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Article #359Re: Several questions on evolution, and mutation (rate)
From: Radford Neal
Date: Wed, 04 Sep 1996 00:00
Date: Wed, 04 Sep 1996 00:00
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In article <dyanega-0309961906530001@catalpa.inhs.uiuc.edu>, Doug Yanega <dyanega@denr1.igis.uiuc.edu> wrote: >> Really? Perhaps you would like to elucidate. Could you tell me the >> frequency of the allele for type "A" blood amongst redwood trees? > >Simple. The frequency is ZERO, as is the frequency of ALL blood type >alleles in that species. If it doesn't have that particular gene, it can't >have the allele. Ahh, come on. Are you seriously maintaining that this sort of simplistic accounting is a practical way of describing how the genomes of different species differ from one another, or change with time? What's the frequency of the allele if it is present in the genome, but never transcribed? How do you count transposable elements? >> You are deeply confused about the nature of scientific theories. The >> sort of technical definition you insist on is an occasionally useful >> internal device for a theory. Such definitions do not establish the >> meaning of the theory in a wider sense. > >Then we are at an impasse, because I think this statement is gibberish, >and that a rigorous definition is essential to any scientific theory, not >"occasionally useful". There is nothing else besides a *definition* that >can establish what a theory is or is not. That's why we *have* >definitions. Actually, we generally *don't* have definitions, *especially* for key concepts. What's the definition of "species"? I know there's a hoary old one about lack of inter-breeding, but it's clearly inadequate. Try asking a physicist for definitions of "mass" or "energy" - you'll either get nothing at all, or a meaningless phrase, or their latest (probably false) theory about Higgs bosons. For "entropy", you'll get two completely different definitions (a thermodynamic definition and a statistical physics definition), which it is thought are equivalent, that being a substantive conclusion of physics. Neither of these allow for the surface area of a black hole making a contribution to entropy, but that didn't stop physicists from deciding that it did. The real meaning of the concepts is always deeper than the textbook definitions, and in particular, any definition that fails to capture the reason the theory is considered important is clearly a provisional technical sort of thing, contingent on current beliefs. >What Mr. Beorn said, was, verbatim: > >> I.e. no evolution occurred - >> adaptation, variability of a species yes - but not evolution. No new >> "creature" was created. > >He *specifically* confused speciation with evolution, and admitted himself >that he believed species could be variable and adapt. In effect, he >admitted that evolution occurred, but denied that evolution leads to >speciation; but what he SAID was this was not evolution. I am perfectly >within my rights to point out to him that he has confused the issue. Do >you or do you not agree that speciation and evolution are NOT synonymous? It is certainly conventional usage to say that evolution occurs when there are changes in allele frequencies, even if these changes are not accompanied by speciation, but this is because biologists believe that the same process *does* lead to speciation in other cases. If it were discovered that changes in allele frequencies *cannot* lead to speciation, it is doubtful that such changes in frequencies would be referred to as "evolution", because this word has been extensively applied to the process (whatever it is) by which the diversity of species on Earth has come into being. That's what the word really means. Radford Neal
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f665a,66df8aa9a503fb91 X-Google-Attributes: gidf665a,public X-Google-Thread: 10a7a9,66df8aa9a503fb91 X-Google-Attributes: gid10a7a9,public X-Google-Thread: 10065c,66df8aa9a503fb91 X-Google-Attributes: gid10065c,public X-Google-Thread: f6a65,66df8aa9a503fb91 X-Google-Attributes: gidf6a65,public From: radford@cs.toronto.edu (Radford Neal) Subject: Re: Several questions on evolution, and mutation (rate) Date: 1996/09/04 Message-ID: <96Sep3.232041edt.1004@neuron.ai.toronto.edu> X-Deja-AN: 178345811 distribution: inet x-nntp-posting-host: yonge.cs.toronto.edu references: <Pine.A32.3.91.960815144016.39360B-100000@flute.aix.calpoly.edu> <dyanega-0309961425120001@catalpa.inhs.uiuc.edu> <96Sep3.191953edt.1015@neuron.ai.toronto.edu> <dyanega-0309961906530001@catalpa.inhs.uiuc.edu> organization: CS Lab, University of Toronto newsgroups: bionet.molbio.evolution,sci.bio.technology,bionet.microbiology,sci.bio.misc originator: root@yonge.cs.toronto.edu