The End of Evolution By Means of Natural Selection

That is true; if only a subset of the population reproduces then the variability in the set that did not reproduce is lost.Your argument appears to be based on the concept that because a subset of all possible mutations is being selected, the population must necessarily trend toward a single genetic standard. To illustrate where this goes wrong, consider this hypothetical bloodline:An organism has 5 genetically distinct offspring (they each have their own unique variations). Two of these do not reproduce, the remaining three having been "selected". These three in turn have 5 genetically distinct offspring each, 2 each of which do not survive (6 lost, 9 reproducing).You seem to be claiming that because the theoretical possibility of having 25 genetically distinct organisms descended from 5 bloodlines is being reduced through selection, that the genetic diversity must necessarily trend toward zero. The problem is that in this example we are left with 9 genetically distinct organisms descended from 3 distinct bloodlines, when we started out with one.The series [1, 3, 9] does not appear to trend toward zero in my view.

This is where you lose *me*; if you are focusing on a single trait then how can you make broad claims about genetic variability? While that particular trait might beat out inferior alternative traits, it says nothing about the overall genetic variation of the population. Indeed, it does not even indicate that this superior trait will not in turn be replaced by a more beneficial mutation. This is where you go wrong. An individual descended from another individual does not lose genetic variability based on if its siblings reproduce or not. Each offspring is an imperfect copy based on the theme of the parent; the individual is not winnowing its own genetics through reproduction, the winnowing occurs through the possibility that it will not reproduce at all.It appears that you think an organism capable of asexual reproduction, if followed down through several generations, would show a narrowing and refinement of beneficial traits.I realize I might not be making my point very well, so I made graphics! The first is what I understand you are talking about, with the circles representing organisms descending in a tree, with the colors representing traits: As each generation goes down certain traits are "selected" and the offspring lose genetic diversity. The problem is that this is a gross misunderstanding of what *actually* happens in evolution. Observe: In this case each organism is based on the traits of its predecessors, but with minor modification. The "selection" comes in when an organism fails to reproduce; for instance if the third generation organism with the yellow quarter fails to reproduce, then the 4th generation population would lack the yellow trait. This acts as a selection pressure toward all the other colors, and away from yellow. However, even with the lack of the yellow trait the fourth generation will be more diverse than any of the previous generations. That is exactly what I am saying, because evolution as you are describing it is incorrect. It does not exist. As the trend continues the species would change, taking on beneficial traits as they crop up and are selected for. That is the fundamental process of evolution; what you are talking about is speciation which does require isolation for those traits to differ significantly enough to prevent interbreeding, but the concept remains the same. Even then, a smaller isolated population would continue in increasing genetic diversity with the beneficial modifications receiving positive selection pressure.