Science and Technology news... :: View topic - H.erectus got part of his food in shallow water

Marc Verhaegen · Guest

Sink or swim?
Bone density as a mechanism for buoyancy control in early cetaceans
Noel-Marie Gray, Kimberly Kainec, Sandra Madar, Lucas Tomko & Scott Wolfe
Anat Rec 290:638-653, 2007

Previous analyses have shown that secondarily aquatic tetrapods, including
whales, exhibit osteological adaptations to life in water as part of their
complex buoyancy control systems. These structural specializations of bone
span hyperostosis through osteoporosis. The past 15 years of paleontological
effort has provided an unprecedented opportunity to examine the osteological
transformation of whales as they make their transition to an obligate
aquatic lifestyle over a 10-million-year period. It is hypothesized that
whales manifest their osteological specialization in the same manner as
extant semiaquatic and fully aquatic mammals. This study presents and
analysis of the microstructural features of bone in early and late archaic
cetaceans, and in a comparative sample of modern terrestrial, semiaquatic,
and aquatic mammals. Bone histology was examined from the ribs of 10
fossilized individuals representing five early cetacean families, including
Pakicetidae, Ambulocetidae, Protocetidae, Remintonocetidae, and
Basilosauridae. Comparisons were then made with rib histology from nine
genera of extant mammals including: Odocoileus (deer), Bos (cow), Equus
(horse), Canis (dog), Lutra (river otter), Enhydra (sea otter), Choeropsis
(pygmy hippo), Trichechus (sea cow), and Delphinus (dolphin). Results show
that the transition from terrestrial, to semiaquatic, to obligate aquatic
locomotion in archaeocetes involved a radical shift in bone function
achieved by means of profound changes at the microstructural level. A
surprising finding was that microstructural change predates gross anatomical
shift in archaeocetes associated with swimming. Histological analysis shows
that high bone density is an aquatic specialization that provides static
buoyancy control (ballast) for animals living in shallow water, while low
bone density is associated with dynamic buoyancy control for animals living
in deep water. Thus, there was a shift from the typical terrestrial form, to
osteopetrosis and pachyosteosclerosis, and then to osteoporosis in the first
quarter of cetacean evolutionary history.

Rick Wagler · Guest

"Marc Verhaegen" <m_verhaegen@skynet.be> wrote in message
news:C49C75D8.1301F%m_verhaegen@skynet.be...
[quote]Sink or swim?
Bone density as a mechanism for buoyancy control in early cetaceans
Noel-Marie Gray, Kimberly Kainec, Sandra Madar, Lucas Tomko & Scott Wolfe
Anat Rec 290:638-653, 2007

Previous analyses have shown that secondarily aquatic tetrapods, including
whales, exhibit osteological adaptations to life in water as part of their
complex buoyancy control systems. These structural specializations of bone
span hyperostosis through osteoporosis. The past 15 years of
paleontological
effort has provided an unprecedented opportunity to examine the
osteological
transformation of whales as they make their transition to an obligate
aquatic lifestyle over a 10-million-year period. It is hypothesized that
whales manifest their osteological specialization in the same manner as
extant semiaquatic and fully aquatic mammals. This study presents and
analysis of the microstructural features of bone in early and late archaic
cetaceans, and in a comparative sample of modern terrestrial, semiaquatic,
and aquatic mammals. Bone histology was examined from the ribs of 10
fossilized individuals representing five early cetacean families,
including
Pakicetidae, Ambulocetidae, Protocetidae, Remintonocetidae, and
Basilosauridae. Comparisons were then made with rib histology from nine
genera of extant mammals including: Odocoileus (deer), Bos (cow), Equus
(horse), Canis (dog), Lutra (river otter), Enhydra (sea otter), Choeropsis
(pygmy hippo), Trichechus (sea cow), and Delphinus (dolphin). Results show
that the transition from terrestrial, to semiaquatic, to obligate aquatic
locomotion in archaeocetes involved a radical shift in bone function
achieved by means of profound changes at the microstructural level. A
surprising finding was that microstructural change predates gross
anatomical
shift in archaeocetes associated with swimming. Histological analysis
shows
that high bone density is an aquatic specialization that provides static
buoyancy control (ballast) for animals living in shallow water, while low
bone density is associated with dynamic buoyancy control for animals
living
in deep water. Thus, there was a shift from the typical terrestrial form,
to
osteopetrosis and pachyosteosclerosis, and then to osteoporosis in the
first
quarter of cetacean evolutionary history.

Interesting abstract. Where>s the part about H erectus?[/quote]

Rick Wagler

Rich Travsky · Guest

Rick Wagler wrote:
[quote]
"Marc Verhaegen" <m_verhaegen@skynet.be> wrote in message
news:C49C75D8.1301F%m_verhaegen@skynet.be...
Sink or swim?
Bone density as a mechanism for buoyancy control in early cetaceans
Noel-Marie Gray, Kimberly Kainec, Sandra Madar, Lucas Tomko & Scott Wolfe
Anat Rec 290:638-653, 2007

Previous analyses have shown that secondarily aquatic tetrapods, including
whales, exhibit osteological adaptations to life in water as part of their
complex buoyancy control systems. These structural specializations of bone
span hyperostosis through osteoporosis. The past 15 years of
paleontological
effort has provided an unprecedented opportunity to examine the
osteological
transformation of whales as they make their transition to an obligate
aquatic lifestyle over a 10-million-year period. It is hypothesized that
whales manifest their osteological specialization in the same manner as
extant semiaquatic and fully aquatic mammals. This study presents and
analysis of the microstructural features of bone in early and late archaic
cetaceans, and in a comparative sample of modern terrestrial, semiaquatic,
and aquatic mammals. Bone histology was examined from the ribs of 10
fossilized individuals representing five early cetacean families,
including
Pakicetidae, Ambulocetidae, Protocetidae, Remintonocetidae, and
Basilosauridae. Comparisons were then made with rib histology from nine
genera of extant mammals including: Odocoileus (deer), Bos (cow), Equus
(horse), Canis (dog), Lutra (river otter), Enhydra (sea otter), Choeropsis
(pygmy hippo), Trichechus (sea cow), and Delphinus (dolphin). Results show
that the transition from terrestrial, to semiaquatic, to obligate aquatic
locomotion in archaeocetes involved a radical shift in bone function
achieved by means of profound changes at the microstructural level. A
surprising finding was that microstructural change predates gross
anatomical
shift in archaeocetes associated with swimming. Histological analysis
shows
that high bone density is an aquatic specialization that provides static
buoyancy control (ballast) for animals living in shallow water, while low
bone density is associated with dynamic buoyancy control for animals
living
in deep water. Thus, there was a shift from the typical terrestrial form,
to
osteopetrosis and pachyosteosclerosis, and then to osteoporosis in the
first
quarter of cetacean evolutionary history.

Interesting abstract. Where>s the part about H erectus?
[/quote]
Links to html and pdf versions of the paper are here:

http://www3.interscience.wiley.com/journal/114265636/abstract?CRETRY=1&SRETRY=0

Absolutely zero mention of erectus.

But that was easily guessed.

Marc Verhaegen · Guest

Savanna Fool now denies H.erectus had high bone density...

Op 11-07-2008 07:26, in artikel 4876EF11.B5C72226@hotmMOVEail.com, Rich
Travsky <traRvEsky@hotmMOVEail.com> schreef:

[quote]Rick Wagler wrote:

"Marc Verhaegen" <m_verhaegen@skynet.be> wrote in message
news:C49C75D8.1301F%m_verhaegen@skynet.be...
Sink or swim?
Bone density as a mechanism for buoyancy control in early cetaceans
Noel-Marie Gray, Kimberly Kainec, Sandra Madar, Lucas Tomko & Scott Wolfe
Anat Rec 290:638-653, 2007

Previous analyses have shown that secondarily aquatic tetrapods, including
whales, exhibit osteological adaptations to life in water as part of their
complex buoyancy control systems. These structural specializations of bone
span hyperostosis through osteoporosis. The past 15 years of
paleontological
effort has provided an unprecedented opportunity to examine the
osteological
transformation of whales as they make their transition to an obligate
aquatic lifestyle over a 10-million-year period. It is hypothesized that
whales manifest their osteological specialization in the same manner as
extant semiaquatic and fully aquatic mammals. This study presents and
analysis of the microstructural features of bone in early and late archaic
cetaceans, and in a comparative sample of modern terrestrial, semiaquatic,
and aquatic mammals. Bone histology was examined from the ribs of 10
fossilized individuals representing five early cetacean families,
including
Pakicetidae, Ambulocetidae, Protocetidae, Remintonocetidae, and
Basilosauridae. Comparisons were then made with rib histology from nine
genera of extant mammals including: Odocoileus (deer), Bos (cow), Equus
(horse), Canis (dog), Lutra (river otter), Enhydra (sea otter), Choeropsis
(pygmy hippo), Trichechus (sea cow), and Delphinus (dolphin). Results show
that the transition from terrestrial, to semiaquatic, to obligate aquatic
locomotion in archaeocetes involved a radical shift in bone function
achieved by means of profound changes at the microstructural level. A
surprising finding was that microstructural change predates gross
anatomical
shift in archaeocetes associated with swimming. Histological analysis
shows
that high bone density is an aquatic specialization that provides static
buoyancy control (ballast) for animals living in shallow water, while low
bone density is associated with dynamic buoyancy control for animals
living
in deep water. Thus, there was a shift from the typical terrestrial form,
to
osteopetrosis and pachyosteosclerosis, and then to osteoporosis in the
first
quarter of cetacean evolutionary history.

Interesting abstract. Where>s the part about H erectus?

Links to html and pdf versions of the paper are here:

http://www3.interscience.wiley.com/journal/114265636/abstract?CRETRY=1&SRETRY=[/quote]
0
[quote]
Absolutely zero mention of erectus.

But that was easily guessed.[/quote]

Rick Wagler · Guest

"Marc Verhaegen" <m_verhaegen@skynet.be> wrote in message
news:C49CD7FA.13028%m_verhaegen@skynet.be...
[quote]Savanna Fool now denies H.erectus had high bone density...

The logic circuits in your brain shorting out again? We merely[/quote]
wondered why the title of your post had nothing to do with
the abstract you posted. Why bone density in whales should
be directly comparable to alleged bone density in erectus is
for you to find out. Instead you just assume it. That>s why
you are dismissed out of hand.

Rick Wagler

Marc Verhaegen · Guest

[quote]Savanna Fool now denies H.erectus had high bone density...
[/quote]
SF:
[quote]The logic circuits in your brain shorting out again? We merely
wondered why the title of your post had nothing to do with
the abstract you posted. Why bone density in whales should
be directly comparable to alleged bone density in erectus is
for you to find out. Instead you just assume it.
[/quote]
My little boy, why don>t you inform before opening your big mouth. That>s
why you are dismissed out of hand.

george · Guest

On Jul 11, 7:27 pm, Marc Verhaegen <m_verhae...@skynet.be> wrote:
[quote]Savanna Fool now denies H.erectus had high bone density...

[/quote]
For density let us use you as an extreme example .
Thank you..

Marc Verhaegen · Guest

Op 12-07-2008 05:29, in artikel
6a8abb39-5b91-4997-aaee-bb47a152678e@d77g2000hsb.googlegroups.com, george
<gblack@hnpl.net> schreef:

[quote]On Jul 11, 7:27 pm, Marc Verhaegen <m_verhae...@skynet.be> wrote:
Savanna Fool now denies H.erectus had high bone density...

For density let us use you as an extreme example .
Thank you..
[/quote]
Another SF who denies erectus had compact bones...

Sigh.

Lee Olsen · Guest

[quote]On Jul 11, 7:27 pm, Marc Verhaegen <m_verhae...@skynet.be> wrote:
Savanna Fool now denies H.erectus had high bone density...
[/quote]
Wetape Verhaegin doesn>t understand yet? How about some scientific
data:

http://tinyurl.com/7u5wo
" In fact, he walked and ran with better mechanics than we do today.
The mechanics of his femur, femur head, pelvis, and lower back are
superior to those of today. We have had to sacrifice some of that
efficiency of walking and running to give birth to children with
larger brains."

"Two indepandent lines of research converged on the
conclusion that early Homo was an efficient runner, the first human
species to be so Leakey (1994:55)."

http://tinyurl.com/2n8y2n
Carl Zimmer Science 2004

"It may come as a surprise to hear that humans excel in running.
Obviously, a leopard can leave us in the dust in a short sprint. But
over longer distances leopards and most other mammals flag. "Most
mammals can>t sustain a gallop over 10 to 15 minutes," says Lieberman.
Humans, on the otherhand, can continue running for hours while using
relatively little energy. "Humans are phenomanenal endurance runners,
in terms of speed, cost, and distance," says Lieberman. You can
actually outrun a pony easily." And yet, he points out, "no other
primates out there endurance run."

http://www.indigenouspeople.net/tarafeat.htm
"The public was amazed at the prowess of the runners and even more so
when the papers reported
that there were better ones at home. One of them was called "The Tiger
of the Sierra"; he had run for
three consecutive days that same year, near Norogachic, Chihuahua,
covering a distance of 300 kilometers,
or 186 miles, of mountainous country."

"Specifically, longer, more linear bodies are better adapted
for heat loss in dry open environments, where evaporative
heat loss from sweating is very effective. All modern-day tall
"elongated"
African (e.g., Nilotics) are restricted to such environments."
Alan Walker and Richard Leakey editors.
1993 The Nariokotome Homo Erectus Skeleton.
Harvard University Press, Cambridge

http://www.naturalhistorymag.com/master.html?http://www.naturalhistorymag.com/1206/1206_samplings.html
Mr. Karoha runs down another ill-equipped-for-savanna kudu.

"The earliest Eurasians preferentially occupied
grasslands and open scrub- and wood-lands, as in
East Africa. Homo ergaster/erectus in East Africa after 1.7 Ma is
associated with hot and dry conditions, and open
grasslands; its post-cranial anatomy, with its long
limbs was geared to long-distance walking across
open ground, and to heat dispersal through upright
posture (Dennell 2003:442)."

http://www.msnbc.msn.com/id/17584912/
"Just because humans have long legs doesn’t make us less aggressive.
Rather, the longer legs are a product of humans’ specialization for
distance running."

"He showed that even the slowest human runners could, with even a
slight head start, outrun lions, cheetahs, leopards, hyenas, and wild
dogs, not by speed, but by out distancing them (Donald Mitchell)."
QUARRY CLOSING IN ON THE MISSING LINK by Boaz, Noel T. 1993 (ISBN:
0029045010)

"From our spring-loaded ligaments to our muscular behinds to our
ability to sweat,
the human body took the ideal shape of a long-distance runner starting
some 2 million years ago,
the researchers say. The long, lean build helped us scavenge widely
scattered kills
and could also have been an advantage when hunting down prey over long
distances."
"We>re lousy sprinters, but we>re really great long-distance
runners,"
said Daniel Lieberman, an anthropologist at Harvard University.

http://tinyurl.com/dcxyw
"A long-distance runner has beaten a leading endurance racehorse over
a distance of 80 kilometres in the United Arab Emirates."

Marc Verhaegen · Guest

Op 12-07-2008 18:29, in artikel
ef8499df-a7f3-4416-a025-24c0f16758fb@k30g2000hse.googlegroups.com, Lee Olsen
<paleocity@hotmail.com> schreef:

[quote]
On Jul 11, 7:27 pm, Marc Verhaegen <m_verhae...@skynet.be> wrote:
Savanna Fool now denies H.erectus had high bone density...

Wetape Verhaegin doesn>t understand yet? How about some scientific
data:

http://tinyurl.com/7u5wo
" In fact, he walked and ran with better mechanics than we do today.
[/quote]
:-D
My little olson boy, why don>t you inform a little bit??

Bramble and Lieberman (2004), in a much-discussed review article in Nature,
cite a number of derived Homo features they claim to be adaptations for more
efficient endurance running in arid, open habitats. However, while some of
these supposedly Œcursorial adaptations¹ appear first in the fossil record
in H. habilis, others appear first in H. erectus, and others still in H.
sapiens, suggesting a much more complex story than proposed by Bramble and
Lieberman. Their conclusions are reached without systematic comparisons
with other animals (including endurance runners) and with general
comparisons restricted to fossil hominids and Pan. Since convergent traits
are strong indicators of evolution in similar environments (Bender 1999), a
systematic comparison with a broad range of animals with a variety of
locomotor strategies would have been more informative.
In addition, discussion of possible locomotion styles is restricted to
walking and running, with no consideration at all given to activities such
as wading, swimming or underwater foraging, yet humans are regular waders
and more accomplished swimmers and divers than other primates. Most of the
list¹s Œadaptations¹ for walking could just as easily be explained by
wading. One of the frequent Œexplanations¹ in the list is ³stress
reduction², a reference to the vertical posture of humans with the weight
resting on two legs. But this says nothing about endurance running, with
standing, wading, walking or short distance running all using a similar
posture, and therefore all requiring stress reduction. Other Œexplanations¹
include ³counter rotation², ³thermoregulation² and ³stabilization², but no
comparative data to corroborate these interpretations are provided. In
other words, their Œexplanations¹ are ad hoc suppositions, applied to one
example (human ancestors) without any consideration as to whether these
supposed adaptations are seen in other animals, which means their
Œexplanations¹ are statistically invalid (n=1). Long legs, and possibly
shortened forearms, could be seen as running adaptations, but these are just
as typical of wading and swimming species compared with runners (Hildebrand
1974: 584, Bender 1999).
In a waterside scenario, wading and swimming would be preadaptative to the
humanlike Œvertical¹ locomotion that Bramble and Lieberman (2004) believe to
be a direct adaptation to endurance running. In our view, frequent
terrestrial locomotion, whether for walking or for (relatively slow)
running, was more recent (Homo sapiens) and could not be derived directly
from an ancestral locomotion in forests, whether on the ground or in the
branches, because in that case a more baboon-like locomotion would be
expected (the Œbaboon paradox¹).

Table 4. Bramble and Lieberman¹s (2004) list of supposedly derived features
of the human skeleton with so-called cursorial functions

Functional role in running & walking according to Bramble & Lieberman
(2004) W = walk R = run Earliest evidence Comparative data. More
likely alternatives in our opinion. NSS = not seen in savannah animals. NSC
= not seen in cursorial animals. NUL = not unexpected in littoral animals.
Enlarged posterior & anterior semicircular canals Head/body
stabilization R H. erectus NSS as far as known. NUL, e.g., for
equilibrium during descent & ascent in diving. Requires more comparative
data.
Expanded venous circulation of neurocranium Thermoregulation R>W H.
erectus NSS. NSC. NUL. Skull base & paravertebral venous networks are
typical of diving species.
More balanced head Head stabilization R H. habilis NSS. NSC. Could
be advantageous in frequent standing rather than running. Alined build NUL.
Nuchal ligament Head stabilization R H. habilis NUL, e.g., in
pronograde swimming.
Short snout Head stabilization R>W H. habilis NSS. NSC. Snout
shortening has to do with mastication rather than head stabilisation.
Tall, narrow body form Thermoregulation R>W H. erectus NUL: long
legs are typical of wading species.
Decoupled head & pectoral girdle Counter-rotation of trunk vs head R
H. erectus? NUL: waterside as well as a mosaic milieus require versatile
locomotions.
Low, wide shoulders Counter-rotation of trunk vs hips R H. erectus?
NUL: Œlow¹ could be for wading as well as for underwater swimming. No
relation to running.
Forearm shortening Counter-rotation of trunk - H. erectus NUL:
typical of frequently swimming species.
Narrow thorax Counter-rotation of trunk vs hips R H. erectus?
Dorso-ventrally narrow. NSS, NSC, NUL: typical of shallow water dwellers,
e.g., platypus, hippo, beaver.
Narrow & tall waist between iliac crest & ribcage Counter-rotation of
trunk vs hips R H. erectus? NUL: waterside as well as mosaic milieus
require a wide range of locomotions.
Narrow pelvis Counter-rotation of trunk vs hips Stress reduction R
R>W Homo? H. erectus had still flaring ilia, presumably for femoral
abduction: NSS, NSC, NUL.
Expanded lumbar central surface area Stress reduction R>W H.
erectus Suggests vertical body. NUL, e.g., for wading.
Enlarged iliac pillar Stress reduction R>W H. erectus Idem.
Stabilized sacroiliac joint Trunk stabilization R H. erectus
Idem.
Expanded surface area for mm. erector spinae origin Trunk stabilization
R H. erectus Idem.
Expanded surface area for m. gluteus maximus origin Trunk stabilization
R H. erectus Idem.
Long legs Stride length R>W H. erectus NUL, typical of wading
species.
Expanded hindlimb joint surface area Stress reduction R>W H.
erectus Suggests vertical body. NUL, e.g., for wading.
Shorter femoral neck Stress reduction R>W H. sapiens Not seen in
H. erectus. Presumably post-littoral.
Long Achilles tendon Energy storage Shock absorption R Homo?
Comparative data are needed. Typical cursorial species are not plantigrade.
NUL.
Plantar arch (passively stabilized) Energy storage Shock absorbtion
Powered plantar-flexion R R>W R>W Homo? NSS. NSC. NUL: plantigrady for
wading and swimming.
Enlarged tuber calcaneus Stress reduction R>W Homo? Cursorials
do not have enlarged heels. NSS. NSC. NUL.
Close-packed calcaneo-cuboid joint Energy storage Stability during
plantarflexion R>W OH-8 Comparative data are needed. NUL.
Permanently adducted hallux Stability during plantarflexion R>W
OH-8 NUL: wading, swimming.
Short toes Stability during plantarflexion Distal mass reduction R>W
OH-8 NSS. NSC. NUL: metatarsal lengthening and toe shortening is to be
expected in swimming & wading.

Most of Bramble and Lieberman¹s Œadaptations¹ are not what we would expect
in a cursorial (running) animal. For example, their list includes ³enlarged
posterior and anterior semicircular canals², but there are no comparisons
with, for instance, giraffes (heads high above the ground), gibbons (fast
and versatile locomotion), kangaroos (cursorial bipeds), or swimming or
diving species. It is conceivable in fact that the frequent change of
posture seen when diving for seafood (descending and ascending) required a
different labyrinth structure, and that the larger Homo erectus labyrinth
was adapted to terrestrial walking and running as well as to wading,
swimming and diving locomotions.
There is no indication that an ³expanded venous circulation of neurocranium²
had anything to do with thermoregulation, but there is long-standing
evidence of expanded venous networks in diving species (Slijper 1936).
More balanced heads and short snouts are not seen in cursorial species,
whether bi- or quadrupedal, and low shoulders are to be expected in wading
and underwater swimming.
What Bramble and Lieberman refer to as ³narrow body form², ³narrow thorax²
and ³narrow pelvis² is not clear to us: compared to most primates, humans
have a relatively broad thorax and pelvis (laterolaterally), and this was
even more so in the case of australopithecines. In our opinion, the
combination of Œflared¹ iliac blades and long and relatively horizontal
femoral necks as seen in Homo erectus indicates well-developed ad- and
abduction, which is obviously not an adaptation for running, but would not
be unexpected and indeed would be advantageous for a species that had to
regularly wade, tread water, swim or climb. In Homo sapiens the pelvis
(bi-iliac diameter) did become narrower and the femoral necks shorter and
more vertical, and we agree with Bramble and Lieberman that this could be
related to more frequent terrestrial locomotion.
Plantar arches, enlarged tubera calcanei, close-packed calcaneo-cuboid
joints and short toes are not seen in cursorials, whether bi- or quadruped,
to the contrary: running species are typically unguli- or digiti-, not
plantigrade, and typically have elongated toes.
In conclusion, comparative data suggest that none of the features described
by Bramble and Lieberman (2004) are typical either of savannah dwellers or
frequently running animals, whether slow or fast. Until the features are
considered in the context of swimming and wading as well as terrestrial
movement, their interpretations should be considered with extreme caution.
As it is, there is no obvious reason why any of the features cited could not
have been of advantage in a littoral environment. We do not deny that
humans today are adapted to terrestrial locomotion including walking and
moderate running, but in our opinion the peculiar human anatomy is not
directly derivable from a typical primate ancestor who moved from closed to
more open, arid habitats.
At least two conspicuous anatomical features of Homo erectus are notably not
included in the list of features cited by Bramble and Lieberman (2004).

1) Homo erectus typically has a more robust, and therefore heavier,
skeleton than all other (fossil and extant) primates, including H. sapiens
and the other apes. One of its defining characteristics is the shape and
size of the femoral bone, which shows cortex thickening and densening
(pachyostosis) and a narrow cavity of the bone marrow (medullary stenosis).
The cranial bones, especially the posterior part (the occiput), are also
notably thicker than in other primates including H. sapiens. Unusually heavy
bones would be a disadvantage for a species relying on endurance running,
and are not seen in running mammals such as dogs or horses, whereas for a
species collecting sessile food from the water¹s edge, including underwater
foraging, they could have been a significant advantage. Human divers such as
the Ama of Korea frequently use weights to help them descend (Hong and Rahn
1967). Slow-diving mammals for sessile foods typically have medullary
stenosis and pachyostosis to a higher degree than in H. erectus (walruses,
dugongs and fossil littoral species such as Kolponomos, Odobenocetops and
some Thalassocnus species), while fast-diving mammals for mobile prey have
light-weight bones (dolphins and sealions).

2) Archaic Homo had a lower and longer brain skull than H. sapiens, with
generally less flexed cranial base and with the eyes somewhat more in front
of the brain (requiring a supraorbital torus for eye protection) rather than
fully below the frontal brain as in H. sapiens, meaning that the eyes would
have been more naturally oriented towards the sky if they were standing with
an upright posture, rather than directed more towards the horizon as is the
case when H. sapiens stands upright. This would be a disadvantage for a
species relying on endurance running because, among other things, more
energy would be needed to look at where the feet were making contact with
the ground. In a diving position, as well as in a more procumbent body
position while wading for food, for example, this would have resulted in the
eyes being more naturally oriented in the direction the individual was
moving (i.e., in the case of swimming and diving, head first through the
water). We are not aware of any models that suggest early Homo ran with a
bent hip posture, but we do note that human sprinters generally run with the
body leaning forward.

Within many contemporary H. sapiens populations there are individuals who
are capable of long distance running, but compared to typical savannah
species, humans are slow and inefficient (Figure 4). Moreover, recent
research suggests that endurance training in athletes sometimes causes
cardial arrhythmias and sudden death (Ector et al. 2007). Even Bramble and
Lieberman (2004) admit that ³humans are mediocre runners in several
respects² and ³running is more costly for humans than for most other
mammals². And since H. erectus generally had, for instance, heavier bones
than H sapiens and longer femoral necks, it must have been an even less
efficient cursorial than extant H. sapiens.

Lee Olsen · Guest

On Jul 12, 11:47 pm, Marc Verhaegen <m_verhae...@skynet.be> wrote:

<nothing relevant>

Here are the facts, bone density facilitates running in Homo:

Mujin wrote:
[quote][...]
"Conclusions: Running, a weight-bearing exercise, is associated with more
favorable geometric and biomechanical characteristics in relation to bone
strength, compared with the weight supported activities of swimming and
cycling. Differences may reflect skeletal adaptations to the specific
mechanical-loading patterns inherent in these sports"
http://www.acsm-msse.org/pt/re/msse/abstract.00005768-200204000-
00018.htm;jsessionid=HJxhg51XTP76vm2Q2tjGNy9JTQCZFcv3xHG8Qh2XL470Kzjk7kPB!-
1601909834!181195629!8091!-1
Clearly weight bearing, high impact activity increases cortical thickness
and decreases medullary cavity sizes. More importantly:
[/quote]
See also
http://www.ncbi.nlm.nih.gov/pubmed/10949001
Total and regional bone density in male runners, cyclists, and
controls.
Medicine & Science in Sports & Exercise. 32(8):1373-1377, August
2000.
...
Conclusion: Running is associated with increased bone density,
particularly in
the leg, whereas cycling is associated with a mild decrease in bone
density in
the spine. In athletes who do both, running exerts a stronger
influence than
cycling.

http://tinyurl.com/7u5wo
" In fact, he walked and ran with better mechanics than we do today.
The mechanics of his femur, femur head, pelvis, and lower back are
superior to those of today. We have had to sacrifice some of that
efficiency of walking and running to give birth to children with
larger brains."

"Two indepandent lines of research converged on the
conclusion that early Homo was an efficient runner, the first human
species to be so Leakey (1994:55)."

http://tinyurl.com/2n8y2n
Carl Zimmer Science 2004

"It may come as a surprise to hear that humans excel in running.
Obviously, a leopard can leave us in the dust in a short sprint. But
over longer distances leopards and most other mammals flag. "Most
mammals can>t sustain a gallop over 10 to 15 minutes," says
Lieberman.
Humans, on the otherhand, can continue running for hours while using
relatively little energy. "Humans are phenomanenal endurance runners,
in terms of speed, cost, and distance," says Lieberman. You can
actually outrun a pony easily." And yet, he points out, "no other
primates out there endurance run."

http://www.indigenouspeople.net/tarafeat.htm
"The public was amazed at the prowess of the runners and even more so
when the papers reported
that there were better ones at home. One of them was called "The
Tiger
of the Sierra"; he had run for
three consecutive days that same year, near Norogachic, Chihuahua,
covering a distance of 300 kilometers,
or 186 miles, of mountainous country."

"Specifically, longer, more linear bodies are better adapted
for heat loss in dry open environments, where evaporative
heat loss from sweating is very effective. All modern-day tall
"elongated"
African (e.g., Nilotics) are restricted to such environments."
Alan Walker and Richard Leakey editors.
1993 The Nariokotome Homo Erectus Skeleton.
Harvard University Press, Cambridge

http://www.naturalhistorymag.com/master.html?http://www.naturalhistor...
Mr. Karoha runs down another ill-equipped-for-savanna kudu.

"The earliest Eurasians preferentially occupied
grasslands and open scrub- and wood-lands, as in
East Africa. Homo ergaster/erectus in East Africa after 1.7 Ma is
associated with hot and dry conditions, and open
grasslands; its post-cranial anatomy, with its long
limbs was geared to long-distance walking across
open ground, and to heat dispersal through upright
posture (Dennell 2003:442)."

http://www.msnbc.msn.com/id/17584912/
"Just because humans have long legs doesn’t make us less aggressive.
Rather, the longer legs are a product of humans’ specialization for
distance running."

"He showed that even the slowest human runners could, with even a
slight head start, outrun lions, cheetahs, leopards, hyenas, and wild
dogs, not by speed, but by out distancing them (Donald Mitchell)."
QUARRY CLOSING IN ON THE MISSING LINK by Boaz, Noel T. 1993 (ISBN:
0029045010)

"From our spring-loaded ligaments to our muscular behinds to our
ability to sweat,
the human body took the ideal shape of a long-distance runner
starting
some 2 million years ago,
the researchers say. The long, lean build helped us scavenge widely
scattered kills
and could also have been an advantage when hunting down prey over
long
distances."
"We>re lousy sprinters, but we>re really great long-distance
runners,"
said Daniel Lieberman, an anthropologist at Harvard University.

http://tinyurl.com/dcxyw
"A long-distance runner has beaten a leading endurance racehorse over
a distance of 80 kilometres in the United Arab Emirates."

jerry warner · Guest

Rick Wagler wrote:

[quote]"Marc Verhaegen" <m_verhaegen@skynet.be> wrote in message
news:C49C75D8.1301F%m_verhaegen@skynet.be...
Sink or swim?
Bone density as a mechanism for buoyancy control in early cetaceans
Noel-Marie Gray, Kimberly Kainec, Sandra Madar, Lucas Tomko & Scott Wolfe
Anat Rec 290:638-653, 2007

Previous analyses have shown that secondarily aquatic tetrapods, including
whales, exhibit osteological adaptations to life in water as part of their
complex buoyancy control systems. These structural specializations of bone
span hyperostosis through osteoporosis. The past 15 years of
paleontological
effort has provided an unprecedented opportunity to examine the
osteological
transformation of whales as they make their transition to an obligate
aquatic lifestyle over a 10-million-year period. It is hypothesized that
whales manifest their osteological specialization in the same manner as
extant semiaquatic and fully aquatic mammals. This study presents and
analysis of the microstructural features of bone in early and late archaic
cetaceans, and in a comparative sample of modern terrestrial, semiaquatic,
and aquatic mammals. Bone histology was examined from the ribs of 10
fossilized individuals representing five early cetacean families,
including
Pakicetidae, Ambulocetidae, Protocetidae, Remintonocetidae, and
Basilosauridae. Comparisons were then made with rib histology from nine
genera of extant mammals including: Odocoileus (deer), Bos (cow), Equus
(horse), Canis (dog), Lutra (river otter), Enhydra (sea otter), Choeropsis
(pygmy hippo), Trichechus (sea cow), and Delphinus (dolphin). Results show
that the transition from terrestrial, to semiaquatic, to obligate aquatic
locomotion in archaeocetes involved a radical shift in bone function
achieved by means of profound changes at the microstructural level. A
surprising finding was that microstructural change predates gross
anatomical
shift in archaeocetes associated with swimming. Histological analysis
shows
that high bone density is an aquatic specialization that provides static
buoyancy control (ballast) for animals living in shallow water, while low
bone density is associated with dynamic buoyancy control for animals
living
in deep water. Thus, there was a shift from the typical terrestrial form,
to
osteopetrosis and pachyosteosclerosis, and then to osteoporosis in the
first
quarter of cetacean evolutionary history.

Interesting abstract. Where>s the part about H erectus?

Rick Wagler
[/quote]
Takes a leap of faithe. Hip bone connected to thy bone
under the sweetness of Jesus or academic purity or something!

Lee Olsen · Guest

On Jul 13, 5:33 am, "Paul Crowley"
<slkwuoiutiuytciu...@slkjlskjoioue.com> wrote:

[quote]
I put Olsen (along with Verhaegen)
in my kill-file about 2 years ago
[/quote]
Message-ID: <aVrSg.14153$j7.330802@news.indigo.ie>
Crowley: "All social institutions -- and especially
those 'sciences' concerned with the nature
of humanity and its origins -- are riddled
with masses of unstated, unrecognised
assumptions."

http://tinyurl.com/3cnmum
Crowley: "Chimps do NOT have the capacity to dig."

http://tinyurl.com/433x24

Paul Crowley · Guest

"Lee Olsen" <paleocity@hotmail.com> wrote in message
news:c8fd4fb9-882f-4ada-831d-7c65592eeef8@l42g2000hsc.googlegroups.com...
On Jul 12, 11:47 pm, Marc Verhaegen <m_verhae...@skynet.be> wrote:

[quote]nothing relevant

Here are the facts, bone density facilitates running in Homo:
[/quote]

I put Olsen (along with Verhaegen)
in my kill-file about 2 years ago
when his Yah-Boo exchange with
Verhaegen had become tedious.

I took him out a couple of hours ago,
assuming that was long over.

What a mistake! . . . right back in.

Paul,

Marc Verhaegen · Guest

[quote]Here are the facts, bone density facilitates running in Homo
[/quote]
:-DDD

you>re a stupid fool, olson boy


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