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Author Topic:   Wells' Icons of Evolution - Peppered Moths
pink sasquatch
Member (Idle past 4095 days)
Posts: 1567
Joined: 06-10-2004


Message 76 of 88 (114788)
06-13-2004 5:43 AM


rock pocket mice the new peppered moth?
Although this may seem off-topic at first, I feel this recent study in wild desert mouse populations serves as a genetic proof of the kind of melanic selection the peppered-moth studies suggest. I'm interested to see if others agree...

The genetic basis of adaptive melanism in pocket mice.Nachman MW, Hoekstra HE, D'Agostino SL. Proc Natl Acad Sci U S A. 2003 Apr 29;100(9):5268-73. PMID: 12704245

Briefly: Populations of "rock pocket" mice live in (mostly light-colored) rock outcroppings in the desert, and since mice avoid open areas, they are effectively geographically isolated to the rock outcroppings. Geologically recent outcroppings have formed through volcanic activity, these outcroppings are dark colored. Mice living on the light-colored rocks have light coats, those on the dark rocks have dark coats - the selection here being predation by birds.

The authors were able to determine the specific gene mutation (a melanocortin receptor) responsible for the melanism in one population of dark mice. Importantly, they were able to show that the dark coat allele was relatively young compared to the (presumably ancestral) light coat allele, since the light coat allele had ten times as many variant neutral polymorphisms. Also, the dark allele is dominant, so its initial recipient would have immediately received the benefits of camoflauge.

I guess part of the lure of the peppered moth is the idea that their selection has been witnessed (depending on who you ask) on a recent human timescale - though I appreciate that the dark mice with the younger allele in the above study are found on the geologically younger outcroppings - new niches were filled by those that adapted.

Unfortunately, the study includes photos of mice of different coat colors on different colored rocks - I'm sure the experiments will be discredited someday because the pictures were likely staged...

To some extent I don't understand the obsession surrounding the peppered moth observation (or its discreditation), given the many other examples of selection.

Thanks.


Replies to this message:
 Message 77 by JonF, posted 06-13-2004 9:07 AM pink sasquatch has not yet responded

  
JonF
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Posts: 4481
Joined: 06-23-2003
Member Rating: 3.2


Message 77 of 88 (114813)
06-13-2004 9:07 AM
Reply to: Message 76 by pink sasquatch
06-13-2004 5:43 AM


Re: rock pocket mice the new peppered moth?
I've seen some rock pocket mice stuff. Another interesting thing about them is that some different populations of dark mice have different mutations for darkness. See Different genes underlie adaptive melanism in different populations of rock pocket mice..

The paper to which you refer is available online (a PDF) at http://www.genetics.wisc.edu/courses/spring04/708/files/nachman3.pdf.

To some extent I don't understand the obsession surrounding the peppered moth observation (or its discreditation), given the many other examples of selection.

Well, it is dramatic, easily understood, and occurred on a short time scale. Also, the issue of staged photographs is easy to present and understand, and it's relatively easy to pull the three-card-monte and switch denunciation of the photographs into denunciation of the validity of the findings.

Cromwell's attacked it in a slightly more sophisticated way than the average creationist poster, but he/she is still relying on Wells' biased and incomplete reporting and interpretations rather than the actual literature.


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pink sasquatch
Member (Idle past 4095 days)
Posts: 1567
Joined: 06-10-2004


Message 78 of 88 (114870)
06-13-2004 5:55 PM
Reply to: Message 6 by cromwell
04-27-2004 5:44 AM


Re: The pepped -up myth
JonF, I don't know that I agree with you that Cromwell's attacks on selection in peppered moths is sophisticated - I feel he discredited his own argument in his first message in this thread:

Cromwell wrote : "All that has happened is a fluctuation of two variants of pre-existing moths,one becoming more dominant over the other in a given period of time and then reverting back to the original dominant variation through yet unknown means. Not natural selection."

To me, in this quote he has essentially stated, 'we witnessed selection occur, but it wasnÕt selectionÕ.

Which is very strange to me since, while trying to discredit predation-by-selection, he specifically proposes two other possible selection forces:

Cromwell: "Birds generally find ladybirds distasteful The bold colouring is a warning to most predators.Camouflage and predation played no part in the melanism of these insects.He also mentions the presence of other melanics in non polluted areas.Wells go’s on to say that several other factors could be involved, including possible differences in the tolerances of larvae to pollutants e.t.c."

(In fact, I would be interested to see a study on larval toxicity susceptibility to death or sterilityÉ it seems to be the best alternative selective force IÕve heard of for this caseÉ)

I donÕt feel that Cromwell is actually arguing against selection, heÕs arguing against predation-by-bird as the specific selective force. Selection is selection regardless of the force Š even divine intervention if you want to take it that farÉ

I would be interested to hear how Cromwell specifically defines selection, since from a genetic point of view he appears to have contradicted himself.

Thanks.


This message is a reply to:
 Message 6 by cromwell, posted 04-27-2004 5:44 AM cromwell has not yet responded

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 Message 79 by JonF, posted 06-14-2004 9:30 AM pink sasquatch has not yet responded

  
JonF
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Posts: 4481
Joined: 06-23-2003
Member Rating: 3.2


Message 79 of 88 (115026)
06-14-2004 9:30 AM
Reply to: Message 78 by pink sasquatch
06-13-2004 5:55 PM


Re: The pepped -up myth
JonF, I don't know that I agree with you that Cromwell's attacks on selection in peppered moths is sophisticated

Oh, I agree that it's not sophisticated on an absolute scale; as I said "slightly more sophisticated way than the average creationist poster", which is pretty darned unsophisticated ;-).

I donÕt feel that Cromwell is actually arguing against selection, heÕs arguing against predation-by-bird as the specific selective force

It appears to me that he's arguing against selection and arguing that peppered moths essentially never rest on exposed tree trunks.

(The latter appears to be an attempt to claim that Wells' "Peppered moths do not even land on tree trunks" is not a lie, merely a sensationalization intended to sell books. Of course, either way it doesn't belong in a scientific debate, and reveals that Wells' knows it's not a scientific debate.)

Of course, Cromwell is welcome to correct me and clarify his/her position.


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cromwell
Inactive Member


Message 80 of 88 (115323)
06-15-2004 9:16 AM
Reply to: Message 79 by JonF
06-14-2004 9:30 AM


Re: The pepped -up myth
I will reply later.It depends on how long this thread remains open.I've had some bad news so i'm not in the right frame of mind, however, i'm not arguing against natural selection, because i don't know enough about it to argue against it.In my religion our printed material agrees with micro evolution.Although to me it all seems dubious.I find that there is a need to learn more by reading up on these forums.

I am debating that natural selection was not evidenced or proved with the current observations, assumptions and calculations thereof on the peppered moths.

My whole argument is wether this is an icon or not.

It hangs on how we see the percentages of the moths seen on the exposed parts of the trees.I believe it to be fractional.
As i only know the basics on statistical matters. I have contacted Aig on this point to see what they say about the peppered moth observations, and wether Majerus observations are to be taken at face value or as statistical averages.Apparently they can take a while to reply.


This message is a reply to:
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Replies to this message:
 Message 81 by JonF, posted 06-15-2004 9:32 AM cromwell has responded

  
JonF
Member
Posts: 4481
Joined: 06-23-2003
Member Rating: 3.2


Message 81 of 88 (115326)
06-15-2004 9:32 AM
Reply to: Message 80 by cromwell
06-15-2004 9:16 AM


Re: The pepped -up myth
t hangs on how we see the percentages of the moths seen on the exposed parts of the trees.I believe it to be fractional.

You can believe what you want, but in science we look for the evidence.

As i only know the basics on statistical matters. I have contacted Aig on this point to see what they say about the peppered moth observations, and wether Majerus observations are to be taken at face value or as statistical averages.Apparently they can take a while to reply.

Since AIG is an obviously biased source, I suggest that you contact a statistician with no axe to grind.


This message is a reply to:
 Message 80 by cromwell, posted 06-15-2004 9:16 AM cromwell has responded

Replies to this message:
 Message 82 by cromwell, posted 06-15-2004 10:32 AM JonF has responded

  
cromwell
Inactive Member


Message 82 of 88 (115335)
06-15-2004 10:32 AM
Reply to: Message 81 by JonF
06-15-2004 9:32 AM


Re: The pepped -up myth
JonF writes...
">>You can believe what you want, but in science we look for the evidence."<<

The evidence is in Majerus data.You have chosen to generalize on the data.I believe that they are straight amounts, giving evidence of the scarcity of moths landing on exposed parts of the tree.

Jonf writes...
">>Since AIG is an obviously biased source, I suggest that you contact a statistician with no axe to grind."<<

I'm sure that they can tell what Majerus data really says about the peppered moths.With this in mind i will contact several pro-evolution and pro creation sites and ask the same question.


This message is a reply to:
 Message 81 by JonF, posted 06-15-2004 9:32 AM JonF has responded

Replies to this message:
 Message 83 by JonF, posted 06-15-2004 11:25 AM cromwell has not yet responded

  
JonF
Member
Posts: 4481
Joined: 06-23-2003
Member Rating: 3.2


Message 83 of 88 (115340)
06-15-2004 11:25 AM
Reply to: Message 82 by cromwell
06-15-2004 10:32 AM


Re: The pepped -up myth
The evidence is in Majerus data.You have chosen to generalize on the data.I believe that they are straight amounts, giving evidence of the scarcity of moths landing on exposed parts of the tree.

You are, yet again, mixing sample nubmers (number of observed moths) with inferred population numbers (the number of moths in the population). You cannot do that and get valid statistics.

Admittedly the sample is biased. But it's the only sample we got, and it shows that some number of peppered moths do rest on tree trunks, and it is unrealistically unlikely to presume that no significant number of peppered moths rest on tree trunks.

I'm sure that they can tell what Majerus data really says about the peppered moths.

What makes you so sure?

With this in mind i will contact several pro-evolution and pro creation sites and ask the same question.

Great! Include either news://talk.origins or post at http://groups.google.com/groups?&group=talk.origins. You'll get lots of garbage replies, but you probably will get some good ones.

This message has been edited by JonF, 06-15-2004 10:26 AM


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KCdgw
Inactive Member


Message 84 of 88 (122736)
07-07-2004 2:31 PM


Exposed?
quote:
The evidence is in Majerus data.You have chosen to generalize on the data.I believe that they are straight amounts, giving evidence of the scarcity of moths landing on exposed parts of the tree

What is the significance of 'exposed' parts of the tree? Are you saying shadows on the resting place decrease the probability of bird predation?

KC


  
Adminnemooseus
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Message 85 of 88 (138562)
08-31-2004 5:10 PM


A notice of Peppered Moth discussion in another topic
There has been considerable (IMO off-topic) discussion of Peppered Moths at the DarkStar's Collection of Quotations topic.

The current most recent message discussing such is message 169.

Adminnemooseus


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JonF
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Posts: 4481
Joined: 06-23-2003
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Message 86 of 88 (418942)
08-31-2007 9:28 AM


Majerus' 2007 study
Majerus has performed a new study specifically designed to address the objections to previous studies. Bottom line: Tuttle and Kettlewell were right. The paper is not yet available, but a PowerPoint presentation and script for that presetnation are available from Majerus Lab Evolutionary Genetics Group. I've extracted some highlights and posted them at Message 265.
  
JonF
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Joined: 06-23-2003
Member Rating: 3.2


Message 87 of 88 (494065)
01-13-2009 11:26 AM


Another Majerus article on the Peppered Moth
Including discussion of the attacks on this example and why it is such a good example. Industrial Melanism in the Peppered Moth, Biston betularia: An Excellent Teaching Example of Darwinian Evolution in Action
  
JonF
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Posts: 4481
Joined: 06-23-2003
Member Rating: 3.2


Message 88 of 88 (494090)
01-13-2009 3:34 PM


Another great article ...
Industrial Melanism in the Peppered Moth, Biston betularia: An Excellent Teaching Example of Darwinian Evolution in Action:

quote:
The largest data set of peppered moths found in the wild was accumulated during a predation experiment that involved researchers climbing trees at dusk and dawn during the flight season of the moth (May to August) over 6 years. Of 135 peppered moths found, 50% were on horizontal branches (Fig. 4), 37% on trunks (Fig. 5), and 13% were on smaller twigs or in foliage (Majerus 2007). Therefore, although Kettlewellā€™s predation experiments have been criticized as being artificial because he released them onto tree trunks, it appears that this element of his protocol was not as flawed as some (e.g., Majerus 1998; Wells 2001) have previously thought.

That's particularly relevant to some of the claims in this thread. The whole article is well wort reading.


  
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