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Marc Verhaegen
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 Posted: Wed Jul 30, 2008 6:32 am Post subject: osteosclerosis = hallmark of an aquatic lifestyle |
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Bone Thickness in Homo erectus
Kennedy GE 1985 JHE 14: 699-708
The presence of such thickened bone (in erectus) is extraordinary; very
few animals (mammal or non-mammal) show similar generalized thickened bone.
Within the order Sirenia, the families Manatidae (Manatees) and the
Halicoridae (dugongs) show not merely thickened bone and medullary stenosis
but complete lack of medullary canal (Fawcett 1942) Š The adaptive advantage
of such heavy, dense bone to the sirenians is apparently to counterbalance
the buoyancy of their large lung volume while submerged. Amedullary bones,
presumably reflecting a similar selective pressure, are also found in
certain Mesozoic marine reptiles (Fawcett 1942) and in living humpback
whales (Ogden 1980).
A morphometric and taxonomic assessment of a hominine femur from the lower
member, Koobi Fora, Lake Turkana
GE Kennedy AJPA 61:429-436
The femoral shaft of Homo erectus, relative to H.sapiens, demonstrates
small anteroposterior diameters, a distally placed point of minimum shaft
breadth, and increased cortical thickness resulting in medullary stenosis.
This pattern has been identified in specimens from Choukoutien (I and IV),
Olduvai (OH 28), and Lake Turkana (KNM ER 737) ... Known H.erectus femora
extend over a broad span and yet show very low, variability; this pronounced
stasis would strongly suggest that, at least in this portion of the
postcranium, H.erectus was in a period of profound morphological stasis.
Body proportions of Homo habilis reviewed
Martin Haeusler & Henry M. McHenry 2004 JHE 46:433-465
... early Homo femora are said to possess an extremely thick femoral
cortex compared to both Australopithecus & modern humans ... medullar
stenosis seems to be typical mainly for later Eurasian H.erectus ...
NT Boaz & RL Ciochon 2004 Oxford UP
Dragon Bone Hill: An Ice-Age Saga of Homo erectus
H.erectus skull bone can be technically descibed as "pachyostotic"
(literally "thick-boned") ... Some species such sirenians have dense bones
throughout their bodies to give them negative buoyancy in the water.
THE POSTCRANIAL SKELETON OF EARLY EOCENE PAKICETID CETACEANS
SI Madar 2007 J.Paleontol.
Osteosclerosis is an increased thickness of the cortex, due to
replacement of trabecular bone with compact bone ...
Evidence of aquatic dependence from bone microstructure. - The
morphological adaptations for aquatic locomotion described above may appear
to suggest that pakicetids represent a very early stage of transition to
life in water, that these animals were not fully committed to an aquatic
environment, and remained better suited for terrestrial than aquatic
pursuits. However, evidence from bone microstructure demonstrates the
contrary - pakicetids were highly derived semiaquatic mammals. Skeletal
ballast was present in all pakicetid taxa (Fig.7). Hyperostosis and
osteosclerosis are found in all regions of the skeleton and are similarly
developed in juvenile and adult individuals of all 3 taxa. Long bone & rib
marrow cavities are either miniscule or absent due to thick cortices or
dense trabecular infill. Even vertebrae have hyperthick cortices.
Bone ballast in the form of osteosclerosis and hyperostosis is an
unmistakable hallmark of an aquatic lifestyle (Fish & Stein 1991; Domning &
de Buffrénil 1991; Taylor 1994; Madar 1998). Skeletal ballast has already
been described in early marine cetaceans (Buffrénil et al.1990; Madar 1998;
Uhen 2004) including Ambulocetus, Basilosaurus Harlan 1834, and Dorudon
Gibbes 1845. Pakicetids differ most from Ambulocetus & subsequent taxa in
their greater diaphyseal osteosclerosis, though all exhibit complete or near
complete infill of marrow cavities by trabecular bone. The increased
trabecular density & cortical hypertrophy found throughout the pakicetid
skeleton suggest an adaptation toward bottom walking or wading, as heavy
skeletons counteract buoyant effects of inflated lungs & furtrapped air. The
increased density of the pakicetid skeleton would have left these early
cetaceans wholly unsuited to running, or even prolonged terrestriality, as
heavy skeletons are energetically expensive to move. In addition, the
hypermineralization (osteopetroses) of pakicetid load bearing elements put
them at increased risk for fracture during terrestrial loading (de Vernejoul
& Bénichou 2001), a risk that rises with velocity. Thus, although they look
superficially similar to their cursorial relatives, it is likely that
pakicetids made few sustained terrestrial forays. The summed evidence of
bone gross morphology and microstructure indicates that pakicetid cetaceans
were fully committed to an aquatic lifestyle, and bore marked adaptations
for bottom walking, paddling, and undulatory swimming modes. |
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Lee Olsen
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| Posted: Wed Jul 30, 2008 6:32 am Post subject: Re: dense bones equal fast runners |
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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.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."
On Jul 29, 6:32 pm, Marc Verhaegen <m_verhae...@skynet.be> wrote:
[quote]Bone Thickness in Homo erectus
Kennedy GE 1985 JHE 14: 699-708
The presence of such thickened bone (in erectus) is extraordinary; very
few animals (mammal or non-mammal) show similar generalized thickened bone.
Within the order Sirenia, the families Manatidae (Manatees) and the
Halicoridae (dugongs) show not merely thickened bone and medullary stenosis
but complete lack of medullary canal (Fawcett 1942) Š The adaptive advantage
of such heavy, dense bone to the sirenians is apparently to counterbalance
the buoyancy of their large lung volume while submerged. Amedullary bones,
presumably reflecting a similar selective pressure, are also found in
certain Mesozoic marine reptiles (Fawcett 1942) and in living humpback
whales (Ogden 1980).
A morphometric and taxonomic assessment of a hominine femur from the lower
member, Koobi Fora, Lake Turkana
GE Kennedy AJPA 61:429-436
The femoral shaft of Homo erectus, relative to H.sapiens, demonstrates
small anteroposterior diameters, a distally placed point of minimum shaft
breadth, and increased cortical thickness resulting in medullary stenosis..
This pattern has been identified in specimens from Choukoutien (I and IV),
Olduvai (OH 28), and Lake Turkana (KNM ER 737) ... Known H.erectus femora
extend over a broad span and yet show very low, variability; this pronounced
stasis would strongly suggest that, at least in this portion of the
postcranium, H.erectus was in a period of profound morphological stasis.
Body proportions of Homo habilis reviewed
Martin Haeusler & Henry M. McHenry 2004 JHE 46:433-465
... early Homo femora are said to possess an extremely thick femoral
cortex compared to both Australopithecus & modern humans ... medullar
stenosis seems to be typical mainly for later Eurasian H.erectus ...
NT Boaz & RL Ciochon 2004 Oxford UP
Dragon Bone Hill: An Ice-Age Saga of Homo erectus
H.erectus skull bone can be technically descibed as "pachyostotic"
(literally "thick-boned") ... Some species such sirenians have dense bones
throughout their bodies to give them negative buoyancy in the water.
THE POSTCRANIAL SKELETON OF EARLY EOCENE PAKICETID CETACEANS
SI Madar 2007 J.Paleontol.
Osteosclerosis is an increased thickness of the cortex, due to
replacement of trabecular bone with compact bone ...
Evidence of aquatic dependence from bone microstructure. - The
morphological adaptations for aquatic locomotion described above may appear
to suggest that pakicetids represent a very early stage of transition to
life in water, that these animals were not fully committed to an aquatic
environment, and remained better suited for terrestrial than aquatic
pursuits. However, evidence from bone microstructure demonstrates the
contrary - pakicetids were highly derived semiaquatic mammals. Skeletal
ballast was present in all pakicetid taxa (Fig.7). Hyperostosis and
osteosclerosis are found in all regions of the skeleton and are similarly
developed in juvenile and adult individuals of all 3 taxa. Long bone & rib
marrow cavities are either miniscule or absent due to thick cortices or
dense trabecular infill. Even vertebrae have hyperthick cortices.
Bone ballast in the form of osteosclerosis and hyperostosis is an
unmistakable hallmark of an aquatic lifestyle (Fish & Stein 1991; Domning &
de Buffrénil 1991; Taylor 1994; Madar 1998). Skeletal ballast has already
been described in early marine cetaceans (Buffrénil et al.1990; Madar 1998;
Uhen 2004) including Ambulocetus, Basilosaurus Harlan 1834, and Dorudon
Gibbes 1845. Pakicetids differ most from Ambulocetus & subsequent taxa in
their greater diaphyseal osteosclerosis, though all exhibit complete or near
complete infill of marrow cavities by trabecular bone. The increased
trabecular density & cortical hypertrophy found throughout the pakicetid
skeleton suggest an adaptation toward bottom walking or wading, as heavy
skeletons counteract buoyant effects of inflated lungs & furtrapped air. The
increased density of the pakicetid skeleton would have left these early
cetaceans wholly unsuited to running, or even prolonged terrestriality, as
heavy skeletons are energetically expensive to move. In addition, the
hypermineralization (osteopetroses) of pakicetid load bearing elements put
them at increased risk for fracture during terrestrial loading (de Vernejoul
& Bénichou 2001), a risk that rises with velocity. Thus, although they look
superficially similar to their cursorial relatives, it is likely that
pakicetids made few sustained terrestrial forays. The summed evidence of
bone gross morphology and microstructure indicates that pakicetid cetaceans
were fully committed to an aquatic lifestyle, and bore marked adaptations
for bottom walking, paddling, and undulatory swimming modes.[/quote] |
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Marc Verhaegen
Guest
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| Posted: Wed Jul 30, 2008 7:00 am Post subject: Re: dense bones equal fast runners :-DDD |
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[quote]Bone Thickness in Homo erectus
Kennedy GE 1985 JHE 14: 699-708
The presence of such thickened bone (in erectus) is extraordinary; very
few animals (mammal or non-mammal) show similar generalized thickened bone.
Within the order Sirenia, the families Manatidae (Manatees) and the
Halicoridae (dugongs) show not merely thickened bone and medullary stenosis
but complete lack of medullary canal (Fawcett 1942) © The adaptive advantage
of such heavy, dense bone to the sirenians is apparently to counterbalance
the buoyancy of their large lung volume while submerged. Amedullary bones,
presumably reflecting a similar selective pressure, are also found in
certain Mesozoic marine reptiles (Fawcett 1942) and in living humpback
whales (Ogden 1980).
A morphometric and taxonomic assessment of a hominine femur from the lower
member, Koobi Fora, Lake Turkana
GE Kennedy AJPA 61:429-436
The femoral shaft of Homo erectus, relative to H.sapiens, demonstrates
small anteroposterior diameters, a distally placed point of minimum shaft
breadth, and increased cortical thickness resulting in medullary stenosis.
This pattern has been identified in specimens from Choukoutien (I and IV),
Olduvai (OH 28), and Lake Turkana (KNM ER 737) ... Known H.erectus femora
extend over a broad span and yet show very low, variability; this pronounced
stasis would strongly suggest that, at least in this portion of the
postcranium, H.erectus was in a period of profound morphological stasis.
Body proportions of Homo habilis reviewed
Martin Haeusler & Henry M. McHenry 2004 JHE 46:433-465
... early Homo femora are said to possess an extremely thick femoral
cortex compared to both Australopithecus & modern humans ... medullar
stenosis seems to be typical mainly for later Eurasian H.erectus ...
NT Boaz & RL Ciochon 2004 Oxford UP
Dragon Bone Hill: An Ice-Age Saga of Homo erectus
H.erectus skull bone can be technically descibed as "pachyostotic"
(literally "thick-boned") ... Some species such sirenians have dense bones
throughout their bodies to give them negative buoyancy in the water.
THE POSTCRANIAL SKELETON OF EARLY EOCENE PAKICETID CETACEANS
SI Madar 2007 J.Paleontol.
Osteosclerosis is an increased thickness of the cortex, due to
replacement of trabecular bone with compact bone ...
Evidence of aquatic dependence from bone microstructure. - The
morphological adaptations for aquatic locomotion described above may appear
to suggest that pakicetids represent a very early stage of transition to
life in water, that these animals were not fully committed to an aquatic
environment, and remained better suited for terrestrial than aquatic
pursuits. However, evidence from bone microstructure demonstrates the
contrary - pakicetids were highly derived semiaquatic mammals. Skeletal
ballast was present in all pakicetid taxa (Fig.7). Hyperostosis and
osteosclerosis are found in all regions of the skeleton and are similarly
developed in juvenile and adult individuals of all 3 taxa. Long bone & rib
marrow cavities are either miniscule or absent due to thick cortices or
dense trabecular infill. Even vertebrae have hyperthick cortices.
Bone ballast in the form of osteosclerosis and hyperostosis is an
unmistakable hallmark of an aquatic lifestyle (Fish & Stein 1991; Domning &
de Buffrénil 1991; Taylor 1994; Madar 1998). Skeletal ballast has already
been described in early marine cetaceans (Buffrénil et al.1990; Madar 1998;
Uhen 2004) including Ambulocetus, Basilosaurus Harlan 1834, and Dorudon
Gibbes 1845. Pakicetids differ most from Ambulocetus & subsequent taxa in
their greater diaphyseal osteosclerosis, though all exhibit complete or near
complete infill of marrow cavities by trabecular bone. The increased
trabecular density & cortical hypertrophy found throughout the pakicetid
skeleton suggest an adaptation toward bottom walking or wading, as heavy
skeletons counteract buoyant effects of inflated lungs & furtrapped air. The
increased density of the pakicetid skeleton would have left these early
cetaceans wholly unsuited to running, or even prolonged terrestriality, as
heavy skeletons are energetically expensive to move. In addition, the
hypermineralization (osteopetroses) of pakicetid load bearing elements put
them at increased risk for fracture during terrestrial loading (de Vernejoul
& Bénichou 2001), a risk that rises with velocity. Thus, although they look
superficially similar to their cursorial relatives, it is likely that
pakicetids made few sustained terrestrial forays. The summed evidence of
bone gross morphology and microstructure indicates that pakicetid cetaceans
were fully committed to an aquatic lifestyle, and bore marked adaptations
for bottom walking, paddling, and undulatory swimming modes.
[/quote] |
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Lee Olsen
Guest
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| Posted: Wed Jul 30, 2008 10:26 pm Post subject: Re: dense bones equal fast runners, proven |
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http://www.naturalhistorymag.com/master.html?http://www.naturalhistorymag.com/1206/1206_samplings.html
Faster than a kudu.
On Jul 29, 11:53 pm, Marc Verhaegen <m_verhae...@skynet.be> wrote:
[quote]Bone Thickness in Homo erectus
Kennedy GE 1985 JHE 14: 699-708
The presence of such thickened bone (in erectus) is extraordinary; very
few animals (mammal or non-mammal) show similar generalized thickened bone.
Within the order Sirenia, the families Manatidae (Manatees) and the
Halicoridae (dugongs) show not merely thickened bone and medullary stenosis
but complete lack of medullary canal (Fawcett 1942) © The adaptive advantage
of such heavy, dense bone to the sirenians is apparently to counterbalance
the buoyancy of their large lung volume while submerged. Amedullary bones,
presumably reflecting a similar selective pressure, are also found in
certain Mesozoic marine reptiles (Fawcett 1942) and in living humpback
whales (Ogden 1980).
A morphometric and taxonomic assessment of a hominine femur from the lower
member, Koobi Fora, Lake Turkana
GE Kennedy AJPA 61:429-436
The femoral shaft of Homo erectus, relative to H.sapiens, demonstrates
small anteroposterior diameters, a distally placed point of minimum shaft
breadth, and increased cortical thickness resulting in medullary stenosis.
This pattern has been identified in specimens from Choukoutien (I and IV),
Olduvai (OH 28), and Lake Turkana (KNM ER 737) ... Known H.erectus femora
extend over a broad span and yet show very low, variability; this pronounced
stasis would strongly suggest that, at least in this portion of the
postcranium, H.erectus was in a period of profound morphological stasis.
Body proportions of Homo habilis reviewed
Martin Haeusler & Henry M. McHenry 2004 JHE 46:433-465
... early Homo femora are said to possess an extremely thick femoral
cortex compared to both Australopithecus & modern humans ... medullar
stenosis seems to be typical mainly for later Eurasian H.erectus ...
NT Boaz & RL Ciochon 2004 Oxford UP
Dragon Bone Hill: An Ice-Age Saga of Homo erectus
H.erectus skull bone can be technically descibed as "pachyostotic"
(literally "thick-boned") ... Some species such sirenians have dense bones
throughout their bodies to give them negative buoyancy in the water.
THE POSTCRANIAL SKELETON OF EARLY EOCENE PAKICETID CETACEANS
SI Madar 2007 J.Paleontol.
Osteosclerosis is an increased thickness of the cortex, due to
replacement of trabecular bone with compact bone ...
Evidence of aquatic dependence from bone microstructure. - The
morphological adaptations for aquatic locomotion described above may appear
to suggest that pakicetids represent a very early stage of transition to
life in water, that these animals were not fully committed to an aquatic
environment, and remained better suited for terrestrial than aquatic
pursuits. However, evidence from bone microstructure demonstrates the
contrary - pakicetids were highly derived semiaquatic mammals. Skeletal
ballast was present in all pakicetid taxa (Fig.7). Hyperostosis and
osteosclerosis are found in all regions of the skeleton and are similarly
developed in juvenile and adult individuals of all 3 taxa. Long bone & rib
marrow cavities are either miniscule or absent due to thick cortices or
dense trabecular infill. Even vertebrae have hyperthick cortices.
Bone ballast in the form of osteosclerosis and hyperostosis is an
unmistakable hallmark of an aquatic lifestyle (Fish & Stein 1991; Domning &
de Buffrénil 1991; Taylor 1994; Madar 1998). Skeletal ballast has already
been described in early marine cetaceans (Buffrénil et al.1990; Madar 1998;
Uhen 2004) including Ambulocetus, Basilosaurus Harlan 1834, and Dorudon
Gibbes 1845. Pakicetids differ most from Ambulocetus & subsequent taxa in
their greater diaphyseal osteosclerosis, though all exhibit complete or near
complete infill of marrow cavities by trabecular bone. The increased
trabecular density & cortical hypertrophy found throughout the pakicetid
skeleton suggest an adaptation toward bottom walking or wading, as heavy
skeletons counteract buoyant effects of inflated lungs & furtrapped air. The
increased density of the pakicetid skeleton would have left these early
cetaceans wholly unsuited to running, or even prolonged terrestriality, as
heavy skeletons are energetically expensive to move. In addition, the
hypermineralization (osteopetroses) of pakicetid load bearing elements put
them at increased risk for fracture during terrestrial loading (de Vernejoul
& Bénichou 2001), a risk that rises with velocity. Thus, although they look
superficially similar to their cursorial relatives, it is likely that
pakicetids made few sustained terrestrial forays. The summed evidence of
bone gross morphology and microstructure indicates that pakicetid cetaceans
were fully committed to an aquatic lifestyle, and bore marked adaptations
for bottom walking, paddling, and undulatory swimming modes.- Hide quoted text -
- Show quoted text -[/quote] |
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