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Ishmael
In: Toronto
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| Mick Harper wrote: | | But that's the curious thing, Martin, they do not change. |
And this is not the least bit controversial.
It is widely acknowledged that long periods of stasis are implied by our existing interpretation of the fossil record. It is this fact which has led to the most popular formulation of present day evolutionary theory: Punctuated equilibrium (although, reading the work of many geneticists interested in tracing evolutionary history, I'm not certain the paradigm shift has quite sunk in).
Of course, it's always possible that Darwin got it right -- that change is constant -- and it's our interpretation of the fossil record that must be re-examined. On the other hand, laboratory work has rather reinforced the view that species change is extremely difficult to engineer.
So, at present, it appears that species tend to remain the same in all their essentials for aeons upon aeons.
And your work -- and our own follow-up investigations (especially the work of D. Crisp) suggests that languages evolve in much the same way. As Crisp points out, a language retains its value to a community in large part as a result of its stability. People have to know that a word they use today means essentially what it meant when they learned it yesterday at their mother's knee. Moreover, they have to be confident that the one who hears the word understands its meaning in the same precise way.
Long and short, as Crisp says, the larger the community, the more stable its language.
Most fascinating, he argues that the same rules must apply to to genetic communities as well! The implication being that rapid change can only occur in small, isolated gene pools (which is a point reminiscent of one of your arguments concerning cultural evolution and small city states).
Perhaps Dan will post his commentary?
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DPCrisp
In: Bedfordshire
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| Surely living things are evolving constantly, through each generation. Nothing is standing still. |
This is an interesting example of the power of the paradigm and illustrates how theories are not in fact treated as the-best-models-we-currently-have-yet-still-hypothetical-and-susceptible-to-continual-efforts-at-falsification.
Evolution is postulated on the basis of visible variation interpreted as a series of small differentiations that lead to a suite of family resemblances. Indeed, species means things that look the same.
But once the principle is accepted, it is now assumed -- and not just by Martin -- to be an active agent in a dynamic world, even though it can be seen to be doing precisely nothing. "It must be happening because that's how we've decided the world works."
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DPCrisp
In: Bedfordshire
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| Perhaps Dan will post his commentary? |
Feel free to dredge up anything you like, Ish... but actually, I feel somewhat reticent about anything with tone of "from what we know about speciation...", because right now I feel like I/we don't actually know anything about speciation. I feel we need to return to the very basics because, as usual, they are glossed over as if self-evident. Family Resemblance is one thing, but then they throw in definitions about incompatible numbers of chromosomes that can't be the general rule...
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Mick Harper
Site Admin
In: London
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Well now, let's muse a while on the reasons for stasis among both animal species and languages. Dan is only half right in his claim (actually it is put forward in THOBR) that languages have to be reasonably stable to fulfil their function that you must be able to converse with anybody you meet in daily intercourse. We know from our own experience (especially watching Hollywood films) that in practice we can comprehend highly divergent forms of English. And that divergence has only taken a few years to take root.
The point about 'speciation' occurring is small discrete populations looks to be correct since were we to take a breeding population from the 'hood and stick them on a desert island they would surely be speaking something incomprehensible within a generation or two. But if they continue to live in West Los Angeles this speech will remain either a mere slang or at most a comprehensible local dialect. It will never develop into a discrete language.
But why do animals need to maintain this level of universal comprehensibility? So long as they can mate with anybody else they should meet in daily intercourse, why does not Evolution allow them to experiment quite radically with their other genes? This would surely increase the chances of adaptive speciation. [One line of evolutionary theory argues precisely this -- that we all possess vast potential variation in our redundant genes.] Or does the process work the opposite way? Do creatures mate on the basis they are experts in recognising a similar gene pool in the other animal? Watching telly nature programmes, this certainly seems quite likely.
If this is true then the "small isolated population" argument would presumably be at least partly on the basis of "the prisoner's dilemma" -- that one will mate with anything when the choice is limited.
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Martin
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If we accept that evolution occurs due to mutations in genetic material passed from generation to generation. Then surely we are changing from generation to generation. Changing and evolving.
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Mick Harper
Site Admin
In: London
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But Martin, surely you appreciate that you are exactly demonstrating the problem with basic evolutionary theory. It is an observable fact that each generation is measurably different from the previous one -- presumably via a unique genetic combination set up by sexual reproduction. But this does not lead to speciation. It does not even seem to lead to any kind of 'drift' since any such cumulative change appears to be overwhelmed by a return to norm. Hence the horsehoe crab born last year is scarcely more different from its immediate parents than from its hundred million year old forbear. Indeed, to engender any kind of cumulative change on any scale seems to require deliberate engineering in the form of human stock-breeding practices.
It is this problem that triggered the change from Darwinism to neo-Darwinism, that is the change from relying on natural selection arising from natural gene re-combination (as we would put it today) to the doctrine that evolutionary change require gene mutation.
But, as THOBR pointed out, we have conducted the equivalent of millions of years of intensive gene mutation through laboratory experiments (mostly with fruit flies) without producing anything very solid in the way of new species. New strains of drosophilida do appear from time to time but that is still a long way from the radical new species that evolution has to produce over and over again in order to account for the millions of species we have in the world today, and more in the past.
This is essentially the source of my own claim that gene mutation plus survival-of-the-fittest via sexual reproduction cannot produce new species in the time available. Now if we had a way that the genes could flash the news of a useful mutation around the gene pool...well, now we'd be talking. Maybe we need some neo-Lamarkianism as well as neo-Darwinism.
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Ishmael
In: Toronto
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| Martin wrote: | | If we accept that evolution occurs due to mutations in genetic material passed from generation to generation. Then surely we are changing from generation to generation. Changing and evolving. |
Mutations, everyone agrees, are actually most often harmful to the organism and to the species. Natural selection tends to eliminate aberrant genes from the gene pool as the individuals that suffer from mutations are often crippled by them. A second force also works to police the gene pool -- sexual selection.
This is known as the "Odd-looking people don't date much" rule.
Studies of sexual selection suggest that the most desirable mates appear to be those who best approximate the genetic mean. This suggests that nature actually abhors extreme deviation and tries to keep the genes of each species closely shepherded around an ideal form.
So even if you get a beneficial mutation that helps a creature find food and better survive predation -- if the girls think that extra arm sticking out of his forehead looks "weird", those genes aren't going to get passed into the general gene pool.
So rather than encouraging change, Darwinian forces appear to be ultra-conservative -- the exact opposite of what theory had anticipated.
I'm afraid it really is back to the drawing board on all of this.
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DPCrisp
In: Bedfordshire
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| Dan is only half right in his claim (actually it is put forward in THOBR) that languages have to be reasonably stable to fulfil their function that you must be able to converse with anybody you meet in daily intercourse. |
Language is like a set of tools, but let's not overdo the analogy. It's not that you can select a tool and then find out how suitable it is for the task. It's not that the task is to fulfil an independent requirement and good tools are the ones that do it well. Rather, language and conversation (and other applications of language) are much more mutually dependant, mutually defining.
The stability of the language consists in the fact that the language is defined by the community that uses it, by the using of it by the community. Correction and confirmation are continuous processes... and only occasionally can anyone say "I'm not wrong, I'm doing something new".
It's not a question of whether a rapidly-changing language could ever be effective or worthwhile or widespread... It's a matter of whether a rapidly-changing language could ever be taught, could ever exist.
| We know from our own experience (especially watching Hollywood films) that in practice we can comprehend highly divergent forms of English. And that divergence has only taken a few years to take root. |
True. But if you can't follow some Northern Irish yokel... and he doesn't slow down, avoid arcane expressions and enunciate carefully... you assume it's because he's an obtuse individual refusing to meet you half way, not that he's speaking a foreign language. There is a common ground to be found. The effort involved in finding it might be used to test foreignness or distance between languages.
| So long as they can mate with anybody else they should meet in daily intercourse, why does not Evolution allow them to experiment quite radically with their other genes? This would surely increase the chances of adaptive speciation. |
I'm not sure that I follow, but I think 'radical' is disallowed. Assuming genes can only affect small subsystems or components of systems, a radical change is most likely to be a disruption, fatal to the other cyclical processes and therefore to the organism. "Different" often means "wrong". And the cycles of life extend outside of the organism: if it's radically different from its parents, they can't provide for it or it can't "plug in" to its ecosystem. Usually. This might be the very thing that leads to a new species from time to time, but it has to be the exception rather than the rule: if there is such a thing as an ecosystem, there can't be very many opportunities for interacting with it differently. Continuity is the hallmark of systems and cycles.
The repetitiveness of living (and linguistic) processes is not so much "...because..." as "it just is".
| Do creatures mate on the basis they are experts in recognising a similar gene pool in the other animal? Watching telly nature programmes, this certainly seems quite likely. |
In a specific way, humans are wired to recognise people of the sort they live with... and there is a genuine reason for saying "they all look the same to me".
On the other hand, we tend to find people of other races (who look different from us, the same as each other) more attractive. This is explained as a way of tending towards diversification (which equates to robustness of the gene pool)... though if you shag someone as soon as you see 'em and fancy 'em, that's one thing; but taking the time to become familiar will surely override the initial impulse and give us different social dynamics.
If birds of paradise are anything to go by, the females can not be choosing mates that are "like me" (males and females are startlingly different, though they presumably waste no time looking to be impressed by any other species), though choosing at all means he's "for me".
| If this is true then the "small isolated population" argument would presumably be at least partly on the basis of "the prisoner's dilemma" -- that one will mate with anything when the choice is limited. |
What do we mean by "isolated population"? Organisms living on top of each other that are 'isolated' in different 'niches' makes some sense... but long-billed and short-billed Galapagos finches are surely physically able to mate regardless of which types of seed they feed on.
But this is where I run out of understanding. If a broad range of trees supports a broad range of bills, so amply illustrating the principle of selection/specialisation, then if long- and short-billed birds were to produce midi-billed offspring, there would still be somewhere for them to live! -- amply illustrating that it's just a matter of individual preferences and family resemblances; that species is not a sharp distinction.
{Always remember: you can have an obvious difference, a stark contrast, without having a discontinuity. On a grey-scale, black is distinctly different from white even though there is nowhere to draw a line and say "light colours this side, dark colours that side".}
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Duncan
In: Yorkshire
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Ishmael wrote:
| Mutations, everyone agrees, are actually most often harmful to the organism and to the species. .. This is known as the "Odd-looking people don't date much" rule. ..Studies of sexual selection suggest that the most desirable mates appear to be those who best approximate the genetic mean. This suggests that nature actually abhors extreme deviation and tries to keep the genes of each species closely shepherded around an ideal form. |
This is counter-intuitive. I think it is the other way around. Women tend to prefer tall muscular men. Men prefer beautiful large breasted women. These people are not ordinary. They are extraordinary. Consider the furore over women and UK size 0. It is the extreme which fascinates. Now if the mutation gives you the looks of Jason Merrick then I might agree but mutation can also be extraordinarily beautiful or attractive.
| So rather than encouraging change, Darwinian forces appear to be ultra-conservative -- the exact opposite of what theory had anticipated...I'm afraid it really is back to the drawing board on all of this. |
Not so therefore. Much of what I've read in this thread recently begs a serious reality check. I offer you a link to the National Academy of Sciences which puts the case for biological evolution. This is your much vaunted monolithic orthodoxy boys. You will find a timeline for evolution, human descent from Australopithecines, the works. I feel like I've rattled one hell of a cage here so please do me the courtesy of considering this systematically. No more rants against orthodoxy or Darwin please. Just tackle the arguments. If you can answer this then I'll hold my hands up. This is it: http://books.nap.edu/html/creationism/evidence.html
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Mick Harper
Site Admin
In: London
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Duncan, you cannot be serious. Anyway, human beings are hardly characteristic. The point -- that gene pools have a built-in tendency to stasis -- is scarcely deniable, the fossil record demonstrates it unambiguously. Even apparently systematic development, such as hind deer always being mounted by the biggest buck around, seems to have very little effect. (Giantism is something else.)
And, Duncan, you must not ever EVER offer up some standard orthodoxy for us to refer to. We have all spent our lives immersed in standard orthodoxy. It is for you to graze it and, should you come up with something that you deem unanswerable, present it here as your own.
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Martin
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The fossil record tells us that living things do not change.
Is this not another paradigm. How do we know this? Horseshoe crabs? Of the hundred thousand or so fossil species how many are found today?
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Mick Harper
Site Admin
In: London
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Good question, but I think rather a lot. The ones we hear about of course tend to be the glamorous extinct stuff. You're hardly going to stop the presses with a fossil armadillo. Actually, now I come to think about it, palaeontology is quite an expensive exercise to mount so 'glamorous' stuff is almost certainly skewing the entire field of study.
But you are correct in one respect: we are dependent on palaeontologists telling us what is a discrete species and what is not so it is not certain when we are dealing with one species that's changed a lot over time. Come to think of it (sigh, again) this is quite important. A whole hatful of reported fossil species might actually be just one species changing over time. This is not the same as the evolution of new species by genetic mutation. Interesting.
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DPCrisp
In: Bedfordshire
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| Studies of sexual selection suggest that the most desirable mates appear to be those who best approximate the genetic mean. |
I think I disagree: in the sense that people are most attracted to -- at any rate, manage to pair off with -- people most like themselves.
On the other hand, I agree: in the sense that people are -- on the whole, on average, even in the 'middle of the gene pool' -- attractive.
| This suggests that nature actually abhors extreme deviation and tries to keep the genes of each species closely shepherded around an ideal form. |
This is counter-intuitive. I think it is the other way around. |
I see what you mean about an ideal in the middle of the spectrum being counter-intutive, Duncan... but you are a card:
| Women tend to prefer tall muscular men. Men prefer beautiful large breasted women. These people are not ordinary. They are extraordinary. |
This is a perversion of the plain facts, Dunc: in any "natural" sense it is blatantly untrue; only in the artifically contrived context of media coverage and hollow expressions of what people would like is it remotely tenable.
| Consider the furore over women and UK size 0. |
Yes do. This extreme repels. There is a furore because this "ideal" is not simply being quietly pursued.
People don't buy fashion magazines because they like what's in them: they like those things because they're in fashion magazines.
| It is the extreme which fascinates. |
An apt choice of words: meaning spell-binding, which must be considered an abnormal condition.
| mutation can also be extraordinarily beautiful or attractive. |
Are you sure you know what you're saying here, Duncan? What does "more beautiful than anyone ever before" mean? A lot of work has already gone into quantifying beauty: it's all about the Golden Ratio and plenty of people already conform to it. How can they get to fit the "ideal" any better?
| So rather than encouraging change, Darwinian forces appear to be ultra-conservative -- the exact opposite of what theory had anticipated... |
Not so therefore. |
I'm completely with Ishmael on this. "Survival of the fittest" is a misnomer since, on the whole, everything does survive: "failure of the most off-the-pace" would be more accurate, though not catchy and not helpful. It behoves us all to keep things just as they are. And that's not what evolution by any continuous forces is supposed to achieve.
| Much of what I've read in this thread recently begs a serious reality check. I offer you a link to the National Academy of Sciences which puts the case for biological evolution. |
"Reality check" and "Orthodoxy check" are not the same thing at all. If Orthodoxy is the standard against which we are to check the, um, orthodoxy, then the results are foregone and the "checking" isn't checking at all.
A little homage to Wittgenstein {Happy Birthday to you, Happy birthday to you...}: consider a man who says "I know how tall I am"... and puts his hand on top of his head to prove it.
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Ishmael
In: Toronto
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| Duncan wrote: | | Ishmael wrote: | | ..Studies of sexual selection suggest that the most desirable mates appear to be those who best approximate the genetic mean. |
This is counter-intuitive. I think it is the other way around. Women tend to prefer tall muscular men. Men prefer beautiful large breasted women. These people are not ordinary. They are extraordinary. |
That's what we tend to think, it's true. Nevertheless, this is one area in which experimentation has produced results contrary to what seems common-sense.
In tests, subjects were shown computer-generated images of faces compiled using software that averages out a number of real-world faces into a composite. The software measures eye-spacing, nose length, lip size...all the attributes associated with facial dimensions. These numbers are then averaged and a composite face compiled, representing the "average" face.
In every case, test subjects tended to prefer the composite average face to any of the real-world faces from which the data was compiled. In essence, the test subjects rewarded the genes that kept closest to the mean and punished the genes that deviated farthest from the average.
But beauty is exceptional? Is it not? Well yes it is. It is exceptional that any one face should closely approximate the perfect mean.
With regard to breast size, I strongly suspect that the actual size of the breast preferred changes with fashion (in the 1920s and 30s, small-breasted women appear to have been all the rage in America, while in the 40s and 50s, it was large breasts and full figures). What doesn't change are the relative proportions preferred. And this too has been measured.
The same experiments have been conducted with ratios of hip to waist and breast (for both men and women) and the same results have been found -- an ideal form appears to exist and each sex prefers the opposite to adhere most closely to this ideal. If the breasts (or chest) are larger than is appropriate to the hip size, the figure is less pleasing than one where the breasts (or chest) are smaller but adhere to the ideal proportion. A man can have too much upper-body muscle and a woman can have too large a bust line, and it isn't necessary to invoke gargantuan dimensions to exceed the ideal form -- it's only necessary to slightly skew the ratio.
Now, on the other hand, one thing these studies consistently fail to report is that sexual preference itself falls along the same kind of distribution curve as does actual distribution of physical characteristics. This means that what is really being measured is the average or mean preference. All we really know is that most people are attracted to those who most closely approximate the mean.
But one final point.
It's important to distinguish between genetic traits and acquired traits. To say that women prefer athletic men to couch potatoes says nothing about what sort of genes are being passed on to each generation. A man might possess all the genetic raw material to win gold in the 400 meters but have spent all his life in a comfy chair affixed to a computer screen, consuming chips and soda.
On the other hand, studies have suggested the predisposition to athleticism (or natural athletic ability) appears to be related to physical beauty. So a chubby woman with a pretty face and proper hip-to-waist ratio is still a good bet to sire the next David Beckham.
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Ishmael
In: Toronto
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| DPCrisp wrote: | | People don't buy fashion magazines because they like what's in them: they like those things because they're in fashion magazines. |
Dan. Don't ever try to enter the field of publishing. You can't hope to succeed if you believe this.
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