[Taxacom] Molecules vs Morphology‏

[John Grehan]

Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-
> bounces at mailman.nhm.ku.edu] On Behalf Of Jason Mate

> My bad, my question wasn´t clear enough: what is your logical basis for
> deciding that one result is false versus another one? 

If you are referring to molecular analysis I don’t have one.

Furthermore, don´t
> you think that the term, false, implies knowledge of historical truth
> that, by definition, is probably unknowable?

Yes, but it was not me making these assertions!

And in regards to your
> example, do you mean to say that they stress the results that are
> congruent with others but simply mention in passing other novel ones?

Correct. Or they find a way of explaining why the supposedly false result has to be wrong.

> What about the other 90%.

Typo - agree 100%

> No, no, no, don´t look into (o through) the Orangutan´s eyes! If your
> results are not falsified by molecular datasets is the reverse also true?

Correct!!

> Because if it is then there is nothing to compare. 

????

And the fossil
> correlation? To what? 

To the morphological relationships of the living.

I honestly do not follow the trials and tribulations
> of anthropology and its favourite topic so you have to tell me how this
> specific example is the crux of molecular vs morphological argument.

Its not the crux so much as a flash point. If it were a matter of some obscure moths no one would give a darn.

> >Or different concepts or different perspectives on the data. More data
> does not necessarily provide a solution.
> >If they dig up a hominid that is a clear precursor to the currently known
> bipedal morphologies, and this hominid
> >looks even more like an orangutan than current hominids, I might say this
> additional data adds further support
> >to the orangutan evidence, whereas molecular systematists might say that
> it is irrelevant in some way.
> 
> John, that is not true, and we both know it. 

I'm sorry, I don't.

Everybody loves a good old
> "missing link" to settle debates. 

Good

Not to mention
> that such fossil is just novel data and as such supports my position: if
> in doubt get more data.

It certainly never hurts. But to show how tricky that can be, there were some worn teeth dated at 10 Ma that were said to be gorilla related because they fell into that size range, but had other features that did not conform to the gorilla, but to the orangutan and its fossil relatives. It is as if one possibility could not be considered.

But yes, new fossil material has the potential to stir things up. There are isolated fossil teeth labeled hominid (australopith) even though they resemble none of the embedded teeth in known hominids. Because they are so late in the fossil record they are assumed to be hominid, even though they have orangutan like characteristics.

> >Yes - if one is a pheneticist and rely on overall similarity through the
> law of large numbers.
> >If the law of large numbers is applied to morphology one will get a
> human-African ape relationship every time,
> >just as one might get a crocodile-lizard grouping every time.
> 
> Sigh, not fair to use the "molecular data is phenetics" card when pressed
> into a corner. 

Not in a corner. Law of large numbers is promoted by molecular argument.

> the distinction is not there. A large number of characters is a large
> number of characters. 

Yes, but a large number of similarities vs a large number of uniquely shard similarities are two different things.


> However, if I have 50 genes, both nuclear and
> mitochondrial, and they point one way, and the morphological data is in
> conflict... lets just say the morphological dataset
> needs some explaining.

Or vice versa.

John Grehan