Cause of Mutations

[bluetrinity]

I have been following the debate about inteligent design with some interest. Now I have a question to you who know things about evolution. Are mutations random or not? Do they occur by chance alone?

 

[AngelusTenebrae]

They are considered random, but they are not what largely contributes to variation. That would be genetic recombination.

 

[trunks2k]

I have been following the debate about inteligent design with some interest. Now I have a question to you who know things about evolution. Are mutations random or not? Do they occur by chance alone?

Yes, they are random by strict definition of the word. But "random" is not equivelent to the randomness seen in say, rolling a fair 6 sided dice. Just because something is random doesn't mean that all outcomes are equally possible or that the proability of indivdual outcomes are always the same.

Technically, it's not chance. If you want to look at everything at a low enough level, very little, if anything, is actually chance. It may appear to be so, but there is always going to be some sort of condition to caused the outcome, we just might not be able to see it. But that's a whole other subject.

But for our purposes, yes mutations are random and happen by chance. But there will be specific conditions in which mutations are more apt to take place. However, natural selection, while technically random by strict definition, is not random in the same way. Natural selection acts as a very good filter that seperates the "good"mutations from the "bad" mutations.

 

[Dragar]

Technically, it's not chance. If you want to look at everything at a low enough level, very little, if anything, is actually chance.

If you look close enough, quantum mechanics turns up - and that seems to be to be a lot to do with genuine chance. (But not every possibility has an equal probability, even in quantum mechanics, and those probabilities are determined by determinstic dynamics.) And since everything is determined by QM, we may as well say that everything is down to chance. But this is unenlightening.

But to the OP: mutations can be thought of as 'chance' to an extent (and only in the 'ignorance' sort of sense, rather than a genunie, 'quantum chance' sort of sense), so long as you bear in mind that small mutations are more likely than large ones, and a whole slew of other conditions that are a result of how DNA works.

Whether those genes are passed on or not, however, is not chance.

 

[Big Rob]

Jesus is the cause of each and every individual mutation, so no they're not random.

 

[trunks2k]

Whether those genes are passed on or not, however, is not chance.

But it is technically still chance. The chance may be 95% probability that a given set of genes will be passed on, but it's still chance. Say you have two birds one with a beneficial mutation and one without. Both are cometeing for the only available mate. The one with the beneficial mutation wins the mate but as he walks towards his mate to "do the deed" he gets hit by lightning and dies.

 

[bluetrinity]

Yes, they are random by strict definition of the word. But "random" is not equivelent to the randomness seen in say, rolling a fair 6 sided dice. Just because something is random doesn't mean that all outcomes are equally possible or that the proability of indivdual outcomes are always the same.

Technically, it's not chance. If you want to look at everything at a low enough level, very little, if anything, is actually chance. It may appear to be so, but there is always going to be some sort of condition to caused the outcome, we just might not be able to see it. But that's a whole other subject.

But for our purposes, yes mutations are random and happen by chance. But there will be specific conditions in which mutations are more apt to take place. However, natural selection, while technically random by strict definition, is not random in the same way. Natural selection acts as a very good filter that seperates the "good"mutations from the "bad" mutations.

But natural selection is just a word that describes a process, right? I mean, strictly speaking it cannot act. It is not even an it because it has no will, right?

 

[trunks2k]

But natural selection is just a word that describes a process, right? I mean, strictly speaking it cannot act. It is not even an it because it has no will, right?

Yes, it's the general phrase for a larger set of processes. It's a process that is technically random. But the results are "skewed" heavily towards beneficial mutations. The process acts as a rather effective filter.

 

[caravelair]

Yes, it's the general phrase for a larger set of processes. It's a process that is technically random.

natural selection is random? i don't think it is.

 

[Dragar]

But it is technically still chance. The chance may be 95% probability that a given set of genes will be passed on, but it's still chance.

Well, I suppose technically - but then we're back to the 'everything is chance' result, which is rather unenlightening.

But...well, yes. To be honest, discussions of 'is this chance?' or whatever seem less and less meaningful the more I consider the concepts.

 

[bluetrinity]

Yes, it's the general phrase for a larger set of processes. It's a process that is technically random. But the results are "skewed" heavily towards beneficial mutations. The process acts as a rather effective filter.

I see. But when we say "beneficial" or "efficient" presumably we (i.e. you) have an idea of how to define "beneficial" or "efficient". In other words, we have to derive a purpose of these processes, in which case the discussion ceases to be about science and starts to be about philosopy. Right?

 

[bluetrinity]

natural selection is random? i don't think it is.

Given that "it" doesn't really exist in its own right (it really is merely a set of processes, no?), how can natural selection be anything but random? And if NS is not random what is it?

 

[Dragar]

Given that "it" doesn't really exist in its own right (it really is merely a set of processes, no?), how can natural selection be anything but random? And if NS is not random what is it?

Ignoring quantum mechanics, it's deterministic.

 

[caravelair]

I see. But when we say "beneficial" or "efficient" presumably we (i.e. you) have an idea of how to define "beneficial" or "efficient". In other words, we have to derive a purpose of these processes, in which case the discussion ceases to be about science and starts to be about philosopy. Right?

no, we do know how to define beneficial. a beneficial trait is defined as a trait that provides a selective advantage. for example, bacteria that are immune to antiobiotics are more likely to produce offspring in an environment where they are exposed to those antibiotics than ones that are not immune. so the immunity is a beneficial trait in that environment. it has nothing to do with philosophy. it's an observation.

 

[trunks2k]

I see. But when we say "beneficial" or "efficient" presumably we (i.e. you) have an idea of how to define "beneficial" or "efficient". In other words, we have to derive a purpose of these processes, in which case the discussion ceases to be about science and starts to be about philosopy. Right?

Beneficial means that it increases one's chances for survival and reproduction. I could have a mutation in me that allows me to digest, say aluminum, and has no other effect - positive or negative. If I live in a aluminum rich environment and nobody else can digest aluminu; it means that I am less likely to die of starvation, as I have an ample food source. Being less likely to starve means I'm less likely to die young, which means I have an increased chance in living long enough to reproduce.

This does not, however, garuntee that I will live that long or that I will in fact reproduce. There are other factors that can cause my genes to not be passed on to anoter generation (i.e., a tower of aluminum cans falling on me and crushing me to death). But all things other things being equal I had a better chance of passing on genes than someone else not having that mutation. Thus, it is a beneficial mutation.

 

[GoSeminoles!]

Given that "it" doesn't really exist in its own right (it really is merely a set of processes, no?), how can natural selection be anything but random? And if NS is not random what is it?

NS is not random in the sense that the environment determines which varieties of a species will leave more offspring. If mutation and NS were both random, then evolution could not get anywhere.

 

[bluetrinity]

NS is not random in the sense that the environment determines which varieties of a species will leave more offspring. If mutation and NS were both random, then evolution could not get anywhere.

So really NS can be thought of providing the framework for radom mutations to develop into either survival enhancing (i.e. beneficial) traits or survivial impeding ('un'-beneficial) traits. This framework can then be defined as 'everything there is' that impacts the chances for survival, or, in brief, the natural world (including all its laws of physics and whatnot) at that point in time. Given that the natural world itself would have to be the result of that same process, we can think of the whole process in terms of its components: random mutations, natural laws (physics etc), and matter.

 

[Silent Bob]

Given that "it" doesn't really exist in its own right (it really is merely a set of processes, no?), how can natural selection be anything but random? And if NS is not random what is it?

Is falling random? Is current propagating a circuit random? No they are ruled by laws of gravity and electricity. In a way so is natural selection the law is simple those who reproduce and survive go on the rest die out. We don't even need to see an apple falling to objerve that.

If a spider is born in the open with a mutation that makes it have no eyes chances are it will not reach an age to reproduce or will not be able to find a mate so the mutation dies. If a spider living in perpetual darkness (cave) is born without eyes it doesnt have any problems whatsoever in fact it saves energy without maintaining what is useless so that one will survive.

Simple, objerved and 200% reasonable. No randomness.

 

[bluetrinity]

Is falling random? Is current propagating a circuit random? No they are ruled by laws of gravity and electricity. In a way so is natural selection the law is simple those who reproduce and survive go on the rest die out. We don't even need to see an apple falling to objerve that.

If a spider is born in the open with a mutation that makes it have no eyes chances are it will not reach an age to reproduce or will not be able to find a mate so the mutation dies. If a spider living in perpetual darkness (cave) is born without eyes it doesnt have any problems whatsoever in fact it saves energy without maintaining what is useless so that one will survive.

Simple, objerved and 200% reasonable. No randomness.

The question was not, if natural laws are random. I agree tha natural laws can be observed. They are the basic ingredient for life to work. The question was where the mutations come from, in your examle being born without eyes. Look at my last post and tell me, if I summarized it incorrectly, please.

 

[GoSeminoles!]

So really NS can be thought of providing the framework for radom mutations to develop into either survival enhancing (i.e. beneficial) traits or survivial impeding ('un'-beneficial) traits. This framework can then be defined as 'everything there is' that impacts the chances for survival, or, in brief, the natural world (including all its laws of physics and whatnot) at that point in time. Given that the natural world itself would have to be the result of that same process, we can think of the whole process in terms of its components: random mutations, natural laws (physics etc), and matter.

I think this is essentially correct. An example using artificial selection may help.

Suppose a dog breeder wishes to take his existing stock of dalmatians to produce a dalmatian 50 inches tall instead of the normal 25. Each litter will yield dogs with a variety of height; this is where randomness comes in. The breeder selects for further reproduction only the tallest individuals in each litter. So in this example, the breeder plays the role of the environment -- the factor which decides which organisms will reproduce.

Now suppose that in the middle of this process the breeder changes his mind and now wants dalmatians with only 1/2 as many spots. Height is now a secondary concern. The breeder will take his stock of dals, who now may average 40 inches in height, and breeds them with this new goal.

This change in goal reflects what may sometimes be natural selection's moving goal posts. For a million years natural selection may favor only the quickest rabbits so they can avoid their many predators. But when rabbits are introduced to Australia where there are very few predators to threaten them, the selection pressure changes radically. Now natural selection will favor, say, the rabbits who can eat the most food at one sitting or the ones who might have the best immunity to strange Australian diseases. With no predators to flee, even the slow rabbits can make a living. Speed becomes a minor trait.