Re: Mendel refutes evolution

BROKEN LADDER wrote:

John Harshman wrote:

I'm not redefining evolution. The scientifically accepted definition
is change in the frequency of alleles within a population, right? So
this happens via mutation/recombination and mortality. I'm not
defining it to be just those things. If you know of any other
processes that can cause a change in the frequency of alleles, please
share them. You would revolutionize evolutionary science.

No he wouldn't. We already know of other processes that alter allele
frequency: meiotic drive, migration, differential reproductive success,
etc.


Meiotic drive is just selection.
Natural selection doesn't have to be
at the level of an organism. As Dawkins illustrates beautifully, there
is competition at the level of alleles. An allele which some how
catalyzes its own disproportionate selection, breaking Mendelian law,
obviously becomes more abundant.

Migration doesn't change the frequency of alleles; just their location.

Here you go counter to the entire history of population genetics. It
changes the allele frequency in two populations: the donor and the
receiver. If you want to consider those as one population, you make it
impossible to study evolution in either of the sub-populations.

Differential reproductive success would just be another form of
selection.

Of course it is. But you didn't say "selection". You said "mortality".

species selection doesn't involve change in allele frequency,
yet it's evolution nevertheless.

What do you mean species selection? There is just individual
selection.

I find it fascinating that you talked about multi-level selection
(individuals, genes) just above, and now claim there is only one level.

Each individual is selected for and lives or dies on his
own laurels. I deny the validity of a term like "species selection".
Could you be more specific?

Ha ha.

Maybe I misunderstand what you mean by
this term.

Surely this term is not new to you? Species selection is a form of group
selection (is that term new to you too?). There are many arguments about
what would count, but I favor a liberal definition: differential
extinction of species based on their fixed characters (i.e., genetic
variation within the species is irrelevant in responding to the
selection). Differential speciation might fall under the definition too,
except that I'm worried just a bit about the need to consider species as
equivalent classes.

And how could any kind of death not involve a change in the
frequency of alleles.

If deaths occur without regard to differences in genotype within the
population. Obviously there will be stochastic fluctuation in allele
frequencies, especially as the population becomes very small. But that
would be irrelevant to the process that's really happening.

If a species dies off, then the frequency of all
the alleles unique to it went to zero from whatever it was before.

This is trivially true, but not useful. It's a really stupid way to
think about species extinction. Do you really want to defend it?

You're arbitrarily distinguishing selection into two types: genetically
discriminant, and not. I agree these have very different affects, but
they are both covered by the term "selection", so there was no need or
sense in saying "there's not just selection, but genetic drift as
well".

I think you have managed to remove all meaning from the term
"selection", if genetic drift is selection.

Oh not at all. The meaning of selection is affecting which
combinations of alleles live or die. If a species dies off because a
meteor stuck its habitat and killed it off, it was still selection,
whether it was on the basis of anything about its genome or not. Just
because it was dumb luck doesn't mean it's not selection. And in some
sense, it is selection actually, even on your terms. Think about
squirrels getting hit in the street. I'd wager that modern day
squirrels are vastly more car-aware than were their ancestors, because
slight brain differences which caused individuals to be averse to the
street, or the sounds of cars, would be disproportionately selected
for. Say we're talking about some mass death event like the eruption
of a volcano that kills off some species that lives exclusively near
it. That's selection in a sense, because it kills of organisms who
aren't volcano-averse. I know that's a bit of a stretch, but there's
just the tiniest bit of mathematical significance to it.

What, if so, would not be selection?

Anything that didn't affect the life/death probability of an organism.

I'm sorry, but this definition is useless. Would you at least agree that
it's non-standard? If you're going to use private definitions for words,
you might at least give some advance warning.

Anyway, natural selection doesn't have to be genetically
discriminant. It can operate on phenotypic differences that have no
genetic component at all; those just aren't important in evolution,
because they aren't inherited. (Peace, Wilkins.)

You mean like a big scar that messes up your camouflage?

Sure.

But differential
reproduction that has nothing to do with genetic or phenotypic
differences, but is due to chance alone, is just not selection. Nobody
uses the term that way.

So you're just saying that selection, in the biological sense, should
only be used for events which seem to have some aspect of selecting
discriminantly, based upon something inherent to an organism's
genetics? That sounds sensible, but it's just terminology, and
arbitrary.

How true. But agreement on arbitrary terms is the first requirement for
communication. Since everybody else uses selection in the sense I do,
and you alone use it in your sense, why not go with the crowd?
Humpty-dumpty's method didn't work very well, even for him. (There's
glory for you.)

I find it odd that in your first paragraph you appeal to standard
definitions and in your second paragraph you reject them entirely.

I don't. I just think you're not seeing my point.

If you have a point, it's obscured by your non-standard terminology.

---( comments about how a species isn't an equivalence class...)---


This is a very odd claim. I don't think it makes any sense

Sure it does. A species is defined as a set, comprised of individuals
who are mutually reproductively compatible. According to this general
concept, which is the central theme of every major definition of
species, from Mayr's to others that are slightly different, everything
about my example holds water.

You are incorrect about Mayr's definition, and even more incorrect about
other concepts. Some of them have nothing to do with reproductive
compatibility.

Species cannot be thought of as distinct
groups. They are infinitely overlapping groups. You cannot draw any
line between two generations and say there is some kind of junction
between two species, even in the sense you discussed of two overlapping
sand piles. You'd have to picture piles where the overlap begins right
at the peak, so that every peak is right next to the other, and it just
looks like one long flat-topped pile of sand.

You can picture that, but it has very little to do with any of the usual
species concepts, none of which extend in time.

but it does
point out the problems of extending species concepts through time.

Well, you have to, because when an organism lived doesn't change what
it was.

No, you don't have to, because we can only apply the usual species
criteria to extant organisms.

Say you theoretically preserved its DNA and cloned it in the
modern era...that individual could then be referred to as potentially
being in the same species as some later descendent of its generation.
Would this not be the case if you had never preserved its DNA and
cloned it? All sorts of absurdities arise when you try to use time as
a delimiter.

You're the one using time as a delimiter. I'm not. Biologists in general
are not.

Also, if we are going to classify fossils into species,
we have to accept that time cannot be a delimiter in a rigide sense,
because otherwise every single fossil organism would be its own
species--since it can't mate with any other organism.

This shows the poverty of empty formalism of the sort you are using
here. We have to accept, by the way, that fossil species are not the
same sort of entities as extant species. If you like the common
bioloigical species concept, that's just plain inapplicable to fossils.
That's why paleontologists use a morphospecies concept that has nothing
to do with interbreeding, actual or potential. (A great deal of mischief
has been done by people confusing species under one concept with species
under the other.)

This reminds me off a great audio piece I heard on CBC's Quirks and
Quarks program. It's about how scientists can't be sure of whether two
fossils are in the same species or not.
http://www.cbc.ca/quirks/media/2005-2006/ogg/qq-2006-03-18f.ogg

It's only like ten minutes long or so. Very basic, but interesting.

Too lazy to listen, but I presume it's the usual arguments. Of course
they can't.

Species work pretty well if you're talking about a limited time and a
limited space, but run into problems both geographically and temporally.
Division of a lineage into successive species is arbitrary, but
fortunately we seldom if ever have to think about that.

Arbitrary? I thought it had to do with the ability to reproduce and
bear fertile offspring.

No, it has nothing to do with that. How could we ever assemble any data
bearing on the question? We can only do that with populations occupying
the same time interval.

You could call me and every organism within space-time
that is reproductively compatible with me, a "species", and you could
even give that set a name if you wanted to, like Homo ladderus. But at
some point in the past there is an individual who is genetically
incapable of producing fertile offspring with me, but is in a common
species with _most_ of the organisms within Homo ladderus. So you'd
have another species that excludes me, but includes him and includes
_most_ of the people in Homo ladderus. Continuing in this fashion,
it's clear to see that every organism fits into many many species, to
the point that it's questionable why one would even want to talk about
species.

No, you get the wrong message. It's questionable why one would want to
extend the concept through time instead of restricting it to a single
time-slice.

Why would you restrict it like that?! It makes the issue confusing and
seemingly arbitrary. It leads to absurdities, at least one of which I
briefly touched on above. It also gives creationists ammo to say
stupid things like, "We never see one species turning into another."
Argh, you stupid creationists!!!

Creationists will seize on anything you do, so it's pointless to pick
your scientific concepts to satisfy them. Species work pretty well in
the modern world, much of the time. Pushing them back in time leads to
the absurdities you mention.

It seems odd, too, that your idea of imperceptible gradation
(true) relies on a black/white distinction between ability to have
fertile offspring and lack of that ability. That, too, is an
imperceptible gradation.

How so? If you breed a horse and a donkey to get a mule, it can't have
offspring with another mule, can it? That's pretty darned black and
white to me. Oh, and for _Napoleon Dynamite_ fans, there's the
loveable liger.

Actually, there are occasional fertile mules. But that's just one
species pair that are pretty well isolated. Other pairs are much less
isolated than that. Isolation is a matter of degree, and there are all
degrees from complete (no fertilization at all, no nuclear fusion, etc.)
to almost none (slight selective disadvantage to F1 hybrids.) May I
suggest my favorite book on the subject?: Speciation, by Jerry Coyne and
H. Allen Orr.

Secondly, the idea of species is really bizarre and questionably utile
to begin with. Say life had never invented sex; then what would we be
doing in taxonomy? Obviously evolutionary divergence would have run
rampant, and the hierarchical taxonomic tree of life would be even more
insane than it is.

That isn't actually obvious to me. Why do you think so?

Because intermixing of genes slows down evolution by orders of
magnitude, especially as an interbreeding populations size grows.

Why?

With
microorganisms that have no gender, on the other hand, the moment they
split from a parent, the offspring start down paths of unrestrained
divergence, and have no intermixing of genes to "bind" them.

There are, however, other cohesive forces, which is why we can recognize
bacterial "species" at all. Selection, mostly.

This
makes the tree of life branch at a frenetic pace. I have read that
many microorganisms can swap genetic information to teach each other
drug resistance and such, but I don't think that could play the kind of
roll that sexual reproduction does. Does this make sense? I admit, I
don't have the kind of biological education that many on this list do.
But I think my ideas stem from very valid critical analyses of
established ways of thinking. My mentor was Dawkins, if that says
much, and he certainly challenges, and arguably castigates, some folks
like Gould. Granted, they are both popularizers.

What does Dawkins actually say on this subject? Why does recombination
slow evolution?

Fortunately for
us all, there are other reasons for "species" coherence than gene flow.
And also fortunately, the tree is regularly pruned in all sorts of ways
that keep it from being messy.

Well, there's lots and lots of extinction, to be sure. But I'd say
that at the non-sexual level, the tree has to be a chaotic wreck.

As it happens, it isn't. The various non-sexual groups (most prominently
bdelloid rotifers) are about as easy to classify as others.

And
ultimately, the world only has so much room. So you can't have too
many species of, for instance, dragonflies on some island...because
they have to have some threshhold population size in order to
successfully mate. This limits the number of species there can be.
But just wait until we colonize other worlds, and there isn't such a
constraint. The Terran taxonomic tree is going to become dizzyingly
incoherent.

----

_But_ we'd be fine, and wouldn't need this concept
of "species". Imagine how that would screw with creationists'
arguments. Way too much emphasis has been put on the idea of
explaining the emergence of new species, with creationists spouting off
lines of reasoning like, "a horse only begets a horse, and it begets a
horse, and it begets a horse, and so on...always the same species...".
Without the idea of "could these things mate?" what sense would there
even be in that terminology?

So yes I accept the concept of saying "here is a set of things which
can mate together". But I find it to be a scientific system that
causes more problems than it solves. I also think that a lot of
people, like Marc, get incredibly confused by it, just leading to
academic problems where you have droves of people, even in the
scientific community, who have a lot of misconceptions about evolution,
and biology in general.

I fail to notice the misconceptions you are talking about here. In
sexual organisms, speciation is a very important process and is worth a
lot of study.

What's important is how organisms change over time, say from a
mesonychid to a modern cetacean.

You should be aware that mesonychids as ancestral cetaceans is not
currently popular. But who are you to say what's important? You have
just thrown out entire sub-disciplines of evolutionary biology. What
gives you the right to decide?

While the reproductive isolation that
becomes entrenched by a divergence into two different species has clear
evolutionary ramifications, I think an error is made when people
synonamize "species" with "kind".

"Kind" is a meaningless term that biologists don't use.

With asexual organisms for instance,
we discuss their similarities and differences, and categorize/name
them, without regard to such a concept.

Not true. We commonly divide them into species too.

They are _all_ different
"species"--they can't reproduce with ANYTHING.

This is a child's version of the biological species concept. That is
only one of many species concepts, many of which have nothing to do with
reproductive compatibility. Ask Wilkins to explain, if you dare.

I'm not saying that
species aren't an interesting concept worthy of study; but that too
much is made of the concept. A great dane and a chihuahua, for
instance, are as visibly different as humans and chimpanzees, even
though they are only separated by a few thousand generations, and can
interbreed. They look as much like two different "kinds" as much as a
zebra and a horse look like two different "kinds".

Here's an interesting proposition. Could we, in a mathematical sense,
view the evolution of sexual species on an equal footing with asexual
organisms, by treating a species as a single asexual organism?

We could, but that would lead us into the realm of species selection,
which you don't like.

In asexual organisms, something rather like speciation
seems also to be important, though its dynamics are quite different in
many respects.

How is it anything like speciation, when speciation just has to do with
reproduction, which asexual species can't perform?

Well, I hope they can reproduce. They just can't have sex. Anyway, like
I said, there are many species concepts other than the one you know.

What is Marc's confusion?

Uhh...where do I begin? He didn't respond to any of my
counterarguments. He just kept calling them stupid. He also strikes
me as not very bright, to be blunt. You obviously are, and that's why
I think this is a more meaningful conversation. Instead of disagreeing
with me, you actually somewhat see the point I'm trying to make and
form a cogent counter argument that at least leaves me with something
to think about. Talking to Marc has been identical to debating
creationists...evasion, confusion, logical fallacies, et al.

I notice that you have done nothing to explain the nature of Mark's
confusion.

You clearly do not understand the Sorites nature of species


I don't see how exactly how Sorites pertains. With species there's a
clear line of demarcation--either two organisms produce fertile
offspring or they don't, right? Either way I don't see what point
you're trying to get at.

No, there is no such black/white dichotomy. Nor is that the definition
of species. There are plenty of separate species that are capable of
producing fertile offspring. Generally, it's enough that there is strong
selection against the success of hybrid individuals in both species.

Every definition of species I've read talks about whether two
populations can interbreed.

If so, every definition you have read is talking about the same species
concept, Mayr's BSC. And there is a lot of give in the concept that a
simple definition doesn't cover. Read the actual literature for
plentiful examples.

If they can, then how can you call them
two different species? Theoretically they could breed until they are
pretty homogenous, and you can't even call them two distinct groups
anymore. "Strong selection against" would just mean a retardant, not a
barrier.

Not true. It all depends on the strength of the selection. This is easy
to see, because you will agree that if the selection against is 1 (no
reproductive success for any hybrid) the populations won't merge. In
practice it doesn't have to be anywhere near that strong.

I used Ernst Mayr's definition of species as the working
model for my discourse, so what definition of species are you using?

Same one. If you take Mayr's definition absolutely literally, then all
sorts of things that Mayr considered species are not species. For
example, one of the groups that Mayr worked on was ducks. If you take
that definition literally, there is pretty much only one species of duck
instead of a hundred or so. Because they occasionally become confused
and form fertile hybrids between species, genera, tribes. Yes, they're
generally fertile. But they have such low mating success (because of
their scrambled mating rituals and physical signals) that gene flow
between the populations is low, and genes don't get transferred. I could
give you dozens of other examples, just within birds. If the populations
don't merge despite hybridization, we call them separate species. So did
Mayr.
I don't know what you mean by "so what?". This is really significant,
because so many people don't think of a species this way. They think
that any given organism is just within a single species, like human or
"horse" or "domestic dog". This is nonsense.

No. It's an understanding that the definition of species is only
applicable across a limited span of time and space. We'll never even
have the data for anything else.

Whether we know how far back the species extend doesn't mean they
weren't there. I mean, imagine now that we have accurate record
keeping and photography, another million years goes by, and we _do_
have records of billions of generations of birds and butterflies and
such, so that we can actually see the graduated evolution. How do we
use species names then? At what point do we decide to change them?

This problem will happen, if it does, long after we are both dead. Let's
not worry about it.

If
you are talking about a species in terms of a node, and saying that a
new species name is only needed when a node bnaches/splits, then there
is no such thing as a homo habilus or any of our ancestral populations
that have occured since the time we branched off from chimpanzees. You
could just call them all homo sapiens.

That assumes that the Homo lineage is entirely unbranched. Why did you
assume that? And anyway, like I said, species concepts encounter
problems when you try to extend them in time. You have hit upon Willi
Hennig's species concept, by the way, which I personally think is silly.

That is, if your view is
correct, then why do we use species names for organisms in the past?

So we have something to call them. But they aren't species in Mayr's
sense, just morphotypes. And if the fossil record is good enough (which
fortunately it isn't very often), the dividing line between morphotypes
is arbitrary.

There are still two heaps of sand if two sand piles adjoin, and they are not
adjacent for the bulk of the piles.


This is a false analogy. To be more accurate, imagine that you use a
specially decorated/colored line of tape on the ground next to all of
the people standing on line in my analogy, who are within 40 meters of
each other. Now understand that beside any person would be numerous
different stripes of this tape. ALL of the points along the line are
points where numerous smecies "adjoin" as you put it. Now to make this
analogy more congruent to biology, let's say we can place people not
just in a line, but anywhere in three dimensional space (like in an
apartment building). Now it's easy to see how every individual would
be in a myriad of smecies.

Species are reproductively isolated at a time and place.


Time and space are irrelevant. Two organisms are in a common species
if they are even _potentially_ able to interbreed. Erst Mayr there.

Individuals whose lifetimes don't intersect are not potentially able to
interbreed.

Sure they are. You could clone one of those in the past. The organism
is no more than the order of its DNA rungs, which can be preserved
through time. Or someone might invent a time machine.

First off, you are wrong about that. The organism is a bit more than its
DNA. There are a number of features that are needed in addition: a few
maternal proteins in the egg, a few pre-existing organelles, and
patterns of imprinting (methylation, mostly).

Second, when someone clones a fossil species or invents a time machine,
call me and I'll worry about the question. But not before.

If you are taking the view that something that can't happen isn't
potential, and if you believe in a determinant universe (which I do)
then any two groups who don't breed _cannot_ breed, since they were
determined by the laws of physics not to, and so if the US erected an
impenetrable wall around its borders, we'd instantly be in a different
species than all the rest of the people in the world, since we would no
longer be potentially interbreedable.

Are you some kind of philosopher? Because this is so far from any
connection to actual biology as to be pointless to a biologist.

Mayr was talking about a short span of time, and didn't even
consider that point. Of course time and space are not irrelevant.

I think some of my questions here pose great problems to this sentence.

I don't. I think they post great problems to the idea of extending
species in time.

If there are no intermediate reproductive clines between them,
then they are *then* species.

What if you have populations A, B, and C, where members of A can
interbreed with B, and B with C, but not A with C. There is a species
of bole weavil in Israel that I read exhibits this phenomenon.

Clinal variation is the reason why space matters. It's the same point as
the cline in time, except that it is in theory possible to test
interbreeding between the separated populations. (In practice, it may
not be, since behavior in captivity may not match behavior in the wild.)

You haven't answered my question. You said that two populations are
said to be species if there are no groups that are interbreedable
between them. Now I asked, what if there is a group C between A and B,
such that 10% of the members of A can breed with 10% of the members of
C, and the same for B and C? Are A and B separate species, or the same
species?

The answer is that this is a case in which the biological species
concept doesn't work well. There's no point in trying to force it to
fit. "Species" is an abstraction that works well enough, enough of the
time, to be useful. Other times it doesn't work, and we might as well
acknowledge that. What's your point?

Or what if a majority of organisms in populations A and B cannot
interbreed with those in the other, but some can. Are they two
different species?

The answer is that there is one species to which all members of B
belong, and another species to which all members of A belong. Then
there are many other species which include some from each. You are
confusing physical isolation (the formation of "isolated"
"populations") with species. Species has nothing to do with time or
place, just ability to bear fertile offspring.

No, that's the wrong answer. The answer is that we can't easily fit such
variation within the compass of the species concept (any species
concept).

You're wrong here to say "any" species concept. This kind of variation
_certainly_ fits into the concept of species that I've been using,
based upon ability to bear fertile offspring, without regard to space
and time. This is a definition that I feel is fair to use according to
Mayr and others, because I don't see anything in any of the definitions
of species on T.O. that says it is limited in space and time. Further,
I've shown hypothetical scenarios that would render time/space
discriminance absurd, such as cloning. My juxtaposition of the species
concept in light of set theory, without regard to space and time, deals
with this "semi-compatible" scenario gracefully.

That's nice, but it doesn't seem to have anything to do with biology.
You are treating organisms as mathematical entities, which they are not.
Your species concept is not a useful one, and bears only a formal
resemblance to Mayr's.

It's not that they belong to many species.

Not according to your take on the concept of species. But I think I've
shown that your take is impractical, and makes unstated stipulations
upon existing definitions of species.

My take is the one that biologists actually use, so it's in fact quite
practical. Yours is a formal abstraction without any actual use that I
can see. Don't pull too much meaning from single-sentence definitions.
If you want to know what Mayr meant, look into what he actually did when
he classified species. (These days we have departed considerably from
Mayr's ideas, but that's another question.)

It's that "species" doesn't always fit the biological facts well. It does so often
enough (especially if we restrict space and time) to make the concept useful.

Right. If you restrict the definition in the way you do, it still has
some (limited) usefulness, although it has a lot of ambiguity. And of
course, it doesn't always fit scenarios like the one I described above,
in which two groups are reproductively semi-compatible. _My_ literal
use of species, without your extensions, accounts for these types of
scenarios without any problems. It also avoids absurdities that creep
in when you "time travel" with cloning.

I'm sure you love the structure you have built, but it's without any
practical uses in biology.

Virtually *all* of it does, as I explained. If you have a child, that
child forms the boundary of a new species, or perhaps several new
species. I've explained this in some detail. To liken this to the
analogy of people lined up on a road, the child is in a group that does
not likely include the furthest person in the smecies of which you are
the end point.

This claim relies on a black/white distinction between breeding/no
breeding that just doesn't exist, and it also assumes that every
mutation is significant in producing reproductive incompatibility, when
in fact the overwhelming majority are just plain neutral. Both of these
ideas are patently false.

This is just horrendously wrong. First of all, this black/white
distinction is clear in Mayr's definition of species and others,
although you've extended his definition with your own caveat of
disregarding space and time, which brings up
absurdities/inconsistencies.

The black/white distinction is in your over-literalism only. Mayr
certainly never intended such a thing, and real organisms make the idea
useless.

As for the latter part, I understand that most mutations either affect
exons, or change a codon to another of its redundant forms, being
neutral in effect.

No. Most mutations are entirely outside of the exons, and indeed outside
any functional DNA at all. The functional parts of the human genome are,
being really generous here, no more than 6% of it. And that's counting
introns, most of which have no function.

But every child in a sexual species has a
completely novel assortment of his parents' alleles, and probably at
least a couple of mutations on introns. If you were to take his
parents' species (in the trans-space and trans-time meaning of the
word) and map them out to the reproductive compatibility fringes, you'd
have millions of end points, such that a child they produce would
almost certainly break reproductive compatibility with one of them.

This is your assertion, but I see no reason why it should be true, and
many why it shouldn't. To recap: most mutations are in the entirely
functionless parts of DNA, and thus can't have any effect. Of the rest,
very few genes have any role in reproductive compatibility; a few
hundred at most out of 25,000 or so.

More importantly, it might add reproductive compatibility, such that
there could be an ancestor of the mother that the male baby could mate
with successfully, but with whom the father could not. For this
reason, your objection about mutationary neutrality is moot.

That seems a non sequitur to me. You will have to explain.

I don't know what point you're trying to make here, but this has
nothing to do with anything I'm saying. I'm talking about mathematical
points, so the literature I've read is irrelevant. I'm talking in
terms of conceptual arguments.

If your concept is just plain wrong, so is your conceptual argument. If
you want to relate your concepts to reality, you have to be guided by
reality.

So your challenge is to prove the concepts wrong, and so far I think
I'm defending my points quite well, although you're raising some very
good points to take into consideration.

We disagree.

I certainly have, but you haven't addressed my arguments. It's
ambiguous to me whether you understand the arguments I made. At first
it seemed you understood, but now I'm not so sure. You said that a new
baby virtually never is a new species. As long as you believe this,
you do not get it.

I think you don't get it. Most mutations have zero effect on
reproductive compatibility. It's a rare baby who belongs to a new
species, even under your definitions.

Nope. EVERY baby, with exceptions being statistically irrelevant. I
explained this above.

I explained why this is wrong. Your belief relies on most mutations
having some effect on reproductive compatibility, when the overwhelming
majority cannot have any effect on anything at all.

And I have already done what you ask in some detail.

You haven't given any examples of micro and macro evolution that would
show how they are different and substantive.

I have if he hasn't.

Where? When? Link?

Too lazy to look. It was in this thread, though. However, species
selection will suffice to begin.

We *are* "within the ancestral species". Every higher taxon or clade was once
a single species, and our direct ancestors were a population within that
species. We are: apes, primates, mammals, theapsids, bony fish, chordates etx.
Each of these groups was once a single species.

I understand your point that every node on the taxonomic tree
represents a single species, from which we descended. But no, we are
not those ancestral species. You could not go back in time to the
ancestral species of all chordates and have sex with the chordate
women. No way man. Just like you're not within 40 meters of somebody
standing a mile behind you on the "highway line". But of course you
are within 40 meters of someone who is within 40 meters of...etc. etc.

I don't get the point either, unless Wilkins was quibbling with your
choice of words, i.e. "within". We are definitely within the ancestral
species, considered as a clade. But we're not within the same biological
species. Just how that all falls out is another problem of extending
species in time.

I was not aware that "ancestral species" had a discrete meaning apart
from "a species that was ancestral to ours". If "ancestral species"
means a species plus all of the species that descend from it, then I'm
not arguing with you about this.

There are no problems with extending the concept through time. There
are logical absurdities if you _don't_ extend it through time.

Not that you have mentioned so far. Unless you're talking about that
time machine again, and if so I think we're pretty safe.

Tsk tsk...you're talking here about species as though it is an
equivalence class, which is totally false. For instance, your
conception of species is, from a set theory view, that it is a set that
does not overlap with any other sets. This is false. Somewhere out
there on this planet, there is a women that I can't bear children with,
even though either of us could bear children with other people.

I'm pretty sure that you can't bear children at all, no matter who you
consort with.

I said "bear children _with_", meaning that together we could bear a
child. I couldn't give birth to it, and she couldn't impregnate
herself.

Generally, bearing a child is considered to be a one-woman operation.
You help with the conception, but that's your last input. This seems
another of your private definitions.

But taking what you meant instead of what you said, I
doubt that's true.

Ask a fertility doctor about this then. Two scenarios are that the
mother is RH negative, but the father (and the baby) are positive.
This can now be treated of course.

Also, you could have a scenario in which there are several genes in
which a dominant allele is necessary to be in place for the child to
live. Say you had ten of these genes, and both parents had
heterozygous allele sets on them. The chances that any fertilized egg
of theirs would survive would be 5.6%.

Note that here we are talking about reduced fertility, not absolute
reproductive incompatibility. See what I mean about there not being a
black/white distinction?

These are just two quick scenarios off the top of my head to show the
plausibility of this kind of problem. I'd imagine if you do some
research, there are some much more impressive examples, as I once saw
on a Discovery Channel special on infertility.

And yet another reason why an overliteral interpretion of Mayr's
definition leads you to absurdity.

However, we can't perform the experiment, so it's moot.

The experiment has been performed billions and billions of times.

I was talking about you specifically.

And there are certainly groups for which it is true, sort of.
(Remember that there is seldom any black/white distinction.) This is why
"species" is a concept that doesn't always apply well to the real world.

I'd say the black and white distinction is just whether two organisms
can produce fertile offspring. This draws a line in the sand between
"can these two groups intermix, or will they diverge". This fits with
Mayr's definition at least.

Again, there is no such black/white distinction in nature, nor does it
determine in such a black/white way whether groups will merge. As I have
explained already.

Strangely, your use of "species" as some kind of simple yes/no test
between individuals is just the sort of essentialism that you are decrying.

I'm decrying using it incorrectly.

You're decrying it incorrectly. You need to learn a bit more about real
organisms than just one short sentence of Ernst Mayr's, interpreted as
some kind of holy writ.

We
aren't in the same species, even though I'm in the same species as
people she's in the same species with. Evolution is not as neat and
clean as a classical taxonomic framework would suggest, and you CAN NOT
think of a species as an equivalance class, because it's not.

I'll let the philosopher deal with that.

Science _is_ philosophy. Science is the application of logic to the
analysis of the empirical.

Them's fightin' words. Call me a philosopher one more time, and we'll
have to step outside.

This seems to be based in some kind of empty, legalistic formalism.
Biology is not mathematics. It's not a formal system.

ALL of science is just math. Math applied to empirical data.

That's silly. Science is frequently much less formal than math, unless
you consider all reasoned argument in natural language somehow to be math.

You just can't blindly apply these definitions in this way.

It's not blind. The only significance the concept of species has is
how it blocks off groups of organisms from intermixing genes, spurring
on their evolutionary divergence. This is where all the accepted
definitions of species spring from, and this is where my argument is
based. It's not blind; it's based in fact.

You desperately need to read some of the literature on speciation, and
on the behavior of actual organisms. You need to learn how species
concepts are actually used by biologists. Your concept is divorced from
biology.

And like I have said, the
idea of species becomes less and less meaningful the further we stretch
it in time and (often) in space.

It is _only_ meaningful if stretched into time, because time has
nothing to do with an arrangement of A T G and C.

Another non sequitur as far as I can see.

.