savanna nonsense (Re: Only idiots believe that humans evolved snorkel noses to run after gazelles
From: Marc Verhaegen (fa204466_at_skynet.be)
Date: 01/31/05
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Date: Mon, 31 Jan 2005 20:03:16 +0100
"Kaz" <KazVorpal@yahoo.com> wrote in message
news:aTsLd.3463$4u.448@fe07.lga...
>>>> Our diving skills & breath hold etc. suggest our ancestors once dived
>>>> parttime for seafood.
>>> Yes, there are plenty of graceful, even intelligent, purely land mammals
>>> out there, and almost none of them can handle themselves underwater the
>>> way a human can. But...and do remember that I consider the AAH to be
>>> reasonably likely...to be fair, SOME of these traits could have been
>>> acquired /after/ we became hominids.
>> What else?? What had you thought?? AAT = littoral phase = Pleistocene
>> Homo "suddenly" spreading along coasts to SE.Asia, N.Africa, W.Africa...
>> (="Out-of-Africa 1"). AAT has nothing to do with hominids (=
>> Pan-Homo-Gorilla, as opposed to pongids = Pongo), only with Homo!
> Well, then wouldn't we be calling it the aquatic hominid theory?
Aquatic Homo, you mean? Everybody incl.Elaine agrees "aq.ape" is a bit
misleading. But since everybody knows the term "AAT", I think we should keep
it. I propose:
1) aquarboreal ape theory (on hominoids),
2) AAT sensu stricto amphibious ancestors theory (on Homo).
> If we're discussing our ancestors becoming upright, then we're talking
> hominoids, not hominids. Becoming upright is what the humanocentric
> sciences has defined as what /makes/ us hominids instead of apes.
It's a ridiculous definition for several reasons:
- our locomotion didn't evolve at once,
- apiths were only partly bipedal: they were arm-hanging & possibly parttime
KWing,
- hominids=Pan+Homo+Gorilla, as opposed to pongids=Pongo,
- that apiths are closer relatives of Homo than of Pan or Gorilla is not
proven at all (and in fact, wrong IMO).
If we want to understand human locomotion, we have to analyse it into its
elements & then compare to other animals, eg, on 2 legs (kangaroo, birds,
some dinos...), straight legs (unlike ostrich), very long legs (ostrich,
flamingo, unlike penguin), straight body (head-body-legs, penguin, unlike
ostrich, flamingo), plantigrady (bear, unlike ostrich), striding (not
hopping), erect trunk (vert.climbers, unlike flamingo), etc. Then it's
clear that we once had vertically climbing ancestors (we knew this already:
early apes), and once swimming ancestors (streamline), and that our
adaptation to cursorialism is very incomplete (eg, plantigrady).
> If we're talking about homo something, not proto-homo something, then it's
> AHT.
Yes.
>>> Perhaps the reason we can hold our breaths and such is that we lived
>>> semi-aquatically as we spread throughout the world along shorelines,
>>> millions of years after we became human.
>> ?? "millions of years after we be became human"?? That will be within
>> the next million years?? :-)
> I was using "human" to differentiate hominids from apes. Probably a bit
> sloppy of me, but from context it should have been evident.
Not evident at all. IMO we became littoral (soon?) after the H/P split c 5
Ma in some coastal forest: P stayed in the forests (still aquarboreal at
first), whereas H left the forests & developed diving etc.: c 1.8 Ma (due to
sea level changes at the time?) they turn up in places as far as Algeria
(Ain Hanech) & Java (Mojokerto). IOW, they spread along shorelines shortly
after we became Homo, but a few millions of years before we became human
(=sapiens).
>>> Of course that wouldn't disprove the AAH, since we still became
>>> hairless, sweaty, and erect way back when, which is still better
>>> explained by a semi-aquatic lifestyle than any other scenario I've seen
>>> proposed. But it's just that we can't date breath-holding, or apparently
>>> long noses, and other stuff like that.
>> Well, external noses are first seen for sure in H.erectus (and possibly
>> in H.rudolfensis, but not in apes, apiths or habilis, see papers of
>> Kennedy).
> Yes, but in Asian erectus.
IIRC (no time to re-read Kennedy), the paper said rudolfensis (Africa) might
also have had an ext.nose. All Homo (Afr., Eur., Asia) had an ext.nose
AFAWCS (as opposed to apes, apiths, monkeys except Nasalis).
> Or is there serious reconstruction of african erectus that is accurate
> enough to differentiate between an Asian-type nose and an African-type
> nose?
Asian- & African-type noses are recent (after the sapiens LCA c 150 ka). I
don't see the relevance for non-sapiens relatives 1-2 Ma.
>>> It could be that we've had multiple periods of semi-aquatic evolutionary
>>> pressure, including (for h.s.cro-magnon) 80k to 20k years ago when
>>> spreading around the planet. With other beach-combing periods for our
>>> other two or three globe-trotting homo sapiens ancestors.
>> Yes. What we can reconstruct today (schematically): - early
>> hominoids c 18-12 Ma: aquarboreal (coastal forests) dispersal along
>> Tethys coasts & islands (eg, Oreopith),
> I still think that the whole thing of deciding that, since we're obviously
> great apes, we're going to lend THEM /our/ name, instead of calling
> ourselves great apes, is as confusing as it is anthropocentric. I mean,
> hominoid is only one letter different than hominid, and to this day I
> misread them when someone switches from talking about one to talking about
> the other.
Well, if we want to discuss hominoid evolution, these terms are extremely
important. Hominoids=hylobatids+pongids+hominids. Hylobatids=gibbons.
Pongids=orang. Hominids=chimps+humans+gorillas.
>> - early hominids c 10-5 Ma: idem, probably more wading (cf. Sahelanthr,
>> Orrorin, Ardip... in wooded swamps...), - early Homo c 2-1 Ma:
>> littoral phase (AAT) along (sub)tropical coasts, beach-combing, diving...
>> (coconuts, shellfish...), - early sapiens c 100 ka: less confined to
>> waterside, modern anatomy.
> Overall, this sounds reasonable to me... but if we're talking about such a
> long span, this actually allows for an even milder semi-aquatic trend. In
> other words, that's enough time for the aquatic influence on selection to
> be a lower percentage of a given ancestor's lifestyle and still have a
> greater effect overall. Actually, it also allows for plenty of
> ancestors living in savanna and plains, too.
?? There are 0 indications for savanna-dwelling ancestors once. 0. We are
diametrically different from savanna dwelling mammals, eg, no keen
olfaction, slow running, water+sodium-wasting thermo-regulation, high nees
of iodium, poly-unsaturated fatty acids, fat, very-large-brained,
plantigrade etc.etc. The savanna theory is the most ridiculous theory I've
ever heard, comparable to the "land bridges" between Africa & S.America in
geology before the theory of plate tectonics. Kaz, try to get rid of these
savanna prejudices as fast as you can. This whole idea goes back to a
misinterpreation of Dart at the time, and all the believers followed their
guru...
"The savanna hypothesis of human evolution was strongly promoted by
Professor Dart in 1924 after the discovery of the skull of Taung in South
Africa's treeless grasslands. He wrote (1925): 'South Africa, by providing a
vast open country with occasional wooded belts and a relatively scarcity of
water, together with a fierce and bitter mammalian competition, furnished a
laboratory such as was essential to this penultimate phase of human
evolution.' And: 'It will appear to many a remarkable fact that an
ultra-simian and pre-human stock should be discovered, in the first place,
at this extreme southern point in Africa, and, secondly, in Bechuanaland,
for one does not associate with the present fringe of the Kalahari desert an
environment favourable to higher primate life. It is generally believed by
geologists (vide A. W. Rogers, "Post-Cretaceous Climates of South Africa,"
African Journal of Science, vol. xix., 1922) that the climate has fluctuated
within exceedingly narrow limits in this country since Cretaceous times.'
While we now known that the South African climate did change since the time
of Taung (Partridge, 1985), Dart was thus convinced that the present and the
ancient environment did not differ significantly and that the Taung child
had lived in such open grasslands. Dart only got recognition a few decades
later. Piltdown Man (rather big brain and big teeth) was unmasked as a fraud
and anthropologists accepted the Taung fossil (small brain, small teeth) as
a more likely link between apes (small brain, big teeth) and humans (big
brain, small teeth). However, they not only accepted Dart's view on Taung's
affinity, but also his view on Taung's lifestyle in a dry and open country.
While many anthropologists today no longer automatically follow the savanna
hypothesis (e.g. Tobias, 1995; Wood, 1996), the idea remains unquestioned in
most popular books."
> It's not like all beneficial traits have to occur over the span of all
> ancestors. Some could be living in deserts, others in rivers and on
> coastlines, and the key traits simply be spreading from the more aquatic
> ones.
Theoretically perhaps, but no ape lives in dry milieus. Homo was no
exception: we need lots of water. Again: there's no evidence whatsoever
that any ape/hominid ever lived in dry savanna.
> Did you catch where I was asking what, if any, evidence there is for a
> plains/savanna solution to our traits, and the sole evidence they could
> come up with was that A. Africanus ate grass?
A.africanus didn't eat grass (dry grasses leave a completely different kind
of micro-wear on the molar enamel), but IMO apiths regularly ate parts of
payrus, bamboo, sedges, reeds... (Graminineae).
--Marc
- Next message: Dar Habel: "Re: An interesting parallel. . . . . ."
- Previous message: Roger Bagula: "Re: Big fat brain (Homo floresiensis)"
- In reply to: Kaz: "Re: Only idiots believe that humans evolved snorkel noses to run after gazelles"
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