Message 93 of 393 (792469)
10-10-2016 10:12 AM
Reply to: Message 33 by Kleinman
10-07-2016 5:32 PM
|They are rare events when a particular mutation must occur at a particular site in the genome to improve fitness.|
And at that level is what I'm talking about when I say that you are wrong to look at these as purely random events on which you should be making probability calculations.
Having a particular mutation at a particular site may or may not be random.
|And natural selection must do something specifically to improve the probability that a particular mutation will occur at a particular site in a genome to improve fitness.|
Wrong. Natural Selection does not do stuff, it is an effect.
|In any stochastic process, it is not possible to predict the outcome of any random experiment. What probability theory does is enable one to predict the relative frequencies of outcomes when the random experiment is done many times. A simple example is tossing a coin. You can not predict whether a head or a tail comes up with any toss. What you can predict is that if you toss the coin many times, about half the outcomes will be heads, the other half of the outcomes will be tails.|
But coin tosses are completely independent. What if the odds of a particular mutation occurring are dependent on previous states?
So what is the frequency of a mutation occurring at a particular site in a genome?
Which mutation and which site?
Any particular mutation at any particular site.
Huh? That's like me asking you the frequency of rolling a 7 on a die, for any die with any number of sides for either a fair or unfair die...
|What I'm trying to get at is the definition of mutation rate. The mutation rate is the probability that mutation will occur at a given site in the genome in a single replication.|
No, it isn't. It is a measurement of how many mutations of a particular type one would expect to see over a given amount of time.
Natural selection is totally relevant. Natural selection must do something very specific in order to improve the probability that a beneficial mutation will occur.
No, that's complete nonsense. Natural selection doesn't do stuff.
It certainly does, natural selection changes the probabilities of particular mutations occurring by changing population sizes.
No, the environment changes the population sizes. Natural selection is the differential successes that the populations have because of the effect that the environment has on them.
And if NS did change the probabilities of mutations occurring, then how could you treat those mutations as random?
|You are changing the mutation rate but you are not changing the fact that mutations are random events.|
If I know what kind of radiation causes which mutations, and I do it on purpose, then those mutations would not be random.
|You need to give us an empirical example where a mutation is not a random event.|
Have you tried doing a Google Scholar search for "non random mutations"?
I'll tell you what; when you start providing evidence for your claims, I'll come back and start looking for sources to provide you.
|Random means something that occurs by chance, not predictable.|
Right, and if whether or not a mutation occurs can be affected by previous states, unlike a coin toss, then those mutations do not occur by chance alone, i.e. they are not truly random.
I'm pretty sure that I hit the nail on the head in my first reply to you: You're misunderstanding what the Theory of Evolution means by calling a mutation random.
It does not mean that all mutations happen purely by chance, like you are using it.
Natural Selection occurs at the phenotype, and from that perspective, mutations do appear to occur purely from chance (and even in this case there are exceptions). The ToE talks about mutations being random with respect to fitness.
That "with respect to fitness" is the important part you are missing, which is allowing you to make the mistake of treating mutations as a result of pure independent chance that you can then do coin-toss-like probability calculations on at the genetic level.
You can't treat all mutations as independent events and then provide a probability calculation to say that the odds of these particular mutations happening in series is impossible.
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| ||Message 33 by Kleinman, posted 10-07-2016 5:32 PM|| ||Kleinman has not yet responded|