What evidence is there for evolution being non-random?

[articulett]

The non-random part to evolution is blindingly obvious: It is a bias (defined by the environment particular organisms find themselves in) that allows more individuals with certain traits survive than others.

In evolution selection criteria must remain fairly stable compared to the rate of random mutations else no organism could adapt.

In mathematical terms, think of arbitrary (near constant) bounding thresholds controlling the selection of numbers from a random number generator. The resulting sets of numbers each still have random components, but have smaller variances and possibly shifted means compared to the original random source.

When the data from a Double-Blind Placebo-Controlled Trial shows the same variance reduction and/or shift in mean, no one explains the active drugs action as "random", do they?

As for stochastic gravity, how about this?

Wow, you speak "engineer", "physics", and "biology".
Thanks for translating. I actually tried the random trials explanation before. The randomization of those who receive the drug allows us to tease out the non-random effects due to the drugs. Double blind studies involve randomness (actually pseudo-randomness via random number generators), but the studies themselves would not be called random or any synonym thereof. There would only be confusion generated by calling such a process random--or stochastic-- there would be no information added to the topic nor would one understand how clinical trials use randomness, but are not "random" themselves.

In any case, I hope Mijo answers my simple questions.

 

[articulett]

Mijo,

Do you accept that life arose through entirely naturalistic means--that it is very unlikely that any sort of "intelligent design" was involved?

Yes or No is fine.

And is your goal to understand it and convey this factual knowledge in a way that works for the most people?

Again--yes or no is fine.

Do you have the slightest clue as to how your words can be misconstrued so that natural selection is glossed over rather than understood?

Yes or no is fine.

If so, then you have the answer to your original question. If not, it's because you had an answer at the get go, and can't "hear" anything that doesn't fit that answer.

And I'll take all wordy answers, oblique answers, and non-answers as a "no". Clarity is important when attempting to facilitate understanding.

 

[Meadmaker]

When the data from a Double-Blind Placebo-Controlled Trial shows the same variance reduction and/or shift in mean, no one explains the active drugs action as "random", do they?

Yes.

Actually, they describe things with random variables.

They say, "Mean life expectancy when using the placebo was 2.5 years. Mean life expectancy with the real drug was 4.7 years."

Now, let's suppose someone, seeing the above study results, were to say, "Life for someone with those conditions can be described by a random (stochastic) process."

The response that is analogous to some of the discussion in this thread would be to say, "You idiot. You don't understand pharmaceuticals. You're a Christian Scientist who thinks we shouldn't take drugs, aren't you?"

ETA: Carrying that thought further. Suppose one of your patients saw the results of the drug study and said, "I've always wanted to see the Taj Mahal. I'll book a flight four years from now." How would you explain to him that this was not an optimal strategy for achieving his life's dream?

 

[jimbob]

Further to Meadmaker's point, the LD50 dose of a drug...

 

[Ivor the Engineer]

Yes.

Actually, they describe things with random variables.

Which possibly can have a variance of zero.

They say, "Mean life expectancy when using the placebo was 2.5 years. Mean life expectancy with the real drug was 4.7 years."

So the action of the active drug w.r.t. a placebo is not random. It shifts the mean +2.2 years. There will almost certainly be a random component added to this shift that gives a distribution around this mean.

Now, let's suppose someone, seeing the above study results, were to say, "Life for someone with those conditions can be described by a random (stochastic) process."

Um, I thought the OP was about the non-random aspects of evolution? Or should we start debating Determinism?

The response that is analogous to some of the discussion in this thread would be to say, "You idiot. You don't understand pharmaceuticals. You're a Christian Scientist who thinks we shouldn't take drugs, aren't you?"

Actually the main problem is the implied summing up of evolution as random. Lots of it is, but some crucial parts are not.

What process cannot be modeled by a set of random variables? Should all phenomenon be treated as random processes, no matter how obvious the trends are in the resulting data?

ETA: Carrying that thought further. Suppose one of your patients saw the results of the drug study and said, "I've always wanted to see the Taj Mahal. I'll book a flight four years from now." How would you explain to him that this was not an optimal strategy for achieving his life's dream?

I'd guess the probability of _not_ dying follows something like a geometric distribution, with time being the random variable, so you should advise everybody you meet to do everything RIGHT NOW!, if doing whatever they want to do before they die is the most important criteria for them.

As for our chap whose taken the drug that indicated it increased life span from 2.5 to 4.7 years, it would depend on the variance around the figure of 4.7 years. If 3 standard deviations was less than 0.7 years then I wouldn't say anything. If it was 2 years then I'd suggest he goes earlier.

 

[jimbob]

Back to evolution.

The optimisation is to an environment that changes randomly. Organisms will evolve to reproduce within their current environment, which is subject to random alterations.

It is also a percentage game where most organisms fail to reproduce (how many eggs does a cod spawn?).

Culling the unsuited is very strong, but many of the ostensibly well-suited are culled too, this is the really random part.

Without the invention of the stirrup would over 8% of Asian men be descended directly from Ghengis Kahn? No, because he would never have been conceived.

A chance arrow at a battle could have also fixed this too.

 

[jimbob]

Something with a variance of zero is either nonrandom, or from an insufficiently large sample to highlight the randomness.

If identical conditions always produce the same outcomes than a system is nonrandom (only pseudorandom, like a computers "random number generator")

If different outcomes are possible* for the same conditions, the system is random.

There might be biases.

*OK, thermodynamics, so maybe practically possible.

What process cannot be modeled by a set of random variables? Should all phenomenon be treated as random processes, no matter how obvious the trends are in the resulting data?

Whether or not humanity would have deveolped or not is a fairly large difference. Whether dinosaurs survived is also a fairly large differnece, so I would argue that obvious trends are swamped by myrad differences that still produce organisms which reproduce.

I guess that IDers can argue that a designer is performing "selective breeding", which is not needed if one accepts "probabilistic" or its synonyms.



Off thread:
I chose my avatar to demonstrate that it is possible to separate the effects of genes and the environment on organisms. The most obvious difference between this mouse and normal mice is the environmental effect of grafting an ear onto its back.

 

[mijopaalmc]

Do you accept that life arose through entirely naturalistic means--that it is very unlikely that any sort of "intelligent design" was involved?

Yes, but I don't see how claiming that evolution in a stochastic process necessarily contradicts this premise.

And is your goal to understand it and convey this factual knowledge in a way that works for the most people?

I have already explained this to you, articulett, here and here in this thread

Do you have the slightest clue as to how your words can be misconstrued so that natural selection is glossed over rather than understood?

Yes, but I don't think that should be a reason to describe evolution as the opposite of what it really is rather than clarifying the terms of our discussion.

If so, then you have the answer to your original question. If not, it's because you had an answer at the get go, and can't "hear" anything that doesn't fit that answer.

And I'll take all wordy answers, oblique answers, and non-answers as a "no". Clarity is important when attempting to facilitate understanding.

Actually, you have not answered my question. You have engaged in completely semantic argument, defined "random" and "stochastic" in such a way that evolution can't be "random" or "stochastic", and dismissed the citations I provided that described evolution as a stochastic process as not supporting my argument without offering reasons why you thought that.

On the whole, you have been very disingenuous. The whole analogy to gravity is false because, while it may be true that a complete theory of gravity may involve stochastic elements, gravity is a deterministic force with respect to classical physics, which fully describes projectile motion on the mesoscale. Natural selection, on the other hand, is inherently about sampling the population for genes that are passed on to the next generation and therefore by definition a stochastic process.

 

[Meadmaker]

Actually the main problem is the implied summing up of evolution as random. Lots of it is, but some crucial parts are not.

No one on this thread ever implied any such thing.

Just to confirm this, I asked mijo what the implication of randomness in evolution was. He confirmed what I suspected. There were no implications. He was just curious why there was such a strong reaction against it.

As was I.

What process cannot be modeled by a set of random variables? Should all phenomenon be treated as random processes, no matter how obvious the trends are in the resulting data?

It depends. Are you studying the trends? Or the anomalies? When I was modelling aircraft dynamics, the trends were easy to model with deterministic models. The anomalies needed stochastic models. Why were the stochastic ones so important? That's what made the plane crash.

To apply this to evolution, are you interested in studying general trends? Deterministic is fine. Are you interested in studying sudden, rapid, change in a species that had been stable? Look for randomness.

 

[articulett]

The question was "what is the evidence that evolution is non-random"?

Is your contention that there is no evidence that evolution is non-random and that it makes perfect sense and is informative to call evolution a "stochastic process"?

If so, my contention is the same as Talk Origins, the Berekely Site, and Dawkins. Describing it that way shows that someone is missing the boat when it comes to understanding natural selection--the way species are shaped and altered by the environment over time. I can't imagine anyone who doesn't already understand natural selection and how it is the force behind Climbing Mount Improbable to get the slightest clue as to the process with such a muddled definition.

I am more than aware of the chance aspects involved in evolution--I agree with and understand the Genghis Khan analogy--but I contend that randomness is the simple part of understanding evolution. Understanding the ways it is non-random is the part that people have problems with--as evidenced by this thread. Natural selection has random components just like the drug trials...just like the evolution of technology or cities. But what evolves and the force behind it is poorly served by using such ambiguous words that say nothing as to the incremental nature of bottom up "design" working through time.

I think the wording used by those who actually teach this concept to many are the words I will stick with. And I think they convey quite clearly how evolution is "non-random" which was the question in the OP.

 

[articulett]

Back to evolution.

The optimisation is to an environment that changes randomly. Organisms will evolve to reproduce within their current environment, which is subject to random alterations.

This isn't correct; it's backwards. The organisms that are better suited to the environment will survive and reproduce preferentially. Organisms don't evolve to fit their environment. The organisms that fit the best will be the ones that survive and reproduce the best.

It is also a percentage game where most organisms fail to reproduce (how many eggs does a cod spawn?).

Culling the unsuited is very strong, but many of the ostensibly well-suited are culled too, this is the really random part.

Without the invention of the stirrup would over 8% of Asian men be descended directly from Ghengis Kahn? No, because he would never have been conceived.

A chance arrow at a battle could have also fixed this too.

Yes. And the randomness is easy to understand. But re-read my correction to the first sentence, because it details a very common misunderstanding people have about natural selection. Organisms do not evolve to "fit" their environment. Organisms are born with genomes and possible mutations and recombinations; they will die with these genomes as well (the genome is information coded in DNA that guides the development of the organism). The environment acts on the organisms and their genomes such that only those with the right combination of genes, luck, environment, forces acting upon it, survival tricks, etc. survive to reproduce. Of those that manage these elimination rounds, a minority will be the top reproducers. Their genomes are like having many lottery tickets in the game of life. The lesser reproducers will also hold tickets, but they are less likely to have their genes represented in future generations. Of the strands of DNA that are represented in future generations many will have come from common ancestors long ago and conserved because of their essential nature. This isn't random or stochastic or a process that is served well by using those words. It's "natural selection"--it builds complexity from the random results of reproduction. It builds complexity from the bottom up--no intelligence needed. Many factors can contribute to an organisms replication success including chance...but only the traits coded for in the DNA will be preferentially passed on to future organisms.

Like the penny example..."wealth" (complexity) can accumulate from randomness so long as selective forces are in place.

 

[jimbob]

This isn't correct; it's backwards. The organisms that are better suited to the environment will survive and reproduce preferentially. Organisms don't evolve to fit their environment. The organisms that fit the best will be the ones that survive and reproduce the best.

Yes, maybe I meant to say that the only oranisms that will evolve are those which reproduce. And any evolution will only only fit their current environment, which itself is subject to random changes.

The nonrandom part of evolution is that only those organisms with the right combination of luck and traits will reproduce. As a result, organisms will tend to fill ecological niches, and certain useful traits will keep re-evolving, nut with subtly different forms.

Yes, but I don't see how claiming that evolution in a stochastic process necessarily contradicts this premise.

I would go further, and say this could be taken as precluding a supernatural explaination. Which is why the IDers are so keen to misrepresent this so they can dismiss it. Far easier to frame nonrandom evolution as the hidden hand of the designer, guiding by controlling the rules, leading to the supernatural evolution of worshipers...

 

[articulett]

Yes, maybe I meant to say that the only oranisms that will evolve are those which reproduce. And any evolution will only only fit their current environment, which itself is subject to random changes.

The nonrandom part of evolution is that only those organisms with the right combination of luck and traits will reproduce. As a result, organisms will tend to fill ecological niches, and certain useful traits will keep re-evolving, nut with subtly different forms.



I would go further, and say this could be taken as precluding a supernatural explaination. Which is why the IDers are so keen to misrepresent this so they can dismiss it. Far easier to frame nonrandom evolution as the hidden hand of the designer, guiding by controlling the rules, leading to the supernatural evolution of worshipers...

And yet, the examples I've illustrated show just the opposite. The Deepak Chopra example, Behe, Kleinman, and the guy who said that it's preposterous to think that this could all come about by chance (that his mama didn't raise "no fool" and that with such overwhelming evidence that something looks designed...he would certainly be foolish to conclude it wasn't.)

It was "designed"--from the bottom up. Without a designer. The way cities evolve. Or landscapes. Or solar systems. Or languages. There is no overseer. It's built on what comes before...not randomly, haphazardly, or willy nilly--but incrementally. It's the incremental changes that selection winnows out that seems to be missing both in general understanding of evolution and in summing it up as chance.

 

[mijopaalmc]

Creationists will argue whatever best their viewpoint at the time, articulett. Notice how DavidJayJordan argued that the non-randomness of evolution implied design:

All biological study shows that evolution is not random but comes from design. Study biology and note that impossibility of one evolving from another. get serious and don't believe the magicians of evolution. Study the specific systems in the bodies of different species and note their differences and instincts as a whole and as separate identities.

Evolution is impossible the more you study and learn.

Not arguing something because a creationist argues it is never a good idea. As shown above, and I'm elsewhere on the internet, creationist argue design from randomness and non-randomness, leaving evolution proponents without a course of action with respect to the relationship between, or lack thereof, between evolution and randomness.

 

[articulett]

Creationists will argue whatever best their viewpoint at the time, articulett. Notice how DavidJayJordan argued that the non-randomness of evolution implied design:

Not arguing something because a creationist argues it is never a good idea. As shown above, and I'm elsewhere on the internet, creationist argue design from randomness and non-randomness, leaving evolution proponents without a course of action with respect to the relationship between, or lack thereof, between evolution and randomness.

This is an example of my point and the point of the creationist argument that says "evolution is the theory that life came to be and evolves by chance." Because summing up evolution this way seems counter intuitive--a designer seems necessary. Until, you learn about natural selection...design from the bottom up. Anyone can see how the internet evolved without a designer...how everyone who participates is a "designer" of sorts. All life forms are participants in evolution in the same way..even if they are just a food source--(they make the consumer better able to survive). Technology doesn't spring up from scratch...it is incrementally built upon the successes before it. It doesn't evolve randomly, although random factors are a part of any design.

I agree that nothing you say can sway a creationist who is mired in a particular kind of thinking. However, I also contend that natural selection is THE KEY to understanding evolution...HOW complexity arises from randomness. It is the key to understanding the "non random" aspects of evolution. It may involve random components, but the process is no more random than the evolution of a city. I don't really care how people come to understand evolution--I am peeved that many go out of their way to mischaracterize it... just as Behe does...and then it makes it harder to understand. It's really not hard to teach kids...but people who have been nursing these arguments and believing a certain way for a long time, are really hard to change. They THINK they understand evolution, but they fail miserably when conveying that understanding.

Natural selection drives evolution very similarly to the way artificial selection does. Only the forces making the choices are not conscious. Humans are conscious, but only of a small aspect of the process and the immediate results. Our long ago ancestors started domesticating wolves...but they could not foresee todays breeds of dogs. We cannot imagine dogs 1000 years hence...or even humanity or technology. But we know it will all be based on incremental changes from where we are at now. Natural selection "chooses" the fittest--...If it dies before producing...for whatever reasons...it cannot be "the fittest". Fittest means that you have to succeed in getting your information copied. The best chain letter in the world, can't be considered "fit" if it isn't sent. (And fitness is only about making copies of oneself allowing changes to accumulate through time--not about worthiness, strength, or anything else.). Just as we can't know about technology that was never invented and can't consider it part of the fittest or best technology...even if it would have been way better than what we see--we also cannot call things that die before passing on genes "fit". We can't know anything about their fitness. We have no way of knowing how many Einsteins or Hitlers were prevented from birth control measures or abortions or hiccups during sex. What might have been is not a factor in understanding natural selection. We can only build upon that which does exist...that which has been built upon before. s

It might be valid not to argue for or against something based on creationist misunderstandings. But if the point is to convey information--especially information as to HOW evolution is NOT random-- then I am convinced that making sure someone can adequately describe the incremental nature of natural selection is vital. Organisms don't evolve themselves...the information they pass on is either selected for future generations, or it isn't. And that is how complexity arises from the randomness. Bottom up design explains a lot of complex systems and processes; I wouldn't gloss over this or use ambiguous terms if it meant somebody might fail to understand this important detauk. Without understanding this, how can someone understand sexual selection or how predator prey relationships drive an evolutionary arms race or bacterial resistance or HIV and it's evolution and how some people evolved resistance due to genes they inherited from ancestors who lived through the plague (were selected when others died due to this beneficial mutation). It's the key to understanding heterozygote advantage and how we can look at DNA and SEE what was selected...what mutations were key mutations in the evolution of a new species... If you don't understand how incremental changes can design from the bottom up, you look at the complexity and an intelligent designer seems likely. If you do understand it, you understand how very very unlikely a designer is--so much waste and cruelty and vestigial structures and DNA and poor design--and still--through the eons, it gives us this amazing tree of life we see before us.

Why would anyone leave this out if their goal was to understand the non random aspects of evolution. Why? Everyone understands the random part. It's natural selection that people cannot intuit without a little help. When you describe evolution as stochastic you are using a definition of fitness that does not correspond with what we understand about genetics. Truly, in genetic terminology, the fitness of a strand of DNA only refers to it's ability to get passed into the future and then built upon. That is all that is meant by "fitness". You are describing evolution using probabilities and words that don't make sense in the context of evolution...you are using them in ambiguous ways that befuddle more than they clarify. It makes more sense to say that the environment chooses which genomes are the fittest than to say organisms with identical fitness don't necessarily survive equally; therefore natural selection is a stochastic process. It's backwards and puts a semantic bit of weirdness into a simple concept and ends up making it less clear. Evolution may well be deterministic if all inputs and all environmental factors being equal. But that is not particularly relevant if the goal is just to understand the non-random aspects of evolution and why biologists say natural selection is the opposite of random--the de-randomizer. They aren't being dishonest--they are clarifying a point that many people, including you, seem very murky on.

 

[mijopaalmc]

But natural selection, at its most fundamental, is not non-random. No matter how you look at it, natural selection is about taking a sample of a population. Fitter individuals are more likely to end up in the sample and therefore pass on their genes to the next generation than they would be if they were picked at random form the population whereas less fit individuals are less likely to end up in the sample and therefore pass on their genes to the next generation than they would be if they were picked at random form the population.

A sample though is an inherently statistical entity and therefore subject to random fluctuations by its very nature. The fluctuations are accentuated when the population is especially small and decrease as the population increases. Therefore, at sufficiently high population sizes, the effects of random fluctuations on selection are negligible and the population can be said to behave deterministically.

 

[whiteyonthemoon]

If the question that evolution is intended to answer is "How did organism X get to be the way it is?" then I can see how it can be argued that natural selection is the opposite of random. In this context evolution is the process that created the genetic code that organism X has. The increase in content of the organism's genome can not come from the random or spurious aspects of it's environment, but it can come from constant pressures. Any culling of the population that cannot be overcome by incremental changes in sequencing cannot contribute to the refinement of the sequence. Such culling does occur, but it's just noise. The continued development of the information content of the gene is entirely due to circumstances which affect many organisms and or generations. Environmental randomness can not contribute useful data. The definitions that we use that seem circular aren't so when they are evaluated only in past tense. We can say that organisms(or genes) are fit because they survived and reproduced. We can say an environmental factor was a selective pressure because it caused some organisms to die and not others. We can say another environmental factor was just random happenstance because it made no contribution to the genetic makeup of any lineage. It's all completely self consistent, and in this model natural selection IS the opposite of random. This formulation of evolution gives clear answers to why organisms have their present forms, and it's terms are unambiguous, non circular, and persuasive. However, it only works in the past (the further the better).

I don't think that the temporal limitations of this theory make it any less interesting or convincing. In this theory we know the past and not the future. That seems about right to me, seems to jive with everything else I've experienced about the flow of time.

 

[Ivor the Engineer]

But natural selection, at its most fundamental, is not non-random. No matter how you look at it, natural selection is about taking a sample of a population. Fitter individuals are more likely to end up in the sample and therefore pass on their genes to the next generation than they would be if they were picked at random form the population whereas less fit individuals are less likely to end up in the sample and therefore pass on their genes to the next generation than they would be if they were picked at random form the population.

A sample though is an inherently statistical entity and therefore subject to random fluctuations by its very nature. The fluctuations are accentuated when the population is especially small and decrease as the population increases. Therefore, at sufficiently high population sizes, the effects of random fluctuations on selection are negligible and the population can be said to behave deterministically.

And if you observe a species evolving and measured a parameter of the population that has a significant selection pressure applied to it, e.g., the length of a bird's beak. Over time you would notice a trend with a random variation on top. The trend is considered the non-random part (growing longer or shorter).

Think of a graph with time on the x-axis and the measurement of some parameter on the y-axis. There will often be a line around which the individual points appear to cluster.

I think where the confusion is coming from is that selection pressures are normally slowly changing random events (i.e. trends) and mutations are quickly changing random events (i.e. noise). For sake of understanding, the slowly changing random component is considered constant (or a simple function of time) over the interval the parameter (with its associated random variation) is measured.

 

[sphenisc]

And if you observe a species evolving and measured a parameter of the population that has a significant selection pressure applied to it, e.g., the length of a bird's beak. Over time you would notice a trend with a random variation on top. The trend is considered the non-random part (growing longer or shorter).

Think of a graph with time on the x-axis and the measurement of some parameter on the y-axis. There will often be a line around which the individual points appear to cluster.

I think where the confusion is coming from is that selection pressures are normally slowly changing random events (i.e. trends) and mutations are quickly changing random events (i.e. noise). For sake of understanding, the slowly changing random component is considered constant (or a simple function of time) over the interval the parameter (with its associated random variation) is measured.

My confusion came from the fact that in your first paragraph trends are a non-random part, but by the third they're random events

 

[Ivor the Engineer]

My confusion came from the fact that in your first paragraph trends are a non-random part, but by the third they're random events

It all comes down to time-scales. Viewing a selection pressure over all-time, it appears random. Viewing it over the time period organisms live for it can be considered constant or a simple function of time.

A nice (and much argued about) example is the effect of climate change and the distribution and population of organisms affected by it on the earth.

In a billion years from now, when we're long gone and aliens are taking hi-tech measurements to determine the earths climate over the last few billion years, will our impact on the climate look causal or just like a random blip on the chart?

In the next 50 years, will the climate of the earth appear random or will there be a trend to observe?