Re: Proven facts (Re: Savanna hunters run down kudus (Re: AAT all washed up(WARNING: graphic photo)




Op 25-07-2007 23:43, in artikel
1185399831.633642.125180@xxxxxxxxxxxxxxxxxxxxxxxxxxx, Lee Olsen
<paleocity@xxxxxxxxxxx> schreef:


PAs usu.look only to the fossil & archeological evidence when they
reconstruct human evolution, but fossils are scarse & incomplete,
fragmented
pieces of bone without soft parts, frequently of uncertain relation to
living species; often, species, age & sex are unknown; sometimes the
geological age & paleo-environment are uncertain.

Liar, you made that up.

Don't be ridiuclous.

No answer, but this irrelevancy:

Says the man who thinks mountain beavers are semi-aquatic (TREE
2002:213-214). Lee-Thorp correctly thrashed tooth- wear data. So did
you when you claimed in TREE that mountain beavers ate the same type
food as capabaras,

Liar:

Liar:
Verhaegen et al. (2002:213-14):
"Tooth microwear studies indicate that
Australopithecus afarensis molar enamel had a
glossy polished surface that is typical of the molars
of capybaras Hydrochoerus hydrochaeris and
mountain-beavers Aplodontia rufa [24].
Both these semi-aquatic rodents feed mainly on riverside herbs,
grasses and the bark of young trees."

OK, my boy, I apologise, you're no liar here, but it doesn't alter the
conclusions: afarensis like capibaras & mountain beavers fed on succulent,
not dry plants. I just googled: " Mountain beaver are strict herbivores and
eat just about any type of succulent vegetation available including plants
that are often inedible to other species such as nettle, bracken fern, and
salal." Glossy appearence of enamel resembled that in capibaras & afarensis
(BTW, gorillas love nettles), IOW, afarensis did not live in dry savanna.
Whether or not we should call mountain beavers semi-aquatic (I guess not, I
probably relied on the word "beaver") is irrelevant here, but repeatingly
trying to use that as an argument (!) only shows your misinformation, lack
of logic, childish behaviour & inability to show us wrong. Keep running
after your kudu, my boy...

______

Marc Verhaegen, Pierre-François Puech and
Stephen Munro
Aquarboreal ancestors?
TRENDS in Ecology & Evolution Vol.17 No.5 May 2002
------------------------------------------------------------------------------
--

Only illiterates think a mountain beaver is semi-aquatic.
http://wdfw.wa.gov/wlm/living/mtn_beavers.htm

Since capybaras are semi-aquatic (have partially
webbed feet) and mountain beavers are terrestrial (do not have webbed
feet),
then it follows (since neither has the same diet) any similarity
between tooth wear of these two animals is purely coincidental and has
nothing what-so-ever to do
with demonstrating an animal is semi-aquatic. This makes a moot point
of the polish observed on
Australopithecus afarensis teeth in trying to make a case for it
eating "swamp herbs" ,
since terrestrial animals like the mountain beaver also have "glossy"
polish on their molars
and do not eat "swamp herbs"

There is another problem to consider, if the research on mountain
beavers is sloppy in this paper,
perhaps the tooth wear study cited is no more accurate, since one of
the authors of TREE 2002
paper is also cited for the tooth wear data [24]. A real research
paper would have cited at least three independent sources.
Citing your own work only is circular and a cheap trick.

One reason this amateur paper is in the "opinion" department of TREE,
rather than accepted as
original research, is because of the ridiculously sloppy
work demonstrated above. Who peer-reviewed this nightmare of mis-
information anyway,
a local kindergarten class?

http://www.scienceinafrica.co.za/2001/december/hominids.htm
Dr. Lee-Thorp correctly points out:
1) For instance, the giant molars of the Australopithecines suggest
that they needed to process very tough food (see figure to the right)
(Ungar, 1998). But phylogenetic history also plays a role in tooth
morphology, and adaptations are not necessarily the same as actual
behaviour. For example, Papio baboons have tooth shapes indicative of
fruit diets, but many modern baboons eat as much as 50% grass for
which they are poorly equipped. The problem is worse in animals that
are 'generalists' (ie. can eat a bit of everything) like hominids.

2) Some foods leave microscopic traces on teeth. Certain diets such as
those rich in hard fruits or grasses leave tiny distinctive damage
patterns on enamel surfaces. Based on different microwear patterns,
Fred Grine suggested that Australopithecus africanus ate a diet with
fleshy fruits and leaves, while A. robustus ate harder, more fibrous
foods (Grine, 1981). Unfortunately microwear only reflects the
consistency of foods eaten in the last few days or weeks, and many
foods, such as animal flesh, are "invisible". Scatters of stone tools
and animal bones in former living sites can provide some clues about
how food was acquired although the stone tools do not tell us much
about diet.

3) None of the hominids analysed so far ate a diet like that of the
modern chimpanzee, gorilla, or even orangutan, all of which eat nearly
100% C3 foods. This is not to say that they did not eat fruits and
leaves - they most probably did. But they also ate quantities of
actual grasses, or animals that ate the grasses, or both. Grass itself
is difficult to process and to extract the nutrients (unless one is
well-equipped to do so, like a cow), so it's difficult to visualise
how such a large ''grass" signature could occur unless the hominids
ate some animal foods. C4 -consuming invertebrate and vertebrate
animals were abundant and easily collected by hominids. Raymond Dart
was on the right track all those years ago, even if his environmental
scenario was not quite right!
The important point is that we now know that all of these hominids
were willing to eat C4 resources that are generally ignored by our
primate cousins, the chimpanzees, gorillas, and orangutans.
Chimpanzees, for instance, stick to C3 'forest' foods even when
grasses or grass-eating animals are abundant. It seems that hominids
early on became dietary generalists who broadened their diets and thus
their resource base. This may have been the seminal step in the
development of the hominid lineage. It makes sense when one considers
that global climates changed between about 4 - 1.8 millions years ago,
causing African forests to be replaced by woodlands and grasslands.





Australopithecine lifestyle

The list shows that some very early hominids, more than later
australopithecines, have been found near lacustrine molluscs (Lukeino and
Tabarin ca. 6.5 and 5 Myr BP). Ardipithecus ramidus, supposedly another
early hominid, must have lived in a wooded habitat, amid predominantly
colobine monkeys (Aramis ca. 4.5 Myr BP). Pliocene australopithecines ca.
4-3 Myr BP apparently frequently dwelt in warm and humid, more or less
closed environments (gallery forest or wooded habitat in Kanapoi, Chad,
Hadar, Makapansgat, but inconclusive for Garusi-Laetoli). Pleistocene robust
australopithecines since 2.5 Myr BP probably lived in generally dryer and
more open landscapes (grassland in Kromdraai and Konso), but their remains
lay in riverbanks, lagoons, marshes, lake-margins, near papyrus (Olduvai)
and reed (Kromdraai, Olduvai, Chesowanja).
Although ?all nine Konso A. boisei specimens were recovered among the
predominantly dry grassland fauna of KGA 10¹ (Suwa et al., 1997), this does
not mean that they lived in a savanna milieu, since ?nearby subsites were
also moist and wooded¹ (Delson, 1997). Fragmentary fossils like those of
Laetoli and Konso are often the remains of carnivore meals (Morden, 1988).
Leopards, which preyed upon australopithecines, prefer to feed in dry
circumstances and therefore drag away their prey, sometimes several hundred
meters (Brain, 1981).
The preponderance of wet environments in our list is striking, but this was
not considered to be inconsistent with a savanna view, because it was
believed that the fossil record sampled a disproportionate number of
habitats related to water (see the above citation from Shipman and Harris,
1988). To be sure, that the hominids have been discovered in humid or wet
habitats does not allow firm conclusions about how much time they spent
there, but the possibility that wetter rather than drier conditions
influenced hominid evolution can not be ignored. Therefore, paleo-ecological
data must be verified and supplemented through anatomical and especially
dental studies of the fossils.
It is generally agreed that all australopithecines have skeletal features of
bipedality. Early graciles also show clear indications of tree climbing such
as curved manual and pedal phalanges, though such features are less obvious
in the robusts.

Dental studies suggest that whereas gracile australopithecines preferred
softer fruits and vegetables, the robusts¹ diet included harder food items
(e.g. Robinson, 1954; Du Brul, 1977; Walker, 1981; Puech, 1992; Lee-Thorp et
al., 1994). Estimates of robust australopithecine bite force suggest
?low-energy food that had to be processed in great quantities¹ and food
objects ?hard and round in shape¹ (Demes & Creel, 1988). Du Brul (1977)
noticed dental isms between the robust australopithecines and the
bamboo-eating giant panda Ailuropoda melanoleuca (broad, high and heavy
cheekbones, reduced prognathism and front teeth, broad back teeth, premolar
molarisation), as opposed to gracile australopithecines, respectively
non-panda bears.

Papyrus and reed were present in the paleo-environment of the later
australopithecines (e.g. Olduvai, Chesowanja, Kromdraai), and Cyperaceae and
Gramineae are part of the diet of living African hominoids. Gorillas eat
sedges and bamboo shoots and stalks, gorillas and chimpanzees eat cane,
chimps and humans eat water lilies, and rice and other cereals are staple
food for humans. Supplementing their diet with parts of grasslike plants
might have been enabled the robusts to bridge the dry season, when fruits
and soft vegetables were scarce.

Studies of dental enamel microwear provide other details. In the early
australopithecines of Garusi-Laetoli and Hadar (A. afarensis 4-3 Myr BP),
the cheekteeth enamel has a polished surface and the microwear looks like
that of the capybara Hydrochoerus hydrochaeris and that of the mountain
beaver Aplodontia rufa (Puech et al., 1986). These animals are semi-aquatic
rodents that feed mainly on sappy marsh and riverside herbs, grasses and
bark of young trees. It has recently become clear that Western lowland
gorillas G. g. gorilla spend some time eating aquatic herbaceous vegetation
(AHV) like Hydrocharitaceae herbs and Cyperaceae sedges (Doran & McNeilage,
1997).
Comparisons of molar enamel in South African fossils show that A. robustus
ate substantially more hard food items than A. africanus (Grine & Kay,
1988). Incisal microwear suggests that A. robustus may have ingested foods
that required less extensive incisal preparation than the foods consumed by
A. africanus, such as fruits (Ungar & Grine, 1991), and ?incisors need not
be employed in the manipulation of hard objects¹ (Ungar & Grine, 1989).
The enamel of the East African robusts (Olduvai and Peninj) displays more
pits, wide parallel striations and deep recessed dentine, resembling that of
the beaver Castor fiber, that eats riverine and riverside herbs, roots of
water lilies, bark and woody plants in a temperate climate. ?Many food
plants growing in marsh land and indeed many grasses, have high
concentrations of siliceous particles known as opal phytoliths. The
consumption of such foods produces a great deal of wear, and the enamel and
dentine have a blunted appearance. Ancient Egyptians ate papyrus shoots
(Puech et al., 1983b) and we suppose that [O.H.16] did the same with swamp
margin plants¹ (Puech, 1992). Whereas the East African robusts seem to have
had aquatic plants and papyrus shoots in their diet and ate more woody
plants than the earlier australopithecines, habilis O.H.16 apparently
supplemented the AHV of the earlier australopithecines with acid fruits
(Puech, 1984). In the habilis cheekteeth, the margins of the striae have
been polished and slightly etched, resembling the microwear of the coypu
Myocastor coypus. This rodent feeds on reed, sedges, marsh plants, fruits
and molluscs in river and lake margins. It thus seems that an early
australopithecine diet of fruits (larger front teeth) and AHV (polishing)
was supplemented with unripe fruits (acid etching) in habilis, and with
woody plants in the robusts (more wear).
The suggestion of Walker (1981) that A. boisei KNM-ER 406 and 729 were
bulk-eaters of whole fruits, ?small, hard fruits with casings, pulp, seeds
and all¹, could explain the deep recessed occlusal dentine, but not the
glossy appearance of heavily polished enamel, which is more typical for
marsh plant feeders. In terrestrial grazers such as sheep, tooth wear is
faster, with a different gradient and fabric-like grooves.
These microwear data are consistent with the strontium/calcium ratios in
Swartkrans fossils (Sillen, 1992). Apart from partial carnivory (rather
unlikely with the robusts¹ dentition, see Du Brul, 1977; Walker, 1981),
Sillen provides two possible explanations for the low Sr/Ca of A. robustus:
eating leaves and shoots of forbs and woody plants (kudu diet), and eating
food derived from a wet microhabitat, for instance, from well-drained
streamside soils.
In our opinion, the coincidence of several independent lines of evidence
(paleo-milieu, dental morphology, enamel microwear, Sr/Ca ratios) leaves
little doubt that some or all australopithecines fed regularly on AHV
growing in shallow waters, much more than Western gorillas do today
(Chadwik, 1995; Doran & McNeilage, 1997). It is conceivable that hominid
bipedality first arose in the shallow waters of gallery or mangrove or swamp
forests. ?One 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 upright¹ (Stringer, 1997). That a gradual evolutionary
transition from forest to marshland is possible is illustrated by the
Western lowland gorillas that spend some time feeding on AHV, wading
bipedally, sitting and playing in marshy forest clearings (Chadwik, 1995;
Doran & McNeilage, 1997; NDR TV film, 1997).- Hide quoted text -

- Show quoted text -



.

Relevant Pages