ken fabos writes:
Greyseal - I don't see how mutations can derive from anything except individuals - whilst a specific mutation can occur independently the chances of that aren't high wheras a mutant gene will be passed to descendents and, as long as that line doesn’t die out, will almost certainly become part of the gene pool.
Hi Ken, I don't think you understand what I mean.
Firstly, mutations happen all the time. Every single child is a mutant since no child is an exact copy of one of the parents (at least not in humans). In addition to pure hereditry, mutations occur as well.
Finally, a particular (beneficial) mutation may originate with one individual, but for that mutation to become general it has to
a) propagate (i.e. there need to be descendants who can carry it hereditarily)
b) be advantageous or at least not disadvantageous whilst doing so.
if you take humans (and this is my interpretation of the history of humans according to my limited understanding of the facts) then at some point there was a population of ape-like creatures. They separated into
at least two groups.
One group set off for the plains of Africa, the other stayed in the jungle.
We will focus on the plains-group - mutations happened continuously by chance to
individuals within this group (well, in the process of their conception). Those which were less hairy (either because or inspite of this!) faired
in general better.
I think you agree with me there. If that's what you meant, you may as well stop here, because you are correct - although there is no reason that a mutation MUST occur in
only one individual. The same random change could occur multiple times - certain changes are small enough, or the population big enough - or the same result could occur in more than one way.
unless they were immediately bald like us, chances are there will be further mutations reducing hairiness, which would again confer better survivability, which would once again mean that more and more of the population (over time) has this new-new gene change.
...and so on.
Now, my method is, to my understanding, what happened. The changes are random, and natural selection working on those changes favour, over time, certain mutations over others.
What's your version?