Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 80 (8863 total)
Current session began: 
Page Loaded: 09-18-2018 8:58 PM
207 online now:
(207 visitors)
Chatting now:  Chat room empty
Newest Member: rldawnca
Upcoming Birthdays: AdminPhat
Post Volume:
Total: 838,657 Year: 13,480/29,783 Month: 926/1,576 Week: 138/303 Day: 29/53 Hour: 0/1


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
1
23456
...
24NextFF
Author Topic:   Peppered Moths and Natural Selection
RAZD
Member
Posts: 19544
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.3


Message 1 of 350 (261386)
11-19-2005 9:47 PM


Take the famous 'peppered moths' of England. Creationists like to twist the truth about this moth, so I will go into both sides here:

(1) Creationist (ICR website) by Dr. John Morris, President of ICR

This is taken directly from the web site:

Here's the well-told scenario. In the early 1800s, nearly all of the individual peppered moths (Biston betularia) were of a light grey, speckled color. Active mostly at night, they needed to hide by day from predatory birds. Since trees and rocks were typically covered with mottled light green, gray lichens, the moths were effectively camouflaged. A rare peppered moth exhibited a dark color and was easily seen by birds; thus they seldom survived. On average, over 98% of all the species were of the light variety, yet with both dark and light were of the same species and were fully interfertile.

Then came the industrial revolution and the air filled with soot, covering the trees and rocks with a toxic film, killing the lichens and darkening the trees. Soon the light variety of moth was easily seen while the darker were camouflaged. By the turn of the century, 98% of the moths were dark. When English medical doctor Bernard Kettlewell studied the phenomena in the 1950s, it became "Darwin's Missing Evidence"—natural selection in action.

Remember that both varieties were present at the start, with the mix of genes producing lights favored over the mix of genes producing darks. As the environment changed, the dark variety had greater opportunity to pass on their genetic mix, and percentages changed. All the while, the two types were interfertile. No new genes were produced, and certainly no new species resulted. This is natural selection in action, but not evolution. Adaptation happens, but the changes are limited.

Please note that this is a creationist site and they have just said that "This is natural selection in action, but not evolution."

He goes on to imply that this disproves evolution because the moth varieties are not now different species. But lets look at this claim:

natural selectionspeciation
theory testedyesno
theory validatedyesno
theory invalidatednono

Because speciation is not tested in this scenario, the results cannot be used to invalidate the theory.

Please note how this creationist website shows you exactly how the mechanism of color change in a population works. The moths did not decide to change color: there were existing genetic variations that made one population more able to survive under one condition and the other population more able to survive under a changed condition.

There are also some valid claims about some bad science done on this issue in early studies, and we will look at that issue below as well.

(2) Evolution and Natural Selection by Dr. Ken Miller, Professor of Biology, Brown University, RI, with additional material by Dr. Bruce Grant, Professor at the College of William and Mary.

We start with Ken Miller's website (Brown University website):

Note first off that this article refers to the two varieties of the moth:


  • Biston betularia typica (the light color version) and
  • Biston betularia carbonaria (the dark color version)

In the scientific name structure (for those unfamiliar with it) we have family (Biston) species (betularia) and variety (typica or carbonaria) designations.

An important distinction is made between 'species' and 'variety' and that is that 'varieties' can interbreed: when the genetic difference is great enough that no viable offspring are created then we would then have a different 'species' - this is the scientific distinction. As we are not talking about species differentiation at this point in this scenario, the speciation part of the theory of evolution is not tested, per se.

From BIOLOGY by Miller & Levine, page 298:

"Kettlewell found that in unpolluted areas, more of his light-colored moths had survived. In soot-blacked areas, more of the dark-colored moths had survived. Thus Kettlewell showed that in each environment the moths that were better camoflaged had the higher survival rate. It was logical to conclude that when soot darkened the tree trunks in the area, natural selection caused the dark-colored moths to become more common. Today Kettlewell's work is considered to be a classic demonstration of natural selection in action."

Please note: "a classic demonstration of natural selection in action." Both websites agree on this.

Now lets look at a scientific critique / review of the original / early studies:

... in 1998, Michael E. N. Majerus of the Department of Genetics at the University of Cambridge carefully re-examined Kettlewell's studies, as well as many others that have since appeared. What he reported, first of all, was that Kettlewell's experiments, indicating that moth survival depends upon color-related camoflage, were generally correct:
"Differential bird predation of the typica and carbonaria forms, in habitats affected by industrial pollution to different degrees, is the primary influence on the evolution of melanism in the peppered moth."

(P. 116, Melanism - Evolution in Action, M. E. N. Majerus, Oxford University Press, New York, 1998).

However, Majerus also discovered that many of Kettlewell's experiments didn't really test the elements of the story as well as they should have. For example, in testing how likely light and dark moths were to be eaten, he placed moths on the sides of tree trunks, a place where they rarely perch in nature. He also records how well camouflaged the moths seemed to be by visual inspection. This might have seemed like a good idea at the time, but since his work it has become clear that birds see ultraviolet much better than we do, and therefore what seems well-camouflaged to the human eye may not be to a bird. In addition, neither Kettlewell nor those who checked his work were able to compensate for the degree to which migration of moths from surrounding areas might have affected the actual numbers of light and dark moths he counted in various regions of the countryside.

These criticisms have led some critics of evolution to charge that the peppered moth story is "faked," or is "known to be wrong."

Neither is true. In fact, the basic elements of the peppered moth story are quite correct. The population of dark moths rose and fell in parallel to industrial pollution, and the percentage of dark moths in the population was clearly highest in regions of the countryside that were most polluted. As Majerus, the principal scientific critic of Kettlewell's work wrote, "My view of the rise and fall of the melanic form of the peppered moth is that differential bird predation in more or less polluted regions, together with migration, are primarily responsible, almost to the exclusion of other factors."

Next, from Dr. Bruce Grant by linked article "Fine Tuning the Peppered Moth Paradigm" (pdf):

In his 34 years of moth hunting, Majerus has discovered 47 peppered moths at rest by day in the wild. ... Majerus separates into categories the position on trees where the moths were located (trunk, trunk/branch joint, branches). While the trunk/branch joint was the most common site, his data indicate that the moths do not all rest in the same place. As Clarke et al. (1994) put it: "Moths habitually resting in only one place will be habitually sought there." ... In truth, we still don't know the natural hiding places of peppered moths.

Morph Specific Behavior. Kettlewell proposed that pale and melanic forms of peppered moths actively seek out different resting sites. To test this idea, he put typicals and carbonaria into a barrel lined with black and white strips of card, and he recorded where they had settled. (The moths are active at night, but remain motionless, unless disturbed, during the day.) From these "barrel" experiments, Kettlewell (1955b) reported morph specific behaviors: carbonaria tended to settle on black, and the typicals tended to settle on white. Kettlewell suggested that the moths accomplish this by comparing the darkness of their body scales to the surface reflectance of the immediately available substrates and that they come to rest where the contrast between the scales and the substrate is least "conflicting."

Despite design problems, Kettlewell’s predation experiments are still instructive. He used the same procedures in two distinctly different places, a habitat disturbed by pollution and an unpolluted habitat, and he got complementary results. His data, in both directions, were in complete accord with the directions predicted by the incidence of melanism in the regions. So, if he was wrong to use the trunks of trees in Birmingham, he was consistently wrong to use the trunks of trees in Dorset. If he was wrong to release the moths during the daylight hours in Birmingham, he was consistently wrong to release the moths at the same time in Dorset. His data, however, show that the variable of regional pollution made a significant difference as to which phenotypes of the moths better survived the conditions imposed by the experiments.

Kettlewell's aren't the only experiments that show this. Majerus recounts five other studies, using variously modified experimental designs, that corroborate fitness differences between the morphs in polluted and unpolluted regions. He also reviews some exceptions. Hindsight has enabled us to find fault with all of these experiments to varying degrees and has helped us to suggest future work. It is not true, however, that these experiments are so seriously flawed that their conclusions are invalid. The conclusion that conspicuous moths are more readily eaten by birds than are inconspicuous moths has been repeatedly confirmed. The findings from the grand bulk of the predation experiments are in qualitative agreement with the direction of changes in melanic frequencies documented among geographically separated populations of peppered moths.

Again, note "While the trunk/branch joint was the most common site" showing that moths do, in fact, rest on portions of the tree trunks. While we cannot say what actual proportion of time is spent in various locations at various times of the day and night, it is absolutely false to claim that peppered moths never rest on the bark of the trees or other locations where the camouflage effect would come into action. Nor can it be argued that the moths are not cognizant at some level of the background they chose to rest on. Focusing on just the main trunk or rocks of the experiments done by Kettlewell is a strawman argument as it does not represent the range of possible resting sites that do involve contrasting visibility or on the other experiments he conducted that showed a preference for camouflaged resting sites, nor does it address the issue of the moths being glued in specific sites to test the differential predation of the insects by birds or that other experiments that were conducted with released moths. Kettlewell's experiments determined (a) that peppered moths apparently selected backgrounds for resting sites that matched their coloring and (b) that birds differentially found and ate moths that were more conspicuous by lack of camouflage first and (c) that there were in fact population shifts between polluted (dark) areas and non-polluted (light) areas.

Thus the claims on the creationist site:


  • "that Kettlewell's compelling argument has not been verified by other investigators" is outright wrong - it is verified by M. E. N. Majerus, in his book Melanism - Evolution in Action (Oxford University Press, New York, 1998) and by others that followed Kettlewell.
  • "Furthermore, we now know that neither dark nor light moths ever spend their days on exposed tree trunks or rocks as depicted in the famous textbook pictures. His original associates have even admitted that the photographs were faked, that the moths were glued onto the tree." And this issue has been discussed above and answered - yes some of the initial science was not done as properly as it would be done today, but the different studies isolated different aspects of the situation, the overall conclusion has been validated, and the effect is confirmed by others.

POINTS IN AGREEMENT


  • there were two varieties of the moth Biston betularia in England before the 'Industrial Revolution' and on average, over 98% of all the species were of the light variety, if not more (the dark variety was first noticed in the early 1800's)
  • the 'Industrial Revolution' filled the air with soot, covering the trees and rocks with a toxic film, killing the lichens and darkening the trees
  • soon the light variety of moth was easily seen while the darker were camouflaged.
  • by the turn of the century, 98% of the moths were of the dark variety, and finally
  • the change in populations was due to predation of the more visible variety.

And thus we see agreement that this example is about the Natural Selection part of evolution, and not about speciation, and further that it cannot be about speciation because it is talking about the relative size of populations of two varieties of the same species of moth.

The website by Ken Miller ends with some recommended Background Reading:

The web page of Bruce Grant, Professor at the College of William and Mary, and especially his paper, "Fine Tuning the Peppered Moth Paradigm." (pdf)

Prof. Grant has also written to rebut charges that the Peppered moth story is fraudulent: "Charges of Fraud Misleading."

Also: William Majerus' book "Melanism - Evolution in Action" can be found on many library shelves. He has a new book about to be published: "Moths."

Enjoy.



Note to ADMIN:

I know there is another thread on the peppered moths, but it relates more to Wells and his "icons" issue. This one addresses creationist implications of lies and fraud, an issue recently asserted by randman, and thus it is topical once more. Let's start clean and not involve Wells in this issue here.

Either {Biological Evolution} or {is it Science} would be okay.

Edited by RAZD, : tyop Maherus fixed

Edited by RAZD, : fixed ICR link

Edited by RAZD, : fixed Ken Miller link

Edited by RAZD, : replaced text block with table


we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)

Replies to this message:
 Message 3 by RAZD, posted 11-20-2005 7:59 AM RAZD has acknowledged this reply
 Message 4 by RAZD, posted 11-20-2005 9:24 AM RAZD has acknowledged this reply

  
AdminNWR
Inactive Member


Message 2 of 350 (261395)
11-19-2005 10:13 PM


Thread moved here from the Proposed New Topics forum.
  
RAZD
Member
Posts: 19544
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.3


Message 3 of 350 (261487)
11-20-2005 7:59 AM
Reply to: Message 1 by RAZD
11-19-2005 9:47 PM


bump for randman
randman is talking about peppered moths again but has not responded to this thread. From
http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=14&t=1135&m=145#145

the old tree trunk peppered moth claim

Biologists soon noticed that in industrialized regions where the dark moths were common, the tree trunks were darkened almost black by the soot of pollution. Dark moths were much less conspicuous resting on them than were light moths. In addition, the air pollution that was spreading in the industrialized regions had killed many of the light-colored lichens on tree trunks, making the trunks darker.

http://www.txtwriter.com/Backgrounders/Evolution/EVpage07.html

What is the error in this information please?

What invalidates the observed natural selection of the moths in this area due to the pollution factors?

{edited to be more specific}

Enjoy.

This message has been edited by RAZD, 11*20*2005 09:33 AM


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.


This message is a reply to:
 Message 1 by RAZD, posted 11-19-2005 9:47 PM RAZD has acknowledged this reply

  
RAZD
Member
Posts: 19544
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.3


Message 4 of 350 (261509)
11-20-2005 9:24 AM
Reply to: Message 1 by RAZD
11-19-2005 9:47 PM


Randman: can you show the moths are NOT an example of natural selection?
Randman in this post on the {Talking some sense into randman} thread
http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=14&t=1135&m=158#158

Despite the rigged pictures and the over simplication of the events. If you have to teach a 5th grader about natural selection, the moths do make for a good example.

But this is what is taught to college students, not just 5th graders. There is, in fact, a whole litany list of traditional arguments listed for evolution that are just flat out wrong, and have been shown to be wrong for decades, but they are still there.

Why?

It's not ignorant people teaching this stuff, or writing this stuff. This is put out by college professors.

To make this claim that it is "just flat out wrong" randman needs to demonstrate that the moths are not an example of natural selection.

I await his demonstration of this.

Enjoy.


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.


This message is a reply to:
 Message 1 by RAZD, posted 11-19-2005 9:47 PM RAZD has acknowledged this reply

Replies to this message:
 Message 6 by Nuggin, posted 11-20-2005 5:42 PM RAZD has acknowledged this reply

  
Yaro
Member (Idle past 4388 days)
Posts: 1797
Joined: 07-12-2003


Message 5 of 350 (261527)
11-20-2005 10:51 AM


Excelent thread RAZD
Great info. Raz! A bit long, but worth the read. I'm sure randman will refute it with no problem however, shame, it probably took you a good while to write. ;)
  
Nuggin
Member (Idle past 384 days)
Posts: 2965
From: Los Angeles, CA USA
Joined: 08-09-2005


Message 6 of 350 (261596)
11-20-2005 5:42 PM
Reply to: Message 4 by RAZD
11-20-2005 9:24 AM


Misreading Randman
First off, Razd, excellent OP here. Lots of info, very well organized.

I think, however, that people have misunderstood Randman's point.

I don't think that Randman is saying that Peppered moths are not an example of natural selection. I think that he is saying that the texts over simplify or mistate the facts.

To a degree he's right.

Your OP is a great example of how it could read in a text book. You give all the important information, and I suspect that Randman wouldn't object to so much info being in the text.

The problem is that these textbooks don't have the time or space to go into this kind of detail. Especially at a grade school level where the kids likely wouldn't understand the concepts, but even at a college level where what's being taught as a primer on the subject.

While the typically scene peppered moths example works well in a text called "Biology and you", I would think they'd go into more detail in a text called "Advanced Theories of Evolutionary Biology".

As far as I understand it, Randman's point is that we should be teaching the whole story, not misleading pieces of it. I agree on principle, but not as principal. (Wow! I couldn't stop myself from that pun!)

You can still teach a kid history, even though you are telling them that people before Columbus thought the world was flat.


This message is a reply to:
 Message 4 by RAZD, posted 11-20-2005 9:24 AM RAZD has acknowledged this reply

    
randman 
Suspended Member (Idle past 2791 days)
Posts: 6367
Joined: 05-26-2005


Message 7 of 350 (261616)
11-20-2005 6:29 PM


pretty much nuggins nails it
And to be frank guys, I have a lot to do in life. I have fairly large family, a company to run, employees to make sure they get paid, etc....I do want to discuss science issues with people, but I grow tired of petty arguments.

I think it would not have been too difficult for anyone to see what my stance was, and not to misrepresent it, and I think the use of the peppered moth story continues not because it is a good example as evidence for evolution because there's not much real evolution taking place, just variation within the genome and variation that can switch back again. So it is very misleading, but imo, evolutionists are loathe to replace misleading material.

Why?

If the goal is education, then you don't want to create false impressions.

Maybe when all these arguments came to the fore, the real goal was not education but acceptance of evolutionary theory.

This message has been edited by randman, 11-20-2005 06:30 PM


Replies to this message:
 Message 8 by RAZD, posted 11-20-2005 6:32 PM randman has responded

  
RAZD
Member
Posts: 19544
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.3


Message 8 of 350 (261617)
11-20-2005 6:32 PM
Reply to: Message 7 by randman
11-20-2005 6:29 PM


but you missed answering the question ...
because there's not much real evolution taking place, just variation within the genome and variation that can switch back again

Is this or is this not natural selection in operation?

Yes or No.

Thanks for your limited time.


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.


This message is a reply to:
 Message 7 by randman, posted 11-20-2005 6:29 PM randman has responded

Replies to this message:
 Message 9 by randman, posted 11-20-2005 6:40 PM RAZD has responded

  
randman 
Suspended Member (Idle past 2791 days)
Posts: 6367
Joined: 05-26-2005


Message 9 of 350 (261622)
11-20-2005 6:40 PM
Reply to: Message 8 by RAZD
11-20-2005 6:32 PM


Re: but you missed answering the question ...
It's natural selection of existing traits. That's all, and from what I read, the whole tree trunk claim is way overstated since reportedly they don't hang out so much on trees, and furthermore, bird vision is a little different spectrum so there's a lot to criticize. It's very misleading, and imo, totally inappropiate as basic evidence for evolution.

A similar process occurred when most of the Indians died due to epidemics the Europeans had built up more resistance having already been decimated, but if we were to speak of that as evolution, it would be seen as racist because it suggests speciation when racial differences are not speciation.

But frankly, if you can't see my point, I have no more interest in repeating it you ad nauseum. You are either capable of grasping the point, or not.


This message is a reply to:
 Message 8 by RAZD, posted 11-20-2005 6:32 PM RAZD has responded

Replies to this message:
 Message 10 by RAZD, posted 11-20-2005 6:48 PM randman has not yet responded
 Message 11 by mark24, posted 11-20-2005 6:49 PM randman has not yet responded
 Message 12 by Nighttrain, posted 11-20-2005 6:59 PM randman has not yet responded

  
RAZD
Member
Posts: 19544
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.3


Message 10 of 350 (261626)
11-20-2005 6:48 PM
Reply to: Message 9 by randman
11-20-2005 6:40 PM


So it is natural selection ...
It's natural selection of existing traits.

That's all natural selection is. This is part of evolution -- the selection mechanism.

So you do agree that this is an example of natural selection, and therefor of the selection mechanism of evolution.

the whole tree trunk claim is way overstated since reportedly they don't hang out so much on trees, and furthermore, bird vision is a little different spectrum so there's a lot to criticize. It's very misleading,

The various studies have shown that the defining difference between the areas where the light variation were predominant were pollution free and the areas where the cark variation were predominant were polluted. Do you disagree with that?

Would you agree or disagree that the only difference in the areas was the sooty pollution and its effects on the environment?

{changed subtitle}

This message has been edited by RAZD, 11*20*2005 06:53 PM


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.


This message is a reply to:
 Message 9 by randman, posted 11-20-2005 6:40 PM randman has not yet responded

  
mark24
Member (Idle past 3087 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 11 of 350 (261627)
11-20-2005 6:49 PM
Reply to: Message 9 by randman
11-20-2005 6:40 PM


Re: but you missed answering the question ...
randman,

bird vision is a little different spectrum so there's a lot to criticize.

So birds have trouble seeing trees, too? :)

A similar process occurred when most of the Indians died due to epidemics the Europeans had built up more resistance having already been decimated, but if we were to speak of that as evolution, it would be seen as racist because it suggests speciation when racial differences are not speciation.

It's still evolution, the ratio of alleles in the population has changed via natural selection (the alleles that confer resistance are now much more prevalent in the population). The same happened with bubonic plague in Europe, a corollary of which makes Europeans more resistant to HIV than other populations. Not macroevolution, not speciation, but still evolution. Racism is neither here nor there.

Mark

This message has been edited by mark24, 11-20-2005 06:50 PM


There are 10 kinds of people in this world; those that understand binary, & those that don't
This message is a reply to:
 Message 9 by randman, posted 11-20-2005 6:40 PM randman has not yet responded

    
Nighttrain
Member (Idle past 1885 days)
Posts: 1512
From: brisbane,australia
Joined: 06-08-2004


Message 12 of 350 (261630)
11-20-2005 6:59 PM
Reply to: Message 9 by randman
11-20-2005 6:40 PM


Re: but you missed answering the question ...
Tell you what, Randy, since it irks you so much. Let`s do a swap. We`ll drop the peppered moths myth if you drop the Flood fable. :D
This message is a reply to:
 Message 9 by randman, posted 11-20-2005 6:40 PM randman has not yet responded

    
randman 
Suspended Member (Idle past 2791 days)
Posts: 6367
Joined: 05-26-2005


Message 13 of 350 (261631)
11-20-2005 7:04 PM


ignorance is bliss for some evos
1. First off, no the study does not rule out all the various factors that could have influenced whether lightly colored or darkly colored moths became more dominant as a result of soot. It could be something else entirely, perhaps another aspect of pollution, coincidence, etc,...

2. Secondly, birds have the ability to see in the UV spectrum and the ignorance of that basic fact renders moot any conclusions about what birds actually see in this instance.

3. Peppered moths are nocturnal and so releasing them in the day-time to draw conclusions about their behaviour also makes the study based on faulty data.

4. In reality, birds are not even the primary predator of peppered moths, but rather bats are. Bats method of sensing prey is totally different, and relies on sound waves and thus bats tend to capture moths in flight rather than while they are resting. This fact further makes the claims of the study to be somewhat fantastic in nature and without solid scientific standing.

5. I have heard but not verified that these same experiments were repeated elsewhere in the world with the opposite results. As such, since the experiment is not repeatable, it falls down on that merit as well.

I do find it amusing that RAZD is now quoting a creationist web-site as evidence, but on the whole, I don't think the OP addresses the basic problems with the study, nor the fact that it doesn't show speciation and is not therefore evidence of even microevolution giving rise to new species and therefore the way it is used is incorrect.

The best we can say is some very poorly done studies might suggest that there is a relationship between the pollutants of the industrial evolution and population sizes of peppered moths, but that other potential causal effects have not been ruled out, nor is there any reason to draw any strong conclusions to the peppered moth experiments as they did not involve peppered moths' primary predators and were riddled with gross errors and flaws.

In fact, to hold the peppered moth experiments as valid science is educational malpractice, presenting very poorly done and erroneous science as somehow something students should accept as valid.

It's a joke, and from my perspective darn near inexcusable for evos to continue to cling to such wildly erroneous uses of data, even moreso when these same evos blast critics like myself as if we are the ignorant ones here.

This message has been edited by randman, 11-20-2005 07:10 PM


Replies to this message:
 Message 14 by mark24, posted 11-20-2005 7:39 PM randman has responded
 Message 15 by JonF, posted 11-20-2005 8:01 PM randman has not yet responded
 Message 16 by RAZD, posted 11-20-2005 8:40 PM randman has responded
 Message 36 by Belfry, posted 11-20-2005 9:57 PM randman has responded

  
mark24
Member (Idle past 3087 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 14 of 350 (261642)
11-20-2005 7:39 PM
Reply to: Message 13 by randman
11-20-2005 7:04 PM


randman,

I just can't help myself...

1. First off, no the study does not rule out all the various factors that could have influenced whether lightly colored or darkly colored moths became more dominant as a result of soot.

We know that light moths on dark backgrounds are more likely to be taken than the other way around (& vice versa), so it stands to reason that predation is the cause of the proliferation of the moth variants. It's obvious.

It could be something else entirely, perhaps another aspect of pollution, coincidence, etc,...

Ad hoc. Do you never tire of committing logical fallacies? If you have a non ad hoc explanation, we'd be delighted to hear it.

2. Secondly, birds have the ability to see in the UV spectrum and the ignorance of that basic fact renders moot any conclusions about what birds actually see in this instance.

Given that birds pick off the light moths on dark backgrounds far easier than the other way around, & vice versa, I fail to see what your point is? The salient point is that a selective advantage exists in moths of various colours on various backgrounds. This we know. How does birds having UV vision make any difference?

3. Peppered moths are nocturnal and so releasing them in the day-time to draw conclusions about their behaviour also makes the study based on faulty data.

Obviously the moths are not camouflaged when they are flying at night, but during the daytime when they are at rest. This is when the selective advantage is evident.

4. In reality, birds are not even the primary predator of peppered moths, but rather bats are. Bats method of sensing prey is totally different, and relies on sound waves and thus bats tend to capture moths in flight rather than while they are resting. This fact further makes the claims of the study to be somewhat fantastic in nature and without solid scientific standing.

Irrelevant. The camouflage works during the day when the moths are at rest, what eats then during the night is neither here nor there.

5. I have heard but not verified that these same experiments were repeated elsewhere in the world with the opposite results. As such, since the experiment is not repeatable, it falls down on that merit as well.

Since it's not verified, we'll ignore this, then.

Mark


There are 10 kinds of people in this world; those that understand binary, & those that don't
This message is a reply to:
 Message 13 by randman, posted 11-20-2005 7:04 PM randman has responded

Replies to this message:
 Message 19 by randman, posted 11-20-2005 9:07 PM mark24 has responded

    
JonF
Member
Posts: 4179
Joined: 06-23-2003
Member Rating: 3.3


Message 15 of 350 (261646)
11-20-2005 8:01 PM
Reply to: Message 13 by randman
11-20-2005 7:04 PM


Re: ignorance is bliss for some evos
1. First off, no the study does not rule out all the various factors that could have influenced whether lightly colored or darkly colored moths became more dominant as a result of soot. It could be something else entirely, perhaps another aspect of pollution, coincidence, etc,...

The statistics have been done. The correlation between pollution and relative frequencies of moth populations is very significant. It's not a coincidence. Perhaps another aspect of pollution ... but, if so, so what? The conclusion is that natural selection changed the population; exactly how this happened is an important question but is not going to change the primary conclusion.

The statistics also demonstrate that bird predation is the major influence on the balance between the two types. There are probably other effects, and there is disagreement about those effects and their relative importance, but bird predation is #1.

2. Secondly, birds have the ability to see in the UV spectrum and the ignorance of that basic fact renders moot any conclusions about what birds actually see in this instance.

Nobody has made any conclusions about what birds actually see (there have been some hypotheses). The fact that birds can see in UV does not render the actual conclusions of the studies moot.

3. Peppered moths are nocturnal and so releasing them in the day-time to draw conclusions about their behaviour also makes the study based on faulty data.

Why? They were never recaptured before the next night, and sometimes two nights passed before recapture.

5. I have heard but not verified that these same experiments were repeated elsewhere in the world with the opposite results. As such, since the experiment is not repeatable, it falls down on that merit as well.

You heard wrong. The same experiments have been repeated elsewhere in the UK and in the U.S. with the same results. The results are repeatable and have been repeated.

See Moonshine: Why the Peppered Moth Remains an Icon of Evolution, The peppered moth: a black and white story after all, FINE TUNING THE PEPPERED MOTH PARADIGM, and Recent History of Melanism in American Peppered Moths.


This message is a reply to:
 Message 13 by randman, posted 11-20-2005 7:04 PM randman has not yet responded

  
1
23456
...
24NextFF
Newer Topic | Older Topic
Jump to:


Copyright 2001-2015 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2018