Re: What were the habitats of early hominids?




Op 23-07-2007 04:48, in artikel
1185158915.919581.133300@xxxxxxxxxxxxxxxxxxxxxxxxxxx, Lee Olsen
<paleocity@xxxxxxxxxxx> schreef:

On Jul 22, 3:21 pm, Marc Verhaegen <m_verhae...@xxxxxxxxx> wrote:

Same old rubbish.

Now for some facts:

Aquatic Ape (non)Theory: Comments on a Recent Guest Lecture
by
Cameron M. Smith
PhD, Department of Archaeology

Who is that??
And what has archeology to do with human evolution??
Instead of this uninformed blabla, why don't you just inform a little bit on
what famous serious PAs today have to say on the savanna fantasies:


Tobias 1995 ³We were all profoundly and unutterably wrong! ? All the
former savannah supporters (including myself) must now swallow our earlier
words ?²
Wood 1996 ³the ?savannah¹ hypothesis of human origins, in which the
cooling begat the savannah and the savannah begat humanity, is now
discredited²
Stringer 1997 ³One of the strong points about the aquatic theory is in
explaining the origin of bipedality. If our ancestors did go into the water,
that would forced them to walk upright ?²
Tobias 1998 ³?Bamford identified fossil vines or lianas of Dichapetalum
in the same Member 4: such vines hang from forest trees and would not be
expected in open savannah. The team at Makapansgat found floral and faunal
evidence that the layers containing Australopithecus reflected forest or
forest margin conditions. From Hadar, in Ethiopia, where ?Lucy¹ was found,
and from Aramis in Ethiopia, where Tim White¹s team found Ardipithecus
ramidus ? well-wooded and even forested conditions were inferred from the
fauna accompanying the hominid fossils. All the fossil evidence adds up to
the small-brained, bipedal hominids of four to 2.5 Ma having lived in a
woodland or forest niche, not savannah.² ³? if ever our earliest ancestors
were savannah dwellers, we must have been the worst, the most profligate
urinators there²
Stringer 2001 ³In the past I have agreed that we lack plausible models
for the origins of bipedalism and have agreed that wading in water can
facilitate bipedal locomotion (as observed in other normally quadrupedal
primates). I have never said that this must have been the forcing mechanism
in hominids, but I do consider it plausible. As for coastal colonisation, I
argued in my Nature News & Views last year that this was an event in the
late Pleistocene that may have facilitated the spread of modern humans.²
Wrangham 2005 ³Here I follow the conventional assumption that hominins
began in the savanna.² ³? the composition of the Okavango as a network of
islands could favor the evolution of bipedalism. For those who envisage
bipedalism as facilitated by the need to traverse or exploit aquatic
environments, an inland delta that generates low islands termitogenically or
hydrodynamically offers rich scenarios.²
Alemseged 2006 ³I believe we should just put the savannah theory aside.
I think they basically became biped while they were living in a wooded,
covered environment ?²

_______


If you were among the unfortunate crowd who spent a good amount of
time listening to visiting lecturer Elaine Morgan recently,
regarding the 'Aquatic Ape Theory', be advised of the following
points.
1. Aquatic Ape Theory has been scientifically reviewed, and, despite
what was presented at this lecture, it has been found to be severely
wanting. AAT is not a 'credible alternative theory'; it is what is
known as a post-hoc accommodative argument. Strictly speaking AAT does
not really have a coherent body of theory, only a few disassociated
(non)explanations for a few biological characteristics of the genus
Homo. People should be aware that AAT is NOT 'mainstream' or 'a viable
alternative' as claimed at the lecture.
2. AAT is poorly regarded because it is a poor explanatory device. It
is poorly regarded because it has been examined and found to be
invalid. It is not poorly regarded because of some scientific cover-up
or paranoia. It is not poorly regarded because scientists cannot
accept change. Scientific knowledge does change, all the time, and it
has been pointed out that science is the worst place to try to hide
anything because fraud will be exposed through experiment. AAT is
simply a theory that has been evaluated (and ditched) by most serious
anthropologists.
3. The presentation on 14 October is an embarrassment to Simon Fraser
University, and the sponsoring hosts. How this pop/crypto/science
'theory' was given equal billing with real research efforts is beyond
me. The fact that the 'theory' was included in a series of lectures
dealing with darwinian processes (The Institute of Humanities' 'Old
Minds and Bodies in New Worlds: A Darwinian Perspective on Our Past,
Present and Future' lectures) is a travesty, as AAT crumbles when
examined for internal darwinian logic. Unfortunately, having the
speaker lecture on AAT was akin to having SFU sponsor Erich von
Daniken to speak about spaceship depictions in Maya tombs.
Here's a point to consider when evaluating AAT. I did not learn this
point from some academic overlord with an anti-AAT agenda; I learned
it while trying to avoid becoming crocodile food in Africa. When I
spent several months with a team at Lake Turkana, Kenya, investigating
some of the most important early hominid sites in the world, one of
our overriding concerns -- while swimming, bathing, or catching fish
with a net -- was to watch out for crocodiles in the shallows. A croc
can be on you, crush your legs in its jaws, and drag you under to
drown before you have time to screech for help.
The fact that crocodiles co-existed in time and space with early
hominids is a colossal blow to AAT, which does not explain what
advantages early humans would have gained by spending time in
crocodile-populated waters; an environment where they could not make
fires, throw stones or sticks, use other tools, or have any hope
whatever of escaping the most common predator. A troop of early
hominids wading in a lakeshore or swampy forest would best be
described as a crocodile banquet. The cute, feel-good images of babies
swimming freely in a pool, shown in the AAT video, have nothing to do
with the real situation of predator avoidance in Africa. Ask the
Dasenich or Turkana people who live around Lake Turkana: only visiting
maniacs swim in that lake.
There's much else to say, but I have a 650-word limit. Please keep in
mind, the 'savanna hypothesis' has indeed been largely abandoned, but
that does NOT validate AAT a priori. Neither is AAT validated because
of the common sentiment that 'it is someone's opinion, and everyone is
entitled to an opinion'. Opinion is not the same thing as scientific
theory.
The damage of this lecture was to those who came to the lecture
expecting, and possibly believing, that AAT was a viable body of
theory. It is not, and it does not deserve that label.
Cheers,
Cameron M. Smith







Op 22-07-2007 20:08, in artikel
j2Noi.29561$C96.1...@xxxxxxxxxxxxxxxxxxxxxxxxxx, claudiusd...@xxxxxxxxxxxxx
<claudiusd...@xxxxxxxxxxxxx> schreef:

Early hominid evolution took place at localities that are treed within
a greater habitat characterized by treelessness, a severe dry season,
migrational herbivores, and larger predators.
Ridiculous:
Uh, . . . er. What? Be specific.

+- everything in it: most early hominids (Samburupith, Sahelanthr, Orrorin,
apiths) are found in/near forest swamps: curved phalanges + bipedal features
suggest wading-climbing. Probably, later hominids (robusts apiths) lived in
more open milieus, but they didn't follow migratory herbivores, of course.
Other later hominids (Homo) apparently were waterside & even show
adaptations for slow diving (= very open, no trees at all...).

Nature 325:305-306, 1987
Origin of hominid bipedalism
Sinclair et al. (1) believe that human bipedalism arose in scavenging
hominid ancestors that had to carry their children while following
migrating
savanna ungulates but this seems highly improbable.
There was no empty niche of migrating scavengers to be occupied by hominid
ancestors.
Yes. I'm the one that informed you of this.

Ah?? You?? And you are...?? Claudius??
I thought I wrote it 20 years ago... :-D

Not only vultures, but aso canid, felid and hyaenid carnivores
were much better preadapted for such a niche. They possessed sharp beaks
or
long canine teeth and did not need to carry stones for cutting carcasses.
Agreed. There is nothing about hominids that can be explained by
scavenging. It's an inane notion.

Yes, but later Homo populations probably scavenged now & then: M.Gutierrez
cs.2001 "Exploitation d¹un grand cétacé au Paléolithique ancien: le site de
Dungo V à Baia Farta (Benguela, Angola)" CRAS 332:357-362: ... almost
complete skeleton of a large whale Balaenoptera sp was found closely
associated with 57 Paleolithic artefacts near Baia Farta ...

Moreover, the bipedal way of locomotion - whether fast of slow - is
inefficient and costly (2,3).
Uh . . . no. It is efficient in comparison to the ape quadrupedalism.

In that case, all apes or even primates would have run on 2 legs. I don't
think bipedalism in se is less efficient than quadrupedalism (ostrich,
kangaroo...), but beginning bipedal cursorialism as in humans of course is
(max.speed over short distances only 36 km/hr).





And
I agree that it is relatively inefficient in comparison to other quadrupedal
species. So only an idiot (Lee Olson and Jason Eshleman) would argue that
this was a migrational adaptation. The resulting diminutive and
slight-shouldered apiths would have been completely vulnerable to the large
predators in treeless habitat. (They, undoubtedly, used [needed] trees to
escape the frequent visits from these predators.)
Another argument against the migrating hypothesis in particular and the
savannah theory of human evolution in general is that it is highly
unlikely
that hominid ancestors ever lived in the savannas. Man is the opposite of
a
savanna inhabitant. Humans lack sun-reflecting fur (4) but have
thermo-insulative subcutaneous fat layers, which are never seen in savanna
mammals. We have a water- and sodium-wasting cooling system of abundant
sweat glands, totally unfit for a dry environment (5).
No duh. This is so obvious it isn't even worth discussing.
Our maximal urine
concentration is much too low for a savanna-dwelling mammal (6). We need
much more water than other primates, and have to drink more often than
savanna inhabitants, yet we cannot drink large quantities at a time (7-8).
The fossils of our hominid ancestors or relatives are always found in
water-rich environments.
Again, all of this is so obvious it's hardly worth mentioning. Obviously
hominids resided at locations at which they had proximity to fresh water
year round--most notably during the dry season.

We must make the distinction between apiths & Homo.
AFAIK, apiths lived always near freshwater.
For Homo, "always" is less certain (more indications of salt water once, at
least parttime).

It is difficult to understand why most anthropologists keep believing in
the
savanna theory (possibly because it goes back to Darwin), or why so many
anthropologists keep trying to seek the most improbable reasons for
bipedalism, while they should know there are much better explanations
(9-11).
Well, they say they don't believe in the savanna theory any more.

Some do, some don't.

Beyond that they seem to have no theory at all. Just like yourself.

Never heard of it? It's called evolutionary theory: inheritance,
recombinations, mutations, selection, opportunistic adaptations,
parallelisms & convergences, gradualism etc. Humans are animals like all
other animals. No exceptions: simply analyse our behaviour, anatomy,
physiology into elementary details (recombination) & compare these to other
animals. Not difficult: eg, human locomotion (striding not hopping, bi- not
quadrupedal, broad-bodied, long-legged, stretched-legged not BHBK, planti-
not digitigrade, ortho- rather than pronograde, aligned, etc.), although now
walking-running, clearly shows rudiments of vertical climbing, of swimming,
& probably of wading. Same can be done with our speech elements, eg, my
paper with S.Munro 2004 "Possible preadaptations to speech - a preliminary
comparative approach" Hum.Evol.19:53-70 suggests we had/have singing-,
breath-hold-, airway-closure- & suction-adaptations. Same can be done with
our food gathering system system: hard-object-feeding, omnivory, dependence
on sodium, iodine & poly-unsat.fatty acids, tool use & handiness... Etc.

Marc, eventually you will have to come to grips with the fact that you don't
have a hypothesis. You seem to have gotten the habitat kind of right. But
you don't have any selective factors in your hypothesis that explains any of
the adaptations that are so plainly apparent in our species.

Selective factors = the milieus where our ancestors lived after the H/P
split c.5 Ma: littoral forest, seaside/deltas, riversides, dry land...





.

Relevant Pages

  • Re: What were the habitats of early hominids?
    ... Comments on a Recent Guest Lecture ... AAT is not a 'credible alternative theory'; ... hominids is a colossal blow to AAT, ... savanna ungulates but this seems highly improbable. ...
    (sci.anthropology.paleo)
  • Re: Bone density in mustelids
    ... A'pith data is wrong savanna hypothesis. ... AAT is not about apes, but about humans: ... hominids is a colossal blow to AAT, ...
    (sci.anthropology.paleo)
  • Re: Bone density in mustelids
    ... A'pith data, wrong savanna hypothesis. ... AAT is not about apes, but about humans: ... it while trying to avoid becoming crocodile food in Africa. ... hominids is a colossal blow to AAT, ...
    (sci.anthropology.paleo)
  • Re: Hs living in caves three miles from the sea (Re:Hslittoral164 ka
    ... A'pith data, wrong savanna hypothesis. ... AAT is not about apes, but about humans: ... hominids is a colossal blow to AAT, ...
    (sci.anthropology.paleo)
  • Re: Barbeque on the savanna
    ... A'pith data, wrong savanna hypothesis. ... AAT is not about apes, but about humans: ... hominids is a colossal blow to AAT, ...
    (sci.anthropology.paleo)
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