A special case in general.
I'd mock you, but the challenge is gone.
As soon as such or such an example is being looked at, we need to verify if the antibiotic resistance wasn't already part of the genome of the population.
Sure, and it is easy to verify in specific cases that is wasn't.
Why make a big deal about this? You admit that it can happen, you admit that it has happened, but you want to submit a caveat that has nothing to do with either of those propositions.
I'll take another example. On windy islands, it is beneficial for beetles to be unable to fly. And so if I bring a new flying beetle species, given enough time one of the individuals will have a mutation which will disable it's capacity to fly. Relatively speaking, this will be done rather quickly, since there are many mutations that can give this result. And so if the species stays there long enough, it will become fixed in the population and so every single beetle will have it, which means the previous version of the genome no longer exists in the population.
OK so far. That's the theory of evolution.
Now at this stage, I remove them from the island and put them back on another windless island. Here, being able to fly would be an advantage again. But how many mutations will be able to give that characteristic back ? Only one, the inverse of the previous.
No.
In fact, it is more likely that a second flight-inhibiting mutation gets in the population through genetic drift
Show your working.
and if this is to happen, then the capacity to fly is by all accounts lost forever for this population
No.
Why did you say "by all accounts"?
Why is this ? Because it is far more easier to destroy something than to improve something. Since natural selection depends on the environment, it gives us the wrong impression that a specific mutation/change value is only relative to it's environment. But it isn't, it still has an intrisect 'destructive' or 'constructive' value (If I can use those terms)
That was just odd.
Not all changes are created equal, and in fact it is much more easier to tumble down mount improbable then to climb up it.
For a single act of genetic transmission from father to son, yes. For the lineage, no. Natural selection means that it
has to "climb Mount Improbable". That's what it does.
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