Syamsu's Objection to Natural Selection...

I'm not sure how sound this line of argument is, there could be any number of factors intoducing variation into a population which are not a good basis for evolution, phenotypic plasticity and environmental factors could both contribute to variation and might produce a suitable target for NS but not evolution.

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The rest of your post is dross. Basicly you imagine I argue like you do, by saying I call evo psychs nazi's. Why would I want to argue like that? That's pointless drivel.

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I agree that it's pointless drivel, but that is exactly what you do, over and over and over.I am assuming, then, that you will not be bringing up social Darwinism in a discussion of Biological Evolution EVER AGAIN.

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Your view on gazelle's is now very peculiar, and well false, since gazelle's aren't actually different the way you imagine them to be different. They are the same generation, after generation, after generation, as the evo psych site you referenced said heritability is generally zero.....

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OK, let's use some other examples.Are the stripes on every single zebra ever born exactly the same?Is every single wild horse the exact same color?Is every single wild horse have the exact same size and weight, do they have the same leg length, head size, eye position, tooth size, ear size, tail length, hoof size?

Wounded King responds to me:

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I'm not sure how sound this line of argument is, there could be any number of factors intoducing variation into a population which are not a good basis for evolution, phenotypic plasticity and environmental factors could both contribute to variation and might produce a suitable target for NS but not evolution.

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Yeah, but that's being disingenuous (which is why I'm regretting into this with Syamsu...I'm dreading that he, too, will be disingenuous.)For example, if the herd is poorly nourished, that's going to decrease their ability to get away from the lions. And so long as the number of new individuals equals the numbers being culled every cycle, then we could even have a situation where the entire herd should fall prey were it not for the fact that they just keep breeding more and thus the predators can never get ahead.However, Syamsu admitted that there are differences: It doesn't matter that they don't differ much. It only matters that they differ. It doesn't matter how small. As long as there is a difference, it can be subject to selection.And if that variation is heritably biological in nature, then it's evolution.------------------
Rrhain
WWJD? JWRTFM!

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phenotypic plasticity and environmental factors could both contribute to variation

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I ask myself, "How does environment produce variation?" The only answer I have is that food supply, for example, can effect an animal's size, which brings us to phenotypic plasticity. And that is a fine target for NS, which you admit. But how can you have NS and not consequently have a change in gene frequencies in the population?------------------
No webpage found at provided URL: www.hells-handmaiden.com

Hi John, actually it turns out that in certian circumstances that the environment can have a degree of influence on mutations. This would have the effect of potentially having a heritable change at least partially under the influence of the environment.Now before the Creationists start to jump with glee, this is not a refutation of Neo-Darwinian NS. Rather, it is an understanding of the proper use of probability vs random. Mutations are not all equiprobable, in fact very few are. And changes in the enviroment can change the localized response to mutations within a cell by changing patterns of exression of various genes through a number of different pathways (i.e. heat shock as a gross example, lack of nutritional resources as another) which can allow for a greater accumulation of mutations. I will not even get into the varying probability of mutations w.r.t. different sequences and the effects that the relaxation of the proofreading controls can have on those. Just another way to get the variation into the population which Syamsu says does not exist.------------------
"Chance favors the prepared mind." L. Pasteur
Taz

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Hi John, actually it turns out that in certian circumstances that the environment can have a degree of influence on mutations.

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Ok. I know that environmental stress can trigger an increase in mutations, but how does that make sense in context? For Wounded King, these things are NOT good for evolution. A population under extreme stress needs to gamble. That IS good for evolution.------------------
No webpage found at provided URL: www.hells-handmaiden.com

Even Darwin, without the benefit of modern findings
in the biological sciences, suggested that natural selection
could operate in differences that we could not see (he mentions
internal organs and 'constitutional difference').That all gazelles have four legs does not mean they have
the same EXACT upper to lower leg ratio or muscular attachment
arrangement. Some seemingly trivial difference could tip the
balance given the right circumstances.As people have pointed out, variation IS a part of basic
biology -- you like Mendel's work, he studied variation in
his plants and proposed a mechanism that explained it.Is genetics NOT part of basic biology?What colour are you eyes?If natural selection is a description of nature, what
justification can you have of ignoring one aspect
of that description ?

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a suitable target for NS but not evolution

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Could you explain that?If NS acts on some trait set, and a change in allelic frequency
is produced, then evolution has occurred.What is suitable/unsuitable in that context?How can you even apply word like 'suitable' to a directionless,
purposeless natural process?

The entire point was that if the variation is environmental/ phenotypic alone and not representative of allelic variation then while natural selection may occur it may not be linked to a change in the allelic frequency of any gene relevant to the trait being selected for. If the only change in allelic frequency is governed by a distribution independent of the action of the genes then you are seeing genetic drift, which is admittedly still evolution but a form entirely unrelated to NS, perhaps I should have specified adaptive evolution.Selection certainly can be directional, there is stabilising selection, disruptive selection and directional selection.Obviously variation representing a change in genetic or heritable epigenetic factors is more suitable for evolution, though not natural selection, to act on than variation due to environmental or purely stochastic factors.[This message has been edited by Wounded King, 08-04-2003]

I certainly don't feel this is any less disingenuous than your original argument.Firstly, we are not unable to gauge the variations in a population, there is no reason why one could not do a thorough study of both morphological and genetic variation in a population of gazelles.Secondly, by environmental factors I wasn't solely reffering to nutrition of the whole herd, I was pointing out that even allowing for a herd of genetically identical gazelles they would almost certainly present a range of phenotypes, cloned animals are usually not completely identical, except for genetically. Diet might be important but more in terms of maternal diet and its effects on the growth of the child.Thirdly, your argument that the continued existence of both predator and prey proves there must be variation, all this continued existence really requires is that the predator not eat more of the prey than the population can replace. Even if the predators could catch the entire gazelle population they need not kill every single gazelle. Given the correction proportions and reproductive rates, i.e. predators are fewer in number and slower to reproduce, I can't see any real problem with having a stable predator/ prey system where the predator can always catch the prey.

and in support of WK and against Symansu's typically uninformed statements about..well about EVERYTHING..gazelles are actually very different from one another...Heredity. 1996 May;76 ( Pt 5):465-75. Related Articles, LinksExtreme genetic differences among populations of Gazella granti, Grant's gazelle in Kenya.Arctander P, Kat PW, Aman RA, Siegismund HR.Department of Population Biology, University of Copenhagen, Denmark.Mitochondrial DNA (mtDNA) control region sequences from six Kenyan Grant's gazelle (Gazella granti) populations were highly divergent among locations. Neighbouring populations not separated by geographical or vegetational barriers exhibited and nucleotide sequence divergence about 14 per cent. A similar level of divergence separates Grant's gazelles from a closely related species, the Soemmering's gazelle (G. soemmeringii). Nuclear microsatellite repeat number variation at two loci also indicated substantial population genetic differentiation. Despite high levels of sequence divergence populations of Grant's gazelles were more closely related to each other than to Soemmering's and Thompson's gazelles (G. thomsoni) as measured by nucleotide sequence divergence at the mtDNA protein coding cytochrome b gene and the nuclear alpha-lactalbumin gene. This pattern of extensive differentiation is hypothesized to have resulted from recently established contacts between formerly allopatric populations.

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The entire point was that if the variation is environmental/ phenotypic alone

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Simply isn't possible-- short of severed limbs or such. There are genetic components to any phenotypic variation even when highly influenced by the environment. For example, a population which finds itself living with a very poor food supply will probably experience stunted growth of some kind. This is environmental, but genetic factors such are metabolism, fat cell response, etc are important.------------------
No webpage found at provided URL: www.hells-handmaiden.com

I would disagree with this..clones vary from one another i.e. cloned cows have different coat color patterns even though they are genetically identical. There is stochastic variation in the development process that is purely environmental, not heritable, and not genetic. Epigenetic variation is heritable (in some cases) but can alter phenotype without genetic alteration.If you are referring to quantiative traits such as height..both genes and environment play a role though it is usually really hard to figure out which and to what extent the genes are involved whereas the environmental cues can be more obvious such as nutrition.

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I would disagree with this...

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Told ya I was going to have to start picking fights with the evolutionists.

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clones vary from one another i.e. cloned cows have different coat color patterns even though they are genetically identical.

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Such as the location of particular spots on a calico cat? hmmm... not sure if this is an appropriate example. Pretend it is. Lets say we clone such a cat. Lets clone about a thousand of them. We remove all the cats with white spots on their foreheads, and breed the rest. The frequency of white-spot-foreheadism will not have changed?

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There is stochastic variation in the development process that is purely environmental, not heritable, and not genetic.

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Such as mutations in the developing embryo? Ok. That makes sense. hmmm.... but that would be genetic? And, depending on when the mutation occured, might be heritable-- but not always. That leave us with developmental weirdness caused by lead exposure, say? Wouldn't there be a genetic component to susceptibility to this sort of thing?

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Epigenetic variation is heritable (in some cases) but can alter phenotype without genetic alteration.

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But unless it is the heritable type, the variantion would be irrelevant to evolution, yes? Ok. It is starting to make more sense.------------------
No webpage found at provided URL: www.hells-handmaiden.com

Never mind lead, what about Thalidomide. A mutation may be heritable but not all developmental plasticity or developmental defects are neccessarily linked to a genetic mutation, or even an epi-mutation. The sort of things Mammuthus is talking about are specifically not mutations, they are probabilistic effects leading to a bit more of some growth factor here than there, slightly more cells joining a particular lineage, a slightly longer toe resulting on one foot perhaps.Your calico cats aren't a bad example, the pattern of X inactivation leading to their unique coats is the right sort of stochastic factor, although the basis of the difference between the cells is obviously inherently genetic.The frequency of white spot foreheadism should not be changed in the following generation, thats right.