Evolution and complexity

I think the Berkeley website is better than textbooks and much more accessible: a couple hours reading can give you a strong idea of the science and it can be updated when errors are found (the problem noted with textbooks).I recommend their Evolution 101 for starters:
Evolution 101 - Understanding EvolutionIt starts with a definition of evolution as used in science, rather than some creationist misconception, and then builds on that with examples.Another good website is from the U of Mich, withCertainly one should use university material, if it is accessible, as this is where evolution is being studied. I understand Harvard (or was it MIT) was posting website course material this year, but I haven't looked to see what they have on evolution yet.Enjoy.

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Oh, heck, I wasn't doing that at all. I mean, you have to plow through a gazillion pages on pigeon breeding before you get to the good stuff. But for anyone who's a scientist or otherwise dedicated to it, I'd put it on the "must read" list.The websites I gave are far better introductions for total newbs, for sure.Edited by Zhimbo, : No reason given.

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And selective pressure also causes stasis(ie,no change) and the more pressure also leads to more stasis.

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Sorry dwise1,this is a obvious nonsequitor.Yourthermos analogy does support stasis, but it cannot rightly be applied here as it is an example of insulation/isolation from selection pressure.
Indirectly it might be argued that more selctive pressure might lead to more stasis, if you include formation of more efficient immune systems or error checking/correcting mechanisms.
Thermal Mass and or Inertial Mass might be better analogies for stasis in this case.Given a large enough popolation(mass), selective pressures would either be dilluted or absorbed.(depending on which analogy you use)Edited by Simonsays, : No reason given.

Sorry, simonsays, not even close. As in a negative-feedback control loop, the selective pressure is there all the time; the perceived effect of that selective pressure depends on where you are relative to the set-point.

Wrong dwise...It was right on. This is what one calls moving the goal posts!
Yes, a negative-feedback control loop can help to preserve stasis.The key words here are feedback and loop.You have neither in a closed system such as a thermos.
The selective pressureis not there, as far as I can see, in such an enviroment(closed system - thermos).
Also, the negative feedback example isn't general like the thermal insulation analogy. It's specific.It only works with specific selective pressures. And your'e still going to get selection and improvement of the negavtive feedback mechanism, or extinction if the proccess is taken to an extreme. Not more stasis.

Oh! You're complaining about the thermos!The only purpose served by that thermos analogy was to demonstrate that the exact same mechanism can produce two very different and apparently contradictory results. That was all.Don't worry about the thermos. It was in no way intended to model any part of evolution.

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Oh! You're complaining about the thermos!

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No, What I'm objecting specifically to is your nonsequitor... And it still exists. I'd assumed your "thermos" analogywas the warrant for your argument,both because of its content,and because of its location.(right after your main assertion)
If your "thermos" analogy is not your warrant, then what is? You have basically reworded your proposition three times(although #3 does lead to an alternate conclusion);1.)

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But if a population is already well adapted to its enviroment then selection pressure will act to resist change and hence keep the population in stasis

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(ITALICS MINE)2.)

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But if the population is already on an "ideal" genome, then selective pressurewill cause it to stay there, thus resulting in stasis

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(ITALICS MINE)3.)

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Wheras specialized species that are finely tuned to their enviroments will have less genetic diversity and will most likely not be able to survive changes in their enviroments

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(ITALICS MINE)Also, your thought experiment seems to focus on population(species?) selection and gene selection(see Dawkin's "Selfish Gene") (i.e.,an ideal genome),not on Darwin's natural selection (selection at the individual organism level)
Given that it came from Gould's and Eldridge's (first ?) conference not unusual .But applicable? I don't know. Edited by Simonsays, : dB coding errors. Punctuation error.

What non sequitur are you talking about? I had written none.Here's the thermos paragraph that seems to have caused you so much heartburn, along with the preceding paragraph that it refers to:

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I don't think we can equate evolution with change, but rather with adaptation. If a population is not well adapted to its environment to start with, then selective pressure would result in change. But if a population is already well adapted to its environment, then selective pressure will act to resist change and hence keep the population in stasis.

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So how does evolution know to change gears like that? Like the thermos, which keeps hot things hot and cold things cold. How does the thermos know which is which? It doesn't. All the thermos does is block the transfer of heat in either direction and the "keeps hot things hot and cold things cold" effects are the natural consequence.

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I started thinking about that several years ago when it was stated on a PBS show about evolution that when a species is not well adapted to its environment then evolutionary change is rapidly, but then as it approaches being well adapted evolutionary change slows down. My reaction was, of course, "say what?". Just how is evolution supposed to know when to speed up and when to slow down?The thermos analogy is from an old joke where a dim-witted individual says it's the most wonderous invention because it keeps hot stuff hot and cold stuff cold, but how does it know the difference? The full extent of the analogy is that the same mechanism just operates the same in both cases; it doesn't need to know anything. The thermos does not need to know whether it contains hot liquid or cold liquid, because its mechanism of preventing the transfer of heat into or out of the thermos bottle has the seeming contradictory effect of keeping hot liquids hot and cold liquids cold. Evolution doesn't need to know how well adapted a particular species is in order to regulate how rapidly it changes; the same mechanisms (not the same mechanism as the thermos'; I never ever claimed that it did) cause different rates of change in different circumstances.Evolution and stasis are not opposites. Stasis is not the absense of evolution, but rather an expected effect of evolution.And of course I'm talking about populations.As you should be able see clearly, there is no non sequitur there. If you still have a problem, could you please state it clearly?

Hi Simonsays,I'm puzzled about why you have a problem with this: Those three statements are correct and consistent. Can you explain where you think the problem lies?I think I can improve upon the thermos analogy by substituting a temperature gradient, meaning things are at different temperatures. The laws of thermodynamics want to smooth out a temperature gradient so that everything is at the same temperature. Heat flows toward cold.So when a cup of coffee is at the same temperature as the air, then there is no heat flow. The cup of coffee doesn't have to know that it's the same temperature as the air, that's just the way heat flow works. This is analogous to a population that is well adapted to its environment.And when a cup of coffee is much hotter than the surrounding air, then there is a net heat flow from the coffee to the air. This is analogous to a population that is not well adapted to its environment. The flow of heat is analogous to change in allele frequencies in the population.--Percy

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What non sequitur are you talking about? I had written none.

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No dwise1. What you haven't written is a warrant. You know ... What I asked you for in my last reply. Without a warrant to connect your proposition to your conclusion you do have a nonsequitor. Again I ask you to present one.(print out the words and/or sentences in your past message/s that constitute your warrant!)

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The thermos analogy is from an old joke where a dim-witted individual says it's the most wonderous invention because it keeps hot stuff hot and cold stuff cold, but how does it know the difference? The full extent of the analogy is that the same mechanism just operates the same in both cases; it doesn't need to know anything. The thermos does not need to know whether it contains hot liquid or cold liquid, because its mechanism of preventing the transfer of heat into or out of the thermos bottle has the seeming contradictory effect of keeping hot liquids hot and cold liquids cold ...

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This sounds like a statement a student of mine made years ago. although, he was just very young, not dim-witted. He commented on how unlucky it was that the tennis balls kept going into the puddles from the recent rain. I said that it wasn't luck. The balls are there for the same reason the water was. (Was it raining tennis balls ?) No, it's just gravity. They both stop at the nearest low points of the court.

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... Evolution doesn't need to know how well adapted a particular species is in order to regulate how rapidly it changes; the same mechanisms ... cause different rates of change in different circumstances.

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Very interesting... Now if you could list for me some of those same mechanisms which under selective pressure lead to stasis ,(ie; balance,equilibrium,or stoppage of flow.)(from the American Heritage Dictionary), instead of different rates of change, then you might actually have a warrant to support your assertion.

Does anybody know what the hell he's talking about?

I think he's afraid of being arrested.

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Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine

A rate of change of 0 is stasis.

Does anyone here (besides me) no what a warrant is in a logical argument? If so, please type out (or copy and paste) the warrant in any of dwie1's replies that you think is applicable in this case:

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And selective pressure also causes stasis (ie,no change) and the more pressure also leads to more stasis.

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I think Percy thinks he has a warrant with his thermal equilibrium (potential energy) model. But I will show in my coming reply to him where I think he misses the mark.Edited by Simonsays, : Grammar and a dB coding error.Edited by Simonsays, : ommitted words.

Oh,ha,ha,ha. Lol.
I'm sorry, I thought this was a science forum. In science forums you are required to back up (support) assertions. Edited by Simonsays, : Changed "your" to "you are".