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Author | Topic: How did Evolution produce Symmetry? | |||||||||||||||||||||||
defenderofthefaith Inactive Member |
Let's try a hypothetical situation. Say you're diving at sea and you discover a carved marble statue. Would you say it was intelligently designed?
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NosyNed Member Posts: 9004 From: Canada Joined: |
Probably, what does that have to do with anything?
How would you decide it is intelligently designed, if you would?
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lpetrich Inactive Member |
An important question is how bilateral symmetry is "implemented"; what developmental-genetic mechamisms cause the two sides to develop in sync? Are there some feedback mechanisms that keep one side from getting too far ahead of the other? It might be interesting to find out if there is some simple reaction-diffusion mechanism that can help maintain such symmetry, as there is for spots and stripes and other color patterns.
An interesting symmetry-generating mechanism was recently discovered; there is an article about it in a recent Nature magazine. It's about how plants grow and what effects produce the positioning of their leaves on their stems. A new leaf is induced by the growth hormone auxin acting on the side of the growing stem tip; this auxin comes from further back in the stem. However, existing leaves soak up auxin, producing auxin shadows in front of them, forcing the next leaves to be offset from their angle in the stem. CBMGNCBI Nature - Not Found Nature Press Release for 20 November Issue [This message has been edited by lpetrich, 11-29-2003]
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Sky-Writing Member (Idle past 5180 days) Posts: 162 From: Milwaukee, WI, United States Joined: |
Ok..I'm new here so take it easy on me for a while...But here is my opinion on the whole symmetry thing.. Let's just say (hypathetically speaking) that someone was born with a short arm. Was that an advantage? Probably not so therefore the traits wouldn't be passed on to the offspring. But if a fish was born with one fin and one of its offspring had 2 and swam faster and better, then it would be seen as an advantage so the traits of the two finned fish will be passed on to the offspring and then the one finners will eventually be weeded out...That's my opinion and theory... Oh and there is a really good program on sexual selection and sexual characteristics by the Discovery Channel.. Can't remember the name but it's quite informing and interesting..I'll get back to you all on the name of it ASAP.
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NoBody Guest |
nevermind, please bump post.
[This message has been edited by NoBody, 12-13-2003]
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world Inactive Member |
snowflakes
...and if this isn't enough, there 31 other classes of symmetry that are used to classify crystals. Please see http://members.aol.com/jmichaelh/part2.html The science is pretty solid on the crystal formation thing. It results from the physical and chemical properties of the crystallizing minerals. No one has been successful in using crystals to prove God, but they are pretty cool.
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Human Being Inactive Member |
Hello. I am new here, but I'm no "newbie". So make no assumptions about me. That said, I would like to preface my comments by stating that a couple people in this thread are arrogance personified, and also delusional about that fact. I think it's obvious who those people are.
What puzzles me is why the concept of Information Theory has not been addressed regarding the "puzzle" of symmetry. It seems painfully obvious to me that one HUGE advantage to symmetry is a decrease in the information necessary to "describe" any highly symmetric entity. While this affects matter both animate and inanimate, it is far more critical to the former. Perhaps amounting to less than a 50% decrease in some life forms, perhaps more than a 50% decrease in others, these "savings" must have an immense impact on the "lifetime" energy consumption of said life forms. Don't underestimate the potential requirements of DNA replication. For those so inclined to accept "open-minded" theorization, I highly suggest Dan Winter's website and specifically his works on recursion. If someone wants to waste their time "debunking" Dan Winter, by all means waste your time. http://www.soulinvitation.com/predictions/index.html I know that other people in this discussion will greatly appreciate the angle that I am introducing. Consider the real costs of DNA as the number of genes increase. The "description" that begets a human being has been highly refined over time, regardless of one's preferred theory to explain said refinement. It seems quite logical to assume that life is the synergy of complication and simplification. I will enjoy responding to any commentary, though I don't promise everyone a response. [This message has been edited by Human Being, 12-14-2003]
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NosyNed Member Posts: 9004 From: Canada Joined: |
You know, HB, that is an interesting idea.
However, I would start off doubting it is actually what is going on for a couple of reasons: The human genome (unlike a bacteria's) seems loaded with more than it "really" needs. If this is true then the savings due to symmetry might be overwhelmed by that. I suspect that the values in symmetry as a survival feature are more important than any savings in DNA management that there might be. My guess would be that if having an asymmetric form was advantageous it would be used and the extra DNA would be carried. However, I sure don't have anyway of proving any of that. My guess is that we don't know enough to figure all that out.
If someone wants to waste their time "debunking" Dan Winter, by all means waste your time. I know that other people in this discussion will greatly appreciate the angle that I am introducing. I'll make another quick guess here. It would, as you say, be a waste of time. I won't bother. It does however belong in another thread as it isn't on topic here.
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Human Being Inactive Member |
Thank you Ned. I apologize to all for the preemptive rebuttal regarding Dan Winter. My desire to avoid a negative tangent arising from his inclusion in my point inspired the tactic. I also wanted to stress how important I feel recursion is towards life. Recursion is the foundation of both self-similarity and symmetry, and the golden ratio can be seen as a tautology resulting from the manifestation of existence that is life.
The human genome (unlike a bacteria's) seems loaded with more than it "really" needs. If this is true then the savings due to symmetry might be overwhelmed by that. I am speaking as a layman here, but I suspect that there are "meta-genes" within our DNA which describe aspects of human life that we have no awareness of. Our knowledge of our own form of life, while seemingly vast, is more likely quite sparse. I do concede I am making an assumption that "symmetry savings" have great relevance towards survival. I am much more comfortable with this assumption than other assumptions I'm reading about in this thread.
I suspect that the values in symmetry as a survival feature are more important than any savings in DNA management that there might be. My guess would be that if having an asymmetric form was advantageous it would be used and the extra DNA would be carried. I firmly believe that "DNA management" IS a survival feature. DNA replication is fundamental to life. Thus, it seems intuitive to me that optimization of this aspect of the life cycle is critical to life's continued advancement. And life has been advancing for billions of years. Indeed, while symmetry strikes me as vastly helpful, of course it does not preclude asymmetry. My last point seems like a restatement of others' previously made points. Provided that symmetry does result in the savings I theorize, it is equally intuitive that life forms who directly choose mates based on fitness indicators would see symmetry increasingly favorably. Such a life form "understands" on an "instinctual" level that symmetry is a boon to fitness and advantageous to enhance within one's offspring. ------------------
HB=CHIMP+TIME
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NosyNed Member Posts: 9004 From: Canada Joined: |
I am speaking as a layman here, but I suspect that there are "meta-genes" within our DNA which describe aspects of human life that we have no awareness of. Our knowledge of our own form of life, while seemingly vast, is more likely quite sparse. I do concede I am making an assumption that "symmetry savings" have great relevance towards survival. I am much more comfortable with this assumption than other assumptions I'm reading about in this thread. We certainly do not know all that much yet, our knowledge is indeed sparse. However, you are proposing things wich we have "no awareness of". Until we have some awareness of them they are wild specultion with no reason for it and nothing further to say about it. Making an assumption isn't very helpful without some idea of how to test it. And you might want to specify "other assumptions". Are there some which are as little evidenced as yours?
My last point seems like a restatement of others' previously made points. Provided that symmetry does result in the savings I theorize, it is equally intuitive that life forms who directly choose mates based on fitness indicators would see symmetry increasingly favorably. Such a life form "understands" on an "instinctual" level that symmetry is a boon to fitness and advantageous to enhance within one's offspring.
Symmetry as a boon --You're not the first to suggest this. Have you read "The Red Queen" by Ridley? Things which are "intuitive" may be right, they are also very often wrong. That is no more than a starting point for the very knowledgable whose intuition might be more to the point than the less knowledgable. ------------------Common sense isn't
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Human Being Inactive Member |
I am the first in this thread to suggest Information Theory as a crucial piece of the symmetry puzzle. I don't want a cookie, but I do want people to consider the crux of my thoughts a bit more than you have. Some of your responses to what I said come off as general-purpose debunkery. That's okay. My conjecture is clearly making you think, albeit in a "Devil's Advocate" way.
Of course if I wanted to spend hours and hours, I could compose a much more thorough post regarding my speculation. My intent, however, was only to introduce myself and a few brief points. I posted because I felt an important part of the discussion was being overlooked. I will leave all with my food for thought. I hope others do more than chew once and spit it out. Perhaps later I will make dessert. ------------------
HB=CHIMP+TIME |
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ChildOfGod2516 Inactive Member |
If it's part of natural selection, then why is it that no one has found any fossils that have more legs on one side or more eye sockets on one side, or something like that? Wouldn't there at least be fossils? Isn't it more likely that we'd find at least some fossils that were not very symmetrical than it is that all the symmetrical fossils that have been found were found.
An example of this is sticking a 'U' shaped magnet in a container of paper clips, nails, and safety pins, is it more likely that you will get the same number of each object on each side or that there will be a different number of each on each side. Even though it IS possible that the first time you take the magnet out the sides will be symmetrical, how likely is it that every single step of evolution created a perfectly symmetrical creature the FIRST time? In the example of the magnet, how many times out of ten would you get the same number of each object on each side? Not many, so how many of the steps of evolution, where there are more possible outcomes, would end up perfectly symmetrical? Most likely not many. In other words,WHAT HAPPENED TO THE FOSSILS THAT AREN'T SYMMETRICAL?
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Abshalom Inactive Member |
Quote: "If it's part of natural selection, then why is it that no one has found any fossils that have more legs on one side or more eye sockets on one side, or something like that? Wouldn't there at least be fossils? Isn't it more likely that we'd find at least some fossils that were not very symmetrical than it is that all the symmetrical fossils that have been found were found." CoD-2516
Does it have to be a fossil, or will the several species of flatfish like flounder suffice?
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Human Being Inactive Member |
How would flatfish "champions" reconcile their favored species' evolutionary path of asymmetry with that of Information Theory? Your positions on other points have been established. Does I.T. preclude their asymmetry? If so, explain how. Tell me, what do *you* think??
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HB=CHIMP+TIME
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Abshalom Inactive Member |
Q: "How would flatfish "champions" reconcile their favored species' evolutionary path of asymmetry with that of Information Theory?"
A: To survive by filling a niche. S: "Your positions on other points have been established."Q: Are you talkin' to me? Q: "Does I.T. preclude their asymmetry?"A: No. Q: "Tell me, what do *you* think??"A: I think I.T. is just another way of expressing the economy of nature. Now, tell me how a Sassafrass tree with its three distinctly and differently shaped leaves fits into *your* theory of I.T.? [This message has been edited by Abshalom, 12-15-2003] [This message has been edited by Abshalom, 12-15-2003]
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