Sticking a fork in Natural Selection (Introduction)

by xeno6696 , Sonoran Desert, Saturday, December 10, 2011, 22:03 (4732 days ago) @ dhw

dhw,

In passing, I'd like to add something to your statement, which I'm sure you will approve of! As far as I can make out, epigenetics only covers adaptation – just as you have said yourself. Adaptation on its own is not enough to account for new organs and species (though as both Tony and Darwin often point out, it's very hard to define "species"). There has to be innovation as well. Perhaps – just perhaps – epigenetics may shed light on this too, but whatever the mechanism, it has to increase the odds against chance.

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?

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?

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

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

I've been bumbling about as of late, but I must stress that I have a great deal of confusion... evolution isn't fast enough, but we accept it... I understand evolution as a demand-based system, but I don't understand how it's unacceptable for current theory to "not be fast enough." To my mind, it works like this:

Normal reproduction results in a great deal of non-deleterious mutations. If the environment is stable over time, I understand that these changes will accumulate--but likely not manifest, because largely, mutations that don't result in death result in:

1. Dormant abilities that don't appear to have any immediate use.

2. Completely benign changes.

The changes don't manifest themselves until "Natural Selection," ie,

3. the organism gains a pure benefit.

4. The environment shifts (either through mobility, seasons, or something else like disaster...)

From my perspective, Natural Selection IS the prime motivator of change. IF an organism isn't required to change until its under stress, then clearly it doesn't really matter where organismal change comes from: 1M dormant epigenetic changes combined with 1M non-beneficial changes means nothing if something about the organism doesn't change in regards to the environment.

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. It's passive from an individual perspective--yet none of us would have a problem with the argument that after the act of intercourse, our kids came about by processes nearly completely uncontrolled from ourselves. (I don't see how the "passive" argument holds...)

--
\"Why is it, Master, that ascetics fight with ascetics?\"

\"It is, brahmin, because of attachment to views, adherence to views, fixation on views, addiction to views, obsession with views, holding firmly to views that ascetics fight with ascetics.\"