Patrick O'Brian Discussion Forum

I wrote sloppily

Bob Bridges

I was thinking that everyone had the same experience in school that I did, so I encapsulated briefly and sloppily, expecting everyone to know what I meant.  Sorry, my bad.  Here's the same thing written out in longhand:

When I was in high school, say in the late '60s, I was taught that pollution in London had gotten so bad that soot and other particulates had darkened the tree trunks, and that moths with light-colored wings were more visible to their predators.  But after a while, moths with darker wings started showing up, more difficult to see.  It's been a lot of years but as I recall this was explained to me, or at least I understood it at the time, as a minor example of evolution in action: The light-winged moths were dying off, but as a species evolved darker wings to survive.  At the time I accepted it.

I later heard the pollution had been somewhat cleared up, the tree trunks began to show lighter in color, and the same process of evolution worked in reverse, that is, moths began to have light wings again.

Later still, when I was in my 20s or 30s I suppose, I read that this is not to be considered an example of a species of moth evolving to survive changing circumstances; there were simply two species or perhaps subspecies of moth.  As the tree trunks darkened, the [sub]species with lighter wings became rarer and the [sub]species with darker wings began to do better.  The reverse happened as the pollution was cleared up.  I accepted this explanation as more likely than evolution by mutation.

Parenthesis: I've noticed that although scientists insist evolution works by random processes, most people including many scientists talk about the "purpose" of various evolutionary changes, as though there is a designer behind it all.  The ones that deny that a hypothetical god has anything to do with it then talk about "Nature" instead.  It seems to me this confuses their language and probably their thoughts as well.  Thus I say above that I understood that the moths had "evolved" darker wings "in order to survive".  This may have been my misunderstanding, but it's how I remember it being presented to me.  Jan, it doesn't sound to me as though you suffer from that confusion.

For akatow: I don't recall anyone telling me it had happened a century before.  (If 150 years ago now, then about 100 years ago when I was in high school.  Boy, time flies.)  I always thought of it as reasonably current, say during the '40s and '50s.  Placing it toward the end of the Industrial Revolution makes more sense.

For YA: As I said, I wrote sloppily.  The above may have made it clear, but when I said the moth species didn't adapt, I meant that a species didn't change their genes to start producing darker wings, but that one species of moth started to do better than the other under the changing circumstances.

Now that I'm required to think about this whole thing, I realize that I don't really know what was happening.  Were the observers at the time mistaking the light- and dark-winged moths for members of the same species?  Were they the same species?  How much genetic variation does it take to produce this difference?  <troll>It's the difference between macroevolution (which seems pretty unscientific to me) and microevolution, which I have no trouble accepting.</troll>

On Fri Aug 25, YA wrote
>My point was he denies adaptation occurs, then describes the process of adaption.
>"...the famous moths didn't adapt... light-winged moths started to die off, and dark-winged moths correspondingly prospered."

> If his implication is that the light winged moths died of depression at not being able to affect color change by force of will, I missed it, and it's moot to my point.  

>Anyway, here's proof of Lamarkianism:

>On Fri Aug 25, akatow wrote
>>I'm missing your point.  The NYT's article was stating the Lamarckian solution (swapped speckled wings), not Bob.

>>But Bob said, "We were told....etc" as if that had been presented to him at some time as a fact.  I certainly hope that is not the case.

>>And I'd be really happy if the 'Trilobites' author rewrote that piece to reflect reality because it's the same fuzzy logic as what the Flat Earth Society is using,e.g. -  The horizon is flat therefore the Earth must be flat.  Don't you believe what your own eyes tell you?

>>The moths didn't swap out their wings and the snakes didn't change their color.

>>On Fri Aug 25, YA wrote
>>>"light-winged moths started to die off, and dark-winged moths correspondingly prospered."

>>>Or, ya know, the population adapted through natural selection.

>>>Enjoy your game of pigeon chess, I'll be over here popping popcorn.

>>>On Fri Aug 25, akatow wrote
>>>>Beware the uneducated...

>>>>Check out YouTube for a stupendous amount of stupidity related to 'proof' of the Earth being flat.  These people are serious - they have 'proof'. Mathematics, Physics and Logic are not subjects with which they are familiar.

>>>>What does this sentence mean? -

>>>>"We were told at the time that they did, but I gather the later conclusion is that light-winged moths started to die off, and dark-winged moths correspondingly prospered."

>>>>Who are 'We' and who told you that?  This happened 150 years ago - in Europe.

>>>>YOU should never have been told that was true in any American science class.

>>>>The black/white moth scenario is a classic example of Charles Darwin's Natural Selection. The white moths die off; the black moths live to procreate.

>>>>Lamarck's theory was that species could 'adapt' (alter their appearance, or whatever other change was necessary) within a single lifetime and pass that change onto their progeny.

>>>>Genetics, anyone?

>>>>On Fri Aug 25, Bob Bridges wrote
>>>>>The article says in part "It’s sort of like the moths in Europe that swapped speckled for black wings during the Industrial Revolution, evading hungry birds by blending in with coal dust."  I read that without a qualm the first time through, forgetting until just now that the famous moths didn't adapt.  We were told at the time that they did, but I gather the later conclusion is that light-winged moths started to die off, and dark-winged moths correspondingly prospered.

>>>>>I have a hard time taking the Flat-Earth society seriously, by the way.  I got the impression somewhere that it's sort of an insider joke, that they don't really believe the earth is flat.  I shouldn't underestimate the stupidity potential—maybe a few do—but not the membership as a whole, surely.

>>>>>On Sat Aug 19, akatow wrote
>>>>>>First we have the swelling ranks of the 'Flat Earth Society', now we have a 'Science' writer for the NYT talking about moths, pigeons and sea snakes 'adapting' (quickly, no less) to pollution!!!!

>>>>>>LaMarck would be proud.

>>>>>>On Sat Aug 19, Hoyden wrote

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