Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site psivax.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!oliveb!hplabs!sdcrdcf!psivax!friesen From: friesen@psivax.UUCP (Stanley Friesen) Newsgroups: net.origins Subject: Re: No Cigarettes, Please Message-ID: <580@psivax.UUCP> Date: Mon, 29-Jul-85 17:54:19 EDT Article-I.D.: psivax.580 Posted: Mon Jul 29 17:54:19 1985 Date-Received: Sat, 3-Aug-85 02:25:21 EDT References: <1318@uwmacc.UUCP> Reply-To: friesen@psivax.UUCP (Stanley Friesen) Distribution: net Organization: Pacesetter Systems Inc., Sylmar, CA Lines: 175 Summary: In article <1318@uwmacc.UUCP> dubois@uwmacc.UUCP (Paul DuBois) writes: > >To proceed: > >What does "survive" in Rich's statement mean? Presumably not that they >don't die, for all organisms do. Also presumably not that they >reproduce more, or else the statement reduces immediately to a >tautology that is not interesting. So it seems to mean "they live >longer than organisms which are not so fit". > In point of fact, the real meaning in evolutionary theory *is* that they reproduce more, even if you think that is an uninteresting tautology! From an evolutionary standpoint longer life is only meaningful if it leads to more reproduction. What is actually significant is extended reproductive success of a genotype. That is an organism which produces so many offspring that they all starve has a lower effective reproductive rate than one which only produces as many offspring as can survive! > >Of course, my own personal choice of x2 is questionable; it depends >what level you look at. At the level of the group, x1 is fitter; it >propagates more. At the level of the individual, x2 is fitter; it >survives longer. > But you see, evolution operates at the *group*(i.e population) level, so that *individual* "fitness" is only significant as a component of population fitness. >Natural selection (now) refers to populations; presumably x1 is fitter >according to that view. Somewhere in here lurks a problem, which is >(from my point of view) a paradox, and which seems (to me) wrong. The >paradox (to me) is that x1, the crappy organism (by my standards), is >judged fitter because it satisfies the criterion of reproductive >success better. A poorer organism produces a fitter population because >of the way fitness is defined. This leaves me feeling, to say the >leaast, somewhat ambivalent. Now of course we need definitions, but >not definitions that "solve" problems which should be investigated >empirically. Here I throw up my hands and "resolve" the paradox by >deciding that the criterion of fitness is worthless. (I put "resolve" >in quotes because obviously this decision does not advance us very >far.) > Ah, but you are confusing the scientific concept of "biological fitness" with the human valuation of fitness. They are seperate ideas. So you prefer organism x2 - fine! But that has nothing to do with science, or the *scientific* concept of fitness. >The error (as it seems to me) is that the link between survival and >reproduction in assessing fitness is unnecessary, or at least >poorly-defined or wrong. It *seems* to me (I may be wrong, so no >flames - just point out my error) that the two are tied together in a >way that cannot logically be required: there is no necessary >relationship between survival of the "fit" individual (measured by >lifespan) and generation of the next "fit" population (measured by >reproductive success). > Quite true! In fact serious evolutionary theorists make no such claim! If we did we would have a hard time explaining annual plants and such like! >By saying that the ones that survive reproduce more (that is what Rich >said, and what Mike I think defended), one makes this link. But on >what basis? I assume on this basis: the ones that survive longer, >leave more offspring *all other things being equal*. I suppose they >will - but why make this assumption? Things are not obviously equal. >To make the theory work? Not a chance. It has to be *shown*, not >assumed. In my example, it's false. Its not a thing to be considered >true or false a priori, but something to be *found out*. > Actually, they are simply speaking imprecisely. There is a demonstrable connection in organisms that reproduce more than once and/or require time to reach reproductive maturity. An organism that fails to reach reproductive maturity has left *no* offspring, so survival longer *can* increase reproduction, and with multiple reproduction longer life generally allows more reproduction events! This is still secondary however. >Let us go back a little. > >Those which are fitter will leave more offspring > but only true if fit *to leave offspring* > or, if fitness *is defined as* leaving more offspring > >and then "fitness" is meaningless, because it says nothing. Try it - >make the substitution of variables: > Ah, but you are treating fitness as a valuation when it is a *measure*. That is fitness is the *measure* of how well an organism does at reproducing itself. The key is to then calculate the *effect* of leaving more offspring on the genetic composition of the whole population, the result of this mathematical model is *changed gene ratios* in which those genes that contributed most to reproductive success have increased the most. Now apply this repeatedly to each generation and you have evolution! To show evolution does not occur youy must now show one of a) solid limitations on variation exist, b) that gene ratios do not change, or c) that genes do not effect reproductive success(i.e. fitness). > fitness = fit to leave offspring, yields > Those which are fit to leave more offspring will leave more offspring > > fitness = leaving more offspring, yields > Those which leave more offspring will leave more offspring > >Not very illuminating. Hence my frequent comments in the past about >vacuity. Mainly because such statements have nothing to do with evolution. The real statement is "Fitness(i.e. reproductive success) causes increased representation in the next generation of similar individuals". > >Let me raise an objection against what I have just written. As >indicated above, fitness is measured by differential reproductive >success. Now, at this point, millions of critics have risen up and >cried "tautology!" One asks, "which are the fittest?" "Those that >survive." "Which survive?" "The fittest." "Oh..." > I repeat, fitness *is* the measure of reproductive success. >But that view *equates* fitness with differential success, and that >is ... (remembernowIamacreationistsoholdyourbreath) ... incorrect! Exactly! Except that it is correct, by *definition*, since that is how we biologist define fitness. >--- > >Final jab: > >It is interesting (to me at least), that creationists are said not to >know what evolution is, and so are consequently said not to know what >they are criticizing. This is often true, unfortunately. But I >suspect, more strongly as time goes by, that many evolutionists don't >know what they are *defending*! Witness the recent posting in which >someone spouted the Darwinian orthodoxy, right down the line, as though >it were considered credible today. Right out of his high-school >textbook, I suppose. > Mainly because most of the evolutionary supporters on the net on not biologists, only laymen with an interest in the subject, which may often be somewhat of date. >Witness also the great importance attached to natural selection by many >on this net. But how important is it in recent evolutionary theory? >Not very, in a number of instances. Michael Lonetto has shown evidence >that he knows this. How many others? Rich is (apparently) still in >the dark ages, carrying this (apparently) *unexamined conviction* >around. Mike H might be, but I doubt it; I suspect that he was trying >to clarify what Rich said, rather than defend it as his own position. > Actually, it is still *very* important, except among certain extreme schools of evolutionary thought such as the most extreme forms of Punctuate Equilibrium and the "neutralist" theories of many microbiologist(who have little experience with organisms under natural conditions). >In any case, what natural selection *is*, how one detects its absence >or presence, how one measures its intensity of effect, are questions >that have all gone largely unanswered and are solved, as far as I can >see, largely by definition. > Well, I gave a simple definition above. And definition is a perfectly valid approach to a problem, provided it fits with the data! Look at how physicist approach the concept of mass. It is simply *defined* as the measure of resistance to acceleration! Or if you use the approach you used above for "fitness" this becomes "Mass is what mass is" by substitution of variables. -- Sarima (Stanley Friesen) {trwrb|allegra|cbosgd|hplabs|ihnp4|aero!uscvax!akgua}!sdcrdcf!psivax!friesen or {ttdica|quad1|bellcore|scgvaxd}!psivax!friesen