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Author | Topic: Symphony by accident | |||||||||||||||||||||||||||||||||||||||
nwr Member Posts: 6408 From: Geneva, Illinois Joined: Member Rating: 5.1 |
I was at the concert hall the other night when suddenly, and entirely by accident, the sound of a Beethoven symphony rang through the hall.
Quite obviously, using the same reasoning as Bolder-dash in Is it an Accident?, that there was music was a complete accident. Jesus was a liberal hippie
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New Cat's Eye Inactive Member
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Is evolution an accident?
Yes and no, sort of... but not really. It depends on how you want to use the word 'accident'. Any particular random mutation could be called an accident. Whether or not the environment selects for or against that particular mutation could be called an accident. Evolution as a whole could be called an accident, in that there is no direction or planning to it. But, that a particular evolved characteristic is working is no accident. The selective mechanism removes that accidental nature of the change. To say 'an eye developed accidentally' is incorrect. The reason these types of arguments are brought up is to ridicule the odds of something that complex happening totally randomly. But the selective pressure removes that random component thereby making it no longer an "accident".
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frako Member (Idle past 305 days) Posts: 2932 From: slovenija Joined: |
Is evolution an accident? Well the same accident a this lets say you have 3 dice and you want to throw a 3 each dice showing nr 1. You throw the dice until you get one dice to show the single dot then you dont throw that dice anymore and only throw the other 2 dice and when the second dice shows 1 dot you stop throwing that one and only throw the last dice until it shows only 1 dot. And so you accidentally get all 3 dice to show 1 dot. Evolution is basically the same accident. Edited by frako, : No reason given.
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ringo Member (Idle past 411 days) Posts: 20940 From: frozen wasteland Joined:
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Once upon a time there was a mother with two daughters and a son. The girls liked to tease their little brother, telling him (among other things) that he was an 'accident'. Not knowing exactly what that meant, he asked his mother, "Was I an accident?" She replied, "I prefer to think of you as a surprise." "What's the difference?" he asked. "Well, an accident is something bad and you don't want it to happen. A surprise is something good and you didn't even know you wanted it until you got it."
(credit to Roseanne Barr) In evolution, a random mutation could be a fatal accident or it could be a happy surprise. There's no way of knowing until it's tested in the laboratory of natural selection. "I'm Rory Bellows, I tell you! And I got a lot of corroborating evidence... over here... by the throttle!" |
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slevesque Member (Idle past 4640 days) Posts: 1456 Joined: |
But then, isn't the majority of mutations fixed through genetic drift ? (ie randomly)
If I'm not mistaken the number of mutations fixed by selection is quite small compared to genetic drift.
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New Cat's Eye Inactive Member |
But then, isn't the majority of mutations fixed through genetic drift ? (ie randomly) If I'm not mistaken the number of mutations fixed by selection is quite small compared to genetic drift. Even if so, the ones we'd need to focus on are the ones with high selective pressure if we're determining how "accidental" gross change is. The accidentality comes up in the face of morphological differences, not from some slight genetic drifting.
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nwr Member Posts: 6408 From: Geneva, Illinois Joined: Member Rating: 5.1 |
slevesque writes:
I'm not sure if this is settled. Actually, I'm not even sure that the terminology is settled.If I'm not mistaken the number of mutations fixed by selection is quite small compared to genetic drift. As far as I know, it is combinations of genes that are most important. Traits may depend on many genes. The mutations add variation to the population. Then the filter of natural selection acts on that variation. My example of music was admittedly an extreme case, intended for emphasis. But the point is that you have randomness that is fed into a filter. In our normal way of talking, we don't use "accident" when there is a directional filter. Jesus was a liberal hippie
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Percy Member Posts: 22391 From: New Hampshire Joined: Member Rating: 5.2 |
slevesque writes: If I'm not mistaken the number of mutations fixed by selection is quite small compared to genetic drift. It seems unlikely to me that there exists a way to count actual fixated mutations and classify them as to whether it was due to selection or drift, so I don't think we could know either way whether what you're claiming is true. Maybe one of the biologists will chime in. We do know that advantageous alleles will be driven toward fixation more rapidly than neutral alleles, but as fixation approaches the effects of drift become more prominent and can actually interfere with fixation. Apparently, in sexual populations recessive advantageous alleles can actually have a better chance of fixation than dominate advantageous alleles simply because of the effects of drift. See Natural Selection, Genetic Drift, and Gene Flow Do Not Act in Isolation in Natural Populations. The most important thing to keep in mind is that the effects of adaptation are prominently in evidence throughout nature, and neutral alleles cannot produce adaptation. --Percy
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Dr Adequate Member (Idle past 284 days) Posts: 16113 Joined: |
But then, isn't the majority of mutations fixed through genetic drift ? (ie randomly) If I'm not mistaken the number of mutations fixed by selection is quite small compared to genetic drift. Sure, but Bolder-dash was talking about the structure of the eye, which is not a product of genetic drift.
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slevesque Member (Idle past 4640 days) Posts: 1456 Joined: |
My example of music was admittedly an extreme case, intended for emphasis. But the point is that you have randomness that is fed into a filter. In our normal way of talking, we don't use "accident" when there is a directional filter. Yes, but the force of the filter must be proportionally as strong as the quantity of randomness flooding in. Someone would still be justified to call it accidental if the filter only gives it a weak direction.
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Dr Adequate Member (Idle past 284 days) Posts: 16113 Joined:
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I had an isolated system and quite by accident it entered a state of higher entropy.
After that, by a complete accident, the random motion of air molecules did not cause my lungs to explode. Later that same day, I accidentally didn't quantum tunnel to the Moon. All sorts of bizarre accidents like that have been happening to me lately.
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slevesque Member (Idle past 4640 days) Posts: 1456 Joined: |
It seems unlikely to me that there exists a way to count actual fixated mutations and classify them as to whether it was due to selection or drift, so I don't think we could know either way whether what you're claiming is true. Maybe one of the biologists will chime in. Population genetics gives us a maximum on fixation by selection, since selection involves killing/inhibiting reproduction of individuals. So it can only select for so much in a given generation, all the rest is hope to genetic drift.
We do know that advantageous alleles will be driven toward fixation more rapidly than neutral alleles, but as fixation approaches the effects of drift become more prominent and can actually interfere with fixation. Apparently, in sexual populations recessive advantageous alleles can actually have a better chance of fixation than dominate advantageous alleles simply because of the effects of drift. See Natural Selection, Genetic Drift, and Gene Flow Do Not Act in Isolation in Natural Populations. And if genetic drift has such on a strong effect on the fixation of mutations, wouldn't one be justified to question if such an amount of randomness can still account for the evolution of complex structures ?
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Dr Adequate Member (Idle past 284 days) Posts: 16113 Joined: |
Yes, but the force of the filter must be proportionally as strong as the quantity of randomness flooding in. Someone would still be justified to call it accidental if the filter only gives it a weak direction. Well, again, the topic was the eye, and whether Richard Dawkins thinks it happened "by accident". Clearly he thinks that the filter of selection is strong enough to produce the eye; consequently, he does not think that the eye is accidental.
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slevesque Member (Idle past 4640 days) Posts: 1456 Joined: |
Well, again, the topic was the eye, and whether Richard Dawkins thinks it happened "by accident". Clearly he thinks that the filter of selection is strong enough to produce the eye; consequently, he does not think that the eye is accidental. I hear you, but your changing the goalpost. My remark was concerning Nwr's OP, which in turn was in reply to Bolder-dash's statement that evolution as a whole is a random process.
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jar Member (Idle past 394 days) Posts: 34026 From: Texas!! Joined: |
slevesque writes: Well, again, the topic was the eye, and whether Richard Dawkins thinks it happened "by accident". Clearly he thinks that the filter of selection is strong enough to produce the eye; consequently, he does not think that the eye is accidental. I hear you, but your changing the goalpost. My remark was concerning Nwr's OP, which in turn was in reply to Bolder-dash's statement that evolution as a whole is a random process. If you look at all the lifeforms that have existed, which one would you say was a desired product? Anyone so limited that they can only spell a word one way is severely handicapped!
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