Prove that macroevolution occurs or has occurred

[iggator2003]

Ok, I'm new to this whole debate thing but I'd like to discuss the
topic of macroevolution. I'm directing this at Dr. Chris. Please prove
to me that macroevolution has occurred and provide scientific evidence
of the occurrences.

I hope that's how you wanted me to start a topic.

Thanks,

iggator2003

[chris.fo...@gmail.com]

> Please prove to me that macroevolution has occurred and provide
> scientific evidence of the occurrences.

These seems like a reasonable discussion topic.

> I hope that's how you wanted me to start a topic.

It's perfect.

Let's see if I can clarify the situation, because we do need to be on
the same page with regard to any scientific discussion - or any
presumption of one.

What, in your own words, is "macroevolution?"

What, to your mind, would constitute "proof?"

Do you understand that the scientific method does not deal in
"proof?" When the average person says that something is "proven," he
or she represents that the topic that is subject to being proven must
be so beyond mutability. In other words, once proven, it is absolute
and not subject to disproof.

Science, on the other hand, does not deal with "proof." It deals with
evidence. The scientific method says that it can disprove things, but
with regard to those things that it can "prove," it can, on fact, only
support with evidence.

I am not a biological scientist, but that is the accepted
understanding in the scientific community.

Furthermore, there is often confusion as to what is meant by
"macroevolution," and the definition varies depending on what it is
that we are addressing. For example, for living species, subject to
observation, macroevolution occurs when speciation occurs, that is,
when an evolutionary event (which is not necessarily an event, again
as often understood in other contexts, that is immediate or even
necessarily quick) results in a new species.

For extinct organisms, the definition is somewhat less precise.

My points have to do with the idea that we must have a common
understanding of the terminology and the meanings of words in a
scientific context, as agreed upon by the scientific community, before
we can presume to embark on a scientific discussion or debate.

Agreed?

[chris.fo...@gmail.com]

Allow me to underscore why common understanding of terms is especially
important. I asked this question:

> What, in your own words, is "macroevolution?"

I am working under the assumption that you are approaching this from a
creationist perspective and that you likely hold to a creationist or
"intelligent design" viewpoint. If that is incorrect, please accept
my apologies.

When creationists presume to attack the idea of evolution, it is often
from the perspective that "microevolution," which is generally defined
as evolutionary change below the species level, has occurred. But
they dismiss it as "adaptation," and not evolution, at all.

When it comes to creationist criticism of "macroevolution," it often
becomes absurd, because creationists will attack evolutionists for
allegedly believing that "cats become dogs," cows become whales, or
crocodiles become ducks. These and many other silly examples are,
according to some creationists, what encompasses "macroevolution."

Macroevolution generally refers to evolutionary change at or above the
taxonomic level of "species," including speciation events, and are not
the sorts of silly things that we often see in creationist
criticisms. Those kinds of criticism are borne of two things:
Ignorance or dishonesty. When ignorance is the factor, the
creationist, usually a lay person, is simply repeating what some other
creationist (often a member of a creationist organization) has said,
without understanding the absurdity of the argument. Dishonesty
occurs when the creationist in question knows full well that
evolutonists do not make the claims that they ridicule, but they
represent them as evolutionary claims, just the same, and ridicule
them, anyway.

You are probably aware, already, that such things, whether by
ignorance or dishonesty, constitute an application of the "straw man"
fallacy.

As a disclaimer, allow me to say that I am not making any assertions
that you have made these kinds of claims or that you would do so. I
merely want to cover the reasons why we must be sure that we are on
common ground with regard to the understanding and correct definition
and understanding of terms as they are used in the scientific
community.

To continue this discussion, please reply to this thread; and let's
limit ourselves to one question or specific topic at a time. In other
words, until we are sure we are on common ground on this issue, please
do not start another comment on a related topic in this thread, and
don't start another thread unless it is another debate topic.

To the other readers and members: This thread is closed except for
iggator2003. Please do not reply to it. Replies will be disapproved.
I will create a separate thread for a Peanut Gallery, which will serve
as a reader comment area for this thread.

Thanks.

[iggator2003]

Agreed.

When I refer to macroevolution I'm referring to evolution outside of a
species, or "upward" evolution for lack of a better term. Basically,
evolution in one species that results in an entirely different
species. This is different than microevolution, which is evolution at
a species level. Microevolution would be variations within a kind,
natural selection, etc.

That is how I and the scientific community have defined macroevolution
and microevolution.

And you are correct. I did not mean prove in the truest sense of the
word and I was loosely using the word as a synonym for evidence. I
agree with you concerning evidence. As one scientist stated, "There is
no evidence for creation. And there is no evidence for evolution.
There is only evidence." So, please provide evidence that
macroevolution occurred.

Thanks for directing me to clarify.

[chris.fo...@gmail.com]

On Dec 19, 1:24 pm, iggator2003 <iggator2...@gmail.com> wrote:
> Agreed.
>
> When I refer to macroevolution I'm referring to evolution outside of a
> species, or "upward" evolution for lack of a better term.

Any term that helps us to envision what it is that we are trying to
illustrate in a print media such as this can be helpful. However, I
would caution against using words such as "upward," since there is no
"upward," necessarily, in either evolutionary science or evolutionary
jargon. However, some scientists do use that kind of terminology in
less formal discussion, so I won't get pedantic about it.

Again, I am not a biologist My doctorates are in history and
theology. However, I have it on good authority that macroevolution
generally refers to evolution that occurs at or above the species
level. While this is supported by a number of professional
references, we can also check the definition provided by Futuyma,
which says that macroevolution is "a vague term for the evolution of
great phenotypic changes, usually great enough to allocate the changed
lineage and its descendants to a distinct genus or higher
taxon." (Futuyma, D., Evolutionary Biology, Sinauer). This
definition, in different wording, also appears in Campbell and Reese,
Biology, 7th edition, a common introductory Biology text. Ernst Mayr
considered speciation to be a form of macroevolution (Evolution 36(6):
119) and this seems to be the accepted definition. Consequently, the
rise of new species from existing populations of another species -
speciation - is macroevolution.

Furthermore, all of my reading on the subject would indicate that
macroevolution is a term that does not have significant meaning inside
the biological community, most of whom consider evolution to occur on
a continuum, with no specific demarcation points. However, since human
beings, as thinking creatures, need those sorts of milestone points,
there has been an attempt at definition. Within the biological
community, macroevolution is simply the result of continuing
microevolution, particularly along different paths, leading to the
establishment of new species, new genera, and so on. Just as the
animals don't classify themselves, and so we classify them according
to imperfect criteria, so too, do we try to classify natural processes
according to criteria and demarcation points that do not always
apply.

> Basically, evolution in one species that results in an entirely different
> species.

Let's be clear that macroevolution is a process that allows for
populations of species to give rise to other species, depending on
accumulated genetic and environmental facts that take place over
time. Consequently, and, again, wanting to nip confusion in the bud,
we both need to understand that macroevolution does not say that one
species evolves into another. Being clear in our language is very
important; and understanding cannot occur unless we are sure of our
verbal representations.

> This is different than microevolution, which is evolution at
> a species level.

Or below, according to my sources.

> Microevolution would be variations within a kind,
> natural selection, etc.

There are a few problems with this. The first is that it is not
altogether accurate. Microevolution and "variations" are not
interchangable terms. Microevolution may result in variations, but
the mechanisms that manifest themselves in both micro- and macro- are
the same. The latter is simply an accumlution of the former and, in
fact, the former may consist of still more collections of more "micro"
changes.

Natural selection is not "microevolution." It is a theory that says
that accumulated changes in organisms lead to what we now call
genotyical (genetic) and phenotypical (genetics expressed in
structural changes in the organism) resulting in populations of
organisms that carry these inbuilt changes into the changing
environment and, as a result, are more capable of surviving and
reproducing in that environment. And, as I have already pointed out,
these genetic and physical changes accumulate, resulting, yes, in
variation in species, but also in speciation events - new species
arise from populations of descendant species.

> That is how I and the scientific community have defined macroevolution
> and microevolution.

In fact, the scientific community does not consider "natural
selection" to be "microevolution." Microevolution is but one part of
evolution that is part of a rich strategy leading to organismal
diversity. Natural selection is a theory that explains how all of
these forms of evolutionary activity - whether micro- or macro- - lead
to what we observe in nature.

> And you are correct. I did not mean prove in the truest sense of the
> word and I was loosely using the word as a synonym for evidence. I
> agree with you concerning evidence. As one scientist stated, "There is
> no evidence for creation. And there is no evidence for evolution.
> There is only evidence."

Which scientist said this?

> So, please provide evidence that macroevolution occurred.

We're not clear on our terms, yet.

> Thanks for directing me to clarify.

You're welcome. But some clarification still needs to be made.

[chris.fo...@gmail.com]

I'd like to address the following so that we can have another
clarification with regard to our debate rules:

> As one scientist stated, "There is no evidence for creation. And there is no
> evidence for evolution. There is only evidence."

I can easily take issue with this and show it to be simple and useless
rhetoric. Instead, I asked what scientist had said this.

But the reason is a simple one: For a scholarly discussion and
debate, and since neither of us are experts in this area, we must
defer to the experts. That means that we cannot make vague claims
about what this or that "scientist" might have said. If we are going
to quote someone, we must identify that person and provide a
reference. That is intellectual, scholarly behavior.

Agreed?

[iggator2003]

Agreed. I did apologize for that and assure you that it won't happen
again. But the statement is true nonetheless. We only have what the
earth and the universe provides us with. The evidence can be
interpreted differently, but it's the same evidence.

[iggator2003]

I'm not exactly sure what further clarification needs to be made.
We're saying the same things in regards to our definitions of
macroevolution. Macroevolution is evolution at or above a species
level. Microevolution is evolution at or below a species level.

Regarding natural selection, variations within a kind, etc. -- these
are examples of microevolution because they are evolution at or below
a species level. Natural selection is just that, selection. It is
selection from an existing pool of genes. No new genes are formed. And
it is more than a theory. It has been observed and is accepted as a
scientific process.

David S. MacMillan III was the writer who stated, "There is no

evidence for creation. And there is no evidence for evolution. There

is only evidence." He is a writer, and I'm not sure if he's a
scientist or not. I apologize for any misdirection. Regardless, the
statement is a good one. There is only evidence.

Hopefully this helps clear things up a bit.

[chris.fo...@gmail.com]

Pardon for the brief delay in responding. It is the holidays, after
all, and I suspect that we are all in some kind of observance.

The statement is not true because you declare it, as such, just as it
is not "useless rhetoric" simply because I declare it, as such. The
idea that there is only evidence and that it is not evidence for or
against something, subject only to interpretation, is nonsense and
laughable when compared to the usefulness of so much evidence gathered
as part of an objective, scientific process.

But I won't really argue this point, because it's clear that your
source is not qualified to make any expert commentary on the subject.
Here is the blog for your source:

http://www.blogger.com/profile/7822164

I will have more to say in my next reply.

[chris.fo...@gmail.com]

On Dec 19, 2:29 pm, iggator2003 <iggator2...@gmail.com> wrote:
> I'm not exactly sure what further clarification needs to be made.
> We're saying the same things in regards to our definitions of
> macroevolution. Macroevolution is evolution at or above a species
> level. Microevolution is evolution at or below a species level.

As simple definitions go, this is acceptable.

> Regarding natural selection, variations within a kind, etc. -- these
> are examples of microevolution because they are evolution at or below
> a species level. Natural selection is just that, selection. It is
> selection from an existing pool of genes. No new genes are formed. And
> it is more than a theory. It has been observed and is accepted as a
> scientific process.

I'm getting from this not only intransigence, but a lack of
understanding as to how Natural Selection works. While simple and
elegant, natural selection is more than just "selection." There are a
number of mechanisms at work. The "existing pool of genes" is
constantly in flux.

> David S. MacMillan III was the writer who stated, "There is no
> evidence for creation. And there is no evidence for evolution. There
> is only evidence." He is a writer, and I'm not sure if he's a
> scientist or not. I apologize for any misdirection. Regardless, the
> statement is a good one. There is only evidence.

The statement is very superficial and quite false. But then, your
source is a 19 year-old blogger.

http://www.blogger.com/profile/7822164

You need to be more discerning about your sources.

> Hopefully this helps clear things up a bit.

We accept a given definition of macroevolution, but the rest continues
to be blurred by your intransigence with regard to allow the theory of
Natural Selection to be properly represented, as well as a rather
sloppy reliance on sources that are, themselves, non-expert.

Your use of MacMillan is a clear example of the argument from
authority fallacy.

Let us both resolve to using only sources that are demonstrably
knowledgeable about the subject.

[chris.fo...@gmail.com]

Being a non-biologist, but being firmly convinced that evolution -
whether macro- or micro- has occured and continues to occur, I am
intellectually obligated to rely on experts for the evidence. One
such article about evidence appears here:

http://www.toarchive.org/faqs/comdesc/

Douglas Theobald, unlike your 19 year-old blogger, holds a doctorate
in biochemistry. His faculty page is here:

http://www.bio.brandeis.edu/faculty/theobald.html

Dr Theobald's expertise is obviously, torso, chest, and head-and-
shoulders over that of either of us, but, in any case, that
establishes his credibility. One thing that should be noticed is that
he is not a 19 year-old, "homeschooled" high school junior being
passed off to us as a "writer" whose only contribution, in any sense,
to the discussion, is a blog.

You'll excuse me, please, for mentioning that, again, but as an
intellectual and the holder of two doctorates, myself, I was quite put
off by the citing of such a person in what I was hoping would be an
intellectually more fulfilling discussion.

At any rate, Dr Theobald's article lays out the criteria for what
constitutes "macroevolution" in very specific terms, at least as far
as those with the best qualification to define it, are concerned.

I think I have already mentioned that, in more specific, scientific
venues, scientists tend to eschew the ideas of macro-and micro-
because, to them, it's all *evolution* and evolution is a continuum of
processes branching in many directions. We set boundaries because
humans need those kinds of distinctions in order to better understand,
in our own limited way, the workings of a universe that is far older
and more complex than we presently are capable of understanding.

We have decided, however, for the purposes of this discussion, to
accept that "macroevolution" refers to evolution at or above the
species level, and that speciation qualifies.

The consequence of that is that if macroevolution involves
evolutionary change at or above the species level, and if we decide
that speciation qualifies, we must then decide what constitutes a
species.

Not surprisingly, what does and does not constitute a species is also
a bit subject to variation in definition, but most biologists define
it as a population of organisms that are reproductively isolated (by
various mechanisms) from each other. That's murky because we also
understand that dogs and wolves are separate species but they are not
necessarily reproductively isolated - interbreeding between wolves and
domestic dogs can result in fertile offspring. This is one of the
reasons that biologists will often use other criteria to distinguish
one species from another, including the related nature of the species
and the fact that the populations may be geographically isolated, and
so, incapable of interbreeding.

One biologist that I read put it rather simply, and I must
paraphrase: The animals don't classify themselves. We classify
them.

This means that we use a rather inexact set of criteria to which
nature does not always adhere.

Here is an article at the University of California, Berkeley, site,
that describes the issue:

http://evolution.berkeley.edu/evosite/evo101/VADefiningSpecies.shtml

As we can see by following the links at Berkeley, speciation is
defined here:

http://evolution.berkeley.edu/evosite/evo101/VBDefiningSpeciation.shtml

"...a lineage-splitting event that produces two or more separate
species."

I'm going to assume that the sort of speciation that you're looking
for will be one in which the result was a population of organisms
arising from another and becoming reproductively isolated from them.
Sympatric speciation addresses this particular kind of speciation.

Evidence for this kind of speciation abounds in the literature. The
most common examples that I have read about, being a layperson,
involve populations of African cichlid fishes, particularly those
inhabiting the East African Great Lakes. Scientists have been
discussing those mechanisms for years and the controversies about them
seem to have settled.

But evidence for sympatric speciation for cichlid fishes in crater
lakes in Cameroon is much stronger. Icthyologists studied the DNA of
the populations of these lakes and discovered that the populations
were monophyletic. They appear to have colonized these lakes only
once, and then diverged into separate species, in overlapping
environmental ranges, and the result is a group of cichlid species
composed of populations that are reproductively isolated from each
other. The total number of species involved in this divergence is
rather staggering. One part of the study, showing transistion or
transversion on mitochondrial DNA, used to establish evolutionary
relationships, resulted in 24 separate species being identified as the
likely results of sympatric speciation events.

Let's consider that an "event," in lay terms, usually means something
that occurs very quickly, if not suddenly, but in scientific terms, an
"event" might take just a bit longer than a few seconds to a few
hours, just as the "Cambrian Explosion" was not an "explosion" in the
commonly understood sense, in terms of time.

Here are some references:

Schliewen, U.K., Tautz, D., and Paabo, S. (1994). Sympatric speciation
suggested by monophyly of crater lake cichlids. Nature 368:629.

Barluenga, M., et al. (2006). Sympatric speciation in Nicaraguan
crater lake cichlid fish. Nature 439:719.

The evaluation of the evidence, of course, involves the use of
scientific understanding and the concept of parsimony. The
establishment of these macroevolutionary events is based on scientific
evidence, taking into account scientific processes without the
invocation of unknown entitites or those not shown to exist.

This is where the red herring about "there is only evidence" comes
into play as a rhetorical device. That there is evidence of
speciation in these cases is undeniable. If we say that the evidence
is only evidence and subject to interpretation, I would be curious to
see an explanation from this evidence that would suggest anything
other than macroevolution - taking into account *only* the evidence
and known processes, without invoking incredulity or unevidenced
entities.

[tnz...@gmail.com]

As an observer of this conversation, I'm terribly sorry to interject.
I simply wish to ask iggator2003 how long it will take to respond.
With respect to the information posted by Mr. Foster, this is a
perfectly disciplined and informative presentation. I only wish that
the conversation was occurring with a little more commitment from your
respondent. As relief from my suspense I may be left to assume his
stated reasons for entering the conversation are as dishonest as his
abrupt disengagement is rude.

[chris.fo...@gmail.com]

Yes, as today is the 11th of January and significant time has passed
since the discussion began and since my last entry, it's probably fair
to say that it's not going to get any further commentary from what was
clearly the creationist side of the debate. It may have been that
having the "writer" referenced exposed as a teen-age, fundamentalist
blogger was embarrassing enough, but once the definitions were clear
and agreed upon, it was an easy matter to prove that macroevolution
had occurred, underscored by references from the professional
literature.

I believe that it is fair to declare the debate closed.

And, yes, for the record, I do believe that simply disappearing from
the debate is mildly "rude," but none of us should view it as anything
beyond that. Believers can be especially sensitive when they have
been confronted with evidence that they cannot answer and retreat back
into the religious shell that they presume protects them is a common
response. Those of us who have been there understand.

These kinds of debates are certainly never about convincing the
believer about the errors of his or her ways. I have found that the
sorts of believers who will actually try to debate these things are
remarkably intransigent - perhaps moreso than those who will not come
into an open debate (e.g., AnnaAgainstAtheists and Josiah and his
various sockpuppets). When the believer's arguments are exposed, they
tend to retreat - there is much to lose in continuing and there is
considerable rationalization.

But for fence-sitters and intellectual believers, that is, those who
will consider and question, discussion such as these can be very
useful.

My thanks to all readers for their attention.