Random mutations

As I understand it random mutations are random WRT to their effect on the fitness of the organism.
Is this the best way to describe it?
If so what evidence is used to support this idea?
What might falsify it?[This message has been edited by judge, 11-25-2003][This message has been edited by judge, 11-25-2003]

Loudmouth:
So, saying that the effect on fitness is random isn't quite accurate, rather mutations are random changes in the DNA which may or may not affect fitness.Judge:
So does it mean random as in "unpredictable".
Is it that the "mutagen" (is that right) is not disposed in any particular way WRT fitness?Loudmouth:I can look up some papers for you if you wish, but suffice it to say that studies that have looked at antibiotic resistance in bacteria, for example, have not seen the same mutation occuring among all resistant bacteria. It doesn't look like there is a mechanism that allows organisms to specifically change their DNA in response to an environmental stress. Rather, mutants are selected for by the environment.Judge:
That would be great if you have the time. I am trying to learn more about the science of this and how science actually works.[This message has been edited by judge, 11-25-2003]

Rrhain:
It seems that selective pressures can be specific enough to result in only those organisms that acquire specific mutations.Judge:
Does this mean that at one point there were (or may have been) organisms that aquire specific mutations and other organisms (which otherwise were much the same) that did not aquire these same mutations; and that the organisms that aquired the mutations were selected for?
And I suppose that the tendency to aquire these mutations is reatained?The result being that we now have some organisms that aquire specific mutations and that although these mutations are in fact random they appear non random (so to speak).Sorry if this is wordy .[This message has been edited by judge, 11-25-2003][This message has been edited by judge, 11-25-2003]

I think it is best if we ignore my last post , I misunderstood something you said and went off into another dimension Rrhain:
judge,Basically, from what I can glean from the abstract, it's kinda like playing a game of Yacht where the only way to get into the next round is to roll five 6s on the very first roll.The die roll is completely random, but the selective pressure is so specific that only a certain type is selected for.Judge:
If there were a realtion between the environment "triggereing" a mutation or even an increased likelihood of a particular mutation it would be difficult to falsify or even find compelling evidence for.Is this correct?And so although it may be possible to "find" anomolies the simplest explanation (and the one which appears to be true) is that particular (beneficial)mutations are never "triggered" by environmental influences.[This message has been edited by judge, 11-26-2003]

Thanks for the replies....I get the WWJD? bit but the next part loses me.