From Newsgroup: sci.anthropology.paleo



https://royalsocietypublishing.org/doi/epdf/10.1098/rsos.241879
Bite force production and theorigin of Homo


The divergence of Homo from gracile
australopiths has been described as a trend
of decreasing dentognathic size and
robusticity, precipitated by stone tool use
and/or a shift to softer foods, including meat.
Yet, mechanical evidence supporting this
narrative is sparse, and isotopic and
archaeological data have led to the suggestion
that a shift away from a gracile
australopith-like diet would not have
occurred in the most basal members of Homo but
rather only with the appearance of Homo
erectus, implying that the origin of our genus
is not rooted in dietary change. Here, we
provide mechanical evidence that Homo habilis
exhibits an australopith-like pattern of facial
strain during biting but, unlike most
australopiths, was not suited for a diet that
required forceful processing by the molar teeth.
Homo habilis was at elevated risk of distractive
jaw joint forces during those bites,
constraining muscle recruitment so as to avoid
generating uncomfortable/dangerous levels of
tension in the joint. Modern humans have similar
limitations. This suggests that selection on
skeletal traits favouring forceful postcanine
processing was relaxed by the earliest stages
in the evolution of our genus, implying that
dietary or food processing changes played an
important role in the emergence of Homo.


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From Newsgroup: sci.anthropology.paleo

On 4/28/25 12:57 AM, Primum Sapienti wrote:

The divergence of Homo from gracile
australopiths

There's a massive assumption. Not only is it NOT assumed
to be a fact by everyone but it wasn't too long ago when
the mainstream insisted it was WRONG.

has been described as a trend
of decreasing dentognathic size and
robusticity,

Well that explains Denisovans with their dainty teeth and...

wait. no. forget I said anything...

Yet, mechanical evidence supporting this
narrative is sparse, and isotopic and
archaeological data have led to the suggestion
that a shift away from a gracile
australopith-like diet would not have
occurred in the most basal members of Homo but
rather only with the appearance of Homo
erectus

So how do you explain the tools?

What about the "Cut marks" evidence?

, implying that the origin of our genus
is not rooted in dietary change.

One MASSIVE problem here, apart from insisting upon our
origins in australopiths when that's mere speculation,
is that there's no model ever conceived where a species
is going to split & coincide in the exact same place at
the exact same time.

Speciation would occur ELSEWHERE: "Isolation is the
engine of evolution."

A POPULATION is isolated, allowed to adapt without genetic
influence from the parent species, and eventually there's
a speciation "event" and now we have two species. AFTER
THAT and only FOLLOWING THAT might the new species spread,
eventually encroaching the environment of the parent species.

Google: Founder Effect.

Google: Punctuated Equilibrium

So even if you've got to pretend that australopiths are our
ancestors, that it is a fact, you can't find habilis and
australopiths in the same place until AFTER they split, AFTER
they were two different species, and habilis could encroach
on the habitat of the australopiths.

But it's dumb.

This idea that Homo arose from australopiths is dumb.









Here, we

provide mechanical evidence that Homo habilis
exhibits an australopith-like pattern of facial
strain during biting but, unlike most
australopiths, was not suited for a diet that
required forceful processing by the molar teeth.
Homo habilis was at elevated risk of distractive
jaw joint forces during those bites,
constraining muscle recruitment so as to avoid
generating uncomfortable/dangerous levels of
tension in the joint. Modern humans have similar
limitations. This suggests that selection on
skeletal traits favouring forceful postcanine
processing was relaxed by the earliest stages
in the evolution of our genus, implying that
dietary or food processing changes played an
important role in the emergence of Homo.

--
https://jtem.tumblr.com/tagged/The%20Book%20of%20JTEM/page/5
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