jbush at afit.af.mil wrote:
>I recently saw on the news a group of mutated frogs (most likely occured
>from the waste we produce). These frogs were surviving, but these
>mutations didn't seem to improve the frogs any. So I was just
>wondereing...
>Has anyone ever observed a true *benefitial* mutation occuring in nature?
>And by the way, don't give me examples of Natural Selection, I know the
>difference.
Yes, unfortunately I know one. Look at AIDS !!!
Well, certainly evolution will be discovered mostly and fastest on the
smallest and most primitive lifeforms, the viruses - if you accept them
as lifeforms. At least they are experienting mutations as much as the
more complex, "real" lifeforms.
As you certainly know, AIDS is so harmful BECAUSE it is mutating faster
than the human imunity system can ever adapt to them.
Why is this so? And why is mutation fastest on this "species"?
1) There are naturally a higher population count of smallest lifeforms,
than for example frogs. So the probability of a "good" mutation is
multiplicated by the pupulation count.
2) The generation cycle is faster.
3) The Ability to protect against mutation is weaker. No double set
of cromosomes. Indeed AIDS - as a retrovirus - has not even the
complementary half of the DNA, so no redundancy at all might
"repair" any mutation.
$) I can't avoid the subject selection here:
As more complex an organism, as less probable is a "good" mutation.
You might improve a nail by a hit with a heavy hammer. The chance
to improve a watch this way is almost zero.....
And AIDS viruses are so primitive - compared to frogs - that there
is a good chance that some percent of the mutations will improve
something, at least it will change the surface of the virusses
hull and therefor improve the survivability against the immunity
system.
5) smaller lifeforms tend to have more children.
One single AIDS virues can certainly force more copies of itself,
than a frog can have, and a frog can have more than a human.
----------
If you count the accumulation of all 5 points above, who wonders that
we CAN see evolution by pure mutation of the AIDS viruses, but we
can't see it with humans?
An interesting URL:
http://www.physics.wisc.edu/~shalizi/Dawkins/viruses-of-the-mind.html
Comments welcome.
