<https://www.cambridge.org/core/journals/evolutionary-human-sciences/article/bipedal-locomotion-in-zoo-apes-revisiting-the-hylobatian-model-for-bipedal-origins/C1DC53BDC1F75F0627B9504A26388E72>
Abstract
Bipedal locomotion is a hallmark of being human.
Yet, the body form from which bipedalism evolved
remains unclear. Specifically, the positional
behavior (i.e., orthograde vs. pronograde) and the
length of the lumbar spine (i.e., long and mobile
vs. short and stiff) of the last common ancestor
(LCA) of the African great apes and humans
require further investigation. While fossil evidence
would be the most conclusive, the paucity of
hominid fossils from 5-10 million years ago makes
this field of research challenging. In their absence,
extant primate anatomy and behavior may offer
some insight into the ancestral body form from
which bipedalism could most easily evolve. Here,
we quantify the frequency of bipedalism in a large
sample (N=496) of zoo-housed hominoids and
cercopithecines. Our results show that while each
studied species of ape and monkey can move
bipedally, hylobatids are significantly more
bipedal and engage in bipedal locomotion more
frequently and for greater distances than any
other primate sampled. These data support
hypotheses of an orthograde, long-backed, and
arboreal LCA, which is consistent with hominoid
fossils from the middle-to-late Miocene. If true,
knuckle-walking evolved in parallel in Pan and
Gorilla, and the human body form, particularly
the long lower back and orthograde posture, is
conserved.
"The only animals in our sample with a
combination of an orthograde body posture and a
long lumbar region of the spine are hylobatids
and, thus, high frequencies of bipedal locomotion
in these lesser apes would align with aspects of
the hylobatian model."
"Here, we investigate the frequency of bipedalism
in a large sample of zoo-housed primates. We
posit that collecting these data on captive
primates is preferable to wild observations for
addressing our particular question given the
different forest structures of the African and Asian
rainforests, and, in this way, zoo data may serve
as a “control” for ecological differences and allow
us to focus specifically on anatomical
predispositions for bipedal locomotion."
Possibly interesting. The authors state a preference for observation of captive
primates as a control. The data was collected by sending a survey to primate caregivers at zoos. They conlcude "These lines of evidence tentatively indicate
that humans and hylobatids reflect the ancestral body form with respect to lumbar mobility and positional behavior." Do note that the genetic evidence places hylobatids further from humans than chimpanzees...
<https://www.cambridge.org/core/journals/evolutionary-human-sciences/article/bipedal-locomotion-in-zoo-apes-revisiting-the-hylobatian-model-for-bipedal-origins/C1DC53BDC1F75F0627B9504A26388E72>
Abstract
Bipedal locomotion is a hallmark of being human. Yet, the body form from which
bipedalism evolved remains unclear. Specifically, the positional behavior (i.e.,
orthograde vs. pronograde) and the length of the lumbar spine (i.e., long and mobile
vs. short and stiff) of the last common ancestor (LCA) of the African
great apes and
humans require further investigation. While fossil evidence would be the most
conclusive, the paucity of hominid fossils from 5-10 million years ago
makes this
field of research challenging. In their absence, extant primate anatomy
and behavior
may offer some insight into the ancestral body form from which bipedalism could
most easily evolve. Here, we quantify the frequency of bipedalism in a
large sample
(N=496) of zoo-housed hominoids and cercopithecines. Our results show that while
each studied species of ape and monkey can move bipedally, hylobatids are significantly more bipedal and engage in bipedal locomotion more
frequently and
for greater distances than any other primate sampled. These data support hypotheses of an orthograde, long-backed, and arboreal LCA, which is consistent
with hominoid fossils from the middle-to-late Miocene. If true, knuckle-walking
evolved in parallel in Pan and Gorilla, and the human body form, particularly the
long lower back and orthograde posture, is conserved.
"The only animals in our sample with a combination of an orthograde body posture and
a long lumbar region of the spine are hylobatids and, thus, high
frequencies of bipedal
locomotion in these lesser apes would align with aspects of the hylobatian model."
"Here, we investigate the frequency of bipedalism in a large sample of zoo-housed
primates. We posit that collecting these data on captive primates is preferable to wild
observations for addressing our particular question given the different forest structures
of the African and Asian rainforests, and, in this way, zoo data may serve as a “control”
for ecological differences and allow us to focus specifically on
anatomical predispositions
for bipedal locomotion."
They conlcude "These lines of evidence
tentatively indicate that humans and
hylobatids reflect the ancestral body form
with respect to lumbar mobility and positional
behavior." Do note that the genetic evidence
places hylobatids further from humans than
chimpanzees...
Abstract
Our results show that while each studied species
of ape and monkey can move bipedally,
hylobatids are significantly more bipedal and
engage in bipedal locomotion more frequently
and for greater distances than any other primate
sampled. These data support hypotheses of an
orthograde, long-backed, and arboreal LCA,
which is consistent with hominoid fossils from
the middle-to-late Miocene.
If true, knuckle-walking evolved in parallel in Pan
and Gorilla, and the human body form,
particularly the long lower back and orthograde
posture, is conserved.
"The only animals in our sample with a
combination of an orthograde body posture and a
long lumbar region of the spine are hylobatids
and, thus, high frequencies of bipedal locomotion
in these lesser apes would align with aspects of
the hylobatian model."
On Friday 18 March 2022 at 17:57:24 UTC, Primum Sapienti wrote:
They conlcude "These lines of evidenceHylobatids are the ancestors of all apes.
tentatively indicate that humans and
hylobatids reflect the ancestral body form
with respect to lumbar mobility and positional
behavior." Do note that the genetic evidence
places hylobatids further from humans than
chimpanzees...
The coding for hylobatid body form is
in the genes of those apes, to which
they can revert when necessary.
<https://www.cambridge.org/core/journals/evolutionary-human-sciences/article/bipedal-locomotion-in-zoo-apes-revisiting-the-hylobatian-model-for-bipedal-origins/C1DC53BDC1F75F0627B9504A26388E72>
Abstract
Our results show that while each studied speciesHylobatids are necessarily small; they rarely
of ape and monkey can move bipedally,
hylobatids are significantly more bipedal and
engage in bipedal locomotion more frequently
and for greater distances than any other primate
sampled. These data support hypotheses of an
orthograde, long-backed, and arboreal LCA,
which is consistent with hominoid fossils from
the middle-to-late Miocene.
come to the ground, and whenever they do,
they flee back to the safety of the trees as
quickly as they can. That is why they are
restricted to the high forests of SE Asia. Their
descendants (which led to gorillas and chimps)
had to be large enough to be able to transit
open ground, at least occasionally) before
they could migrate/expand to Africa.
However, larger apes have to be able to
scoot up trees. This means that their spines
have to be (relatively) shorter than those of
gibbons. They cannot afford to have flexible
waists. Their bodies have to form a solid,
rigid unit, powering strong muscles in their
trunks and upper thighs. In other words
they have to be similar to chimps, gorillas
and orangutans. When they progress on
the ground, they will do so quadrupedally.
If true, knuckle-walking evolved in parallel in PanThe long lower back and orthograde
and Gorilla, and the human body form,
particularly the long lower back and orthograde
posture, is conserved.
(upright) posture is not viable in a large
primate which needs to climb trees with
ease and speed. The only 'conservation'
that is possible is in the genes: i.e. if the
taxon needs to recover a set of ancestral
traits, it can probably reactivate the
relevant genes fairly quickly.
"The only animals in our sample with aNot unreasonable thinking, but it
combination of an orthograde body posture and a
long lumbar region of the spine are hylobatids
and, thus, high frequencies of bipedal locomotion
in these lesser apes would align with aspects of
the hylobatian model."
ignores both geography, and the fact
that hylobatids are restricted to SE Asia.
On Saturday, March 19, 2022 at 7:32:33 PM UTC-4, Paul Crowley wrote:conspecifics to food sources. Sleeping in bowl nests limited leg length but not arm size, sleeping in domeshields limited arm size but not leg size.
On Friday 18 March 2022 at 17:57:24 UTC, Primum Sapienti wrote:
They conlcude "These lines of evidenceHylobatids are the ancestors of all apes.
tentatively indicate that humans and
hylobatids reflect the ancestral body form
with respect to lumbar mobility and positional
behavior." Do note that the genetic evidence
places hylobatids further from humans than
chimpanzees...
The coding for hylobatid body form is
in the genes of those apes, to which
they can revert when necessary.
<https://www.cambridge.org/core/journals/evolutionary-human-sciences/article/bipedal-locomotion-in-zoo-apes-revisiting-the-hylobatian-model-for-bipedal-origins/C1DC53BDC1F75F0627B9504A26388E72>
Abstract
Sleep is absolutely critical to survival, a specific mode of locomotion is not. Hylobatids have long pregnancies indicating a previously larger body size (eg kiwi), perhaps between siamang and bonobo. Fleeing predators was secondary to beatingOur results show that while each studied speciesHylobatids are necessarily small; they rarely
of ape and monkey can move bipedally,
hylobatids are significantly more bipedal and
engage in bipedal locomotion more frequently
and for greater distances than any other primate
sampled. These data support hypotheses of an
orthograde, long-backed, and arboreal LCA,
which is consistent with hominoid fossils from
the middle-to-late Miocene.
come to the ground, and whenever they do,
they flee back to the safety of the trees as
quickly as they can. That is why they are
restricted to the high forests of SE Asia. Their
descendants (which led to gorillas and chimps)
had to be large enough to be able to transit
open ground, at least occasionally) before
they could migrate/expand to Africa.
However, larger apes have to be able to
scoot up trees. This means that their spines
have to be (relatively) shorter than those of
gibbons. They cannot afford to have flexible
waists. Their bodies have to form a solid,
rigid unit, powering strong muscles in their
trunks and upper thighs. In other words
they have to be similar to chimps, gorillas
and orangutans. When they progress on
the ground, they will do so quadrupedally.
If true, knuckle-walking evolved in parallel in PanThe long lower back and orthograde
and Gorilla, and the human body form,
particularly the long lower back and orthograde
posture, is conserved.
(upright) posture is not viable in a large
primate which needs to climb trees with
ease and speed. The only 'conservation'
that is possible is in the genes: i.e. if the
taxon needs to recover a set of ancestral
traits, it can probably reactivate the
relevant genes fairly quickly.
"The only animals in our sample with aNot unreasonable thinking, but it
combination of an orthograde body posture and a
long lumbar region of the spine are hylobatids
and, thus, high frequencies of bipedal locomotion
in these lesser apes would align with aspects of
the hylobatian model."
ignores both geography, and the fact
that hylobatids are restricted to SE Asia.
Sleep is absolutely critical to survival,
a specific mode of locomotion is not.
Hylobatids have long pregnancies indicating a previously larger
body size
Fleeing predators was secondary to beating conspecifics to food
sources.
Sleeping in bowl nests limited leg length but not arm
size, sleeping in domeshields limited arm size but not leg size.
On Monday 21 March 2022 at 09:44:53 UTC, DD'eDeN aka note/nickname/alas_my_loves wrote:
Sleep is absolutely critical to survival,Primates sleep in trees. Posture and
support arrangements vary, but none
have systematic problems.
a specific mode of locomotion is not.Gibbons (as such) cannot expand beyond
forests of high trees, since they are so
small, so slow and so vulnerable on the
ground.
Hylobatids have long pregnancies indicating a previously largerAn indication, but very slight and far from
body size
dispositive.
unique and extraordinarily fast mode of
locomotion in the trees.
determined the fundamentals of the
body shape of apes (centralised spines,
flat chests, loss of tails, poorly-positioned
hearts), even if some of their descendants
grew much larger, and ceased to be
capable of fast brachiation.
Fleeing predators was secondary to beating conspecifics to foodHylobatids have no predators in their
sources.
normal habitat.
outside its boundaries, that they can never
leave.
Sleeping in bowl nests limited leg length but not armBowl-nest fantasy, up there in la-la land
size, sleeping in domeshields limited arm size but not leg size.
with unicorns and floating-ape babies.
.Sleep is absolutely critical to survival,..
Primates sleep in trees. Posture and
support arrangements vary, but none
have systematic problems.
Only arboreal bowl nesting great apes have drastically shortened legs, while numerous primates scoot up trees.
Gibbons are the second fastest primate ground bipeds.
.Hylobatids have long pregnancies indicating a previously larger..
body size
An indication, but very slight and far from
dispositive.
It is typical of body/metabolism changes. Their trunks shrank while their limbs did not.
What matters to them is their.
unique and extraordinarily fast mode of
locomotion in the trees.
A derived condition.
Their ancestors were slower.
Achieving that.
determined the fundamentals of the
body shape of apes (centralised spines,
flat chests, loss of tails, poorly-positioned
hearts), even if some of their descendants
grew much larger, and ceased to be
capable of fast brachiation.
Fast brachiation is derived from slow brachiation, cf avian flight, piscine swimming speed.
On Monday 21 March 2022 at 20:07:22 UTC, DD'eDeN aka note/nickname/alas_my_loves wrote:
I've no idea which species you think.Sleep is absolutely critical to survival,..
Primates sleep in trees. Posture and
support arrangements vary, but none
have systematic problems.
Only arboreal bowl nesting great apes have drastically shortened legs, while
numerous primates scoot up trees.
have "drastically shortened legs"
no one (other than you) thinks any
species of primate has legs the
length of which are determined by
its sleeping position.
Gibbons are the second fastest primate ground bipeds.I've no idea what this means.
distances?
predators are much faster.
As for all other species, their body shape.Hylobatids have long pregnancies indicating a previously larger..
body size
An indication, but very slight and far from
dispositive.
It is typical of body/metabolism changes. Their trunks shrank while their limbs did not.
fits their niche.
while brachiating to form a ball with their
bodies, which is swung on very long arms.
What matters to them is their.
unique and extraordinarily fast mode of
locomotion in the trees.
A derived condition.
An evolved faculty
Their ancestors were slower.
They couldn't have been faster.
ancestors were monkeys that insofar
as they could brachiate at all, were
much slower at it.
Not in any worthwhile sense.Achieving that.
determined the fundamentals of the
body shape of apes (centralised spines,
flat chests, loss of tails, poorly-positioned
hearts), even if some of their descendants
grew much larger, and ceased to be
capable of fast brachiation.
Fast brachiation is derived from slow brachiation, cf avian flight, piscine swimming speed.
every small monkey can brachiate --
but not with speed or comfort. One
population in one restricted locality
~ 24 ma specialised in doing so -- for
many generations -- and became the
ancestors of all gibbons and all apes.
Presumably it did not happen often
because such potential proto-gibbons
became less good at other abilities
(fast vertical climbing?) that were
important within and between
monkey species.
.Only arboreal bowl nesting great apes have drastically shortened legs, while..
numerous primates scoot up trees.
I've no idea which species you think
have "drastically shortened legs"
All great apes which sleep in arboreal bowl nests, as stated repeatedly, succinctly, correctly.
but
no one (other than you) thinks any
species of primate has legs the
length of which are determined by
its sleeping position.
All fauna sleep. Sleeping in a bowl nest directly influences body form, long legs
don't fit.
Gibbons are the second fastest primate ground bipeds...
I've no idea what this means.
More fallacy. Only humans are faster.
In any case, all likely ground predators are much faster..
Step away from the savannah, Gilligan.
Blah blah.
The can fold up their legs..
while brachiating to form a ball with their
bodies, which is swung on very long arms.
Once more, that is modern hylobatids in fast brachiation.
Their.
ancestors were monkeys that insofar
as they could brachiate at all, were
much slower at it.
Duh.
..Fast brachiation is derived from slow brachiation, cf avian flight, piscine >>> swimming speed.Not in any worthwhile sense.
Blah blah.
Almost every small monkey can brachiate --.
Wrong.
but not with speed or comfort. One.
population in one restricted locality
~ 24 ma specialised in doing so -- for
many generations -- and became the
ancestors of all gibbons and all apes.
Vertical posture while climbing, walking and slow brachiating.
Presumably it did not happen often
because such potential proto-gibbons
became less good at other abilities
(fast vertical climbing?) that were
important within and between
monkey species.
Why does parsimony terrify some people?
On Wednesday 23 March 2022 at 04:18:25 UTC, DD'eDeN aka note/nickname/alas_my_loves wrote:
If this is a common rule (for all fauna) you.Only arboreal bowl nesting great apes have drastically shortened legs, while..
numerous primates scoot up trees.
I've no idea which species you think
have "drastically shortened legs"
All great apes which sleep in arboreal bowl nests, as stated repeatedly, succinctly, correctly.
will, of course, be able to quote studies
around the topic.
but
no one (other than you) thinks any
species of primate has legs the
length of which are determined by
its sleeping position.
All fauna sleep. Sleeping in a bowl nest directly influences body form, long legsIf a species needs long legs -- or long
don't fit.
arms -- for any reason, it's not going to
be bound by its sleeping arrangements.
It will alter them long before there's
any change in anatomy.
Gibbons are the second fastest primate ground bipeds...
I've no idea what this means.
More fallacy. Only humans are faster.Quadrupedal chimps are much faster than
humans on the ground. The same applies
to most monkeys, e.g. baboons. (I'm
assuming that your humans are not in
cars or helicopters.)
The context was the restriction of gibbonsIn any case, all likely ground predators are much faster..
Step away from the savannah, Gilligan.
to SE Asia, and the likelihood that they
could have spread to Europe/Africa.
There were far too many areas where
the gibbons would never have had high
canopies, and they could not have lived
in (nor traversed) open ground -- beyond
a few metres.
Blah blah.
So articulate
Gibbons have been around for ~23 MyrThe can fold up their legs..
while brachiating to form a ball with their
bodies, which is swung on very long arms.
Once more, that is modern hylobatids in fast brachiation.
-- doing fast brachiation.
Their.
ancestors were monkeys that insofar
as they could brachiate at all, were
much slower at it.
Duh.
So articulate
..Fast brachiation is derived from slow brachiation, cf avian flight, piscineNot in any worthwhile sense.
swimming speed.
Blah blah.
So articulate
Almost every small monkey can brachiate --.
Wrong.
So articulate
"brachiate": to progress by swinging from hold to hold by the arms
An animal with two arms and gripping
hands can brachiate. To do it as well as
a gibbon, you need small size, long arms,
etc., etc.
Primates often have a vertical posturebut not with speed or comfort. One.
population in one restricted locality
~ 24 ma specialised in doing so -- for
many generations -- and became the
ancestors of all gibbons and all apes.
Vertical posture while climbing, walking and slow brachiating.
when climbing, in any brachiating they
do, and sometimes when walking.
None of this can lead (or has led) to
the drastic change in morphology that
we see in gibbons and all other apes.
Presumably it did not happen often
because such potential proto-gibbons
became less good at other abilities
(fast vertical climbing?) that were
important within and between
monkey species.
Why does parsimony terrify some people?You're confusing parsimony with vacuity.
If, for example, you remove predators
from your evolutionary scenario, you can
greatly simplify the problems that your
taxon supposedly encountered. This is
the strategy adopted by standard PA
(not that they ever set out solutions).
It's also common among the Watery Ape
theorists. It's also yours.
Another favourite device is to ignore
every significant morphological change
in the taxon, and claim "It was just a
change in the genes" or "it just happened"
or "it can be ascribed to their everyday
activities" , and in your bizarre scenario,
to the way they wanted to sleep.
That's not parsimony. It's mindlessness.
Quasi-hylobatids, ancestors of all living hominoids
Quasi-hylobatids, ancestors of all living hominoids..
My dear boy, hylobatids are as derived as gorillas, orangs, humans & chimps.
Op maandag 21 maart 2022 om 13:10:52 UTC+1 schreef DD'eDeN aka note/nickname/alas_my_loves:
Quasi-hylobatids, ancestors of all living hominoids:-DDD
My dear boy, hylobatids are as derived as gorillas, orangs, humans & chimps.
On Friday 25 March 2022 at 07:56:58 UTC, littor...@gmail.com wrote:
Derived from what?Quasi-hylobatids, ancestors of all living hominoids..
My dear boy, hylobatids are as derived as gorillas, orangs, humans & chimps.
The standard chest shape for terrestrial
animals -- including cercopithecoids -- is
"narrow and deep", with the heart located
at the lowest possible point when all four
limbs are touching the ground. Whereas
in apes the chest shape is "broad and
shallow".
See Figure 7 (about half-way through) in: https://onlinelibrary.wiley.com/doi/10.1111/joa.12454#
When, why and how did the hominoid
chest evolve?
On Friday 25 March 2022 at 07:56:58 UTC, littor...@gmail.com wrote:
Derived from what?Quasi-hylobatids, ancestors of all living hominoids..
My dear boy, hylobatids are as derived as gorillas, orangs, humans & chimps.
The standard chest shape for terrestrial
animals -- including cercopithecoids -- is
"narrow and deep", with the heart located
at the lowest possible point when all four
limbs are touching the ground. Whereas
in apes the chest shape is "broad and
shallow".
See Figure 7 (about half-way through) in: https://onlinelibrary.wiley.com/doi/10.1111/joa.12454#
When, why and how did the hominoid
chest evolve?
The context demonstrates that figure 7 shows the divergence after the monkey-ape split,
but the common ancestor had a skeletal frame midway
between them, very typical of nonspecialized arboreal-terrestrial taxa.
On Friday 25 March 2022 at 12:48:10 UTC, DD'eDeN aka note/nickname/alas_my_loves wrote:
The context demonstrates that figure 7 shows the divergence after the monkey-ape split,Which of the following is more parsimonious?
A) A taxon split, into X and Y.
Both X and Y changed their forms drastically
finding new roles (or allied sets of niches) in the
forest -- abandoning their former niches.
B) A taxon split, into X and Y.
X was the old taxon, and stayed pretty much the
same, occupying the same set of long-established
niches; Y was new, and radically different -- as
the result of finding and occupying a wholly new
niche (or set of niches)
but the common ancestor had a skeletal frame midwayA childish conception of evolution. It's like
between them, very typical of nonspecialized arboreal-terrestrial taxa.
claiming that hominins and chimps had an
ancestor that was equally adept (and equally
clumsy) at both bipedal and quadrupedal
running & walking.
The scapulae MUST be either at the side
of the chest (as with monkeys and nearly
all mammals) or on the back (hominoids).
They can't be hovering at some midway
position.
On Friday, March 25, 2022 at 8:04:36 PM UTC-4, Paul Crowley wrote:
On Friday 25 March 2022 at 12:48:10 UTC, DD'eDeN aka note/nickname/alas_my_loves wrote:
The context demonstrates that figure 7 shows the divergence after the monkey-ape split,Which of the following is more parsimonious?
A) A taxon split, into X and Y.More likely their niches abandoned them due to climate change or other externality.
Both X and Y changed their forms drastically
finding new roles (or allied sets of niches) in the
forest -- abandoning their former niches.
See scapula position in tarsiers, lemurs, tupaia vs baboons.
B) A taxon split, into X and Y.Less likely unless the diverging populations were separated in 2 different locations (or as in Homo, a new ground shelter evolved).
X was the old taxon, and stayed pretty much the
same, occupying the same set of long-established
niches; Y was new, and radically different -- as
the result of finding and occupying a wholly new
niche (or set of niches)
Nope, entirely wrong. Upright bipedal habit allows scapula to shift, palmigrade pronograde quadrupedalism forbids shift, ape knucklewalking allows the shift.but the common ancestor had a skeletal frame midwayA childish conception of evolution. It's like
between them, very typical of nonspecialized arboreal-terrestrial taxa.
claiming that hominins and chimps had an
ancestor that was equally adept (and equally
clumsy) at both bipedal and quadrupedal
running & walking.
The scapulae MUST be either at the sideThey certainly did at the LCA monkey/ape split, in association with arboreal bipedalism and slow brachiation initiation.
of the chest (as with monkeys and nearly
all mammals) or on the back (hominoids).
They can't be hovering at some midway
position.
I was seeking if birds had scapula more like monkeys-dogs on side of thorax, or apes-humans on back.whale meat being dark, but not sure if related. Is whale blubber white or black fat?)
https://chickenandchicksinfo.com/do-chickens-have-shoulders/
I guess there is a parallel between white vs brown fat and white meat (chicken breast light because rarely flies) and dark meat (pheasant breast dark because strong flier), mitochondria higher in dark tissue. (Reminds me of O2-bearing myoglobin in
Chicken shoulder meat is called 'oyster', a delicacy in Japan.
Avian scapulae are of medullary bone, store calcium for eggs, not hollow for flight like wing bones.
Proto-birds used WAIR to climb trees, Wing Assisted Incline Running, where the arms didn't need to grasp branches to climb. I witnessed a duck doing this last month.
On Friday, March 25, 2022 at 10:46:58 PM UTC-4, DD'eDeN aka note/nickname/alas_my_loves wrote:
On Friday, March 25, 2022 at 8:04:36 PM UTC-4, Paul Crowley wrote:
On Friday 25 March 2022 at 12:48:10 UTC, DD'eDeN aka note/nickname/alas_my_loves wrote:
The context demonstrates that figure 7 shows the divergence after the monkey-ape split,Which of the following is more parsimonious?
A) A taxon split, into X and Y.More likely their niches abandoned them due to climate change or other externality.
Both X and Y changed their forms drastically
finding new roles (or allied sets of niches) in the
forest -- abandoning their former niches.
See scapula position in tarsiers, lemurs, tupaia vs baboons.
B) A taxon split, into X and Y.Less likely unless the diverging populations were separated in 2 different locations (or as in Homo, a new ground shelter evolved).
X was the old taxon, and stayed pretty much the
same, occupying the same set of long-established
niches; Y was new, and radically different -- as
the result of finding and occupying a wholly new
niche (or set of niches)
Nope, entirely wrong. Upright bipedal habit allows scapula to shift, palmigrade pronograde quadrupedalism forbids shift, ape knucklewalking allows the shift.but the common ancestor had a skeletal frame midwayA childish conception of evolution. It's like
between them, very typical of nonspecialized arboreal-terrestrial taxa.
claiming that hominins and chimps had an
ancestor that was equally adept (and equally
clumsy) at both bipedal and quadrupedal
running & walking.
The scapulae MUST be either at the sideThey certainly did at the LCA monkey/ape split, in association with arboreal bipedalism and slow brachiation initiation.
of the chest (as with monkeys and nearly
all mammals) or on the back (hominoids).
They can't be hovering at some midway
position.
whale meat being dark, but not sure if related. Is whale blubber white or black fat?)I was seeking if birds had scapula more like monkeys-dogs on side of thorax, or apes-humans on back.
https://chickenandchicksinfo.com/do-chickens-have-shoulders/
I guess there is a parallel between white vs brown fat and white meat (chicken breast light because rarely flies) and dark meat (pheasant breast dark because strong flier), mitochondria higher in dark tissue. (Reminds me of O2-bearing myoglobin in
traditional function of supplying thrust in the direction of travel and lift to support body weight, the wings of ground birds act to enhance hindlimb function(Dial, 2003). Specifically,the WAIR hypothesis suggests that during a substantial portion ofChicken shoulder meat is called 'oyster', a delicacy in Japan.
Avian scapulae are of medullary bone, store calcium for eggs, not hollow for flight like wing bones.
Proto-birds used WAIR to climb trees, Wing Assisted Incline Running, where the arms didn't need to grasp branches to climb. I witnessed a duck doing this last month.A recently described behavior, wing-assisted incline running (WAIR), documents the use of wings to enable bipedal ground birds to `run' up vertical surfaces(Dial, 2003). This challenging and unexpected activity requires that in contrast to the
WAIR has been documented in the juveniles and adults of four species of ground birds, and involves the simultaneous use of flapping wings and running legs to ascend steep inclines (Dial,2003). WAIR permits extant ground birds, and may have permittedproto-birds, to use their hindlimbs more effectively in retreat to elevated refuges (cliffs, boulders, trees, etc.). It has been hypothesized that as these animals negotiate precipitous inclines (>60°), they alter their normal flight stroke to develop
Note: Proto-birds had claws, primates nails.
Note: Monkeys have quadrupedal dog-like thorax, but lemurs & tarsiers never run quadrupedally. Monkey quadrupedalism is novel, as is ape bipedalism and derived knucklewalking quadrupedalism.
A recently described behavior, wing-assisted incline running (WAIR), documents the use of wings to enable bipedal ground birds to `run' up vertical surfaces(Dial, 2003). This challenging and unexpected activity requires that in contrast to thetraditional function of supplying thrust in the direction of travel and lift to support body weight, the wings of ground birds act to enhance hindlimb function(Dial, 2003).
DD'eDeN aka note/nickname/alas_my_loves wrote:traditional function of supplying thrust in the direction of travel and lift to support body weight, the wings of ground birds act to enhance hindlimb function(Dial, 2003).
A recently described behavior, wing-assisted incline running (WAIR), documents the use of wings to enable bipedal ground birds to `run' up vertical surfaces(Dial, 2003). This challenging and unexpected activity requires that in contrast to the
They're all secondarily flightless!
Are you actually trying to pretend that wings evolved as a way for flightless birds
to climb because flying was an evolutionary failure?
They're secondarily flightless. They evolved from fully flying ancestors.
-- --
https://jtem.tumblr.com/post/679763679359680512
Which of the following is more parsimonious?.
..
A) A taxon split, into X and Y.
Both X and Y changed their forms drastically
finding new roles (or allied sets of niches) in the
forest -- abandoning their former niches.
More likely their niches abandoned them due to climate change or other externality.
B) A taxon split, into X and Y..
X was the old taxon, and stayed pretty much the
same, occupying the same set of long-established
niches; Y was new, and radically different -- as
the result of finding and occupying a wholly new
niche (or set of niches)
Less likely unless the diverging populations were separated in
2 different locations (or as in Homo, a new ground shelter evolved).
See scapula position in tarsiers, lemurs, tupaia vs baboons.
..but the common ancestor had a skeletal frame midwayA childish conception of evolution. It's like
between them, very typical of nonspecialized arboreal-terrestrial taxa. >>..
claiming that hominins and chimps had an
ancestor that was equally adept (and equally
clumsy) at both bipedal and quadrupedal
running & walking.
Nope, entirely wrong. Upright bipedal habit allows scapula to shift,
palmigrade pronograde quadrupedalism forbids shift, ape knucklewalking
allows the shift.
On Saturday 26 March 2022 at 02:46:58 UTC, DD'eDeN aka note/nickname/alas_my_loves wrote:Genetically.
Essentially nonsense. Gibbons have been aroundWhich of the following is more parsimonious?.
..
A) A taxon split, into X and Y.
Both X and Y changed their forms drastically
finding new roles (or allied sets of niches) in the
forest -- abandoning their former niches.
More likely their niches abandoned them due to climate change or other externality.
for 20+ Myr. Large apes: chimps/gorillas/orangs
for 10+
Rivers change courses. Climate changes niches.Separation for a few 100 K years (or evenB) A taxon split, into X and Y..
X was the old taxon, and stayed pretty much the
same, occupying the same set of long-established
niches; Y was new, and radically different -- as
the result of finding and occupying a wholly new
niche (or set of niches)
Less likely unless the diverging populations were separated in
2 different locations (or as in Homo, a new ground shelter evolved).
a million) is common. See Bonobos --
presumably the Congo river changed its
course. In this case both populations
continued (more-or-less) in their ancient
niches.
Really? Bats?See scapula position in tarsiers, lemurs, tupaia vs baboons.You'd need to study live animals to see
where their scapulae are located. but
these animals are so small, that their
location is almost irrelevant.
weigh around 100 grams -- half an apple orMice have bigger brains than blue whales proportionately.
two medium eggs. Tupaia are only slightly
larger. These are tiny, nearly mouse-sized.
Size matters. Muscle power and bone
strength scale more than proportionately.
That's highly relevant when a taxon withYey mice mostly stay the same size and shape.
a new body form comes into existence.
Smaller animals can afford much more
plasticity.
~5 kg. The very first ones were probably
less than half that.
could brachiate to some extent --
better than one double its size with the
same anatomy.
favoured more of that activity, the small
monkey could readily specialise in it.
Firstly, we're talking about chests,..but the common ancestor had a skeletal frame midwayA childish conception of evolution. It's like
between them, very typical of nonspecialized arboreal-terrestrial taxa. >>..
claiming that hominins and chimps had an
ancestor that was equally adept (and equally
clumsy) at both bipedal and quadrupedal
running & walking.
Nope, entirely wrong. Upright bipedal habit allows scapula to shift,
and the bones and ligaments around
them. Bipedalism is primarily about
legs and the pelvis.
about evolutionary developments
before 20 ma when there were no
bipeds.
If you were right, you should be able to
refer to numerous primate (& other?)
species (> ~2kg) which have scapula in
the gibbon/hominoid position -- on
their backs. Let's see the list.
Hominoid chests became shallow and
broad so that the spinal column could
be central. That was to enable fast
brachiation.
with shallow, broad chests.
palmigrade pronograde quadrupedalism forbids shift, ape knucklewalking allows the shift.Nonsense on every level. K/walking is
quadrupedal, with a horizontal trunk.
..More likely their niches abandoned them due to climate change or other externality....
Essentially nonsense. Gibbons have been around
for 20+ Myr. Large apes: chimps/gorillas/orangs
for 10+
Genetically.
Separation for a few 100 K years (or even..
a million) is common. See Bonobos --
presumably the Congo river changed its
course. In this case both populations
continued (more-or-less) in their ancient
niches.
Rivers change courses. Climate changes niches.
..See scapula position in tarsiers, lemurs, tupaia vs baboons...
You'd need to study live animals to see
where their scapulae are located. but
these animals are so small, that their
location is almost irrelevant.
Really? Bats?
Tarsiers..
weigh around 100 grams -- half an apple or
two medium eggs. Tupaia are only slightly
larger. These are tiny, nearly mouse-sized.
Size matters. Muscle power and bone
strength scale more than proportionately.
Mice have bigger brains than blue whales proportionately.
..
That's highly relevant when a taxon with..
a new body form comes into existence.
Smaller animals can afford much more
plasticity.
Yey mice mostly stay the same size and shape.
Modern small gibbons weigh..
~5 kg. The very first ones were probably
less than half that.
??
A monkey of that size could brachiate to some extent --..
??
much..
better than one double its size with the
same anatomy.
?!
If the circumstances..
favoured more of that activity, the small
monkey could readily specialise in it.
How many do? None.
....It's like..
claiming that hominins and chimps had an
ancestor that was equally adept (and equally
clumsy) at both bipedal and quadrupedal
running & walking.
Nope, entirely wrong. Upright bipedal habit allows scapula to shift,
Firstly, we're talking about chests,
Then why'd you bring up scapulae?
and the bones and ligaments around
them.
Bipedalism is primarily about..
legs and the pelvis.
??
If you were right, you should be able to..
refer to numerous primate (& other?)
species (> ~2kg) which have scapula in
the gibbon/hominoid position -- on
their backs. Let's see the list.
What drugs are you on?
Hominoid chests became shallow and..
broad so that the spinal column could
be central. That was to enable fast
brachiation.
Wrong. First upright climbing and slow brachiation.
Find other mammals >~2kg with shallow, broad chests...
Why?
..palmigrade pronograde quadrupedalism forbids shift, ape knucklewalking..
allows the shift.
Nonsense on every level. K/walking is
quadrupedal, with a horizontal trunk.
You snipped too much. What are you responding to?
On Sunday 27 March 2022 at 03:14:08 UTC+1, DD'eDeN aka note/nickname/alas_my_loves wrote:
..More likely their niches abandoned them due to climate change or other externality....
Essentially nonsense. Gibbons have been around
for 20+ Myr. Large apes: chimps/gorillas/orangs
for 10+
Genetically.
Do you think each taxon now occupies quite
different niches from (say) 10 ma, while
retaining their genetic inheritance?
The climate has been extremely variableSeparation for a few 100 K years (or even..
a million) is common. See Bonobos --
presumably the Congo river changed its
course. In this case both populations
continued (more-or-less) in their ancient
niches.
Rivers change courses. Climate changes niches.
for the past 1-1.5 myr --- with ice-ages and
interglacials. Yet there seems to be no
change whatever in either the chimp or
the bonobo niches.
..See scapula position in tarsiers, lemurs, tupaia vs baboons...
You'd need to study live animals to see
where their scapulae are located. but
these animals are so small, that their
location is almost irrelevant.
Really? Bats?
The physical demands placed by flight
on bats and birds are so great that each
have to be 'precisely engineered'. That
does not apply to much more generalist
ground-living (or tree-living) mammals.
Mice species come and go with greatTarsiers..
weigh around 100 grams -- half an apple or
two medium eggs. Tupaia are only slightly
larger. These are tiny, nearly mouse-sized.
Size matters. Muscle power and bone
strength scale more than proportionately.
Mice have bigger brains than blue whales proportionately.
..
That's highly relevant when a taxon with..
a new body form comes into existence.
Smaller animals can afford much more
plasticity.
Yey mice mostly stay the same size and shape.
rapidity, but the body form remains
much the same. I am talking about NEW
body forms -- particularly that of gibbons/
hominoids.
Modern small gibbons weigh..
~5 kg. The very first ones were probably
less than half that.
??
As I said, we need a lot of plasticity
here. You don't get that in big, slow-
reproducing animals.
A monkey of that size could brachiate to some extent --..
??
What's the problem? If there's a long
thin horizontal branch with fruit at the
end of it, the small proto-gibbon
monkey brachiates along it and gets
the fruit, faster and more effectively
than a non-brachiating monkey.
much..
better than one double its size with the
same anatomy.
?!
One double the size has much greater
problems acquiring such skills. Ever
notice how small Olympic gymnasts
usually are?
If the circumstances..
favoured more of that activity, the small
monkey could readily specialise in it.
How many do? None.
Modern gibbons are already quite
small. They leave not enough room
for even smaller ones,
See the next line -- the bones and ligaments....It's like..
claiming that hominins and chimps had an
ancestor that was equally adept (and equally
clumsy) at both bipedal and quadrupedal
running & walking.
Nope, entirely wrong. Upright bipedal habit allows scapula to shift,
Firstly, we're talking about chests,
Then why'd you bring up scapulae?
around the chest (i.e. incl. scapulae).
and the bones and ligaments around
them.
Bipedalism is primarily about..
legs and the pelvis.
??
What's your problem? It would not
be too difficult to portray a bipedal
baboon, with the standard chest
(narrow and deep) but with almost-
human legs and pelvises
What's your problem? You claim thatIf you were right, you should be able to..
refer to numerous primate (& other?)
species (> ~2kg) which have scapula in
the gibbon/hominoid position -- on
their backs. Let's see the list.
What drugs are you on?
scapulae can readily move from the
side (as in monkeys, etc.) to the back
(as in gibbons/hominoids). So why
doesn't it happen? Why can't you
quote examples?
I know that this is your 'opinion'. GodHominoid chests became shallow and..
broad so that the spinal column could
be central. That was to enable fast
brachiation.
Wrong. First upright climbing and slow brachiation.
alone knows how you arrived at it. It's
based on nothing. It's contrary to all
available evidence.
Find other mammals >~2kg with shallow, broad chests...
Why?
You claim that they exist -- or should exist.
All you need are animals (incl primates)
that climb trees (when upright) and do
a bit of brachiation.
You claim that palmigrade pronograde..palmigrade pronograde quadrupedalism forbids shift, ape knucklewalking >>> allows the shift...
Nonsense on every level. K/walking is
quadrupedal, with a horizontal trunk.
You snipped too much. What are you responding to?
quadrupedalism forbids the shifting of
the scapulae from the side to the back.
Whereas ape quadrupedalism allows it.
Tarsiers & lemurs are proto-primates
which unlike monkeys did not become dog-like running quadrupeds.
They tend to posture upright, with heads swiveling on a vertical axis in orthograde fashion. This was the ancestral form of primates, not the quadrupedal baboon form.
Apes moved scapulae slightly rearward, monkeys slightly sideward.
Ape ancestors never had baboon-like ancestors with deep narrow chests,
but did have the generalized mammalian arboreal form, slightly deeper
and narrower chests than modern apes.
They had inherited the upright cranial orientation from proto-primates,
and this induced the habits of upright vertical climbing, upright bipedal branch walking, upright slow brachiation while monkeys went more to ground-based pronograde quadrupedalism (though all primates tend to
sit upright).
Most of what you said above does not reflect my opinion.
On Monday 28 March 2022 at 10:13:04 UTC+1, DD'eDeN aka note/nickname/alas_my_loves wrote:
Tarsiers & lemurs are proto-primatesYou've no good basis for that assertion.
Tarsiers are so different from the bulk
of primates (being nocturnally active
for a start) that they're most unlikely
to be representative of anything early.
Lemurs came from tiny numbers which
rafted from Africa ~40 ma. Africa
probably had a great variety of primates
(and proto-primate hang-ons) at the
time.
which unlike monkeys did not become dog-like running quadrupeds.Primates generally live in trees. Dog-
running quadrupeds (i.e. baboons)
seem to have evolved around 2 ma
when there were relatively few
diurnal predators around (hominins
had got rid of most).
They tend to posture upright, with heads swiveling on a vertical axis in orthograde fashion. This was the ancestral form of primates, not the quadrupedal baboon form.True, but they still had the ancient
dominant mammalian body-form,
like that of terrestrial animals: narrow
and deep chests. A powerful reason
is needed to change something so
fundamental and their ancestors
never one.
Apes moved scapulae slightly rearward, monkeys slightly sideward.This is nonsense. Your hypothetical
midway position is impossible for an
animal that has to cope with gravity.
No extant animal >~2kg has scapulae
in that position
Ape ancestors never had baboon-like ancestors with deep narrow chests,All primates had ancestors with deep
narrow chests -- that's the default form
with the heart in its optimal position.
Apes changed from that -- for powerful
reasons that also involved a centralised
spine, the loss of tails and an aversion
to bodies of water.
but did have the generalized mammalian arboreal form, slightly deeperFantasy. You've no evidence for this.
and narrower chests than modern apes.
They had inherited the upright cranial orientation from proto-primates,Monkeys (& not apes) also sleep upright
and this induced the habits of upright vertical climbing, upright bipedal branch walking, upright slow brachiation while monkeys went more to ground-based pronograde quadrupedalism (though all primates tend to
sit upright).
-- usually huddled together along a
branch. That's 12 hours of the 24 being
vertical, apart from their daytime
climbing, eating, sitting and grooming.
All this 'verticality' should have the effect
you postulate on their anatomy -- on
their spines, chests and locations of their
scapulae. But it doesn't. Drastic changes
in anatomy only come about as the result
of intense selective pressure.
Vertical climbing, walking on branches
and slow brachiation do not provide the
selective pressure you imagine.
(I don't think you grasp 'selection' at all,
and you attribute all change to genes, or
randomness, or some such.)
Most of what you said above does not reflect my opinion.It was mostly questions that you
can't answer
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