h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Well, there *is* a way that the moth could be an example of selection but not evolution.

Suppose that wing colour is a non-genetic characteristic and is set either dark or light essentially at random (It isn't, of course). Now, in a light environment the dark ones get picked off, so the population becomes mostly light. But because wing colour is a non-genetic characteristic, it's not the case that the moth is evolving, though it is being selected.

However, moth camoflage is well known to be a genetic characteristic, so it is evolved. But there is a difference between selection and evolution, to whit:

mutated reproduction + selection = evolution



> "Maybe it's just my personal view that fiddling around with the existing range of variation doesn't constitute evolutionary change."

Well, yes, it is just your personal view. Using normal definitions of things like 'evolutionary change', 'fiddling around' with existing characteristics is evolution in action. Trying to get out of an argument by redefining your terms is a classic philosopher's trick, and I can't say I'm impressed.

> "It seems totally implausible to me that there could even BE a hardwired need for belief. I certainly don't see that it might be a trivial matter to evolve it!"

This, on the other hand, closely marks my position too. I don't see the point, in a design sense, from a hardwired need for belief. Why not softwire it in society, and piggy-back the information on the existing parent->child communication protocols? Much better solution, really.

-Martin

"They all seem to have this mental category marked "stuff I believe even though I can't really explain why"... Ben included."

Oh, I can explain why I believe what I do, Hoo. Most of the time I choose not to.

B

Incidentally, check out <./>info</.> Hoo's suddenly leading the pack in terms of longest posts...
-Lucinda

Me? The thirteenth Duke of Wimborme? Here? Top of the list of most verbose researchers on the site? How *did* that happen?

"Science isn't a religion."

I stand by that. Science is no more a religion than "Star Wars" is a religion. Which is to say that it IS a religion for some people. And you can guess what I think of them, in either case...

Some people can turn *anything* into a religion. Like Mrs. Elronhubbard from the Post Office and her holy guardian sprout, Barry...

H.

You surprise me by arguing against yourself, Martin. You get it right when you say that evolution requires reproducible mutations. Yet when I refer to 'fiddling around with the existing genetic variation', ie; selection (natural or not), without any mutation, you accuse me of redefining the terms. I don't see how we disagree here.

I wanted to keep it fairly light rather than dragging out the Majerus (1998) study relating to the peppered moth, which reaches a similar conclusion. Still, if needs must etc.

It's the repetitive nature of the stuff rather than incomprehensibility that causes the boredom; plus, of course, the now universally acknowledged inordinate length of that post. Methinks H doth protest too much!

You force me to drag in the Majerus (1998) study of the peppered moth research. There it is shown that natural selection, but not evolution is taking place. Evolution requires reproducible mutations as Lucinda/Martin remarks. (Even though he/she seems to think he/she is disagreeing with me. Obviously a popular hobby this week).

Since most of Hoo's post is an attack on me (more so than on my thinking it should be noted) I can't blame anyone for being bored by my rebuttal. Still, unsubscribe if you haven't the wit to skip my contributions and read the others.

Would that Majerus 1998 reference refer to the book "Melanism: Evolution in Action" (Oxford University Press, 1998)? Strange how the title of the book would contradict the conclusion.

Ste

That's the one. These publishers will do anything to titles in order to sell books!

This was actually intended as a question, not as a dismissal. Belief in general is presumably necessary when we have to act or explain in the absence of complete information. And if it works, or seems to work, the first time we're loathe to give it up.
The possibility of higher order (inspired?) beliefs (in a heirarchichal sense) must have evolved, but it may be just something that comes along with the system as a whole.

Pepper moths and hedgehogs: who says the initial mutation and the selection HAVE to operate close together in time, so long as the mutation is not so spectacularly unsuccessful that it disappears?

Noggin

"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." (p. 155). Majerus, 1998.

Does that sound like evolution to you?

They don't Nog. In fact some sequence of mutations must have given rise to the genetic variation in the moth population. It waited millions of years for a change in the environment known as the industrial revolution, before its usefulness became apparent Though maybe volcanic dust etc could have had a similar effect previously.

The point is that this shows genetic variability in action through natural selection. What it does not show is evolution in action at the time considered (the industrial revolution).

But it could happen that prior to the mutation all the moths were one colour, and that after the (later) period of selection they were all a different colour. That would be evolution, wouldn't it? The question of whether it's evolution or not is therefore decided AFTER the event (depending on the final outcome).

Noggin

Hmm. Not convinced I'm afraid.

Natural selection is a facet of evolution, you cannot isolate the two. If something is evolving, natural selection is involved, if something is being naturally selected, it is said to be evolving.

Let's stick with the moths. Natural selection cannot work alone in evolution, as Martin was pointing out (I think). It needs raw material to work with. This is generated by a combination of mutation, genetic drift, gene flow, etc. The melanic form of the moth could not have come about unless the allele for wing pigment did not mutate to a dark allele, it could not have become more prevalent in the population via genetic drift and the melanic allele could not have been spread about without gene flow. Natural selection simply does not and cannot happen alone.

Yes, industrial melanism is used as an example of natural selection, but that does not mean it is an example of natural selection instead of evolution. In the context of evolutionary theory, such a claim is meaningless (as explained above).



Ste

"My view of the rise and fall of the melanic form of the peppered moth..."
This sounds like opinion rather than an argument.

"...differential bird predation..."
That'll be natural selection.

"...together with migration..."
Gene flow.

Also genetic drift (random sampling error leading to a change in the allele frequencies every generation) simply HAS to be a factor.

So, yes that sounds like evolution.

Ste

So is the variation between breeds of dog an example of evolution? Or is it unnatural selection and even unnatural gene flow and unnatural genetic drift? Except that it's natural anyway since dog breeders are natural beings!

I think you've invented evolution without mutation. Join the Lamarckian Society - do not pass go - do not collect a Nobel prize.

I think you know the answer to this question. Evolution occurs in natural populations, dog breeds are hardly what one could call natural. You could even go one step further and say that *because* natural selection is absent therefore the dogs are not considered to be evolving, i.e., that you cannot have natural selection without evolution, and vice versa, which is the point I was making earlier.



Ste

Ah, picking at straws and insults, how dissapointing. Lamarck wasn't totally wrong by the way. Acquired characteristics are inherited in some cases.

Ste

So what *do* you call the process that results in the various dog breeds? If it is unknown to biology, breeders could hardly use it! Since the peppered moth example results from human intervention, albeit unintentional, how is that different?