Sticking a fork in Natural Selection (Introduction)

by dhw, Sunday, December 11, 2011, 16:45 (4732 days ago) @ xeno6696

MATT: One of the key findings of the beta-lactamase experiment I discussed earlier, is that when the E. coli cells were under stress, they "invented" the ability to metabolise lactase. Why can you not extend the logic of "need precipitates change" to organs, if they do indeed work for genes?

Round we go. Matt, you have sent me rooting back into your past posts. On 27 July at 20.42 you stressed that “the beta-lactamase experiment was NOT integral to the species. Several generations continued with the bacteria moving along just fine – only more slowly…the gene sequence changed in a manner consistent with random mutations…it clearly demonstrates that SOME beneficial changes CAN come by chance.” Now you are arguing that it wasn’t by chance but by need. You really can’t have it both ways – either this was a random mutation (your original argument) or it was an adaptation required by the environment.

MATT: I keep getting tripped up in Natural Selection discussions, partially because I always lose sight of the fact: Evolution by Natural Selection works ONLY on a demand basis... the organism comes under stress and then the organism adapts... again I ask, why is there some need to assume that need doesn't precipitate change?

When have I ever argued that need doesn’t precipitate change? That is the whole point of adaptation! But your confusion over the beta-lactamase experiment highlights the issue of what causes change. One cause is the need to adapt, and the other is random mutation. Nobody knows to what extent these two causes overlap. All we know is that if the changes do not enable the organism to survive in the given environment, Natural Selection will result in its being eliminated.

MATT: Both yourself and David have chastised me about the idea of currently accepted evolutionary theory as not "being fast enough."

No, that has not been the issue at all with me. You have been chastised firstly because you insisted that NS was synonymous with evolution, and now because: “From my perspective, Natural Selection IS the prime motivator of change.” NS does not motivate anything. Changes in the environment may well be the prime motivator, because organisms must ADAPT or die, but random mutations are the other motivator and may account for INNOVATIONS (new organs). But again these will not survive unless they are useful in the given environment. NS does not MOTIVATE either form of change – it only determines whether these changes will survive. It is passive (David’s term, not mine) in the sense that it doesn’t create anything. It only works on what already exists. The argument concerning the SPEED of evolution has nothing to do with NS. David’s point is that the speed is too great for chance to have created this vast variety of organs and organisms in the given amount of time.

MATT: But I really don't understand what's wrong about the idea of a demand-based evolutionary system--the one we have.

Nothing is wrong with it. All that’s wrong is your insistence that Natural Selection takes place before there is something to select.

MATT: I've been bumbling about as of late.

Because you keep trying to prove that Natural Selection takes place before there is something to select.

MATT: I realize David and you both consider this a passive process, but it's only passive from a naive perspective... ie, the process of a new individual being created (sexually or asexually) is hardly what I would call passive.

DAVID: Selection occurs AFTER reproduction produces a new organism in a hopefully new and capable form.

Exactly. Or to put it another way, Natural Selection cannot take place until there is something to select.

Summary: NS does not create anything. Random mutations may be creative. NS does not motivate anything. Changes in the environment motivate changes in the organism (= adaptation). NS decides which changes – by random mutation or adaptation– will survive. Nothing can be selected, even by Nature, before there is something to select.
QED, LOL, DHW