You can find this information if you read the thread. Do you have to be spoon fed everything?
This is pretty ironic, coming from you of all people. I don't feel like combing through a thread with thousands and thousands of posts -- what is so hard about just telling me? I think your refusal speaks volumes about your character.
Why don’t you tell us what your credentials are, you claim you understand how mutation and selection works, tell us why.
I am a video game programmer, employed by Activision, with a B.S. in Computer Science that includes credits in molecular biology. Is that outstanding? Not at all. But it is the truth.
How does mutation and selection work? Here is an example of a coherent, well thought out, and easy to follow argument -- the kind you are incapable of producing Kleinman. I could be wrong on many points, but at least I put my ideas into a form readable by others so they have the opportunity to show me where I am wrong.
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Given a population and environment, any mutation in any individual of the population can be measured by the change in relative reproductive fitness of the individual as affected by that mutation. Mutations that
increase relative reproductive fitness are termed "beneficial," while those that decrease it are termed "harmful." Furthermore, the relative change in fitness can be "strong" or "weak," depending on just how large the change is.
When relative reproductive fitness is increased, an individual has a relatively higher chance to propagate its DNA to the next generation by having offspring. When decreased, the opposite occurs. These offspring, in turn, have the same fate. Over time, the changed percentages (relative to the other individuals in the population) lead to the mutation either being present in the vast majority of individuals' genomes (evolution) or hardly any (no evolution). This is "selection."
That is it. There is nothing more to evolution.
Where does "optimization/sorting" fall in this process? Clearly, the selection process can be viewed as a type of sorting, because individuals with higher relative reproductive fitness tend to be placed "ahead" of those with lower. Furthermore, the selection process can be said ` There are two important distinctions from a typical sorting algorithm, however, that are very important.
First,
the individuals sort themselves, not some external entity. Thus, there is no such thing as the "sorting slowing down" -- it always proceeds at a rate determined by the species life cycle and nothing else.
Second, selection is fact
not simple sorting. Rather, it is a process that can be
viewed as somewhat analagous to sorting. The sorting influences the results of selection, but selection happens every generation regardless.
What does this mean for evolution and multiple selective pressures?
First of all we need to define exactly what we mean by "rate of evolution." For this discussion, it means "rate of fixation of mutations into the species' genome," or in other words, how long it takes on avearge for a given mutation to spread so that a good majority of the individuals in the population carry it.
Second, we need to define "selective pressure," which for this discussion is simply a factor in the environment that, when paired with a mutation, leads to a given change in relative reproductive fitness. A "stronger" pressure results in a larger change than a "weaker" pressure, given the same pairing.
Knowing all of this, generating some fairly accurate ideas of what will happen to a population subjected to multiple selective pressures of varying strengths is not difficult.
The individuals still sort themselves according to relative reproductive fitness, in the same amount of time as before. Those with the most/strongest beneficial mutations will tend to have the most offspring, those with the fewest/weakest beneficial mutations will tend to have the least, and vica versa for harmful mutations.
The difference is that, because a single mutation is not responsible for determining relative fitness anymore, it will take more generations for a given mutation to either spread throughout the population or disappear from the population, depending on the difference that mutation affects in relative fitness.
The change still happens, however, and furthermore, the distribution of all the mutations changes in parallel. This brings us to Adequate's graph. Because the distribution of all mutations is changing at once, in
parallel, the extra time it takes for any one of them to be fixed in the genome is more than made up for. Adequate's graph shows the results that this fact leads to.
Suppose you have 50 pressures, and each of them takes on average 100 generations to result in their corresponding mutations being fixed (evolution). Then if you apply them all back to back, one at a time, it will take 50 x 100 or 5000 generations for all the mutations to be fixed and the evolution completed. Now suppose you apply them all at once. It doesn't matter that it may take much, much longer for each mutation to be fixed -- as long as they are all finished by generation 4999, the
average number of generations to fixation will be
less than before. And that means a faster rate of evolution. Does this actually happen? Adequate says it does, and I will whip up a little simulation of my own to see for myself. My hunch is "yes, it does."
In the context of all the studies Kleinman cites, this doesn't matter -- the goal of the pressures is to actually kill off the population, and so taking longer for a resistance mutation to be fixed is extremely damaging. If the entire population is dead by generation 2000, then
obviously evolution will be profoundly slowed.
ETA: Everyone, please critique these ideas if they seem wrong in any way -- I want to show Kleinman what an intelligent discussion between educated people actually looks like.