Re: Behe in the latest Protein Science

On 3 Sep 2005 06:41:48 -0700,
Richard Forrest <richard@xxxxxxxxxxxxxx> wrote:
> Larry Moran wrote:
>> On 2 Sep 2005 21:34:33 -0700,
>> RobinGoodfellow <lmeyerguz@xxxxxxxxx> wrote:
>> > Keith H Duggar wrote:
>>
>> [snip]
>>
>> >> On the other hand, "macroevolution" is
>> >> often used to describe a concept that already has a clear
>> >> name "speciation". So it seems to me that evolution could
>> >> use a terminology tune-up. Especially now that public
>> >> controversies are creating and fostering confusion.
>> >
>> > I am actually inclined to get rid of the terminology altogether.
>> > As far as I am concerned evolution is evolution: only the time
>> > scales and the amounts of genetic change differ. I think the
>> > distinction should exist only if there are fundamentally different
>> > processes underlying "micro" and "macro": and right now, that
>> > does not appear to be the case.
>>
>> Here's a short list of things that are covered by the field of study
>> known as "macroevolution." None of them can be fully explained by
>> extrapolation of microevolutionary processess.
>>
>> 1. speciation, especially cladogenesis
>
> Emm...speciation *is* cladogenesis.
> Speciation events have been observed. No processes other than those
> involved in 'microevolution' are required.

Really? What about geographical isolation? That isn't part of any
micrevolution theory that I know. Since microevolution refers to events
within a population how can it cover the creation of new populations by
splitting?

You are making the mistake of only thinking about events that occur
in one lineage. You are fogetting about the events that lead to
the splitting of a lineage.

> TO gives many such examples. You need to go through *every one* of
> those examples and demonstrate *from the evidence* that speciation has
> not occure, otherwise this is simply an unfounded assertion.

What are you taking about?

>> 2. species sorting/selection
>
> I don't even know what you mean by this. Do you?

I know what it means. It's very obvious from your statements that
you have no idea what it means. Would you at least agree that species
selection, if it occurs, cannot be explained by microevolution?

>> 3. punctuated equilibria
>
> What's wrong with natural selection?

There's nothing wrong with natural selection. Do you have a problem
with it? Meanwhile, the pattern of punctuated equilibria cannot be
fully explained by microevolutionary processes.

>> 4. mass extinctions
>
> What have mass extinctions to do with macroevolution? If an asteroid
> the size of Manhattan hits the earth, what else do you expect?

The effect of mass extincions is an important part of the field of
macroevolution. It cannot be fully explained by microevolution. The
possible regularity of mass extinction certainly isn't covered in
most population genetics courses.

>> 5. unique events such as the Cambrian explosion
>
> What was unique about it?

It only happened once. That's what unique means.

>> 6. long term trends
>
> Why???
> Perhaps you can explain how one can have evolutionary events happening
> for billions of years without 'long-term trends'?

The study of long-term trends is a major part of the field of
macroevolution. Examples are the increasing size of horses over time
and the increase in brain size in the hominid line. Both of these require
explanations that go beyond simple increases in the frequency of alleles
in a population. For example, they involve the birth of new species and
the extinction of others. The explanation will involve speculations
about the selective advantage (or not) of certain characters and
how they interact with the environment over a long period of time.

You are making the same mistake you made above. You are focusing on
the one particular pathway that led from an ancient ancestor to the
modern species. You are only seeing the fact that allele frequencies
changed in that one lineage as you trace it from species to species.
You are ignoring all of the events that led to its differential
survival. You are ignoring all the external reasons why allele
frequencies changed. That's what macroevolution is all about.

>> 7. convergent evolution
>
> Why???
> If the shape of a tuna is best suited for swimming quickly through
> water, this is the shape that natural selection tends to. I fail to
> see any problem. Perhaps you can explain.

Microevolution involves changes in the frequency of alleles within
a population. Convergent evolution requries that you examine different
lineages and recognize that they have acquired similar adaptations.
Comparing different species is not microevoluton. It's part of the
field of macroevolution. You can study microevoluton until the cows
come home but it won't ever reveal the fact that two different species
have converged.

>> 8. the relationship between birds and reptiles
>
> So what evidence which is used to support the accepted evolutionary
> path can be interpreted in a way which matches the evdience more
> closely, and can predict what we may find in the future?

What?

>> 9. diversity and disparity
>
> Why?

Because they both involve examination of entire ecosystems with
multiple species. That's not part of the field of microevolution.
How does microevolution explain that one clade has dozens of
species while another has only one or two?

>> 10. biogeography (e.g., marsupials in Australia)
>
> Why?

Because geography isn't part of microevolution. No course in
microevolution will cover moving continents or the consequences of
joining of North and South America.

>> 11. the importance of contingency
>
> Please explain: I have no idea what you mean by this.

I'm sorry that you have no idea what contingency means.

>> 12. evidence of developmental constraints
>
> What's wrong with genetics?

There's nothing wrong with genetics that I know of. Is this
something else you don't understand?

>> 13. the evolution of symbiosis and parasitism
>
> Why?

Because it's there.

>> 14. predator-prey relationships
>
> Why?

Do you think papers on predator-prey relationships will only talk
about allele frequency changes within a population? Don't you think
they'll also talk about how one species affects another?

>> 15. evolution of complex ecologies
>
> Why?

This is getting boring ... don't you know anything about evolution?

>> > That said, I have no problem with "macroevolution" being defined as
>> > "speciation". I just don't think that definition is particularly
>> > interesting.
>>
>> It's also wrong. Why do you have a problem with the scientific term
>> "macroevolution?" Evolutionary biologists don't have a problem. They
>> us it all the time. They know the difference between macroveolution
>> and speciation. So do I. Why don't you read a basic textbook on
>> evolutionary biology and let me know which part of macroevolution
>> you would like to discard (or reduce to microevolution)?
>
> 'Macroevolution' is a *descriptive* term. It is not a term which
> describes a process. It is a convenient shorthand for evolution on
> larger scales.

That is (mostly) correct. It's a word that is used to describe a
field of study. It's a very different word than "microevolution."
I thought you knew that but I guess I was wrong.

> Although the suggestion has been made that processes *in
> addition* to natural selection are involved, the more we learn about
> the complex interaction between genetics and development (look up
> "Evo/Devo"), the less we need to hypothesise supplementary mechanisms.

You should learn about hierarchical theory and especially species
selection. You might change your tune.

> Nature is full of papers about many aspects of this exciting field
> of research. I suggest you familiarise yourself with this rapidly
> developing field rather than relying on the utterly discredited
> sources you draw on.

Hmmm .... one of us appears to ignorant of a lot of evolutionary
theory. It ain't me.



Larry Moran






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Relevant Pages

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