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Topic: John A. Davison: Is Evolution Finished?
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Rex Kerr
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posted 24. March 2004 00:57
That sounds like a good way to generate two species of humans, Jurie. Of course, if it's merely social and preferences change, then there won't be time for differences to accumulate to enforce genetically what was once merely extremely strong preference.
One can find this kind of thing going on right now, in fruit flies, in "Evolution Valley" in Israel (and in Brazil, and in several other places, as I recall).
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nosivad
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posted 24. March 2004 05:26
Nosivad has always "stuck with the science" which is why he has abandoned the Darwinian scheme. I have presented my thesis in several published papers and summarized much of my earlier view in the unpublished Manifesto which was thoroughly discussed on "brainstorms" some time ago.
I have no intention of allowing someone to characterize me as some sort of religious fanatic. My religious views are those of Albert Einstein. I realize that my Prescribed Evolutionary Hypothesis would indicate an incredible intelligence at work in the past, but it is perfectly comparable with the intelligence that produced Mendeleef's Periodic Table of the Elements, Newton's Laws of Motion and Einstein's Relativity. Those laws bear those scientists names because they are the ones that DISCOVERED those prescribed laws. In proposing that comparable laws have operated in the living world. I am joining with Leo Berg by concluding that chance had very little to do with either ontogeny or phylogeny. What we are beginning to discover through molecular biology fully supports the prescribed view of the living world and the Anthropic Principle in general. Darwin and Wallace DISCOVERED absolutely nothing and accordingly their hypothesis is without scientific foundation. Wallace of course finally realized that, much to his credit.
AS for "sticking to the point" I have just presented my point and I will stick to it until it has been experimentally and observationally discredited, thank you very much.
[ 24. March 2004, 07:20: Message edited by: nosivad ]
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Jurie
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posted 24. March 2004 06:15
Rex Kerr wrote quote:
That sounds like a good way to generate two species of humans
Doesn't sound good to me at all - despite millenia of separation (60k+ years?), Australian aboriginals are still human.
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charlie d.
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posted 24. March 2004 08:35
Jurie:
reproductive isolation underlies the current biological definition of species (it may be arguable in some respects, but to paraphase Churchill about democracy, it's the worse definition of species, all others excepted).
Reproductive isolation can be the result of physiological/genetic incompatibility (eg, leading to infertility), but it may also simply be an effect of sexual preferences. Rex above mentioned some examples. Another good one is the Siberian warblers, which exist in two forms which do not interbreed at all because they do not recognize each other's mating song. If one follows the two variants south, east and west of the Himalayas respectively, one finds that there are progressively divergent, interfertile song variants all the way around the ring, meeting at the south of the mountain range. The two forms of warblers in Siberia are, technically, separate species, isolated through assortative mating. However, because there exist interfertile intermediate forms, the term species does not strictly apply.
So, to get back to your question, if two human ethnic groups found each other so repulsive that they would not breed no matter what, they would be indeed in the same situation as the Siberian warblers. However, as we all know humans are far less sexually picky than most other animals, especially birds.
[ 24. March 2004, 08:38: Message edited by: charlie d. ]
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nosivad
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posted 24. March 2004 11:10
charlie d, I am talking about real honest to God speciation and the formation of the higher taxonomic categories. Behavioral isolation is trivial by comparison. Besides the issue is not whether two forms prefer to interbreed. It is the physiological test of whether or not they can produce a fertile hybrid. Has that been applied? I answer probably not and it probably won't be either.
[ 24. March 2004, 14:40: Message edited by: nosivad ]
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charlie d.
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posted 24. March 2004 11:57
quote:
charlie d, I am talking about real honest to God speciation and the formation of the higher taxonomic categories. Behavioral isolation is trivial by comparison. Besides the issue is not whether two forms prefer to interbreed. It is the physiological test of whether or not they can produce a fertile hybrid. Has that been applied? I answer probasbly not and it probably won't be either.
The two warbler variants geographically overlap in a vast area,, but, as the paper I linked to shows, in that area there is no evidence of genetic admixture at either mitochondrial or nuclear genome level. In other words, the two variants are completely reproductively isolated in nature. That's the biological definition of species.
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nosivad
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posted 24. March 2004 14:57
charlie d That is one biological definition of species. As a bench scientist I would prefer the physiological definition of hybrid strerility. For years, Darwin's finches were held to be several different species, but of course they are not and that did not even require a laboratory test, but simply field observation. I don't really expect anyone to artificially inseminate warblers but until they do I will stand pat. On the other hand, there is an amazing amount of mimicry in birds as every bird watcher is aware, just as there is in Drosophila. The production, by unrelated animals, of similar or even identical phenotypes is perfectly compatible with my Prescribed Evolutionary Hypothesis.
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charlie d.
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posted 24. March 2004 15:09
quote:
charlie d That is one biological definition of species. As a bench scientist I would prefer the physiological definition of hybrid strerility. For years, Darwin's finches were held to be several different species, but of course they are not and that did not even require a laboratory test, but simply field observation. I don't really expect anyone to artificially inseminate warblers but until they do I will stand pat.
I guess you are therefore also withholding judgemement about the status of humans and chimpanzees as different species, pending artificial insemination experiments (bi-directional, I assume). Fair enough, I guess.
That's of course an impossibly impractical (and therefore useless) definition of species - it would paralize taxonomy until every artificial cross of every species with every other is performed. In the meanwhile, I think the rest of the world will keep using the (not one, as you say) biological definition of species.
[ 24. March 2004, 15:10: Message edited by: charlie d. ]
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nosivad
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posted 24. March 2004 18:18
charlie d There is nothing impractical about an empirical test. What is impractical is to refuse to apply it. The Darwinians apparently no longer test their hypothesis. As for the Chimp/Human cross, Josef Goebbels, Hitler's propaganda minister, claimed that it had been attempted unsuccessfully when he said - "It has not yet been demonstrated that nonAryans cannot hybridize with apes." I'll bet it has been attempted many times, if for no other reason than to have something to charge admission for in some side show. It probably doesn't work. Speaking of practical, plant an animal breeders have experimented with hybridization to great success. Speaking as a bench scientist, I am a great believer in the experimental method. It is the final determinant of the truth.
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charlie d.
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posted 24. March 2004 19:37
nosivad, we are descending into some pretty bizarre stuff here. Are you really saying that you would provisionally suspend H. sapiens' status as a separate species until hybridization experiments with every other species has been conducted? Are you really saying that your trust in the experimental method extends to unsubstantiated hearsay about carnival owners and nazi doctors? Let's be serious.
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Rex Kerr
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posted 24. March 2004 21:17
We could turn the question around. Once two groups of organisms are rendered reproductively isolated by whatever mechanism, what is to prevent accumulation of mutations from eventually causing hybrid sterility?
[ 24. March 2004, 21:18: Message edited by: Rex Kerr ]
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nosivad
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posted 25. March 2004 07:52
charlie d You are twisting my words and my meaning to suit your own views. I never at any time suggested experimental hybridization with apes. The one lesson from plant breeders is that hybridization most frequently results in sterility or a profound decrease in reproductive efficiency. In any event there is no reason to consider hybridization as a significant factor in evolution.
Since I am a curious person by nature, is there anyone out there within cybershot who sees any merit in my perspective? If there isn't, I may take my heresies elsewhere as I never did enjoy lecturing to an empty hall.
[ 25. March 2004, 07:54: Message edited by: nosivad ]
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charlie d.
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posted 25. March 2004 08:32
quote:
charlie d You are twisting my words and my meaning to suit your own views. I never at any time suggested experimental hybridization with apes. The one lesson from plant breeders is that hybridization most frequently results in sterility or a profound decrease in reproductive efficiency. In any event there is no reason to consider hybridization as a significant factor in evolution.
Of course you did not, and I hope my post was not construed to imply that. All I said was that in the absence of hybridization studies you seem not to be willing to grant a group of organisms the status of species. This is what you said for the genetically isolated warblers: quote:
I am talking about real honest to God speciation and the formation of the higher taxonomic categories. Behavioral isolation is trivial by comparison. Besides the issue is not whether two forms prefer to interbreed. It is the physiological test of whether or not they can produce a fertile hybrid.
[and in a later post:]
I don't really expect anyone to artificially inseminate warblers but until they do I will stand pat.
So, if you are not willing to even talk about "real, honest-to-God" species until hybrid sterility of organsims like the Siberian warblers is demonstrated, the same should apply to humans (and all other species as well).
Again, this is just to show that a definition of species based strictly on hybridization (including artificial means) is untenable, besides being biologically meaningless. Species are the only taxonomic group with biological meaning because they represent a genetically cohesive group of organisms isolated from all other such groups. Although in certain specific contexts one can use differnet definitions to better highlight the specific features under analysis, I think almost everyone in biology agrees that ultimately it is this biological definition that supersedes all others in terms of epistemological significance and empirical usefulness.
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nosivad
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posted 25. March 2004 10:22
The origin of species remains a mystery. I am perfectly willing for you to have the last word, as it is obvious to me that your commitment to Darwinism is irreversible. Just declare victory and let it go at that. I learned long ago that I am unable to communicate either with Fundamentalist Biblical Literalists or intractable neoDarwinians. Why do I continue to waste my time? In the meantime I wait for a response to my previous post. I have been virtually alone in this business since 1984. That is too long.
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nosivad
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posted 25. March 2004 10:37
I just sent back the page proofs for "Is Evolution Finished". I hope someone, somewhere will publish a rebuttal. History indicates that is very improbable but rebuttals will continue I am sure from anonymous critics on forums such as this one.
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