Subject: Re: talk.origins faq Hitler claim part 3 Date: 1 September 2005 Message-ID: firstname.lastname@example.org
> > > Natural selection therefore needs
> > > to be redefined to take account of beneficial not being preserved.
> > It is. What the hell do you think the word "tendency" means? It means
> > that not every individual with a trait will reproduce, but, *when*
> > there is natural selection, individuals (note the plural; this means a
> > population) with one trait will *tend* to reproduce at a significantly
> > higher rate than inidividuals (note plural again) with the alternative
> > trait.
> So since you take account of beneficial being destroyed *within*
> natural selection, then I can say that natural selection results in
> individual beneficial variants being destroyed,
No. *When* there is natural selection, namely an environmental factor that significantly favors one variant over another, that factor is *added on* to the background level of chance alone leading to loss of individuals that would occur in that environment *even if* there were no selective difference between the traits. Malthus explicitly points out that any organism can readily outreproduce the carrying capacity of its environment.
Let me give an example. Mice that live in most deserts have agouti fur (sandy colored). But in the American southwest there are "islands" with sand that came from black lava rock. The carrying capacity of these "islands" for the agouti mice is lower than the surrounding environment because of *increased* losses specifically to visually-oriented predators (mainly hawks and owls to a lesser extent). That does not mean that agouti mice are immune to visually-oriented predators in the sandy colored areas. There is predation of agouti mice by visually-oriented predators even there. And there is also loss due to disease (which doesn't care what color the mice are) and predators that are not as visually-oriented (pit vipers in particular). And the visually-oriented predators also make use of non-color clues (motion, sound). It is just that the agouti mice stand out more in the black lava areas.
As long as all you have is agouti mice, there is no natural selection because you do not have two variants. There *is* environmentally caused loss of reproductive capacity -- by predation of all sorts and by disease.
Now, let's introduce a melanic variant (interestingly but not surprisingly, the melanic variants in these widely separated "islands" are due to changes in *different* genes -- almost as if the variants were due to chance local mutation rather than intentional design ;-)). This melanic variant is significantly less likely to be preyed upon by visually-oriented predators *in the black sand area*. [The opposite is true in the sandy-colored regions, where the melanic variant stands out.]
The difference in visually-oriented predation between the melanic and agouti variants is *significant*. But the melanic variants are still susceptible to disease, to predation by non-visually oriented predators, and even by visually-oriented predators who detect motion, sound, or even visually detectable shape because of an unfortunate choice of background within the black-sand area. There are still constraints on the reproductive success of the melanic variants in this region. But the melanic variant is *significantly less likely to be* (not absolutely protected from being) spotted by a visually oriented predator than an agouti mouse; it is favored (beneficial) in the black-sand environment.
But the melanic variants still die of disease *at the same rate as the agouti variant in sandy-colored areas. They still are preyed upon by pit vipers who do not rely on visual cues, but heat, at the same rate as the agouti variant. There *is* an environmental factor or cause favoring the melanic variant *in the black-sand areas* (and disfavoring it in the surrounding sandy-colored areas). Natural selection is occurring here. But it certainly is not an absolute protection. And it is NOT that the environment is *protecting* or doing anything active to encourage the reproduction of the melanic mice in these islands. It is merely that, because of the black background, the melanic mice are not being knocked off quite as rapidly as the agouti mice *in this local environment*. There is *nothing* intentional or teleological about this process. And the losses of the melanic mice in the black-sand area is not *due to* or a *consequence of* their being melanic. Being melanic can only be *beneficial* in that environment relative to being agouti. But that does not make melanic mice perfect reproducing machines. There will still be substantial loss of mice in this environment due to the environment (disease and predators, including visually-oriented predators who won't miss seeing all the melanic mice, only a greater percentage of them). These other factors, however, treat both agouti and melanic mice equally and thus are not *causal* or *selective* reasons that favor one variant over the other.
The consequence, of course, is that the black-sand islands wind up having a high frequency of melanic mice isolated in a sea of agouti mice in the surrounding sandy-colored areas. That is exactly what natural selection would predict, adaptation to local conditions by differential reproduction of randomly generated variants, isn't it?
> as well as extinction
> of beneficial, when the chance of reproduction doesn't turn out the way
> it is more likely to turn out?
> Oh wait no, chances of reproduction may not actually turn out against
> the fittest in natural selection, because the fittest have a special
> superduper value-laden infused chance of reproduction.
Fitter, nando, fitter. Fitness is *comparative* not an *absolute*. And unless your environment has only a single factor, there are many ways for the environment to prevent reproduction (a consequence of the mathematics of Malthus) that having the particular traits being examined does not affect.
Selection is really not *for* a trait. It is a *relative* relaxing of the Malthusian fate that the environment always poses -- that potential reproductive capacity is always greater than carrying capacity of the environment, meaning that there will always be losses. That is, in a particular environment, some traits are lost *significantly* less than others in the Malthusian calculation. *When* that happens, we say that the trait that loses less is better adapted to those environmental conditions than the alternative. That is natural selection.
> That you emphasize *when* must mean that you go looking after the fact
> to attribute a name to the occurrence, and if the outcome is the way
> *you like it to be* then you call it natural selection.
You mean that you actually object to my insisting that we observe that natural selection occurred before I use that term to describe what happened? Unlike you who call everything that can possibly happen natural selection, treat it as an individual and not a population property, and produce an indigestible mishmash of mental goo, meaning nothing?
And I am not choosing which outcome (which trait is the "winner" and which is the "loser" in the specified environment) is beneficial on the basis of "I would like it to be" the beneficial one. The "winner" and "loser" is determined *after determination that natural selection has occurred* by noting which trait has greater (or lesser) [note comparative rather than superlative] reproductive success, not by some arbitrary "out-of-the-blue" assignment of the term by me. Just because I would like my team to win a football game doesn't mean that I get to declare it the "winner". I (a fan, not a player) have no control over which team wins a football game; and I have even less control over which trait gets declared to be the 'fitter' one. The winner of the football game is the team with the most points; the winner of the fitness game is the one with the greater reproductive success. I don't know of any other way to identify, in reality, which trait is more beneficial, than by actually *observing*, after determining that there is a significant difference, which variant has more reproductive success, do you? I can make educated guesses based on knowledge of the traits and the environment, but actually determining which is beneficial requires direct observation. I only insist that there *actually* and *in reality* be a significant (detectable) "winner" and "loser" rather than saying that a result that is statistically indistinguishable from a "tie" is "natural selection". That determination of significant difference is what tells me that there is a high probability that some environmental factor is, in fact, *selectively* distinguishing between the phenotypes and that the result is not merely chance fluctuation. Notice all those "in reality" and "in fact" comments. Like most scientists, I insist that my findings be based on observations and determinations of significance rather than fuzzy-brained verbiage that is meaningless, like the junk you have posted.
> But if the
> chances did not turn out the way you liked, then there was no natural
Natural selection only occurs when there is an *identifiably* non-chance relative discrimination between variants. Natural selection is a quantitative, not qualitative population concept. Having the more beneficial trait does not *absolutely* prevent any individual with the trait from dying early or failing to reproduce. Natural selection does not and cannot prevent chance loss (meaning unrelated to the traits being examined) from happening. It only means that one trait is *favored* and has a greater *probability* of reproductive success than the other.
> Yep.... that's the way of the Darwinist, stunning....
Your continued ignorance of statistics and biology certainly is stunning.
BTW, I gave, a few posts back, a simple analysis of how you could determine whether natural selection occurred or if a result was simply due to chance (it involved chi square). You ignored that.
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