Freethought & Rationalism Archive

AnthonyAdams45 · 02-23-2003, 04:18 PM

I can't believe anyone rose to this naive bait. Nature has no goal. Nature just is. Survival is not a goal, survival just is. Consciousness have goals. Consciousnesses may want to survive, and thus have survival for a goal, but nature, not conscious, has no goal. The initial post is completely question-begging and loaded.

When did you stop beating your wife anyway?

Starboy · 02-23-2003, 05:02 PM

Quote:

Originally posted by Keith
I should have made myself more clear. I didn't mean across different species, I was responding to Starboy's post which said..."a better way to understand adaptation is to realize that FOR A GIVEN SPECIES not every creature alive OF THAT SPECIES is identical to all other members." (emphasis added)

Sorry for the confusion. Anyway, do we observe any differences within the same species in terms of these complex structures?

Keith

Keith what do you mean by complex structures, brain, eye, ear? I am no biologist and I do not know much about bats, but for humans the answer is obvious. It is also obvious for cats and dogs. I personally have observed a great deal of variation in these complex structures among those animals. Examples of adaptation come up all the time. There is a variant of cats with recessed testicles. To the cursory examination they look like they have been neutered. This is a direct result of selection pressure caused by animal control efforts. We all know stories about bacterial adaptation to anti-biotic, again the result of changes in the environment causing the natural selection for resistant bugs. If you think about it I am sure you can come up with many other examples.

In these examples there may be a will at work, but the outcome is the exact opposite of what was intended. So who or what is directing the evolution of antibiotic resistant bugs and do they know what they are doing?

Starboy

Principia · 02-23-2003, 07:22 PM

I think this thread should belong in E/C...

But, there is a good thread discussing the evolution of bat echolocation, here

Quote:

Keith: The first problem is how does an animal (or nature) know IN ADVANCE what kinds of organs to start developing or perfecting for its future evolutionary needs, and secondly, how does "nature" orchestrate all of the necessary design, development, and refinement processes in all 300 parts, without some intelligent and purposeful guidence of some kind.

To the 2nd question: By mutations and differential reproductive success (commonly referred to as natural selection).

The question being asked is already loaded with the wrong concepts. There is no evidence that "future evolutionary needs" are "perfected" by any means. Nor has the Lamarckian concept of directed mutations borne fruit.

The usual point to make here is that intelligent agency is akin to a catalyst for a chemical reaction. Sure, it can facillitate the generation of design, but science has demonstrated for the large part that in the case of the evolution of life, an intelligent agency is an unnecessary postulate. Nor, for that matter, does it make for good science.

Principia · 02-23-2003, 08:56 PM

Quote:

Keith : Tell me if I'm wrong...what we observe in animals tells us that in terms of some of their most complex body parts there isn't any discernable variation. I'm talking about their eye structure, ear structure, and so on.

You mean things like eye color?

Quote:

Int J Cancer 2001 Jun 15;92(6):906-12

Eye color and cutaneous nevi predict risk of ocular melanoma in Australia.

Vajdic CM, Kricker A, Giblin M, McKenzie J, Aitken J, Giles GG, Armstrong BK.

Cancer Research and Registers Division, New South Wales Cancer Council, Sydney, Australia.

Ethnicity, cutaneous nevi and eye color are generally accepted risk factors for melanoma of the eye, although case-control studies have produced conflicting results. We sought to determine the constitutional risk factors for melanomas of the choroid, ciliary body, iris and conjunctiva in Australia. A population-based case-control study was conducted, with case ascertainment from a prospective national incidence survey and randomly selected community controls. Two hundred and ninety cases aged 18-79 years and diagnosed between 1st January 1996 and 31st July 1998 were enrolled with 916 controls frequency matched by age, sex and State or Territory of residence. Risk of choroidal and ciliary body melanoma (n = 246) was increased in people with grey (OR 2.9, 95% CI 1.5-5.5), hazel (OR 2.2, 95% CI 1.4-3.7) and blue eyes (OR 1.7, 95% CI 1.0-2.7) compared with brown eyes. Risk was also increased in those with 4 or more nevi on their back, those unable to tan, and those who squinted when outdoors as a child. Risk was reduced in people born other than in Australia and New Zealand (OR 0.7, 95% CI 0.5-1.0). Non-brown eye color was a risk factor for iris melanoma (n = 25). No risk factors were identified for conjunctival melanoma (n = 19). Eye color is the strongest constitutional predictor of choroidal and ciliary body melanoma, and may indicate a protective effect of melanin density at these sites. An independent association with cutaneous nevi suggests a role for other genetic factors. Copyright 2001 Wiley-Liss, Inc.

or sexual dimorphism?

Quote:

Evolution Int J Org Evolution 2001 Jul;55(7):1373-85

Phylogenetic analysis of sexual dimorphism and eye-span allometry in stalk-eyed flies (Diopsidae).

Baker RH, Wilkinson GS.

Department of Entomology, American Museum of Natural History, New York, New York 10024, USA. richard.baker@ucl.ac.uk

Eye stalks and their scaling relationship with body size are important features in the mating system of many diopsid species, and sexual selection is a critical force influencing the evolution of this exaggerated morphology. Interspecific variation in eye span suggests there has been significant evolutionary change in this trait, but a robust phylogenetic hypothesis is required to determine its rate and direction of change. In this study, the pattern of morphological evolution of eye span is assessed in a phylogenetic framework with respect to its function in the sexual system of these flies. Specifically, we examine within the family Diopsidae the pattern of increase and decrease in sexual dimorphism, the morphological coevolution of eye span between males and females, and the evolutionary flexibility of eye-span allometry. Based on several different methods for reconstructing morphological change, results suggest a general pattern of evolutionary flexibility, particularly for eye-span allometry. Sexual dimorphism in eye span has evolved independently at least four times in the family and this trait also has undergone several reductions within the genus Diasemopsis. Despite most species being dimorphic, there is a strong phylogenetic correlation between males and females for mean eye span. The coevolution between the sexes for eye-span allometry, however, is significantly weaker. Overall, eye-span allometry exhibits significantly more change on the phylogeny than the other morphological traits. The evolutionary pattern in eye-span allometry is caused primarily by changes in eye-span variance. Therefore, this pattern is consistent with recent models that predict a strong relationship between sexual selection and the variance of ornamental traits and highlights the significance of eye-span allometry in intersexual and intrasexual signaling.

or perhaps myopia (i.e. structural changes to the globe)?

Quote:

Ophthalmologica 2003 Mar-Apr;217(2):115-8

Familial high myopia linkage to chromosome 18p.

Lam DS, Tam PO, Fan DS, Baum L, Leung YF, Pang CP.

Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong, Hong Kong, China.

A locus for autosomal dominant high myopia was reported on chromosome 18p. We sought to confirm this finding and narrow the reported interval by analyzing high myopia among families of Hong Kong Chinese, in whom myopia is common. In 15 families with a possibly autosomal dominant inheritance of high myopia (>/=-6 dpt) in at least 2 generations, 10 chromosome 18p markers were analyzed for linkage with high myopia. Two-point linkage analysis showed trends toward linkage of markers D18S476 and D18S62 with high myopia, with maximum logarithm of odds (LOD) scores of at least 1.1 and 1.7, respectively. Multipoint analysis of those 2 markers gave a maximum LOD score of at least 2.1. To attempt to account for likely genetic heterogeneity, 5 families showing evidence of linkage of the 2 markers with high myopia were selected for further multipoint linkage analysis, resulting in a maximum LOD score of 2.4 at D18S476. While multiple genetic and environmental factors likely contribute to myopia, these data are consistent with the possibility of a locus on chromosome 18p. Copyright 2003 S. Karger AG, Basel

or color-blindness?

Quote:

Am J Hum Genet 2002 Aug;71(2):422-5

Mutations in the cone photoreceptor G-protein alpha-subunit gene GNAT2 in patients with achromatopsia.

Kohl S, Baumann B, Rosenberg T, Kellner U, Lorenz B, Vadala M, Jacobson SG, Wissinger B.

Molekulargenetisches Labor, Universitats-Augenklinik, Auf der Morgenstelle 15, D-72076 Tubingen, Germany.

Achromatopsia is an autosomal recessively inherited visual disorder that is present from birth and that features the absence of color discrimination. We here report the identification of five independent families with achromatopsia that segregate protein-truncation mutations in the GNAT2 gene, located on chromosome 1p13. GNAT2 encodes the cone photoreceptor-specific alpha-subunit of transducin, a G-protein of the phototransduction cascade, which couples to the visual pigment(s). Our results demonstrate that GNAT2 is the third gene implicated in achromatopsia.

I think I will stop here, before I get into the rest of the non-lethal genetic abnormalities (read: interspecies variations) related to the eye. The point here, of course, is that genetic variations do exist, and that it is possible for these variations to result in altered (or even loss of) functions that can be selected upon.

Keith · 02-23-2003, 10:27 PM

Quote:

Originally posted by Principia

"You mean things like eye color?

or sexual dimorphism?

or perhaps myopia (i.e. structural changes to the globe)?

or color-blindness?"

I'm overwhelmed! I can honestly say that I have absolutely no idea what to make of all this! Thanks, Principia.

Keith

02-24-2003, 07:36 AM

Quote:

Originally posted by Principia
. The point here, of course, is that genetic variations do exist, and that it is possible for these variations to result in altered (or even loss of) functions that can be selected upon.

Impressive, very impressive, but who did you say did this "selecting?"

Principia · 02-24-2003, 08:02 AM

Quote:

Originally posted by Amos
Impressive, very impressive, but who did you say did this "selecting?"

Wrong question, Amos. Once again, a personal "selector" is an unnecessary postulate for understanding the process of differential reproductive success. A phenotype that is "selectable" is biological jargon for a variation (be it morphological, biochemical, behavioral, symbiotic, etc.) that alters the ability of the organism to reproduce with respect to its environment. A "selected" phenotype is one that can be determined to confer a reproductive advantage to the particular organism with respect to its environment. If one wishes to personify Nature, God, Invisible Pink Fairies, or whatever then so be it. Science, as a collective human enterprise, is just as happy to ignore such personifications.

I would encourage those of you interested in persuing this matter in the Evolution/Creation forum.

Philosoft · 02-24-2003, 08:14 AM

The original question is arguably philosophical, but in light of the more recent substantive dialogue, I'm sending this to E/C...

Marlowe · 02-24-2003, 09:16 AM

Quote:

When we use the word nature we're just using it to represent a concept, the concept of life, evolution, etc. The reason why all life is striving to survive is not because someone programmed them to do so, it's because of what happened millions of years ago when the first anaerobes were formed, and the whole "Hot Thin Soup" theory.

The big problem with the Hot Soup theory was the idea that chance would lead to spontaneous construction of complex molecules like DNA - in fact mathematicians calculated that it would take far in excess of the 4.5 billion years the earth has been around for it to happen. Biologists still repeated the Hot Soup theory because it was all we had. Then, the Hot Soup theory was greatly refined by complexity theorists, particularly Stuart Kauffman.

Quote:

In that time one day out of chance,

Actually it's not really out of chance. The new science of complexity shows how in a sea of different chemicals, complexity increases - that is more and more differing chemicals build up in a localized area until a certain threshold is reached, wherein autocatalytic sets spontaneously form. These are loops of chemical reactions where one chemical (A) becomes a catalyst for other chemicals (B and C), which combine to form a catalyst that forms (A). These loops start out simple and then more loops build up in localized area. Since chemicals are moving about in the soup, running into and catalyzing each other eventually by their natural properties they recombine into larger autocatalytic sets, with more components. The same process of increasing complexity occurs again as the autocatalytic sets become more complex and eventually lead to the formation of highly complex moelcules that can replicate themselves - such as RNA and DNA.

A detailed description of Kauffman's theory can be found in his book At Home in the Universe. What it finally comes down to is that there is a decent mathematically based theory for how life came to be, it involves not chance but the natural way in which the universe is structured - which is for systems to build greater and greater levels of complexity - see Waldrop's Complexity - the emerging science at the edge of order and chaos.

Do the laws we are in the midst of discovering via Complexity mean there is intent in the universe? Not really. Complexity specifically exists in a borderland between order and chaos. Intent (or purpose, of life knowing how to create an eye, etc) suggests order. Chaos is randomness. Turns out that life and evolution are not either - they are both.

02-24-2003, 10:37 AM

Quote:

Originally posted by Principia
. A "selected" phenotype is one that can be determined to confer a reproductive advantage to the particular organism with respect to its environment. If one wishes to personify Nature, God, Invisible Pink Fairies, or whatever then so be it. Science, as a collective human enterprise, is just as happy to ignore such personifications.

That's fair enough but then don't use the word select because this verb implies that a choice was made by an organism.

02-23-2003, 04:18 PM	#41
AnthonyAdams45 Regular Member Join Date: Jul 2000 Location: Florida Posts: 156	Goal? Who scored? I can't believe anyone rose to this naive bait. Nature has no goal. Nature just is. Survival is not a goal, survival just is. Consciousness have goals. Consciousnesses may want to survive, and thus have survival for a goal, but nature, not conscious, has no goal. The initial post is completely question-begging and loaded. When did you stop beating your wife anyway?

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02-24-2003, 08:14 AM	#48
Philosoft Veteran Member Join Date: Feb 2002 Location: Southeast of disorder Posts: 6,829	The original question is arguably philosophical, but in light of the more recent substantive dialogue, I'm sending this to E/C...

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