Re: Hominid Diet Examined

"Rich Travsky" <" traRvEsky"@hotmMOVEail.com> "answered" in message
news:4301742D.81249601@xxxxxxxxxxxxxxxxxx
> Marc Verhaegen wrote:

> > Thank you very much, Travsky. This again beautifully confirms our views
on apith diets.

As usual, an irrelevant & wrong answer from Travsky:

> You mean OTHERS' views. You do no real work of your own.

I mean OUR, my boy.
Marc Verhaegen & Pierre-François Puech 2000.
P-F.Puech was one of the first (remember the Franco-American Hadar
expeditions in the 70s?? ring a bell??) to investigate afarensis enamel
microscopically.
Okidoki? got it?

> > From a paper with prof.Puech (one of the very first to investigate
afarensis
> > enamel electromicroscopically, see refs below):
> >
> > "Hominid Lifestyle and Diet Reconsidered: Paleo-Environmental and
> > Comparative Data"
> > > > Musée de l'Homme à Paris, BP 191, 30012 Nîmes 4, France
> > Human Evolution 15: 151-162
> > (the whole paper can be found at
> > http://allserv.rug.ac.be/~mvaneech/Verhaegen.html )
> > ... Dental studies suggest that whereas gracile australopithecines
preferred
> > softer fruits and vegetables, the robusts' 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 quantities' and food
> > objects 'hard and round in shape' (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 objects' (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 plants' (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 all', 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 robusts' 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 upright' (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).
> >
> > :-)
> >
> > Marc Verhaegen
> >
> > http://www.onelist.com/community/AAT
> >
> > _______
> >
> > "Rich Travsky" <traRvEsky@xxxxxxxxxxxxxxx> wrote in message
> > news:42F39C78.2AFB1864@xxxxxxxxxxxxxxxxxx
> > > Sez it's supposed to be in the Aug 4th Nature, but nothing on line
yet...
> > >
> > >
> > > http://live.psu.edu/story/12922
> > >
> > > University Park, Pa. -- A Penn State researcher is part of the team
that
> > > developed techniques that have generated insights into dietary
> > divergences
> > > between some of our human ancestors, allowing scientists to better
> > > understand the evolutionary path that led to the modern-day diets
that
> > > humans consume.
> > >
> > > "Our new techniques are allowing us to get beyond simple dichotomies
and
> > > helping us understand the processes by which dietary evolution is
> > > working," said Peter Ungar, professor of anthropology at the
University
> > > of Arkansas.
> > >
> > > Ungar and Robert Scott, postdoctoral fellow at the University of
> > Arkansas,
> > > with colleagues at the Worcester Polytechnic Institute, State
University
> > > of New York at Stony Brook, Johns Hopkins University School of
Medicine
> > > and Penn State, report their findings in the August 4 issue of the
> > journal
> > > Nature.
> > >
> > > The researchers, including Alan Walker, Evan Pugh professor of
biological
> > > anthropology and biology at Penn State, investigated microscopic wear
on
> > > the teeth of two species of ancient hominims -- Australopithecus
> > africanus,
> > > which lived between 3.3 million and 2.3 million years ago, and
> > Paranthropus
> > > robustus, which lived between 2 million and 1.5 million years ago.
The
> > pits
> > > and scratches found on the teeth offer a visual history of the type
of
> > food
> > > consumed by the tooth's owner. Pits indicate a diet of hard, brittle
> > foods,
> > > like nuts and seeds, while scratches imply a diet of tough foods,
like
> > > leaves and possibly meat.
> > >
> > > Traditional examinations of these ancient teeth -- counting pits and
> > lines
> > > on a black and white electron micrograph image -- suggested that A.
> > > africanus ate tough foods and P. robustus dined on hard, brittle
fare.
> > > However, the researchers used a new technique developed by Ungar and
his
> > > colleagues that combines engineering software, scale-sensitive
fractal
> > > analysis and a scanning confocal microscope to create a reproducible
> > texture
> > > analysis for teeth -- and the analysis tells a more complete story.
The
> > > researchers looked at both roughness, or complexity, and
directionality
> > in
> > > the teeth they examined.
> > >
> > > "Since food objects interact with teeth, we have different kinds of
> > > complexity in different diets. Directionality also correlates with
diet,"
> > > Scott said. Hard foods like nuts and seeds tend to lead to more
complex
> > tooth
> > > profiles, while tough foods like leaves lead to more scratches, which
> > > corresponds with directionality.
> > > ...
> > > The analysis showed that the two species had significant amounts of
> > overlap in
> > > their diets and that while P. robustus had more complexity in its
tooth
> > wear,
> > > indicating that it ate more hard and brittle foods than A. africanus,
it
> > ate
> > > tough foods as well.
> > >
> > > The researchers believe that this indicates that the species
frequently
> > ate the
> > > same types of foods, but that in times of scarcity or seasonal
changes,
> > P.
> > > robustus changed its diet to include foods that differed from those
of A.
> > > africanus.
> > >
> > > "The difference in their evolution in terms of diet is not driven by
> > their
> > > preferences, but by scarcity," Ungar said. "It gives you a whole new
way
> > of
> > > thinking about dietary adaptation."
> > > ...
> > >
> > >
> > > scarcity...


.

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    ... the robusts' diet included harder food items ... > Gramineae are part of the diet of living African hominoids. ... Incisal microwear suggests that A. robustus may have ingested foods ... bark and woody plants in a temperate climate. ...
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  • Re: Hominid Diet Examined
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