[Taxacom] Orang possibilities

Wed Sep 9 16:19:04 CDT 2009

John,
[I wrote] > These days the great apes (formerly Pongidae) are usually considered to be Hominidae too, though nobody has yet dared to widen the (subjective!) concept of
> the genus Homo to include Pan and/or Pongo and/or Gorilla!
[John Grehan replied] That is not correct.
[my reply] Er ... which bit is not correct, John, and why? I can assure you that in plenty of published articles the former Pongidae is subfamily Ponginae of family Hominidae, and contains only Pongo, while Homininae contains Homo, Pan, and Gorilla. Gibbons are usually out in a separate family Hylobatidae.

Note that whether you think Pongo or Pan is closest to Homo, the old notion of Pongidae (excluding Homo) is paraphyletic!

If you just meant that it wasn't correct that 'though nobody has yet dared to widen the (subjective!) concept of the genus Homo to include Pan and/or Pongo and/or Gorilla!', because somebody has, then fine, it was only an offhand remark!

Just a thought, but of course there doesn't have to be a single extant species of great ape closest to Homo. It is in principle possible for Homo to be the sister taxon of all the extant great apes, or any pair of them (such as Pongo + Pan)...

Stephen
________________________________________
From: taxacom-bounces at mailman.nhm.ku.edu [taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of John Grehan [jgrehan at sciencebuff.org]
Sent: Thursday, 10 September 2009 12:01 a.m.
To: TAXACOM at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Orang possibilities

From: Stephen Thorpe [mailto:s.thorpe at auckland.ac.nz]
Sent: Tuesday, September 08, 2009 11:33 PM

>Extra 2% - not significant at all if its just primitive retention
> But the molecular people must know that! How do they tell if a DNA
sequence is
> plesiomorphic vs. apomorphic? If it was primitive retention, you would
expect to
>  find the same sequence more widely in ancestral primates, wouldn't
you?

This gets to the core question and the matter is rather nuanced. When
there is reference to a 1% or 2% etc difference, the complimentary
percentage of similarity refers to all matching bases. In studies of DNA
hybridizaiton that generated such figures there was no knowledge of
which base matched with which and so no way to even theorize primitive
vs derived. Molecular systematists have since figured this out and
acknowledge the non-cladistic nature of DNA hybridization and its
inferiority to subsequent sequence analysis, yet at the same time also
quoting the result as if it were totally valid (presumably because it
fits the sequence result.

Sequence analysis is problematic because one has no trace of what base
replaced what base. In many studies the initial homology is determined
by alignment theory which imposes overall similarity of the total 'best'
match to determine the individual homology. Some studies use outgroup
comparisons to root the tree, but this does not negate the initial
problem of base replacement, or the extremely limited sampling of the
outgroup (as if a few species will give the total picture of base
representation).

While molecular theorists vehemently deny any such problems and
therefore uncertainty over the result for hominid origins, they are at
the same time now jumping to SINE comparisons as truly cladistic (a
necessary argument only if the other methods are indeed problematic)
while introducing another set of assumptions that are also problematic.

For almost all evolutionary biologists, including pretty much everyone
who has commented on this list, the nuances don't matter. They invoke
the law of large numbers and the consistency of the molecular result to
accept that the molecular result is nevertheless right and the
morphological result is wrong.

>At present the morphological evidence suggests the monophyly of
>hominids with respect to other large bodied hominoids

> These days the great apes (formerly Pongidae) are usually considered
to be
> Hominidae too, though nobody has yet dared to widen the (subjective!)
concept of
> the genus Homo to include Pan and/or Pongo and/or Gorilla!

That is not correct.

John Grehan
________________________________________
From: taxacom-bounces at mailman.nhm.ku.edu
[taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of John Grehan
[jgrehan at sciencebuff.org]
Sent: Wednesday, 9 September 2009 3:10 p.m.
To: TAXACOM at mailman.nhm.ku.edu
Subject: [Taxacom] Orang possibilities

At present the morphological evidence suggests the monophyly of hominids
with respect to other large bodied hominoids, and that they are more
closely related to orangutans than chimpanzees, so the possibility
suggested has no immediate support.

With regard to sampling of diversity it depends on what that is in
reference to. The details of sampling of characters is documented in the
appendix to our article.

Variation of features within populations has not been documented to my
knowledge. But I've looked at thousands of individuals of different
geographic origins and all are consistently the same with respect to
some of the visible characters (e.g. ear structure, receded hairline,
forward cranial hair). Others may vary.

John Grehan

-----Original Message-----
From: Steve Manning [mailto:sdmanning at asub.edu]
Sent: Tuesday, September 08, 2009 4:50 PM
To: John Grehan; TAXACOM at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Why Australians are more real than Americans:
implications for taxonomy!

As a non-expert in the field, I just thought of a third possibility
along with the orangutan and chimp possibilities:  Maybe humans evolved
more than once, at least once from an ancestor closer to chimps and at
least one other time from an ancestor closer to orangs.  Is that a
possibility either or both sides could live with?  Can it be falsified?
If so, how?

How much of human, orang, and chimp diversity has been sampled, both
morphologically with regard to the 28-45 human-orang morphological
synapomorphies alluded to and with regard to DNA human-chimp
synapomorphies?  Do any of the well-studied morphological characters
vary between or within human populations?  Or between or within chimp or
orang populations for that matter?  Same exact questions for the
molecular analyses.

Finally, are there biogeographical correlations with any of the above
variations, morphological or molecular, if any, that have been found
WITHIN humans? WITHIN orangs? or WITHIN chimps?

Steve Manning

At 10:12 PM 9/6/2009, John Grehan wrote:
>I know its always tempting to get a sideways dig in, but its no more
>informative than to say that its "up there with Thorpian denial of the
>evidence that points to the human-orangutan relationship"
>
>John Grehan
>
>-----Original Message-----
>From: taxacom-bounces at mailman.nhm.ku.edu
>[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Stephen Thorpe
>Sent: Sunday, September 06, 2009 5:53 PM
>To: Richard Pyle; TAXACOM at mailman.nhm.ku.edu; 'Jim Croft'
>Subject: Re: [Taxacom] Why Australians are more real than Americans:
>implications for taxonomy!
>
> >So... if I understand you correctly... you're under the
>delusi...err....impression that "real" species boundaries exist in
>nature outside of human imagination and convenience -- correct?
>
>It is manifestly self-evidently so! To deny this is up there with
>Grehanian denial of the evidence that points to the human-chimp
>relationship!
>Importantly, though, I am NOT saying that species boundaries are ALWAYS

>absolutely precise and clear, and indeed, there isn't an absolutely
>precise boundary between Australia and ocean either - the tide goes in
>and out and it is a fuzzy boundary. Nevertheless, Australia does have
>"real" boundaries in nature outside of human imagination and
>convenience
>-- correct?
>
>To see the "real" species boundaries, you only have to imagine a world
>in which there were none. I hope you have the capacity for imagination!
>:) In such a world, every morphotype would grade imperceptibly into
>every other morphotype. Species boundaries would have to be imposed
>completely arbitrarily.
>
>I repeat a previous analogy: there are heavy people and there are light

>people, but it is not a very useful classification because of the
>continuum between them. But if all people of a certain intermediate
>weight class died out, then we could classify people usefully by
weight.
>It would not be a taxonomic classification, but it could be! Imagine a
>world with two extant species of Homo, morphologically identical except

>that one species were 30-60kg, and the other species 70-120kg as
>adults...
>
>Stephen
>
>________________________________________
>From: Richard Pyle [deepreef at bishopmuseum.org]
>Sent: Monday, 7 September 2009 9:36 a.m.
>To: Stephen Thorpe; TAXACOM at mailman.nhm.ku.edu; 'Jim Croft'
>Subject: RE: Why Australians are more real than Americans: implications

>for taxonomy!
>
> > Yes, Richard, species ARE real entities in the world! They might not

> > have existed in a world where there was an unbroken continuum
> > between diverse morphologies, but in our world there are "gaps"
> > which break the biotic realm up into species.
>
>Please... for the sake of us all... don't get me started. :-)
>
>So... if I understand you correctly... you're under the
>delusi...err....impression that "real" species boundaries exist in
>nature outside of human imagination and convenience -- correct?
>
>If so, we are operating under fundamentally different presumptions
>about the nature of biodiversity, so we will never arrive at a mutual
>understanding of what is meant by a "taxon concept circumscription"*.
>
>No sense cluttering the list again with this debate -- there are enough

>iterations of it in the Taxacom archives.
>
>Aloha,
>Rich
>
>*Note: My use of the elaborated term "taxon concept circumscription" is

>to disguish it from "species concept" (in the sense of "biological
>species concept", "phylogenetic species concept", etc.) -- which is an
>equally contentious and very-much related debate, but still quite
>different from the "species are real" debate.
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