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Author | Topic: DarkStar's Collection of Quotations - Number 1 | |||||||||||||||||||||||
Adminnemooseus Administrator Posts: 3976 Joined: |
Take the moth stuff to:
Wells' Icons of Evolution - Peppered Moths or perhaps:
Book Review: Of Moths and Men This topic closed. Adminnemooseus Comments on moderation procedures? - Go to Change in Moderation? or Thread Reopen Requests
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Percy Member Posts: 22492 From: New Hampshire Joined: Member Rating: 4.9 |
I think the moth stuff is just clarification, not discussion, while we await DarkStar's response. This thread is actively on-topic. DarkStar is providing quotes, and we're responding, the last response to his quotes being earlier today. See my Message 141 and DBlevin's Message 143 for very recent detailed responses to DarkStar quotes.
--Percy
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Percy Member Posts: 22492 From: New Hampshire Joined: Member Rating: 4.9 |
PaulK writes: So far as I know the question is the degree to which bird predation is the selective factor. Maybe I'm just unaware of the data, but my understanding is that bird predation has not been objectively established as the cause of changing melanism proportions in peppered moth populations in response to polution. What we know is that polution favors melanism in peppered moth populations. What we suspect is that bird predation is the causative factor, and that somehow coloration is protective, though we don't know how. You could argue, I suppose, that bird predation must be responsible by the process of elimination, because what else could it possibly be? But this would be an ID style argument. Just as Kettlewell defenders prefer bird predation as the answer to the peppered moth melanism question, IDists prefer God as the answer to the evolution question. IDists say it must be God because we can't figure what else it could be, while Kettlewellists say it must be bird predation because we can't figure out what else it could be. Just to point out that there are other alternatives, and not to suggest this is the actual answer, perhaps melanism helps moths survive because it is more heat absorbant and allows them to stay warmer in polluted environments where less sunlight reaches the ground. --Percy
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PaulK Member Posts: 17827 Joined: Member Rating: 2.3 |
As I understand it bird predation is known as a factor. This article establishes that it has been established as the major (but not only) factor
Moonshine: Why the Peppered Moth Remains an Icon of Evolution
quote:
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Percy Member Posts: 22492 From: New Hampshire Joined: Member Rating: 4.9 |
In the release/recapture experiments, the moths would have been in the tree canopy.
In the direct observation of bird predation, the moths were on the tree trunks. It's been a couple years since I read Hooper's book, so I don't recall the details. Issues that occur to me now (not necessarily the ones Hooper raised, and not necessarily correct) are that the moths come out at night, so does color really matter? Do we know where the moths go during the day? Does moth predation happen during the day or at night? I would agree that a connection had been established if someone could explain just where and when the birds eat the moths, and why coloration is a factor. --Percy This message has been edited by Percy, 08-27-2004 03:26 PM
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PaulK Member Posts: 17827 Joined: Member Rating: 2.3 |
OK so the moths were (mainly) in the canopy in the release-and-recapture experiment.
We know that something was removing adult moths from the population - and favoured dark moths in unpolluted areas and light moths in polluted areas. Predation is the most likely explanation. We know from the other experiments that birds displayed the same selective bias, and we know that they do hunt in the canopies (and on the trunks and branches where the moths have also been seen). And if the colour during the night matters less (and I'd agree there) then the moths were probably eaten during the day while they rested. Most birds are active durng the day. Sounds like a good case for bird predation to me.
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Percy Member Posts: 22492 From: New Hampshire Joined: Member Rating: 4.9 |
There's good circumstantial evidence that bird predation is related to melanism, but this is akin to a murder case where you have motive and opportunity, but you can't place the suspect and the victim in the same room. At the end of the day, no one knows where and when the birds eat the moths or why color is a factor.
We seem to be imitating the Creationist tactic of trying to persuade on the basis of insufficient evidence, arguing endlessly and pointlessly when the evidence just isn't there. I feel like evolutionists have put their foot in the mouth with the peppered moth example. In this foremost example of natural selection in the wild, we can't tell Creationists where and when the birds eat the moths, and what we have been telling them for 50 years is wrong. I wonder what happened to DarkStar. --Percy
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Percy Member Posts: 22492 From: New Hampshire Joined: Member Rating: 4.9 |
Please don't be distracted by the posts from me and PaulK seeking clarification of our positions on the peppered moth example. The topic of the thread remains your quotes. A number of people replied to your list of quotes. My analysis of the quotes is in Message 141
--Percy
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PaulK Member Posts: 17827 Joined: Member Rating: 2.3 |
I don't see this conversation in the same way you do.
Which if any of the follwoing statements would you disagree wiht: 1) We know that there is a selective effect going on (the release and recapture results) 2) We have good reason to beleive that bird predation is a part of it (the experiments with captive moths, combined with the fact that moths do rest on the trunks). 3) Given our background information it is reasonable to extrapolate the results of the experiments with captive moths to other parts of the trees, including the canopy. 4) While this does not constitute absolute certainty it does present a strong case that bird predation is a major factor in the selection
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Percy Member Posts: 22492 From: New Hampshire Joined: Member Rating: 4.9 |
Here's an analog of how it sounds to me:
Which if any of the following statements would you disagree with:
This constitutes a strong case that Jesus was a real person. I think the evidence that differential bird predation is related to melanism is stronger than the evidence for Jesus, but the fact remains that the foremost example of natural selection in the wild has holes in it. If we want to continue to push this example then it behooves us, given the unhappy history of this example, to do the work necessary to nail this down. Otherwise we're in the situation where our foremost example isn't certain, and all other examples are less certain. If I were a Creationist I would continue to jump all over this. --Percy
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PaulK Member Posts: 17827 Joined: Member Rating: 2.3 |
I would object to the third in that I don't believe that any of the Biblical records are eyewitness accounts from Jesus' life. And I would qualify the last with the fact that Josephus' major mention of Jesus is lkely an interpolation in whole or in part (the second, shorter message most likely is genuine).
If I accepted them all then I would agree that they constituted a strong case that there was a historical Jesus (which I believe anyway). I really don't see the problem here.
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Percy Member Posts: 22492 From: New Hampshire Joined: Member Rating: 4.9 |
But I would object to some items on your list, such as #2. To me it seems an individual matter of when one decides, "I've checked this enough, that's good enough for me." Trying to convince Creationists of such a key point on less than ironclad evidence doesn't seem like it would be persuasive, and would tend to lessen their confidence in the scientific approach.
I wonder if DarkStar has abandoned the thread. --Percy
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PaulK Member Posts: 17827 Joined: Member Rating: 2.3 |
Well as we've seen in other threads Creationists usually value their own opinions over virtually anything short of absolute proof. I don't really think that we should set "good enough to convince a closed-minded creationist" as anything other than a practical guideline for use in dealing with such individuals.
Now we can disucss why you don't feel that the experiments with captive moths were good enough to conclude that birds will take moths off tree trunks if you like. Or you can explain where you were going with your last couplweof posts but right nw I really don't see what you are objecting to.
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Percy Member Posts: 22492 From: New Hampshire Joined: Member Rating: 4.9 |
PaulK writes: I don't really think that we should set "good enough to convince a closed-minded creationist" as anything other than a practical guideline for use in dealing with such individuals...Or you can explain where you were going with your last couple of posts but right nw I really don't see what you are objecting to. In general, I would agree. But we're talking about the foremost example of natural selection in the wild, an example whose fundamental tenet, that degree of melanism protects moths from bird predation on tree trunks, has been shown false. I think the screw-up obligates us to fill in the blanks before we can legitimately continue offering this as a premier example of natural selection in the wild.
Now we can disucss why you don't feel that the experiments with captive moths were good enough to conclude that birds will take moths off tree trunks if you like. The experiments conclusively demonstrated that birds will eat moths off tree trunks. Unfortunately, the peppered moth apparently doesn't light on tree trunks. --Percy
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NosyNed Member Posts: 9003 From: Canada Joined: |
...before we can legitimately continue offering this as a premier example of natural selection in the wild.
Isn't "premier" simply being the most famous which comes from being "oldest" and in lots of old text books. How big a deal is this now? Are there other examples that could replace this is the textbooks didn't have so much "momentum"?
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