2011-05-24, 01:23 AM
Eosian Wrote:It can be environmental; ie: UV radiation (sunlight) can alter DNA as can chemical exposure and numerous other things and it can occur just due to freak chance. There is no solid answer for all of it because in most circumstances we have no idea what the variables are. You didn't see variation in your tests because they were too tightly controlled, no chance for external stimuli to introduce deviations and not enough generations for nature to have done it itself.
Yeah, radiation, viruses, chemicals seem environmental (though that's far from enough) whist genetic transposition and/or errors in reproduction seem pretty random to me.
That certainly did put one new thing into perspective: Environments COULD drive the mutations while fitness guides the selection. Without external factors, few (or just less) changes would happen (I recall there being background genetic variation, but I have no clue what it is).
Once driven, the changes are selected for/against and produce the 'final' result of the fittest variation.
Those two are pretty separate.
@ Mira: I have to admit Biology and Chemistry are two of my least favorite subjects.