Re: Re: Evolution is not a fact

On Thu, 24 Jul 2008 16:12:02 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> enriched this group when s/he
wrote:

Ye Old One wrote:
On Wed, 23 Jul 2008 06:51:32 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> enriched this group when s/he
wrote:

Ye Old One wrote:
On Tue, 22 Jul 2008 09:55:27 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> enriched this group when s/he
wrote:

Ye Old One wrote:
On Tue, 22 Jul 2008 08:34:15 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> enriched this group when s/he
wrote:

Ye Old One wrote:
On Tue, 22 Jul 2008 06:46:13 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> enriched this group when s/he
wrote:

Ye Old One wrote:
On Mon, 21 Jul 2008 15:09:45 -0700, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> enriched this group when s/he
wrote:
[snip]
OK, now you're starting to sound like backspace. Do you even read what I
write?
Not all the time. There are not enough hours in the day. I tend only
to skim posts by evolutionists and concentrate on countering the lies
of the creationists.
I was referring to what I wrote in the paragraph you supposedly were
responding to, not my entire oeuvre.
Sorry. I this case, yes I did read it. And I thought I responded to
it.
My point was that you did not. You merely repeated what is fast becoming
your mantra.
What I've done is to put it in the words that I understand, keeping it
as simple as possible.
You have kept it simpler than possible. What you said was merely
repetition of a catechism, not a response to my statement.

I believe I made it as clear as I could. It is far from "a summary of
the principles of Christian religion in the form of questions and
answers, used for teaching."
[snip]
See, that's an appropriate response only if you confuse macroevolution
with saltation.
All I see is evolution. All made of what some term micro evolution. I
don't see anything else.
I'm trying to get you to see something else, but apparently without
success. Perhaps if I mention that macroevolution doesn't necessarily
involve any big changes?

I have several times mentioned species
selection as an example of this sort of thing, and so far you haven't
addressed it.
Well, you see, at the moment I'm having a hard time trying to work out
exactly what you mean by "species selection".
Is that bccause you've never heard the term before, and are not familiar
with the extensive scientific literature on the subject, or because you
think the term is poorly defined? Species selection is differential
extinction
Extinctions I understand.

and/or speciation among species,
Speciation among species? Ok, species split, for one reason or
another, but what are you saying causes that other than multiple steps
of micro evolution?
Yes. I'm talking about differences in the rate of speciation between
groups. These can be influenced by fixed characters. The most famous
example is between snails with planktonic larvae and snails with brooded
larvae. The latter have a much higher speciation rate. All things being
equal, brooding species would thus come to predominate. (Now in fact
they may also have a higher extinction rate, but that's not important to
the concept.)
But the evolution that led to the two branches was the sum of small
changes at a genetic level. The fact that, now, way down the line, one
has an advantage over the other, traces back to the earlier genetic
changes.
Yes. But that advantage was not selected for at the individual level.
So? There is no rule that says it should be.
Yes. But selection at the species level is not microevolution, because
no allele frequencies change in any population.

Selection is not, in itself, evolution. If the genetic makeup of a
species prevents is survival, and thereby it becomes extinct, that is
not an act of evolution - the evolution is the genetic change that led
to that point.

You are determined to be wrong about everything you say. Selection *is*,
in itself, evolution. It's a change in allele frequencies in a
population, and that's evolution by definition. Now you seem to be
claiming that anything that isn't a change in allele frequencies in a
population is not evolution, also by definition. Most biologists would
not agree with that claim.

No, that is not what I'm saying.

What I'm saying is that evolution occurred as a change in the genetic
matrix of a population. There is no evolution without that genetic
change. Speciation can only occur through genetic change.

Changes in the external pressures applied to a species may enhance of
dampen a species ability to survive, just as it does at the individual
level. But without genetic change there is no evolution.

Both traits were (presumably) selectively favored within each
population. So we can't attribute the species selection to individual
selection. However the traits became fixed in their respective
populations is a separate question than their affects on speciation and
extinction rates.
Mmmm. Still not getting this clear.

As I see it the speciation is the result of minor steps of genetic
change that becomes endemic in a population.
Generally true. But not relevant to my point.

I'm not getting your point.

Apparently, though I'm not sure why. Species selection is not about
speciation. It's selection between species that already exist. Therefore
the processes of specation, whatever they are, are not relevant to my point.

Ok, but then, apart from creating new environments for possible
evolution to exploit, that selection is not evolution.

Once you have two
different populations then external pressures can select one or the
other. One could even become extinct. In other words external
pressures select the outcome but it is still the genetic changes that
provide the evolution.
So selection is not evolution?

Not in itself. The evolution is what led up to the animal that is
subject to the selection.

Nobody would agree with you on this, I suspect.

Possibly, but then we already know that the definition you are putting
forward is "controversial".

You could use identical logic to say that
natural selection is not evolution,

I would agree. Natural selection is the process that prevents billions
of different species all still being alive today. It opens new avenues
that genetic changes can exploit.

That was gibberish, in my opinion.

I would have thought it was clear and simple.

since mutations to individuals
provide the evolution, and external pressures merely select among
individuals. Species selection is a direct analog to natural selection.
Species vary, and much of that variation may be due to natural
selection. But we don't care at this level, just as it didn't matter all
that much to Darwin's theory what the actual source of individual
variation was. That was input. If species selection affects the
distribution of traits in the biota, that's evolution. But it's not
microevolution. It's macroevolution. Note, again, that macroevolution
doesn't require any big steps in order to qualify as macroevolution.

I think I'm starting to see where you are coming from.

That would be good, but so far I see no evidence of it.

Oh I am beginning to see, I'm just not agreeing with what I see.

depending on differences in
characters that are generally fixed within the respective populations.
It's analogous, at the species level, to natural selection. It doesn't
require that any allele frequencies change in any populations, yet it
changes the distribution of characters in the biota.
Outside forces can remove something from the mix, that it natural
selection. But surely it is the diversity provided by micro evolution
that allows for natural selection to work? Where is the macro
evolution?
I don't understand your objection here. I'm not talking about natural
selection. Species selection doesn't involve any changes in allele
frequencies in any population. It involves differential speciation and
extinction of populations. Are you in fact unfamiliar with the term and
its literature?
It is not a term I've seen before this thread, and I thought from your
earlier posts that it was clear. Now, from your reply above things are
not looking clear at all.

Speciation comes about as a result of a genetic drift.
In passing, I deny this. Most speciation appears to happen as a
byproduct of natural selection operating independently in two
populations.
But you don't have that without genetic drift.
Wherever did you get that idea? All you need is two environments that
select for different characters, and some of those characters have to be
coincidentally related to reproductive isolation.

But all of those characters are the result of genetic differences.

Yes. What does that have to do with genetic drift?

Duh!

I would suggest reading Coyne & Orr if you're interested.

Some species
can, of course, become extinct for a wide gambit of reasons. Evolution
produces the cannon fodder for natural selection to work on. What
other form of selection are you talking about?
I'm talking about species selection. If my description is not clear,
then google it and read someone else's. Or ask me specific (pun
unintentional) questions.
What do you mean by the term "species selection"?
This is really simple. It's a form of group selection. Some people
demand that the characters being selected be "emergent", i.e. not
present in individuals but only in the species as a whole. I would not
make this demand, only that the characters in question must be fixed
within each species. That is, the selection must not result from changes
in allele frequencies within populations. As in the snail example I
provided.

However, in the snail example, the changes had already occurred to
produce, after time, the speciation. That one or the other species can
go extinct later does not alter the evolutionary steps the led to
them.

All irrelevant. You seem to believe, if I understand you, that only
mutation is evolution. Natural selection isn't evolution, nor is species
selection. Nobody would agree with this claim.

The only reasonable definition I can find is at
http://en.wikipedia.org/wiki/Species_selection#Species_selection_and_selection_at_higher_taxonomic_levels

[quote]
Species selection and selection at higher taxonomic levels

It remains controversial among biologists whether selection can
operate at and above the level of species. One particular defender of
the idea of species selection was S.J. Gould who proposed the view
that there exist macroevolutionary processes which shape evolution at
and above the level of species and are not driven by the
microevolutionary mechanisms that are the basis of the Modern
Synthesis. If one views species as individuals that replicate
(speciate) and die (go extinct), then species could be subject to
selection and thus could change their occurrence over geological time,
much as heritable selected-for traits change theirs over the
generations.

For evolution to be driven by species selection, differential success
must be the result of selection upon species-intrinsic properties,
rather than for properties of genes, cells, individuals, or
populations within species. Such properties include, for example,
population structure, their propensity to speciate, extinction rates,
and geological persistence. While the fossil record shows differential
persistence of species, examples of species-intrinsic properties
subject to natural selection have been much harder to document.

[end quote]

Which is just about as clear as mud.
You seem to have a mental block. It seems to me that the first paragraph
is quite clear.

Well, it does say it is controversial.

You are a master of the irrelevant statement.

How can "It remains controversial among biologists whether selection
can operate at and above the level of species." be irrelevant?

The second is talking about that need for "emergent"
properties, which I think is pointless, and I suggest you forget about
it. Otherwise, what isn't clear?

The whole bloody idea :)

No, seriously, I'm starting to see some of what you are saying. I
don't altogether accept it, and as yet I'm not ready to accept that
there is more than one type of evolution, but things are getting a
little clearer.

Well, that's something.

Your unfamiliarity with the term does suggest
that you are not sufficiently knowledgeable about the subject of
macroevolution to make pronouncements about its nonexistence, by the way.
It seems from the above quote that I'm not the only one who has
doubts.
As I have been saying all along, if you will look back. It is, however,
a long way from saying that macroevolutionary processes may not be
important in evolution to saying that there is no such thing. You seem
to believe it's a logical contradiction. And of course we have to have a
term for a phenomenon in order to argue about its existence.

Comparative survival. It is the engine of genetic change that leads to
species that can then suffer extinction or survival.

I have no idea what you were trying to say there,

It is clear enough.

unless it was another
irrelevant digression.

Genuinely John, if you can come up with a convincing argument for
macro evolution that is not based on multiple steps of micro evolution
(which I believe is all that evolution is based on) then I will be the
first to nominate it as a post of the month.
The snail example wasn't based on multiple steps of microevolution.

I disagree.

Do you have a reason for your disagreement?

Yes. To arrive at the two species you had to have multiple steps of
microevolution.

Again, if you think of species as the units of selection, all you need
is that species have to vary -- you don't care how that variation arose,
just as with individual selection -- and that variation has to affect
their relative speciation and extinction probabilities.

But that, in itself, is not evolution in my books. The evolution is
what leads to the different species.

Since you have previously claimed that only mutation, and not selection,
is evolution, this must be wrong. Mutation doesn't lead to different
species.

Of course it does - there is no other way to get the genetic
differences that produce speciation.

Selection and/or drift does.

Now if you claim by definition that there can be no evolution beyond the
species level,

Evolution is a continuing process. Scientists can declare a species
separate from another, but the evolution that led to the point is all
microevolution.

it certainly does follow that there are no
macroevolutionary processes. But I don't know of anyone who would agree
with such a definition. Just as one can consider microevolution to be
changes in allele frequencies in populations, one can consider
macroevolution (or at least some of it) to be changes in characteristic
frequencies in groups of species. It's the changes that do not result
from microevolution that we're interested in here, even if the species
ultimately gained those characteristics through microevolution.

Mmmm.

--
Bob.

.

Relevant Pages

  • 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: Defining&testing "macroevolution" (was: Testing the Laws of Intelligence)
    ... as evolution is strictly defined. ... For example, in the case of a ring species, we make it ... clearly two populations definition are ... cross-breed success relative to mono-breed success, ...
    (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)
  • Re: Bipedalism in different substrates
    ... evolution occurs when a species ... It does this by reducing variation. ... > Selection is a brake, a mechanism to reduce variation, to weed out ...
    (sci.anthropology.paleo)
  • Re: Locust Grove mans book challenges
    ... there is some evidence for species selection. ... But we first must establish that species selection is coherent as a concept. ... In MacArthur & Wilson's work, no speciation happens, and extinction is purely local, so that's not macroevolution. ... evolution' does a magnificent job of explaining how organisms got to ...
    (talk.origins)
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