeding still leads to high degrees of randomness in some traits. Presumably with better knowledge of genetics and associated traits we could get selective breeding to the point where the result is not random in the layman's sense of the word.

Walt

 

[Taffer]

OK, "random" and "stochastic" mean the same thing; the former has a colloquial meaning that is less precise, so it is preferable in a formal setting to use the latter.

Taffer, the beauty of physics (and IMO biology) is how order emerges from stochastic processes. Just a very few simple rules, imposed on top of random phenomena, yields order at the high level, but stochasm remains at the low levels. The thermodynamics of gases is an excellent example of this.

Maxwell-Boltzmann statistics model the atoms of a gas as tiny classical particles. These particles are modeled as bouncing around randomly, with random speeds in random directions. However, the average velocity is zero- and the average speed is dependent upon the temperature, by a very simple equation:
E_K = kT
and the pressure outward of the gas is equal in all directions, dependent upon the volume, temperature, and number of molecules, and is defined by:
PV = NkT

These extremely simple (and very accurate) equations are derived from the underlying stochastic behavior of the component molecules. And from this behavior is garnered the three laws of thermodynamics, and a great deal of other physics. Slight corrections have proven necessary, as with many such theories; but the kinetic theory of gases stands as an achievement as impressive and enduring as Newton's deceptively simple laws of motion, or Kekule's realization of the only possible form of the benzene ring.

And the point is, they emerge from randomness, with only a very few very simple rules added. Just as evolution by natural selection does. This appears to be a general characteristic of the most powerful and descriptive scientific theories: the emergence of order at the high level from chaos at the low.

I think that both sides here are right, and both are wrong. Right, in that evolution represents chaos, in the environment and the production of novel characteristics; and in that overall, high level order emerges from the chaotic underpinnings and can be clearly observed in the world around us. Wrong, in that each says the other's order or chaos is somehow not so.

What is NOT correct is the creationists' claims that order cannot emerge from chaos. We encounter examples of order emerging from chaos all the time; they are all around us. To claim that goddidit for evolution is tantamount to maintaining that goddidit for the laws of thermodynamics and is manipulating all those molecules to make the pressure come out uniform at the macroscopic level. We have math that says that the underlying chaos is necessary for it to come out that way in thermodynamics; and that same type of math says it is also necessary for evolution to work the way it does. Anyone with any sort of scientific training at all has to cringe every time they hear the creationists twist math and logic the way they do.

So stop arguing, you guys. It's senseless. It's random, and it's orderly. That's how the universe is. If you wanna say God did that, well, I can't prove you wrong. Yet. But we're getting close.

Very well put. I agree, variation in a population is random. I agree, there are many random elements to evolution. My only disagreement is that selection is not random.

If one wishes to call the whole process random because it has random elements, that is fine. All that really concerns me is that it is understood that a non-random element is imposed in the process, and that is how the order arrives from chaos. Selection is the 'rule', so to speak.

But yes, I hear you. The argument is getting a little silly.

 

[Walter Wayne]

I see the same mischaracterization of the argument for evolution being random (in more than the technical sense) being given again and again.

(Through out this post I am using the definition of random I gave in my response to Taffer, unless I specifically specifiy the technical defintion.)

I am not saying that "evolution is random because one aspect of it is." I am saying evolution is random because of the traits of the process that is acting on those random elements. For those stating that "one can't evolution is random just because it has random elements" that is not a summary of my argument. I notice some people stating that evolution isn't random because the selection process which acts on mutation isn't random. But you can't say evolution is non-random because one or more elements of it are.

Determistic processes can do several things to the randomness of inputs.
1. Some processes (trivial) will have outputs that aren't even technically random.
2. Some processes will "hide" the randomness making the output non-random.
3. Some processes will exhibit the same randomness as the inputs
4. Some processes will exagerate the randomness of inputs

So the randomness of the output is dependent on the traits of the process. If you hear anybody state, evolution isn't random because selection is not, their argument is somewhat lacking.

Alot of the basic principles we take for granted about stochastic processes are dependent on basic properties of the underlying random variables. So for instance, each roll of a fair die is independent of the last one. The fact that the last few rolls came up 6 doesn't mean that the next roll is any more or less likely to come up a 6. The other characteristic of dice rolling is that the probability of a given roll isn't a function of time (what is called a stationary process).

Populations do go through periods of duress where numbers are small. You can't depend on large numbers and such to even out the randomness in the same way a casino depends on people playing over and over to do so. And with heredity you can't forget the past. The fact that random motion of particles leads to gas laws, or random throws of dice leads to casinos making big money does not mean that other systems become less random by frequent iteration.

If you won't be convinced that evolution is random, then at least be unconvinced of its non-randomness as well. And recognize that anyone who says evolution is non-random because selection is non-random hasn't made a good argument.

Walt

 

[mijopaalmc]

Very well put. I agree, variation in a population is random. I agree, there are many random elements to evolution. My only disagreement is that selection is not random.

If one wishes to call the whole process random because it has random elements, that is fine. All that really concerns me is that it is understood that a non-random element is imposed in the process, and that is how the order arrives from chaos. Selection is the 'rule', so to speak.

But yes, I hear you. The argument is getting a little silly.

This is going to ring rather hollow, especially after Schneibster described it so beautifully and eloquently, but I never meant to deny that evolution didn't appear non-random or ordered. Having taken a year of physical chemistry during my undergraduate tenure, I understand the power of what one poster somewhere in one of the threads devoted specifically to the stochastic characteristics of evolution called the "ensemble mean". Such a property of an ensemble (i.e., a collection of independent yet interacting systems, such as gas molecules) describes the properties of the ensemble in terms of properties of its constituent systems. Thus, temperature is the mean kinetic energy of the molecules in a gas, and the pressure is the mean number of impacts of gas molecules against the container holding the gas. Similarly, the "progress" of evolution, in so far as we can speak of progress without a discernible goal, is the "ensemble mean" of many millions of generations of random mutation and probabilistic or stochastic natural selection. Thus, while evolution occurs through a series of random processes, over sum total of evolutionary time, unfavorable fitness complements are weeded out and favorable fitness complements are conserved.

I'm sorry that my posts never got around to acknowledging the overall "non-randomness" of evolution (albeit from constrained stochastic processes), and I apologize for any confusion that my posts have caused.

Again, I would like to compliment Schneibster on such a masterful reconciliation of the idea of randomness and order. Thank you for dong what I failed to do.

 

[articulett]

I agree that the whole thing could be called random given certain definitions--but I don't like referring to evolution as random because creationists use that argument to extrapolate the tornado going through a junkyard and building a 747 argument. I think it's confusing and let's people say that scientists say that this all happened by chance. Yes...sort of...but via eons and ratcheting and endless experiments with only the "luckiest" or "best" or "fittest" surviving to be built upon.

Because creationist exploit language via semantic games (e.g. "theory")--I wouldn't say evolution is random. Understanding evolution means understanding that mutations are relatively random...whereas the mutations that stick around to be built upon are the ones that worked--that is, they were selected by the environment.

The best sperm of the millions may not get to the egg--but the worst ones certainly won't, and the less fit ones that make it, might not survive...might not reproduce...or might reproduce at a lesser rate. But out of the trillions upon trillions produced every day, sometimes there is a winner--and even amongst those winners we see amongst us...not all seem very "winning" given the rigorous selection process and eons of time to tinker on the "design".

 

[Schneibster]

If we were arguing with woos, I might agree, articulett. But we're not, at least not so far (evilution threads seem to draw them like ripe fruit draws flies). It is a deep truth that randomness leads to order. I pity those who are incapable of seeing that and must construct lies about big daddies in the sky to explain it all.

 

[Walter Wayne]

Because creationist exploit language via semantic games (e.g. "theory")--I wouldn't say evolution is random. Understanding evolution means understanding that mutations are relatively random...whereas the mutations that stick around to be built upon are the ones that worked--that is, they were selected by the environment.

And if you are debating woos?

Really, they'll warp it which ever way you do it. Insist it isn't random and creationists will say we are describing a random system perfectly, but refusing to call it that because "evilutionists are afraid to debate is honestly, because they'll lose."

And one of them will have a link to this thread, including the debate and your statement that you wouldn't say it is random, when debating with woos.

And they would take it out of context and never notice that we aren't discussing spontaneous generation of 747's from junkyards.

 

[Dr Adequate]

It's interesting how you left out the last sentence, which I quoted and emphasized at least once before ...

... and which follows on from the statement that "Stochastic" is "often" used in this way, without adding anything to it.

"Stochastic is often used as counterpart of the word "deterministic," which means that random phenomena are not involved. Therefore, stochastic models are based on random trials, while deterministic models always produce the same output for a given starting condition."

Please do explain the reason why it is "interesting" how I "left out the last sentence".

 

[Dr Adequate]

Artificial selection as it is presently is still random.

This does seem something of a reductio ad absurdum of your position, which is in fact how I intended it.

As such while the evolution of some traits in selectively bred animals becomes highly predictable, you get with it some disorder that it happens to be associated with ... Presumably with better knowledge of genetics and associated traits we could get selective breeding to the point where the result is not random in the layman's sense of the word.

Which is?

If this involves predictability, then I would point out that evolution by natural selection can be depressingly predictable. What will happen if we introduce a new antibiotic?

Can anyone give a link to that recent sudy on the length of lizard legs?

Or there's all those studies on guppies, of course.

 

[Meadmaker]

You are kidding, right? "There is no way that randomly assembling parts can give rise to animals, much that a 747 cannot randomly assemble itself." A paraphrase, I know, but I'm sure no-one would argue that no creationist has ever used that argument. It stems from a key misunderstanding of evolution.

It does stem from a key misunderstanding of evolution, and it's a thoroughly ridiculous argument. However, it isn't saying that "evolution is random". Saying "evolution is random" doesn't give any credence at all to the "tornado in a junkyard" arguments.

What happens is that someone makes a very sensible statement, "Evolution is a random process." Then someone else (a creationist and/or ID supporter) says, "That means that things spontaneously assemble. That would be like assembling a 747 by sending a tornado through a junkyard." Incredibly, then, the response from biologists is to say, "Evolution isn't really random."

The key error made by creationists is the belief that random processes cannot create complex entitities. They are wrong. It is possible to assemble complex entities through random processes. It is not possible to throw all the parts of a watch together and hope you get a watch, but it is possible to create a random process which, given enough time, will assemble a cell. Probably, there is even a non-contrived one that could even assemble a watch, but that is left as an exercise for the reader.

 

[Paul C. Anagnostopoulos]

Usually, JREF is pretty sympathetic to using the technical, mathematically precise, definition of a word. Why is this one different?

It's not different, as long as one is careful to use an accurate definition of random process:

"... in a random process there is some indeterminacy in its future evolution described by probability distributions."

The environment is the source of skewed probability distributions in the random process of variation and natural selection. Therefore evolution is not random with respect to the environment. Most people think random means random with equal probabilities, as in a throw of a die. That is why calling evolution random is misleading.

~~ Paul^WP

 

[Meadmaker]

So, what do you consider the "outcome" of evolution?

If the outcome is "a large set of specific individual genomes," then yes, the outcome of evolution is random, in the sense of being completely sensitive to and completely controlled by the random inputs from outside the system.

If the outcome is "a world full of diverse and complex life," then no, the outcome is not random. It'll come out that way every time.

Respectfully,
Myriad

Bravo!

I couldn't have said it better myself. In fact, I didn't.

 

[Dr Adequate]

What happens is that someone makes a very sensible statement, "Evolution is a random process."

It's not sensible, it's extremely misleading.

Incredibly, then, the response from biologists is to say, "Evolution isn't really random."

Incredible. I guess that those uppity biologists must think that they understand biology.

* shakes head *

 

[Dancing David]

So here's my first post, with my first two cents: I think people are overthinking this way, way too much.

Can we predict which random mutations will be strongly disfavoured? Of course we can. A mutation that breaks oxygen metabolism in obligate anaerobes will be selected against. A mutation that prevents heart muscle from developing in cheetahs will be selected against.

Given an environment and an organism, we can predict with high certainty mutations or changes that will be disfavoured. Therefore, evolution in that framework is emphatically not random.

And evolution does not happen as much in those situations, what is 'radiation of a species','climate change' or 'collapse of a food species'.

It is still random in which effect the change in the genome has, and therefore the effect on morphology is random in relation to any given enviroment. Much less the interaction with new and changing enviroment. Can you tell me where a spider that is air borne plankton will land?

 

[drkitten]

It's interesting how you left out the last sentence, which I quoted and emphasized at least once before:

That's because it's not as helpful as you seem to think.

"Therefore, stochastic models are based on random trials, while deterministic models always produce the same output for a given starting condition.

Unfortunately, if you take this pseudo-definition seriously, it's possible for a model to be both stochastic and deterministic. The Gambler's Ruin is an example. If you sit down at a (fair) roulette wheel (random trials) with a finite bankroll and play long enough, you will always lose your entire bankroll (the same output).