Re: Locust Grove mans book challenges

r norman wrote:
On Sun, 31 Aug 2008 20:16:59 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> wrote:

r norman wrote:
On Sun, 31 Aug 2008 18:56:13 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> wrote:

r norman wrote:
On Sun, 31 Aug 2008 16:35:18 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> wrote:

r norman wrote:
On Sun, 31 Aug 2008 15:28:42 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> wrote:

r norman wrote:
On Sun, 31 Aug 2008 08:39:33 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> wrote:

John Wilkins wrote:
John Harshman <jharshman.diespamdie@xxxxxxxxxxx> wrote:

John Wilkins wrote:
John Harshman <jharshman.diespamdie@xxxxxxxxxxx> wrote:

Let's keep this simple. Do you understand what species selection is? Do
you understand why it can't be reduced to changes in allele frequency
within populations?
If I may interrupt - is there the *slightest* evidence that species
selection is a real effect? Any imaginary process may be irreducible,
but that's not quite the same thing as saying it is counterevidential to
a theory it can't be reduced to...
Yes, there is some evidence for species selection. But we first must establish that species selection is coherent as a concept. Norman is questioning whether any macroevolutionary processes *can* exist. After
we settle that, we can get to the question of whether any such process
is important.

But of course it's a real effect. It necessarily follows from the existence of species with different characters. Nobody denies that group
selection of all sorts is real. The question is whether it's strong enough to do anything.
First off, species selection is not identical to group selection, you
can have cases of the latter without the former.
I never said otherwise. Species selection is a form of group selection.

Second, *I* doubt that
species selection is coherent. At best anything that happens with
species is sorting, not selection, because species do not reproduce with
heritable traits subject to selection.
Of course they do. If they didn't, we wouldn't be able to determine phylogeny. I don't understand this objection.

Which is kind of why I asked if there is *evidence* of species
selection. I am perfectly willing to give up my objections to it if it
has actually got an empirical basis.
I don't understand this point of view either. Species selection, or any other sort of group selection, is merely a consequence of imperfect replication in which differences affect the probability of reproduction (speciation) or death (extinction). I don't see how you can claim that species don't inherit characters, or that they don't reproduce. The only remaining question is whether any of these characters are relevant to speciation or extinction. And it seems to me obvious that some of them are.

The classical example of species selection is in marine snails. Some have planktonic larvae, and some brood their young. Presumably these characters became fixed through selection. The claim is that brooding species speciate more often than planktonic species, simply because geographic isolation is more likely for brooders. Various sorts of evidence have been advanced for this claim. I see that Dave Jablonski has a review of species selection coming out in Ann. Rev. Ecol. Syst., apparently to be out in December. I'm sure he discusses that case, since it's his. Googling on his name will produce a great many older citations.

I'll mention another in birds. There was a publication a while back that compared sister groups, one with intense sexual selection and one without. The sexually selected groups were significantly more speciose than their sisters. I would suggest that this is due to the tendency of sexual signals to change rapidly, and so to increase the chance that isolated populations will become different enough to fail to recognize each other during the period of isolation. This may happen through selection or drift, but the point is that if there is selection, its not selection on speciation rate, but on something within the population.
Would you argue that, say, Wilson and MacArthur's theory of island
biogeography, relating species diversity to island size and distance
to mainland is an example of macroevolution or is it simply an
ecological process at work?
In MacArthur & Wilson's work, no speciation happens, and extinction is purely local, so that's not macroevolution. If you incorporated speciation and species extinction, you could end up with a macroevolutionary model. There's some interesting work going on these days in bird diversification that does extend island biogeograpy in that direction.
So local extinction is not macroevolution and a bunch of local
extinctions is not macroevolution but if all local populations go
extinct for exactly the same reason then it is and if the population
happened to be endemic then it is? That is a strange notion of
evolution that be considered simply ecology under particular
circumstances.
No stranger than the idea that a rat losing its tail is not microevolution but a rat dying before breeding is. Remember that in species selection, species are the individuals. Extinction is death; speciation is reproduction. Local extinction is neither.

You seem to have a prior commitment against the idea of macroevolution. Where does it come from?
I do have some prejudices and preconceptions.

First, I am an organismal biologist and I think of the organism as the
prime agent acting in the world. Maybe I do feel some resentment
about the molecular people arguing that genes are the basis for
everything and taking over control of departments (and the purse
strings) and transfer that to the people who now would have aggregates
of organisms do the same. Maybe it is "biological level of
organizationism" -- I am an organism and therefore other categories in
biology are less important. No matter, I am definitely prejudiced in
favor of organisms, although I do recognize that cells have some
independent life especially since a great number of organisms are
simply cells.
I suggest that the best thing to do about this would be just to get over it.

Then there is the whole problem of defining 'species' so that there
are definite objects to study in macroevolution. There are special
circumstances where the notion of individual organism is blurred but
that problem doesn't even approach the problem of defining species.
Then there is the problem of the extent to which species are actually
'natural objects' in the real world as opposed to human constructs.
These are fights I probably should have with John W, who probably
agrees with me on the problem of defining species but who, I seem to
recall, argues that they actually exist, whatever they are.
I agree that species are abstractions, and so are individuals. In many cases they are very useful abstractions, and that seems to me to be all we need.

Then there is the practical side of things. What I call 'classical
evolution' does a magnificent job of explaining how organisms got to
be the way they are, both in the structural/functional sense and in
the historic sense. The theory explains the tree of life. That it
doesn't explain why the tree is shaped exactly as it is doesn't
matter. Call that a different subject and treat it differently. As
I indicated, my impression is that at least some aspects of what you
call macroevolution are already long-standing parts of ecology and I
see no particular reason to reclassify all our organizational charts
just so you can have your own private spot to call your own.
This seems a problem in your perception. Ecologists generally have not thought in evolutionary terms, and so have considered species as static elements in communities, and haven't thought about deep time either. Somebody really has to consider the evolutionary implications of these ecological factors. Ecologists aren't in that business. Evolutionary biologists are. I don't understand why you want to define this sort of thing away from evolution. The main fields capable of studying macroevolution are paleontology and comparative biology. Not ecology.

Then there is the issue prompted by the original poster in this thread
who complained that evolution is not defined by evolutionists and you
piping in to agree completely.
Nonsense. The original poster's idea was silly, and had little to do with your summary and my comments. Science is not made of one-sentence definitions, nor should it be.

That is another matter that certainly
complicates the fight against ID and creationism. Classical evolution
is clearly defined and stated and contains all the problems that ID
and creationists rail against. It already contains the development
of the diversity of life forms and the origin of 'new' structures and
body plans and species and higher taxa. Call your field something
different and it makes the battle cleaner and clearer and still lets
you do your thing completely unimpeded.
You are suggesting that evolutionary biology be adjusted to take the feelings of creationists into account?

So your arguments against macroevolution are 1) you like organisms, 2) you don't think species are real enough, 3) you think it should be left to ecologists, and 4) creationists demand a simple definition. Do you really consider those to be rational arguments?
You asked whether I had a prior commitment against the idea of
macroevolution and that is what I told you. Commitments are different
from rational scientific arguments. I don't see the need for
macroevolution. And I am very aware of statements such as the
concluding section of the t.o. FAQ on the topic:

"Macroevolution is at least evolution at or above the level of
speciation, but it remains an open debate among scientists whether or
not it is solely the end product of microevolutionary processes or
there is some other set of processes that causes higher level trends
and patterns. It is this writer's opinion that macroevolutionary
processes are just the vector sum of microevolutionary processes in
conjunction with large scale changes in geology and the environment,
but this is only one of several opinions held by specialists."

So if it the question is really open as to whether or not
macroevolution really is nothing more than the product of
microevolutionary processes, why does it bother you that I happen to
be on one side of the question? And if "this writer" declares that
there really is no such thing as macroevolution distinct from
microevolution, then why does it bother you that I happen to agree
with him (but only in this ONE instance, John W!).?
What bothers me is your lack of any rational argument for this position.

Then there is actual biological literature that questions whether
mechanisms like species sorting really are important in what we
actually see in the world. There are many papers referring to the
fact that there has long been debate in evolutionary biology about the
status of macroevolution as distinct from microevolution, some
concluding that there is but other claiming the reverse.

I am not alone in my objection and you well know that.
Why should I care about whether you are alone? And is this your fifth argument against macroevolution, that some people deny that it exists, for unspecified reasons?

I am trying to match your list of posts defining macroevolution as
"all the stuff we macroevolutionary biologists are interested in". You
have not yet produced a simple clean justification for it

That's true, nor am I interested in any such definition.

with
examples of specific phenomena that cannot be explained by the
application of already known microevolutionary or ecological
principles.

It seems to me that it's enough to provide an example that can't be explained by microevolutionary principles. Did you want to claim that the application of ecological principles to evolution can't be called evolution? Natural selection has been called the effect of ecology on genetics; shall we leave natural selection for the ecologists and geneticists to fight over, and abandon the discipline of evolutionary biology entirely?

There is a general principle often applied to science to the effect of
not multiplying entities. I believe this predates the modern
synthesis and is attributed to Billy the Barber.

And I believe it has nothing to do with our discussion.

To be specific, I have several times mentioned the fact that
competitive exclusion, something you call macroevolution, is simply
ecology in action. Variations in rates of speciation can also, in my
opinion, be explained in terms of mechanisms already known and
studied. It is my impression that what you call macroevolution is
simply the product of the fact that a full understanding of life
requires factors other than evolution, unless you want to expand the
notion of evolution to include all of biology, not to mention geology
and meteorology and astronomy to include all the factors that result
in changes in species number and distribution.

Well, we aren't going to get anywhere here. You appear to think that the word "evolution" must, by definition, apply only to changes in allele frequencies within populations. Because whatever I serve you, you say it's spinach and to hell with it, there's nothing we can discuss. I think that variation in rates of speciation/extinction is evolution, and thus a legitimate subject for evolutionary biologists. Certainly nobody else is interested in looking at it. I suppose we can continue to investigate it as long as we're careful to say we're only doing it as a hobby?

.

Relevant Pages

  • Re: Macroevolution FAQ 2.1D
    ... Macroevolution - its definition, philosophy and history ... "microevolution" is, and by this they seem to mean that whatever evolution is ... evolutionary change at or above the level of species. ...
    (talk.origins)
  • Re: Macroevolution FAQ 2.1D
    ... > Macroevolution - its definition, ... > "microevolution" is, and by this they seem to mean that whatever evolution is ... > evolutionary change at or above the level of species. ...
    (talk.origins)
  • Re: Seanpit, ID and complexity
    ... random mutation and I assume natural selection. ... think (using empirical evidence to support your position) each of them ... I, in fact, did define evolution: ... Even Paley recognized variation within a species. ...
    (talk.origins)
  • Re: Re: Evolution is not a fact
    ... All made of what some term micro evolution. ... exactly what you mean by "species selection". ... different populations then external pressures can select one or the ...
    (talk.origins)
  • Re: Evolution is not a fact
    ... All made of what some term micro evolution. ... selection as an example of this sort of thing, and so far you haven't addressed it. ... exactly what you mean by "species selection". ... Natural selection is the process that prevents billions ...
    (talk.origins)
Loading