Evolution, as many percieve it, is wrong.

[fantome profane]

So wouldn't evolution be random but natural selection follow the predictable patterns?

No, I don’t think that is right either. Natural selection is part of evolution and natural selection is not random. Evolution is not totally random. Mutation is random, we cannot predict what kind of mutations will occur but in some instances we are able to predict which mutations will be selected.

 

[Jayhawker Soule]

Natural selection is part of evolution and natural selection is not random. Evolution is not totally random. Mutation is random, we cannot predict what kind of mutations will occur but in some instances we are able to predict which mutations will be selected.

"Random" is an elusive quality in a causal universe, and it is unclear to me that the term has much value except as a poor antonym for 'purposive'.

 

[Ryan2065]

No, I don’t think that is right either. Natural selection is part of evolution and natural selection is not random. Evolution is not totally random. Mutation is random, we cannot predict what kind of mutations will occur but in some instances we are able to predict which mutations will be selected.

But if you cannot predict the outcome of a process it is random (well this is how I interpret the definition of random). Because you cannot predict if a creature is going to grow bigger, get a different color, not change at all, etc, etc, etc you cannot predict what the outcome is going to be of a change in the environment (which brings about evolution). Because you cannot predict the outcome, I consider it random.

 

[Jayhawker Soule]

But if you cannot predict the outcome of a process it is random (well this is how I interpret the definition of random).

Sounds a bit like Humpty-Dumpty to me. Actually, it sounds just plain wrong.

 

[Ryan2065]

Sounds a bit like Humpty-Dumpty to me. Actually, it sounds just plain wrong.

So what would you call a system where you cannot predict the outcome?

 

[Jayhawker Soule]

So what would you call a system where you cannot predict the outcome?

Shucks, Ryan, I'm not sure, but 'unpredictable' comes to mind, and I think that a vernacular that equates 'unpredictable' with 'random' is every bit as unnecessary and problematic as a vernacular that equates 'evolution' with 'progress'.

 

[logician]

I think the idea of "random" here is that you cannot restart the tape of life and guarantee that the outcome of evolution would be the same. In fact the probalility is almost certain that the outcomes would be different.

 

[Jayhawker Soule]

I think the idea of "random" here is that ...

Granted, but why would you preferentially refer the term 'random' over 'unpredictable'?

 

[painted wolf]

you can say that flipping a coin is random... but the results will allways be heads or tails. (thus it is predictable)
Unpredictable means it could just as easily turn into a butterfly and not land at all.

Evolution is not heads or tails. You can not predict what will happin in the next several millionn years, no matter how fun it is to try.

wa:do

 

[Yerda]

Mutation is random....

I'm not so sure.

...we cannot predict what kind of mutations will occur...

Why not?

 

[Zeno]

Ok, I'm going to try to clarify a few things, here goes.

Evolution by definition is not random. Things do not arise on their own from nothingness. An eye does not just randomly pop into existence. Natural selection guides this process.

DNA mutations in general are "random" but only in terms of "lack of selection." The individual base-pair mutations themselves are not "selected for." There exists no physical process that selects for which base-pair to mutate.

Aspects of mutations that are "non-random":

• Purines are more likely to mutate into purines, as they are more likely to "hide" from the DNA repair mechanisms. Also, pyrimidines are more likely to mutate into other pyrimidines, for the same reason. These mutations are called Transition mutations. Transversions occur when a purine mutates into a pyrimidine or vice versa - these are less likely because the DNA repair mechanisms are more likely to catch them.
• Silent mutations will be more frequent then say Nonsense mutations. Because with silent mutations you will have no loss of amino acid or functions. Nonsense mutations code for a premature stop codon and will truncate the amino acid. Missense mutations will code for a different (albeit complete) amino acid and are less common than silent mutations, but more common than Nonsense mutations.
• If a heterozygous individual ( a carrier) for a certain recessive allele has normal functioning, then this allele will more likely be passed on then a different allele which alters the functioning of a carrier.
• Most other non-random characteristics of DNA mutations are derivatives of these.

The key point is that billions of these mutations happen over billions of years. The negative ones are weeded out very efficiently by natural selection. And in changing environments, the positive ones are selected for with great efficiency.

 

[fantome profane]

I'm not so sure.

Why not?

There seems to be a lot of difficulty concerning the use of the word “random”. It is a word that can be used in different ways and there can be different degrees of “randomness”. Random doesn’t necessarily mean that anything is possible, or that everything is equally possible. It is possible to have a certain degree of randomness within certain parameters. It is also possible for some outcomes to be more likely than others and still call the process random.

As to the question of whether genetic mutations are random, I think Zeno has responded to that question better than I can when he talks about the non-random elements. I think we can say that mutation is not completely random. Some mutations are more likely than others. Mutations may be more likely to occur on one part of the chromosome rather than other parts. Mutations may even be more likely in some environments than in others. But despite all this I still feel comfortable in saying that genetic mutation is random. There is no evidence that it is guided by any conscious force, and although it obeys certain physical laws, these physical laws do not seem to be guiding mutation in any specific direction. So yes, within certain parameters mutation is random.


And here is another thought.

Dr. Kenneth Miller has suggested that it is possible that genetic mutations may be influenced by quantum fluctuations. The number of atom that make up a microscopic gene is although huge, very small when compared to the number of atoms that make up any macroscopic object. It is possible that the quantum fluctuations that are factored out on the level of objects that we can see and interact with may not be totally factored out down at the microscopic level of the gene. If this is the case then genetic mutation may be even more random than we realize.


At any rate I don’t believe that we currently have the ability to predict what kind of mutations will happen and when.

 

[Yerda]

There seems to be a lot of difficulty concerning the use of the word “random”. It is a word that can be used in different ways and there can be different degrees of “randomness”. Random doesn’t necessarily mean that anything is possible, or that everything is equally possible. It is possible to have a certain degree of randomness within certain parameters. It is also possible for some outcomes to be more likely than others and still call the process random.

Fair enough. It depends what you mean by random. It seems some people like to use random as a way of saying uncaused.

Dr. Kenneth Miller has suggested that it is possible that genetic mutations may be influenced by quantum fluctuations. The number of atom that make up a microscopic gene is although huge, very small when compared to the number of atoms that make up any macroscopic object. It is possible that the quantum fluctuations that are factored out on the level of objects that we can see and interact with may not be totally factored out down at the microscopic level of the gene. If this is the case then genetic mutation may be even more random than we realize.

I don't have a sufficient understanding of physics or physical chemistry to know what to make of this.

At any rate I don’t believe that we currently have the ability to predict what kind of mutations will happen and when.

Perhaps. We can say quite confidently though that certain conditions like a highly reducing environment will lead to certain types of mutation. Lactim-lactam tautomerisation of DNA bases will often result in substitution mutations [at single points] in the daughter DNA strand during replication etcetera.

At any rate, I'm not sure random and predictable make good antonyms. Random, to me, suggests lack of pattern and reason.

 

[painted wolf]

All I know is no one would have predicted something like the Hammerhead shark evolving from the normal shark. They are an amazing abberation and good evidence for the thoery of punctuated equilibrium.

wa:do

 

[logician]

All I know is no one would have predicted something like the Hammerhead shark evolving from the normal shark. They are an amazing abberation and good evidence for the thoery of punctuated equilibrium.

wa:do

Better evidence for punctuated equilibria is in the Burgess shale in the original "flowering" of multicellular life, or the rapid evolution of mammals following the demise of the dinosaurs. Various abberations like the hammerhead shark may or may not be such good examples.

 

[painted wolf]

more and better precambrian fossils are helping to demistify the "cambrain explosion".
Still a very intresting time period.
Hammerheads are an example of a single unique family suddenly appearing semingly out of nowhere and then rapidly diversifying.

That one in a million mutation that proves wildly successful.

wa:do

 

[Ryan2065]

you can say that flipping a coin is random... but the results will allways be heads or tails. (thus it is predictable)
Unpredictable means it could just as easily turn into a butterfly and not land at all.

Evolution is not heads or tails. You can not predict what will happin in the next several millionn years, no matter how fun it is to try.

So evolution is more complicated than flipping a coin therefore it is unpredictable? There are a set number of things that can happen with the evolution of a species. The size can change, speed, environment it lives in, etc. But these things can be listed out on a piece of paper. We can predict what changes could occur, we just don't know which one of these changes will occur, if any.

So I still stand by my original statement saying evolution is random. We can list all the possibilities that could happen, we just don't know which possibilities will happen.

 

[lunamoth]

So I still stand by my original statement saying evolution is random. We can list all the possibilities that could happen, we just don't know which possibilities will happen.

Evolution is not random. It is a combination of random changes + natural selection. Beneficial changes are retained, non-beneficial changes are lost, which is a non-random process.

In natural selection the selection process is affected by conditions in the environment. But the mechanism is not too much different from artificial selection used in breeding in which humans intervene and select for traits they desire.

 

[Yerda]

So I still stand by my original statement saying evolution is random. We can list all the possibilities that could happen, we just don't know which possibilities will happen.

If you take unpredictable as synonymous with random then your original statement ('evolution is random') is tautological. Why bother?

 

[logician]

From the dictionary.

American Heritage Dictionary - Cite This Source
ran·dom

1. Having no specific pattern, purpose, or objective

From this definition, evolution is pretty much a random process, at least in having no purpose or objective, although some patterns may emerge from time to time.