From:    Chris Ho-Stuart
To:      All                                    Msg #67, Sep-30-93 08:12AM
Subject: Re: Man's origins (was: re: A friendly Challenge)

Organization: Uppsala University
From: cjhs@Alger.docs.uu.se (Chris Ho-Stuart)
Message-ID: 
Newsgroups: talk.origins,alt.atheism

trott@gandalf.rutgers.edu (Richard Trott) writes:

>cjhs@Alger.docs.uu.se (Chris Ho-Stuart) writes:

>>Help me out here. How is the term "pongid" defined? I checked out
>>all this stuff once as part of a debate in talk.origins, but here
>>in Sweden I don't have easy access to biological textbooks.

>>I was under the impression that "pongid" included both gorillas and
>>chimpanzees, though not orangutangs (I forget the technical term) or
>>hominids.

>According to Futuyma's _Evolutionary Biology_ text (2nd edition, 1986,
>page 510, table 1), the family Pongidae includes orangutans,
>chimpanzees, and gorillas.  Hominidae, of course, includes only
>humans.  (I am, of course, only speaking of living species.  There are,
>of course, extinct hominids.)  Hylobatidae include gibbons and siamangs.
>Cercopithecidae, which are in superfamily Cercopithecoidea, rather than
>superfamily Hominoidea which is where the others are classified, includes
>Old World monkeys.

Thanks: that is exactly what I was looking for. I was evidently
mistaken: orangutangs *are* in Pongidae.

Technically hominidae is not included within pongidae. This means that
pongidae is not monophyletic, which suggests to me that our current
taxononmic terminology is a hang over from times when humans were
thought to be so exceptionally unique that they should rate their own
family.

I think taxonomy would reflect our improved understanding of
evolutionary relationships much better if hominidae was included
within pongidae -- which would mean that there was no such thing as a
pongidae/hominidae split.

However, so be it. Now consider the evolutionary tree, given that
it is now accepted that orangutangs split from humans/chimps/gorrillas
before that part of the bush diverged into the modern species.

As it stands, we have:

             /\
            /  \
           /    \
          /      X        <--- either    X     or
         /      /|\                     / \           /\
        /      / | \                   /\  \         /  X
       /      /  |  \                 /  \  \       /  / \
      /      /   |   \
orang  gorilla chimp human
\________  ______/
         \/
      Pongidae      Hominidae

By conventions established before the above evolutionary tree was
known, the subtree Hominidae has been pruned from the Pongidae
subtree, so Pongidae is not monophyletic. Now let "X" be the most
recent common ancestor of humans and any of the modern pongidae
species.  "X" should be considered within pongidae, or else we have
the really unfortunate situation that Pongidae is merely a clipping of
leaves from the evolutionary bush, excluding the very species which
first developed those features by which Pongidae can now be identified!

I remain, of course, not-an-expert!

Feliciations -- Chris Ho-Stuart