Aquarboreal ancestors?
Marc Verhaegen
http://journals.bmn.com/journals/list/latest?jcode=tree
Opinion
================================================================
Aquarboreal ancestors?
http://reviews.bmn.com/journals/atoz/latest?pii=S0169534702024904&node=TOC%4
0%40TREE%40017%4005%40017_05
New evidence confirms the idea that human ancestors were not
savannah-dwellers at all, but instead became bipedal in swampy forests, and
evolved during the Ice Ages into coastal omnivores along the Indian Ocean.
================================================================
Marc Verhaegen, Pierre-Francois Puech and Stephen Munro
Aquarboreal ancestors? [Opinion]
Trends in Ecology & Evolution, 2002, 17:5:212-217
Abstract
According to biomolecular data, the great apes split into Asian pongids
(orang-utan) and African hominids (gorillas, chimpanzees and humans) 18-12
million years ago (Mya) and hominids split into gorillas and
humans-chimpanzees 10-6 Mya. Fossils with pongid features appear in Eurasia
after c. 15 Mya, and fossils with hominid fossils appear in Africa after c.
10 Mya. Instead of the traditional savannah-dwelling hypothesis, we argue
that a combination of fossil (including the newly discovered Orrorin,
Ardipithecus and Kenyanthropus hominids) and comparative data now provides
evidence showing that: (1) the earliest hominids waded and climbed in swampy
or coastal forests in Africa-Arabia and fed partly on hard-shelled fruits
and molluscs; (2) their australopith descendants in Africa had a comparable
locomotion but generally preferred a diet including wetland plants; and (3)
the Homo descendants migrated to or remained near the Indian Ocean coasts,
lost most climbing abilities, and exploited waterside resources.
john thrum
death on sci.archaeology. Give it a rest. Mankind's origins are much more
complex than that.
john thrum
Marc Verhaegen
"john thrum" <missoulaleo@DIE_SPAMBOT_DIEearthlink.net> schreef in bericht
news:pOap8.1488$nt1.1...@newsread2.prod.itd.earthlink.net...
You don't seem to know what you are talking about?
FYI
http://allserv.rug.ac.be/~mvaneech/Symposium.html
http://archive.outthere.co.za/98/dec98/disp1dec.html
http://www.onelist.com/community/AAT
_________
Trends in Ecology & Evolution Vol. 17, No. 5, May 2002
http://journals.bmn.com/journals/list/latest?jcode=tree
Marc Verhaegen, Pierre-Francois Puech and Stephen Munro
Opinion
gen2rev
>
> "john thrum" <missoulaleo@DIE_SPAMBOT_DIEearthlink.net> schreef in bericht
> news:pOap8.1488$nt1.1...@newsread2.prod.itd.earthlink.net...
> > Oh no. Not the aquatic ape theory again. That's already been beaten to
> > death on sci.archaeology. Give it a rest. Mankind's origins are much
> more
> > complex than that. john thrum
>
> You don't seem to know what you are talking about?
>
> FYI
> http://allserv.rug.ac.be/~mvaneech/Symposium.html
> http://archive.outthere.co.za/98/dec98/disp1dec.html
The above link doesn't work.
Marc Verhaegen
"gen2rev" <gen...@crosswinds.net> schreef in bericht
news:3CA61E61...@crosswinds.net...
> Marc Verhaegen wrote:
> >
> > "john thrum" <missoulaleo@DIE_SPAMBOT_DIEearthlink.net> schreef in
bericht
> > news:pOap8.1488$nt1.1...@newsread2.prod.itd.earthlink.net...
> > > Oh no. Not the aquatic ape theory again. That's already been beaten
to
> > > death on sci.archaeology. Give it a rest. Mankind's origins are much
> > > more complex than that. john thrum
> >
> > You don't seem to know what you are talking about?
> > FYI
> > http://allserv.rug.ac.be/~mvaneech/Symposium.html
> > http://archive.outthere.co.za/98/dec98/disp1dec.html
>
> The above link doesn't work.
Sorry, I didn't check for some time. This should work
http://allserv.rug.ac.be/~mvaneech/outthere.htm
Marc Verhaegen
Mike Noren
>> Oh no. Not the aquatic ape theory again. That's already been beaten to
>> death on sci.archaeology. Give it a rest. Mankind's origins are much
>more
>> complex than that. john thrum
>
>You don't seem to know what you are talking about?
Isn't it what it's always been - free speculations about human traits
discussed out of context?
Pterosaur fossils are usually found in lake sediments, they lack hair
(to avoid staying wet) or they have hair (to avoid getting cold in the
water), they have hollow bones (improves buoyancy), beaks which are
adapted to catching fish, hind feet suitable for steering with, front
appendages not dissimilar to those of a ray... Why, pterosaurs must be
aquatic. Or possibly aeroaquatic.
My favourite part about the aquatic ape theory is that many of the
proposed characters are such that had we been exactly opposite, it
would still be compatible with the theory: example, humans have
reduced body hair and subcutaneous fat - like a seal. Obviously an
adaptation to a life in water. However imagine we had no subcutaneous
fat and a dense fur coat - like an otter. Obviously an adaptation to a
life in water.
This also means that this theory can never be disproven, will never
die, and I am pissing in the wind.
John Brock
I think you are being a bit unfair. I'm not a huge fan of the
Aquatic Ape theory, but from what I've seen it does appear to be
more than merely a tendentious interpretation of traits which could
go either way. Humans are strikingly different in appearance, in
particular in terms of fat and body hair, than their nearest
relatives, and they swim much better. The sort of moderate aquatic
phase Marc Verhaegen is suggesting -- wading in marshes and seashores
-- doesn't strike me as being totally crazy.
The thing is, nobody would have proposed the Aquatic Ape theory if
we had hair and fat like an otter, because that would have made us
a typical land mammal. (BTW, I though seals had dense fur, as in
"fur seals". You are thinking of manatees perhaps?). The primary
claim that the Aquatic Ape theory makes is that we have a suite of
characters which is unknown among among terrestrial mammals but
*not* unknown among aquatic mammals. The fact that this suite is
not *universal* among aquatic animals really doesn't weaken the
basic argument.
That said, I'm not arguing that AA is actually true, or even that
it's the most reasonable interpretation of the characters in
question. I'm just saying that I have never seen any arguments
which would cause AA to fail my own personal "that's crazy" test.
--
John Brock
jbr...@panix.com
P Bowles
He may be, but the point that the aquatic ape is a theory necessarily based on
conjecture and comparison rather than on evidence is valid - comparisons with
predominantly cold-water animals with an almost exclusively marine lifestyle
like seals are clearly implausible.
I'm not a huge fan of the
>Aquatic Ape theory, but from what I've seen it does appear to be
>more than merely a tendentious interpretation of traits which could
>go either way. Humans are strikingly different in appearance, in
>particular in terms of fat and body hair, than their nearest
>relatives, and they swim much better. The sort of moderate aquatic
>phase Marc Verhaegen is suggesting -- wading in marshes and seashores
>-- doesn't strike me as being totally crazy.
The proboscis monkey commonly wades through deep rivers and mangrove wetland
and is a strong swimmer - to an extent the same is true of the orang-utan and
of unrelated mammals like sloths (and the aforementioned otter), all of which
are heavily furred and appear to have evolved in similar rainforest habitats
which gave rise to our ancestors, not to mention every living species of ape
(gibbons included). The aquatic ape theory, even in its newly revived form,
does nothing to explain human differences from their close relatives. It can't
even explain why humans are different from sloths, for that matter...
>The thing is, nobody would have proposed the Aquatic Ape theory if
>we had hair and fat like an otter, because that would have made us
>a typical land mammal. (BTW, I though seals had dense fur, as in
>"fur seals". You are thinking of manatees perhaps?)
Depends very much on the species - leopard seals and elephant seals are largely
hairless, for example.
. The primary
>claim that the Aquatic Ape theory makes is that we have a suite of
>characters which is unknown among among terrestrial mammals but
>*not* unknown among aquatic mammals.
This is akin to saying that whales have characteristics found in aquatic
mammals but not in terrestrial mammals, and therefore whales could never have
evolved from a terrestrial species - the leap of logic is not justified by the
evidence. The absence of evidence for predominantly aquatic humans (such as
fossils preserved in river or coastal sediment, or evidence of adaptions
unequivocally suited to an aquatic lifestyle in our forebears) makes any
assumption about an aquatic past untenable.
Philip Bowles
Daniel Snyder
deal with these ridiculous furballs and their
gargantuan brains in the direction of a good
debunking of the AAT? I couldn't find one
on the Net last night.
P Bowles
I don't know of any authoritative refutations, but gen2rev identified the
problem with debunking the aquatic ape theory - how do you refute a theory
which is unsupported by evidence? The aquatic ape, in all its forms, is based
entirely on speculative comparisons with living animals of various sorts, and
the only way to counter an argument like this is with more speculation such as
that already presented on this thread - for instance, the fact that no other
swamp or moist forest primate, or even mammal, has evolved similar
characteristics to humans despite similar environmental pressures - human
physiological uniqueness would seem to be a powerful argument *against* the
aquatic ape as mammals with lifestyles similar to those proposed by the theory
(bipedal waders, strong swimmers in marsh or riverine habitat) exist today but
share none of the characteristics the theory suggests that we owe to this
lifestyle.
Philip Bowles
P Bowles
Correction: It was Mike Noren rather than gen2rev who identified the problem
with the aquatic ape earlier in the thread.
Philip Bowles
Mike Noren
>>My favourite part about the aquatic ape theory is that many of the
>>proposed characters are such that had we been exactly opposite, it
>>would still be compatible with the theory: example, humans have
>>reduced body hair and subcutaneous fat - like a seal. Obviously an
>>adaptation to a life in water. However imagine we had no subcutaneous
>>fat and a dense fur coat - like an otter. Obviously an adaptation to a
>>life in water.
>>
>>This also means that this theory can never be disproven, will never
>>die, and I am pissing in the wind.
>
>I think you are being a bit unfair. I'm not a huge fan of the
>Aquatic Ape theory, but from what I've seen it does appear to be
>more than merely a tendentious interpretation of traits which could
>go either way.
Really? Haven't noticed. All I've read have capitalized heavily on
things such as that Lucy was found in sediment deposited in a pond or
swamp (instead of, presumably, in a tree), that infants have a
breathing reflex for a few days after birth, and that humans have less
hair than chimps (which incidentally we don't - we just have _shorter
and thinner_ hair).
> Humans are strikingly different in appearance, in
>particular in terms of fat and body hair, than their nearest
>relatives, and they swim much better.
Humans don't swim worth a sh*t unless taught how to, as attested by
the thousands of people who drown each year. I don't know if anyone's
tried to teach a chimp to do breast strokes, but one might note that
ability to swim is a primitive trait among primates (and so more
likely to have been *lost* in the apes than *gained* in humans), and
also that the only monkey I know which does live an aquarboreal life
(proboscis monkey) have not developed much any traits similar to
humans. Except the magnificent nose.
> The sort of moderate aquatic
>phase Marc Verhaegen is suggesting -- wading in marshes and seashores
>-- doesn't strike me as being totally crazy.
No, it's just an unfalsifiable hypothesis based on idle speculations.
>The thing is, nobody would have proposed the Aquatic Ape theory if
>we had hair and fat like an otter, because that would have made us
>a typical land mammal. (BTW, I though seals had dense fur, as in
>"fur seals". You are thinking of manatees perhaps?).
Fur seals are a special group of seals, and considered quite
primitive. Most seals have a sparse short fur which doesn't do much
for their isolation, instead relying on a thick layer of blubber (take
a look at a walross, for instance).
> The primary
>claim that the Aquatic Ape theory makes is that we have a suite of
>characters which is unknown among among terrestrial mammals but
>*not* unknown among aquatic mammals.
I just made a similar case for pterosaurs.
>question. I'm just saying that I have never seen any arguments
>which would cause AA to fail my own personal "that's crazy" test.
It's not crazy - it's just speculative and unfalsifiable, like
essentially all 'hypothetical ancestor' scenarios.
My personal, equally unfalsifiable, guess is that we have these traits
because we're neotenous apes, and that our perceived water adaptations
are retained juvenile characters lost in adult apes. Perhaps one could
call it the baby ape theory.
Mike Noren
And I dont think you will find one. Partly because it's unfalsifiable,
and hence also undebunkable, partly because the guys in the field
(which, thank god, I'm not), the ones who should be doing the
debunking, get all touchy-feely about this theory. Call it keeping an
open mind or call it whoring for grants, but the kid gloves are on.
Marc Verhaegen
"Mike Noren" <michae...@nrm.se> schreef in bericht
news:mkmcauk2dhvn7gcdi...@4ax.com...
> Replying to "Marc Verhaegen" <marc.ve...@village.uunet.be> :
>
> >> Oh no. Not the aquatic ape theory again. That's already been beaten
to
> >> death on sci.archaeology. Give it a rest. Mankind's origins are much
> >> more complex than that. john thrum
> >
> >You don't seem to know what you are talking about?
>
> Isn't it what it's always been - free speculations about human traits
> discussed out of context?
:-) Apparently you haven't read the paper..
Marc Verhaegen
http://www.onelist.com/community/AAT
http://allserv.rug.ac.be/~mvaneech/Verhaegen.html
Marc Verhaegen
"John Brock" <jbr...@panix.com> schreef in bericht
news:a877v8$6jk$1...@panix2.panix.com...
> The thing is, nobody would have proposed the Aquatic Ape theory if
> we had hair and fat like an otter, because that would have made us
> a typical land mammal. (BTW, I thought seals had dense fur, as in
> "fur seals".
Furseals have very dense fur AFAIK, sealions & common seals have less dense
fur. Many of them lack underfur, and the largest ones (Weddell sealions,
walrusses, elephant seals) have no fur at all, at least the adult males.
Marc Verhaegen
"P Bowles" <pbo...@aol.com> schreef in bericht
news:20020331110055...@mb-fr.aol.com...
....
> (gibbons included). The aquatic ape theory, even in its newly revived
form,
> does nothing to explain human differences from their close relatives. It
can't
> even explain why humans are different from sloths, for that matter...
I suggest you read read the paper first.
....
> Depends very much on the species - leopard seals and elephant seals are
largely
> hairless, for example. ....
Leopard seals do have fur. AFAIK the only rurless pinnipeds are adult male
walruses, Weddell sealions & elephants seals
Rain
<marc.ve...@village.uunet.be> writes
>Trends in Ecology & Evolution Vol. 17, No. 5, May 2002
>http://journals.bmn.com/journals/list/latest?jcode=tree
>
>
>
>Opinion
My opinion is that the aquatic ape theory is null and void. The aquatic
animals used for comparison have 50, 40, 30 million years of evolution
behind them we only have 3 million.
This is just what jungle gorillas do.
--
The Carbon
http://www.earthpoetry.demon.co.uk
RC
John Wilkins
> "P Bowles" <pbo...@aol.com> schreef in bericht
> news:20020331110055...@mb-fr.aol.com...
>
> ....
> > (gibbons included). The aquatic ape theory, even in its newly revived
> form,
> > does nothing to explain human differences from their close relatives. It
> can't
> > even explain why humans are different from sloths, for that matter...
>
> I suggest you read read the paper first.
>
> ....
>
> > Depends very much on the species - leopard seals and elephant seals are
> largely
> > hairless, for example. ....
>
> Leopard seals do have fur. AFAIK the only rurless pinnipeds are adult male
> walruses, Weddell sealions & elephants seals
>
Marianne Riedeman says (p3)
The hair or fur has laregly disappeared in walruses ... although a close
examination of the skin reveals a sparse covering of coarse hairs in
some species. Phocid and otariid seals have retained a fur coat that is
plainly visible, although the coats of sea lions and some phocids are
more sparse and streamlined than those of most land mammals....
The fur seals, however, are well known for their thick fur...<eq>
Riedman, Marianne. The Pinnipeds: Seals, Sea Lions, and Walruses.
Berkeley: University of California Press, 1991.
--
John Wilkins
Occasionally making sense for over 46 years
Mike Noren
>> >You don't seem to know what you are talking about?
>>
>> Isn't it what it's always been - free speculations about human traits
>> discussed out of context?
>
>:-) Apparently you haven't read the paper..
>
>Marc Verhaegen
>http://www.onelist.com/community/AAT
>http://allserv.rug.ac.be/~mvaneech/Verhaegen.html
>
I looked at the referenced sites.
The first was a discussion board, with, as far as I could tell,
nothing but idle speculations.
The second is an article in the vein of the 'documentaries' sometimes
seen on TV, where 'may' 'could' 'might' 'possibly' and 'perhaps' are
piled upon eachother until eventually they are treated as facts
leading to a conclusion.
Several of the statements are, to my eyes, surprising: what kind of
dentition suggests a diet of fruit (soft), water plants (soft), and
grass (extremely hard)?
And the statement about great ape fossils from 12 - 8Myrs ago; I
wasn't aware that any ape fossils had been found from that period?
The rest is the standard fare speculation. Take this sentence, for
instance:
"The fossil data indicates that the early australopithecines of 4-3
million years ago lived in waterside forests or woodlands; and their
larger, robust relatives of 2-1 million years ago in generally more
open milieus near marshes and reedbeds, where they could have waded
bipedally."
What is this based on? Lucy, found in sediment deposited in a pond.
Never mind that most fossils, also of e.g. birds and bats, are
preserved in aquatic sediments. And speculation.
Corvùn & Celeste Sæpius
none that doesn't either imply neotony, adaptation for
savannah-habitat, or combination of the two. Evidence against it:
makes no sense for hominids to loose hair density as an aquatic
adaptation since the body itself has not been streamlined, giving
human ancestors no speed advantage in the water -- upper limbs retain
brachiating-type movement and lower limbs locked into back & forth
motion (VERY undesirable for an aquatic lifestyle)...um...let's
see...the position of the foramen magnum to perch the skull atop a
vertical spinal column (this makes sense for a wading animal, but not
manueverable swimmer who needs less body hair!), the loss of the
opposable first didgit on the foot (can't even grip objects under
water to keep steady in a current)...and I'm sure I could extend the
list at least one power of magnitude if I really thought hard about
it.
The aquatic ape theory is garbage -- all it does is create a
less-plausible (and overly simplistic) answer to a complicated
question.
And as for Lucy being found in sediment that used to be a pond: do the
AAT supporters think that if Lucy wasn't a wannabe sea-lion that she
accordingly didn't even need to get a sip of water every once in a
while? I mean JESUS! Of course Our ancestors spent *some* time in or
at least near the water, and this may have helped in some of the
features that distinguish us from our fellow apes -- but the AAT guys
think that the layer of fat that humans have proves their theory
because they see a similarity to whale blubber. Sorry guys, but Lucy
wasn't some 1,000 lb seal at the north pole! Blubber doesn't make any
sense for even an aquatic species at that period of time in that area!
Fuck'n Duh! Besides, MOST endotherms have at least a thin layer of fat
beneath the skin.
AAT doesn't need to be debunked. Anyone with even a gradeschool
understanding of evolution can see that it's total bullshit.
Seriousely, what's going on here? Remedial Anthropology?
--
Corvun Sępius
~ Coven of the Shadow Moon ~
"Hear Now the Words of the Witches,
The Secrets We Hid in the Night,
When Dark was Our Destiny's Pathway,
That Now We Bring Forth into Light!"
"Mike Noren" <michae...@nrm.se> wrote in message
news:g6ueaucdu93letojv...@4ax.com...
Jim McGinn
"Corvųn & Celeste Sæpius" <theol...@hotmail.com> wrote in message
news:uaf9p9d...@corp.supernews.com...
I've read many online critiques of AAT. This was the sharpest, most
accurate and most learned that I've read. If Marc understood half of what
you were talking about here he'd be stunned into eternal silence.
And if elephants had rocket engines strapped to their butts . . .
Jim
P Bowles
>accurate and most learned that I've read. If Marc understood half of what
>you were talking about here he'd be stunned into eternal silence.
>
>And if elephants had rocket engines strapped to their butts . . .
I'm inclined to agree - I stand corrected, the theory can and has been truly
debunked.
Philip Bowles
P Bowles
>form,
>> does nothing to explain human differences from their close relatives. It
>can't
>> even explain why humans are different from sloths, for that matter...
>
>I suggest you read read the paper first.
>
It may surprise you to learn that someone can read the articles you posted
links to and remain unconvinced by the aqautc ape, but I have indeed done that
- none refute any of the points I've made, least of all the fact that mammals
with an 'aquaboreal' lifestyle in tropical forest today have developed none of
the adaptions seen in humans to cope with that lifestyle. Surely you must
realise that drawing comparisons between humans and completely unrelated
cold-water animals with a completely different body size, shape and a totally
marine lifestyle (like seals or whales) is extremely simplistic as the
environmental conditions and selective pressures at work are entirely different
(and as far as I know no form of the aquatic ape theory has ever proposed that
our ancestors led a lifestyle as heavily dependent on a marine environment as a
seal's). Some of the points made in the articles have merit - coastal humans
undoubtedly learned to use tools to eat shellfish and humans obviously needed
good access to water sources, but it is a huge leap from this to supposing that
humans had a largely aqautic lifestyle at some stage in their past, let alone
that this was a major influence on human evolution - human fishermen today
don't show any specific adaptions to an aquatic lifestyle, and it's hard to see
why a proto-human drinking from lakes or grubbing in rock pools for shellfish
would have done so.
Philip Bowles
Marc Verhaegen
news:1f9ydrp.16aoc9c1ko5uv4N%john.w...@bigpond.com...
.......
> > > Depends very much on the species - leopard seals and
> > > elephant seals are largely hairless, for example. ....
> >
> > Leopard seals do have fur. AFAIK the only furless pinnipeds are adult
male
> > walruses, Weddell sealions & elephants seals
>
> Marianne Riedeman says (p3)
> The hair or fur has laregly disappeared in walruses ... although a close
> examination of the skin reveals a sparse covering of coarse hairs in
> some species. Phocid and otariid seals have retained a fur coat that is
> plainly visible, although the coats of sea lions and some phocids are
> more sparse and streamlined than those of most land mammals....
> The fur seals, however, are well known for their thick fur...<eq>
> Riedman, Marianne. The Pinnipeds: Seals, Sea Lions, and Walruses.
> Berkeley: University of California Press, 1991.
> John Wilkins
Yes. Thanks. Young walruses (odobenid) & female Weddell sealions (otariid) &
elephant seals (phocid) retain fur, but the adult males are furless (depends
on the subspecies in walruses I believe). Of the otariids, the furseals
generally have very dense fur, but in sealions it's usu. less dense.
Marc Verhaegen
> Replying to "Marc Verhaegen" <marc.ve...@village.uunet.be> :
>
> >> >You don't seem to know what you are talking about?
> >>
> >> Isn't it what it's always been - free speculations about human traits
> >> discussed out of context?
> >
> >:-) Apparently you haven't read the paper..
No answer?
> > Marc Verhaegen
> > http://www.onelist.com/community/AAT
> > http://allserv.rug.ac.be/~mvaneech/Verhaegen.html
> I looked at the referenced sites.
> The first was a discussion board, with, as far as I could tell,
> nothing but idle speculations.
Yes, of course, just like here...
Please have a look at the files. (You can also find our TREE paper there.)
> The second is an article in the vein of the 'documentaries' sometimes
> seen on TV, where 'may' 'could' 'might' 'possibly' and 'perhaps' are
> piled upon eachother until eventually they are treated as facts
> leading to a conclusion.
It's one of the papers presented at the "Water and human evolution"
symposium 2 years ago. All very speculatieve, of course (what had you
expected?), but you can find articles pro & con at the website
http://allserv.rug..be/~mvaneech/Symposium.html
> Several of the statements are, to my eyes, surprising: what kind of
> dentition suggests a diet of fruit (soft), water plants (soft), and
> grass (extremely hard)?
Read our TREE paper & the refs eg, of Puech & of Ungar.
Trends in Ecology & Evolution 17, No. 5, May 2002
Aquarboreal ancestors?
http://reviews.bmn.com/journals/atoz/latest?pii=S0169534702024904&node=TOC%4
0%40TREE%40017%4005%40017_05
Marc Verhaegen, Pierre-Francois Puech and Stephen Munro
> And the statement about great ape fossils from 12 - 8Myrs ago; I
> wasn't aware that any ape fossils had been found from that period?
Not my fault, Mike...
> The rest is the standard fare speculation. Take this sentence, for
> instance:
> "The fossil data indicates that the early australopithecines of 4-3
> million years ago lived in waterside forests or woodlands; and their
> larger, robust relatives of 2-1 million years ago in generally more
> open milieus near marshes and reedbeds, where they could
> have waded bipedally."
> What is this based on?
4-3 Ma apiths: waterside forests & woodlands:
§ Ardipithecus ramidus: 'Sedimentological, botanical and faunal
evidence suggests a wooded habitat for the Aramis hominids [.] Aquatic
elements (turtle, fish, crocodile) are rare. Large mammals (hippopotamus,
proboscideans, rhinos, equids, giraffids, bovines) are rare. Primates are
very abundant' (WoldeGabriel et al., 1994); '[.] interpreted to have been a
closed woodland. At Aramis, aquatic species and large mammals are rare, and
colobines make up over 30% of all vertebrate specimens collected' (Leakey et
al., 1995).
§ Kanapoi KNM-KP 29281 Australopithecus anamensis: Fish, aquatic
reptiles, kudus and monkeys are prevalent. 'A wide gallery forest would have
almost certainly been present on the large river that brought in the
sediments' (Leakey et al., 1995).
§ Chad KT 12 A. cf. afarensis: 'The non-hominid fauna contains
aquatic taxa (such as Siluridae, Trionyx, cf. Tomistoma), taxa adapted to
wooded habitats (such as Loxodonta, Kobus, Kolpochoerus) and to more open
areas (such as Ceratotherium, Hipparion) [.] compatible with a lakeside
environment' (Brunet et al., 1995).
§ Hadar, Afar Locality: 'Generally, the sediments represent
lacustrine, lake margin, and associated fluvial deposits related to an
extensive lake that periodically filled the entire basin' (Johanson et al.,
1982)
§ Hadar AL.333 A. afarensis: 'The bones were found in swale-like
features [.] it is very likely that they died and partially rotted at or
very near this site [.] this group of hominids was buried in streamside
gallery woodland' (Radosevich et al., 1992).
§ Hadar AL.288 gracile A. afarensis: Lucy lay in a small, slow
moving stream. 'Fossil preservation at this locality is excellent, remains
of delicate items such as crocodile and turtle eggs and crab claws being
found' (Johanson & Taieb, 1976).
§ Makapan A. africanus: '[.] very different conditions from those
prevailing today. Higher rainfall, fertile, alkaline soils and moderate
relief supported significant patches of sub-tropical forest and thick bush,
rather than savannah. Taphonomic considerations [.] suggest that
sub-tropical forest was the hominins' preferred habitat rather than
grassland or bushveld, and the adaptations of these animals was therefore
fitted to a forest habitat' (Rayner et al., 1993; see also Reed, 1993; and
Wood, 1993).
§ Taung australopithecine: 'the clayey matrix from which the Taung
cranium was extracted, and the frequent occurrence of calcite veins and void
fillings within it (Butzer, 1974, 1980) do suggest a more humid environment
during its accumulation' (Partridge, 1985).
2-1 Ma robust apiths: more open wetlands:
§ Kromdraai: A. robustus was found near grassveld and streamside or
marsh vegetation, in the vicinity of quail, pipits, starlings, swallows, and
parrots, lovebirds and similar psittacine birds (T. N. Pocock in Brain,
1981).
§ Turkana KNM-ER 17000 and 16005: A. aethiopicus was discovered near
the boundary between overbank deposits of large perennial river and alluvial
fan deposits, amid water- and reedbucks (Walker et al., 1986).
§ Lake Turkana: 'The lake margins were generally swampy, with
extensive areas of mudflats [.] Australopithecus boisei was more abundant in
fluvial environments, whereas Homo habilis was rare in such environments [.]
Australopithecus fossils are more common than Homo both in channel and
floodplain deposits. The gracile hominids [.] seem to be more restricted
ecologically to the lake margin than are the robust forms' (Conroy, 1990).
§ Ileret A. boisei: 'the fossil sample reflects climatic and
ecological environmental conditions differing significantly from those of
the present day. At Ileret, 1.5 Myr ago, climatic conditions must have been
cooler and more humid than today, and more favourable to extensive forests
[.] The prominence of montane forest is particularly striking [.] dominated
by Gramineae and Chenopodiaceae appropriate to the margins of a slightly
saline or alkaline lake' (Bonnefille, 1976).
§ Chesowanja A. boisei: 'The fossiliferous sediments were deposited
in a lagoon [.] Abundant root casts [.] suggest that the embayment was
flanked by reeds and the presence of calcareous algae indicates that the
lagoon was warm and shallow. Bellamya and catfish are animals tolerant of
relatively stagnant water, and such situation would also be suitable for
turtles and crocodiles' (Carney et al., 1971).
§ Kaye E. Reed 1997 "Early hominid evolution and ecological change
through the African Plio-Pleistocene" JHE 32:289-322: "... Reconstructed
habitats show that Australopithecus species existed in fairly wooded,
well-watered regions. Paranthropus species lived in similar environs and
also in more open regions, but always in habitats that include wetlands."
If the robust apiths lived in wetlands, they must have waded bipedally
there, just as western lowland gorillas frequently do.
Marc Verhaegen
Marc Verhaegen
"Corvųn & Celeste Sæpius" <theol...@hotmail.com> schreef in bericht
news:uaf9p9d...@corp.supernews.com...
> Who says the aquatic ape theory can't be debunked? Evidence for it:
> none that doesn't either imply neotony, adaptation for
> savannah-habitat, or combination of the two.
1) Neoteny doesn't explain anything: it's only a description of possible
genetic mechanisms. It doesn't explain why we got larger brains, why we
became biped etc.
2) Savanna?? :-D You still believe in the savanna fantasies? No sensible
paleo-anthropologist still does, Saepie (=vocative of Saepius? :-)): human
physiology is the opposite of that of savanna-dwelling mammals. See part of
my Scientific Correspondence letter to Nature many years ago
Nature 325:305-306, 1987
"Origin of hominid bipedalism"
Sinclair et al. (1) believe that human bipedalism arose in scavenging
hominid ancestors that had to carry their children while following migrating
savanna ungulates but this seems highly improbable.
There was no empty niche of migrating scavengers to be occupied by hominid
ancestors. Not only vultures, but aso canid, felid and hyaenid carnivores
were much better preadapted for such a niche. They possessed sharp beaks or
long canine teeth and did not need to carry stones for cutting carcasses.
Moreover, the bipedal way of locomotion - whether fast of slow - is
inefficient and costly (2,3).
Another argument against the migrating hypothesis in particular and the
savannah theory of human evolution in general is that it is highly unlikely
that hominid ancestors ever lived in the savannas. Man is the opposite of a
savanna inhabitant. Humans lack sun-reflecting fur (4) but have
thermo-insulative subcutaneous fat layers, which are never seen in savanna
mammals. We have a water- and sodium-wasting cooling system of abundant
sweat glands, totally unfit for a dry environment (5). Our maximal urine
concentration is much too low for a savanna-dwelling mammal (6). We need
much more water than other primates, and have to drink more often than
savanna inhabitants, yet we cannot drink large quantities at a time (7-8).
...
1. Sinclair, A. R. E., Leakey, M. D. & Norton, M. Nature 324, 307
(1986).
2. Washburn, S. L. & Moore, R. Ape Into Human, 77-78 (Little, Brow
and Company, Boston, 1980).
3. Wheeler, P. E. J. Hum. Evol. 13, 91 (1984).
4. Macfarlane, W. V. in Adaptations of Domestic Animals (ed. Hafez,
E.) 164-182 (Lea and Febifer, Philadelphia, 1968).
5. Montagna, W. in Biological Anthropology (ed. Katz, S. H.) 341-351
(Freeman, San Francisco, 1975).
6. McFarland, W.N., Pough, F.H., Cade, T.J. & Heiser, J. B.
Vertebrate Life, 674 (Collier Macmillan, London,1979).
7. McFarland, D. Animal Behaviour, 267 (Pitman, London, 1985).
8. Schmidt-Nielsen, K. Desert Animals, 67 (Dover Publications, New
York, 1979).
...
Marc Verhaegen
"Rain" <r...@earthpoetry.demon.co.uk> schreef in bericht
news:tnLrqfEG...@earthpoetry.demon.co.uk...
> My opinion is that the aquatic ape theory is null and void. The aquatic
> animals used for comparison have 50, 40, 30 million years of evolution
> behind them we only have 3 million.
If you had read the paper, Rain, you would have known, that it's NOT about
an "aquatic" (sensu cetacean) lifestyle..
================================================================
Aquarboreal ancestors?
http://reviews.bmn.com/journals/atoz/latest?pii=S0169534702024904&node=TOC%4
0%40TREE%40017%4005%40017_05
New evidence confirms the idea that human ancestors were not
savannah-dwellers at all, but instead became bipedal in swampy forests, and
evolved during the Ice Ages into coastal omnivores along the Indian Ocean.
================================================================
Marc Verhaegen, Pierre-Francois Puech and Stephen Munro
Aquarboreal ancestors? [Opinion]
According to biomolecular data, the great apes split into Asian pongids
(orang-utan) and African hominids (gorillas, chimpanzees and humans) 18-12
million years ago (Mya) and hominids split into gorillas and
humans-chimpanzees 10-6 Mya. Fossils with pongid features appear in Eurasia
after c. 15 Mya, and fossils with hominid fossils appear in Africa after
c.10 Mya. Instead of the traditional savannah-dwelling hypothesis, we argue
Mike Noren
>> >> Isn't it what it's always been - free speculations about human traits
>> >> discussed out of context?
>> >
>> >:-) Apparently you haven't read the paper..
>
>No answer?
Actually, I thought that
http://allserv.rug.ac.be/~mvaneech/Verhaegen.html WAS the article. I
now see you provide a reference, and I'll have a look at it.
>Please have a look at the files. (You can also find our TREE paper there.)
OK.
>> The second is an article in the vein of the 'documentaries' sometimes
>> seen on TV, where 'may' 'could' 'might' 'possibly' and 'perhaps' are
>> piled upon eachother until eventually they are treated as facts
>> leading to a conclusion.
>
>It's one of the papers presented at the "Water and human evolution"
>symposium 2 years ago. All very speculatieve, of course (what had you
>expected?)
That was in fact exactly what I expected. However, I seem to recall
you referred me to that article in response to my statement that the
AAT is nothing but idle speculation about human traits discussed out
of context.
>> Several of the statements are, to my eyes, surprising: what kind of
>> dentition suggests a diet of fruit (soft), water plants (soft), and
>> grass (extremely hard)?
>
>Read our TREE paper & the refs eg, of Puech & of Ungar.
>Trends in Ecology & Evolution 17, No. 5, May 2002
>Aquarboreal ancestors?
Will do. It will be quite interesting to see the details of this novel
type of dentition.
>> And the statement about great ape fossils from 12 - 8Myrs ago; I
>> wasn't aware that any ape fossils had been found from that period?
>
>Not my fault, Mike...
True. Do you have a reference?
>> The rest is the standard fare speculation. Take this sentence, for
>> instance:
>> "The fossil data indicates that the early australopithecines of 4-3
>> million years ago lived in waterside forests or woodlands; and their
>> larger, robust relatives of 2-1 million years ago in generally more
>> open milieus near marshes and reedbeds, where they could
>> have waded bipedally."
>> What is this based on?
>
>4-3 Ma apiths: waterside forests & woodlands:
More or less.
>§ Ardipithecus ramidus: 'Sedimentological, botanical and faunal
>evidence suggests a wooded habitat for the Aramis hominids [.] Aquatic
>elements (turtle, fish, crocodile) are rare.
Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
>§ Kanapoi KNM-KP 29281 Australopithecus anamensis: Fish, aquatic
>reptiles, kudus and monkeys are prevalent. 'A wide gallery forest would have
>almost certainly been present on the large river that brought in the
>sediments' (Leakey et al., 1995).
Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
>§ Chad KT 12 A. cf. afarensis: 'The non-hominid fauna contains
>aquatic taxa (such as Siluridae, Trionyx, cf. Tomistoma), taxa adapted to
>wooded habitats (such as Loxodonta, Kobus, Kolpochoerus) and to more open
>areas (such as Ceratotherium, Hipparion) [.] compatible with a lakeside
>environment' (Brunet et al., 1995).
Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
>§ Hadar, Afar Locality: 'Generally, the sediments represent
>lacustrine, lake margin, and associated fluvial deposits related to an
>extensive lake that periodically filled the entire basin' (Johanson et al.,
>1982)
Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
>§ Hadar AL.333 A. afarensis: 'The bones were found in swale-like
>features [.] it is very likely that they died and partially rotted at or
>very near this site [.] this group of hominids was buried in streamside
>gallery woodland' (Radosevich et al., 1992).
Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
>§ Hadar AL.288 gracile A. afarensis: Lucy lay in a small, slow
>moving stream. 'Fossil preservation at this locality is excellent, remains
>of delicate items such as crocodile and turtle eggs and crab claws being
>found' (Johanson & Taieb, 1976).
Ie at least this one probably died in the water, although this doesn't
really lend support to an 'aquarboreal' lifestyle for Lucy either.
(And incidentally it seems vertebrate paleontologists have a different
view of what is 'delicate' than invertebrate paleontologists)
>§ Makapan A. africanus: '[.] very different conditions from those
>prevailing today. Higher rainfall, fertile, alkaline soils and moderate
>relief supported significant patches of sub-tropical forest and thick bush,
>rather than savannah. Taphonomic considerations [.] suggest that
>sub-tropical forest was the hominins' preferred habitat rather than
>grassland or bushveld, and the adaptations of these animals was therefore
>fitted to a forest habitat' (Rayner et al., 1993; see also Reed, 1993; and
>Wood, 1993).
Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
>§ Taung australopithecine: 'the clayey matrix from which the Taung
>cranium was extracted, and the frequent occurrence of calcite veins and void
>fillings within it (Butzer, 1974, 1980) do suggest a more humid environment
>during its accumulation' (Partridge, 1985).
Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
Again, fossils tend to be found in sediments deposited in water
because sediments accumulate in water but erodes in air.
If one million Lucys all died on mountain slopes only the ones which
happened to be flushed into a lake (or slipped on the embankment and
drowned) would fossilize.
Simply put, finding a fossil in a lacustrine sediment is not in any
way proof it actually lived there.
>2-1 Ma robust apiths: more open wetlands:
And here you just did one of those glidings to conclusion. Your
references speak of forest, not of open wetlands.
>§ Kromdraai: A. robustus was found near grassveld and streamside or
>marsh vegetation, in the vicinity of quail, pipits, starlings, swallows, and
>parrots, lovebirds and similar psittacine birds (T. N. Pocock in Brain,
>1981).
Ie this fossil suggest an 'aquarboreal' lifestyle for the ancestors of
lovebirds and swallows.
>§ Turkana KNM-ER 17000 and 16005: A. aethiopicus was discovered near
>the boundary between overbank deposits of large perennial river and alluvial
>fan deposits, amid water- and reedbucks (Walker et al., 1986).
Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
>§ Lake Turkana: 'The lake margins were generally swampy, with
>extensive areas of mudflats [.] Australopithecus boisei was more abundant in
>fluvial environments, whereas Homo habilis was rare in such environments [.]
>Australopithecus fossils are more common than Homo both in channel and
>floodplain deposits. The gracile hominids [.] seem to be more restricted
>ecologically to the lake margin than are the robust forms' (Conroy, 1990).
This is speculation on Conroys part. It's not like the amount of
fossils allows one to actually make a statistical evaluation (and even
if they did, living on the banks of a lake does not necessarily imply
an 'aquarboreal' lifestyle).
>§ Ileret A. boisei: 'the fossil sample reflects climatic and
>ecological environmental conditions differing significantly from those of
>the present day. At Ileret, 1.5 Myr ago, climatic conditions must have been
>cooler and more humid than today, and more favourable to extensive forests
>[.] The prominence of montane forest is particularly striking [.] dominated
>by Gramineae and Chenopodiaceae appropriate to the margins of a slightly
>saline or alkaline lake' (Bonnefille, 1976).
Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
>§ Chesowanja A. boisei: 'The fossiliferous sediments were deposited
>in a lagoon [.] Abundant root casts [.] suggest that the embayment was
>flanked by reeds and the presence of calcareous algae indicates that the
>lagoon was warm and shallow. Bellamya and catfish are animals tolerant of
>relatively stagnant water, and such situation would also be suitable for
>turtles and crocodiles' (Carney et al., 1971).
Well, atleast that implies it, like lucy, died in situ, or were
flushed there during torrential rains. Still not really support for an
'aquarboreal' lifestyle, although it is support for the view that they
atleast occasionally, possibly voluntarily, entered water.
>§ Kaye E. Reed 1997 "Early hominid evolution and ecological change
>through the African Plio-Pleistocene" JHE 32:289-322: "... Reconstructed
>habitats show that Australopithecus species existed in fairly wooded,
>well-watered regions. Paranthropus species lived in similar environs and
>also in more open regions, but always in habitats that include wetlands."
So do Zebras, Lions and extant humans. Ie this fossil doesn't suggest
an 'aquarboreal' lifestyle, only that they needed regular access to
water (and fossilized in lacustrine sediments). Which, regarding early
humans, I'd say is fairly uncontroversial.
>If the robust apiths lived in wetlands, they must have waded bipedally
>there, just as western lowland gorillas frequently do.
And that is another gliding into conclusion based on 'could'
'possibly' 'might' speculation.
I will give you one piece of advice, though: rewrite the article and
send it to Nature. You're almost guaranteed to be accepted, and you
will get instant widespread acceptance of your theory.
>Marc Verhaegen
Gerrit Hanenburg
>§ Kaye E. Reed 1997 "Early hominid evolution and ecological change
>through the African Plio-Pleistocene" JHE 32:289-322: "... Reconstructed
>habitats show that Australopithecus species existed in fairly wooded,
>well-watered regions. Paranthropus species lived in similar environs and
>also in more open regions, but always in habitats that include wetlands."
But the following sentence in that paper says: "Homo is the first
hominid to exist in areas of fairly open, arid grassland." If you
accept this ecological structure analysis with regard to
Australopithecus and Paranthropus then why reject it with regard to
Homo?
Gerrit
P Bowles
>paleo-anthropologist still does, Saepie (=vocative of Saepius? :-)): human
>physiology is the opposite of that of savanna-dwelling mammals.
Of course human physiology has more in common with forest animals than savannah
ones - the fact that human evolution progressed through many of its crucial
stages in a forested environment is now fairly well-established. However, it
cannot be denied that at some stage our ancestors left the forests, and the
environment they encountered upon doing so was savannah - had they been unable
to adapt to some degree, we would not be here.
One assumption aquatic ape theorists make which is unjustified is that we lost
our thick body hair while still inhabiting a forest. We cannot know this - we
have only skeletal remains from early hominids, no hair or skin. There is no
particular reason to suppose that hair loss occurred at the same time as, for
instance, increased brain size or bipedalism. You only need to look at the
thickness and rate of growth of human hair in northern populations compared
with equatorial ones to know that losing or gaining hair is an adaption which
can occur over very short timescales. Unlike most savannah species, our
ancestors would have had dark skin and exposing this skin to the powerful
savannah sun makes evolutionary sense as a way to increase vitamin production
within the human body.
Philip Bowles
Mike Noren
>
>"Corvųn & Celeste Sæpius" <theol...@hotmail.com> schreef in bericht
>news:uaf9p9d...@corp.supernews.com...
>> Who says the aquatic ape theory can't be debunked? Evidence for it:
>> none that doesn't either imply neotony, adaptation for
>> savannah-habitat, or combination of the two.
>
>1) Neoteny doesn't explain anything: it's only a description of possible
>genetic mechanisms. It doesn't explain why we got larger brains, why we
>became biped etc.
Actually that is not entirely true, although selection is probably the
driving force. Well, it is true of bipedalism, but not re: brain size,
subcutaneous fat, or shorter/thinner hair.
>2) Savanna?? :-D You still believe in the savanna fantasies?
Your own references speak of a milieu reminiscent of a forest savanna,
with gallery forest around the bodies of water.
>No sensible
>paleo-anthropologist still does, Saepie (=vocative of Saepius? :-)): human
>physiology is the opposite of that of savanna-dwelling mammals.
It is?
>See part of
>my Scientific Correspondence letter to Nature many years ago
Yes, lets.
>Nature 325:305-306, 1987
>"Origin of hominid bipedalism"
>Sinclair et al. (1) believe that human bipedalism arose in scavenging
>hominid ancestors that had to carry their children while following migrating
>savanna ungulates but this seems highly improbable.
Well, that's your speculation against Sinclairs.
>There was no empty niche of migrating scavengers to be occupied by hominid
>ancestors.
Speculation - you can not possibly know that.
> Not only vultures, but aso canid, felid and hyaenid carnivores
>were much better preadapted for such a niche.
Speculation - you can not possibly know that.
> They possessed sharp beaks or
>long canine teeth and did not need to carry stones for cutting carcasses.
One might equally well put it as that they COULDNT carry stones for
driving off competitors.
>Moreover, the bipedal way of locomotion - whether fast of slow - is
>inefficient and costly (2,3).
I am skeptical about this claim, but it may be true.
>Another argument against the migrating hypothesis in particular and the
>savannah theory of human evolution in general is that it is highly unlikely
>that hominid ancestors ever lived in the savannas.
Assertion.
> Man is the opposite of a
>savanna inhabitant. Humans lack sun-reflecting fur (4) but have
>thermo-insulative subcutaneous fat layers, which are never seen in savanna
>mammals.
One might point out that the part of our upright body which is most
subjected to the sun, the head, is indeed covered in a thick layer of
fur. And I think you will find that subcutaneous fat is found in e.g.
baby chimps.
(And in pigs, for that matter, are they 'aquarboreal'?)
>We have a water- and sodium-wasting cooling system of abundant
>sweat glands, totally unfit for a dry environment (5).
And yet e.g. the bushmen of Kalahari do OK. We have to be able to find
water, but that doesn't mean we have to live in or even near it.
> We need
>much more water than other primates, and have to drink more often than
>savanna inhabitants, yet we cannot drink large quantities at a time (7-8).
On the other hand we can bring water, and this is based on study of
extant humans, which've been able to bring water along for probably
the last twenty thousand generations.
BTW, I in an earlier post adviced you to write to Nature. I was
actually completely unaware that you already had done so; it just
seemed to me as if your article fit Natures profile exactly.
>Marc Verhaegen
Marc Verhaegen
> Replying to jbr...@panix.com (John Brock) :
> >I think you are being a bit unfair. I'm not a huge fan of the
> >Aquatic Ape theory, but from what I've seen it does appear to be
> >more than merely a tendentious interpretation of traits which could
> >go either way. John Brock
>
> Really? Haven't noticed. All I've read have capitalized heavily on
> things such as that Lucy was found in sediment deposited in a pond or
> swamp (instead of, presumably, in a tree),
You don't seem to have read much...
> that infants have a
> breathing reflex for a few days after birth,
Irrelevant. Nobody's argument.
> and that humans have less
> hair than chimps (which incidentally we don't - we just have _shorter
> and thinner_ hair).
Notefven read the relevant literature?
Shorter & thinner hairs is what Hardy said.
Why IYO do humans have shorter & thinner hairs than chimps?
> > Humans are strikingly different in appearance, in
> >particular in terms of fat and body hair, than their nearest
> >relatives, and they swim much better.
>
> Humans don't swim worth a sh*t unless taught how to, as attested by
> the thousands of people who drown each year.
Is this an argument?
1) Dou deny humans descend from arboreal ancestors?? If not, why do humans
have fear of heights? Why are humans so bad in climbing trees?
2) Pure land mammals don't drown: they don't swim. In fact, swimming is one
of the safest sports, safer than jogging...
> I don't know if anyone's
> tried to teach a chimp to do breast strokes,
I don't know about chimps, but gorillas do breast strokes (unlike most
pirmates BTW, who rather paddle like dogs).
> but one might note that
> ability to swim is a primitive trait among primates (and so more
> likely to have been *lost* in the apes than *gained* in humans
:-D You think all the apes *lost" their swimming skills?? chimps lost
them, goruillas lost them, orangs lost them, etc.??
> ), and
> also that the only monkey I know which does live an aquarboreal life
> (proboscis monkey) have not developed much any traits similar to
> humans. Except the magnificent nose.
Please read our TREE paper.
It's obvious that you have to discern several (gradual) phases:
1) Proboscis monkeys are arboreal: all their food is in the trees, they only
wade to reach other trees.
2) Australopiths had "aquarboreal" features (adaptations to trees & water)
for living in water-rich forests or wetlands (exactly where their bones have
been found: gracile a'piths in swamp forests, robust a'piths in wetlands):
they had some sort of bipedalism (wading in waist-deep forest swamps, as
bonobos & gorillas occasioanlly do), had knuckle-walking features (wading in
ankle-deep water, as gorillas do), and had a lot of climbing features (eg,
curved finger & toe bones, to graps branches).
3) Homo: lost most climbing features (eg, we have straight finger & toe
bones, unlike apes & a'piths), but developed diving skills (with a bit of
training we can stay a few minutes unerwater, which no pure land mammal can
do). A seaside lifestyle nicely explains our typical features (eg, less
haired than chimps, more fat, larger brain, more erect, breath-hold skills
etc.). It also explains how H.ergaster-erectus could disperse over the world
in such a short time (fossils or Acheulian tools ca.1.8-1.7 Ma have been
found in Algeria, Georgia, Java, S-Africa, Kenya).
> > The sort of moderate aquatic
> > phase Marc Verhaegen is suggesting -- wading in marshes
> > and seashores-- doesn't strike me as being totally crazy.
>
> No, it's just an unfalsifiable hypothesis based on idle speculations.
No, it's based on comparative evidence.
> >The thing is, nobody would have proposed the Aquatic Ape theory if
> >we had hair and fat like an otter, because that would have made us
> >a typical land mammal. (BTW, I though seals had dense fur, as in
> >"fur seals". You are thinking of manatees perhaps?).
>
> Fur seals are a special group of seals, and considered quite
> primitive. Most seals have a sparse short fur which doesn't do much
> for their isolation, instead relying on a thick layer of blubber (take
> a look at a walross, for instance).
You have to consider fur & SC fat apart:
- elephants have no fur & no SC fat,
- mammoths had thick fur & thick SC fat layers,
- humans have SC fat, but no fur,
- most mammals have fur, but no SC fat.
Fur loss is seen in, eg, (overlapping groups):
- all fully aquatic mammals (= cetacea & Sirenia),
- very large semi-aquatic ones (male Steller-sealions, walrusses, elephant
seals, hippos, Asian rhinos),
- some medium-sized tropical semi-aquatic ones (babirusas, pygmy hippos),
- the very large "pachyderms" (vs. the equally large, but more
slenderly-built giraffes),
- some burrowing tropical species (naked molerats, aardvarks...),
- some domestic (sub)tropical species (eg, naked dogs & pigs).
Conclusion: human furlessness could be due to friction (wearing clothes),
having been tropical and/or having been semi-aquatic.
Thick SC fat is more exclusively seen in species that spend a lot of time in
water.
P Bowles
However, they are able to swim, at least at birth - this is true of all mammals
with, so far as I know, only two exceptions (the common and pygmy hippopotami).
Without training, human infants lose this ability just as many land mammals do.
>> but one might note that
>> ability to swim is a primitive trait among primates (and so more
>> likely to have been *lost* in the apes than *gained* in humans
>
>:-D You think all the apes *lost" their swimming skills?? chimps lost
>them, goruillas lost them, orangs lost them, etc.??
If they were lost in a common ancestor with only neonatal abilities remaining
in the apes, why would this seem implausible?
but developed diving skills (with a bit of
>training we can stay a few minutes unerwater, which no pure land mammal can
>do).
Who has tried to train other land mammals to do this in order to test this
hypothesis? How do you communicate to such a mammal that you want it to learn
to hold its breath for so long at a time - simply dunking it underwater until
it splutters doesn't constitute 'training'.
A seaside lifestyle nicely explains our typical features (eg, less
>haired than chimps, more fat, larger brain, more erect, breath-hold skills
>etc.). It also explains how H.ergaster-erectus could disperse over the world
>in such a short time (fossils or Acheulian tools ca.1.8-1.7 Ma have been
>found in Algeria, Georgia, Java, S-Africa, Kenya).
Another explanation is that they used some form of boat or raft which, due to
its wooden or reed structure has not survived - there are plenty of instances
of animals found in areas they could only have reached across the sea, but no
one suggests that all the animals found on Flores (for instance) had to swim
across. Komodo dragons and Nile crocodiles, yes, and possibly the archaic
elephants, but not the insects, amphibians, small lizards and snakes, small
mammals etc. It's far more likely that gaps in the archaeological record have
caused us to underestimate the technological skills of early hominids than that
they were Olympic-class swimmers - even if they could swim out to Flores, why
would they bother if they didn't know it was there? Leaping into the ocean and
hoping that sooner or later you'll hit dry land does not seem an adaption
terribly well-suited to survival...
Philip Bowles
Gerrit Hanenburg
>Another argument against the migrating hypothesis in particular and the
>savannah theory of human evolution in general is that it is highly unlikely
>that hominid ancestors ever lived in the savannas. Man is the opposite of a
>savanna inhabitant. Humans lack sun-reflecting fur (4) but have
>thermo-insulative subcutaneous fat layers, which are never seen in savanna
>mammals. We have a water- and sodium-wasting cooling system of abundant
>sweat glands, totally unfit for a dry environment (5). Our maximal urine
>concentration is much too low for a savanna-dwelling mammal (6). We need
>much more water than other primates, and have to drink more often than
>savanna inhabitants, yet we cannot drink large quantities at a time (7-8).
>...
Well, that may count for the average western city slicker, it doesn't
count for a well acclimatized person (Harrison et al. 1988).
Studies of ecological morphology of early Homo indicate that they were
well adapted to dealing with heat stress (Ruff 1991, Walker 1993).
Based on its crural and brachial indices the mean annual temperature
of the environment of the Turkana boy (KNM-WT 15000) is estimated to
have been 29.2 C and 30.8 C respectively.
And Feibel et al. (1991) report that the Lake Turkana region had much
the same climate 1.5 Mya as it has today (i.e. arid).
Feibel, C.S., Harris, J.M., and Brown, F.H. (1991).
Palaeoenvironmental context for the Late Neogene of the Turkana Basin.
In Harris, J.M. Koobi Fora Research Project Vol. 3: The fossil
ungulates: geology, fossil artiodactyls, and palaeoenvironments. p.
321-346.
Harrison, G.A. et al. (1988). Human Biology: An Introduction to Human
Evolution, Variation, Growth, and Adaptability, 2nd Ed. Oxford Univ.
Press.
Ruff, C.B. (1991). Climate and body shape in hominid evolution.
Journal of Human Evolution 21: 81-105.
Walker, A. (1993). Perspectives on the Nariokotome Discovery. In
Walker, A. and Leakey, R. The Nariokotome Homo erectus Skeleton.
Springer Verlag. p. 411-430.
Gerrit
Rain
<marc.ve...@village.uunet.be> writes
>
>"Rain" <r...@earthpoetry.demon.co.uk> schreef in bericht
>news:tnLrqfEG...@earthpoetry.demon.co.uk...
>
>> My opinion is that the aquatic ape theory is null and void. The aquatic
>> animals used for comparison have 50, 40, 30 million years of evolution
>> behind them we only have 3 million.
>
>If you had read the paper, Rain, you would have known, that it's NOT about
>an "aquatic" (sensu cetacean) lifestyle..
Well, it is fact that our line of humans developed from coastal-living
groups. So there is no argument with this. (My apologies for my original
post. I see red when the words 'aqua' and 'ape' appear together in front
of me.) ;-)
Gerrit Hanenburg
>>Moreover, the bipedal way of locomotion - whether fast of slow - is
>>inefficient and costly (2,3).
>I am skeptical about this claim, but it may be true.
It isn't. See Rodman & McHenry (1980): "The actual costs of travel for
walking humans are slightly less than those predicted for a
quadrupedal mammal of the same size" (p.104), while it is much more
efficient compared to chimpanzee quadrupedalism, and that is where the
comparison is most relevant because we share a more recent common
ancestor with chimps than with artiodactyls.
Rodman, P.S. & McHenry, H.M. (1980). Bioenergetics and the Origin of
Hominid Bipedalism. American Journal of Physical Anthropology 52:
103-106.
Gerrit
P Bowles
>>> animals used for comparison have 50, 40, 30 million years of evolution
>>> behind them we only have 3 million.
>>
>>If you had read the paper, Rain, you would have known, that it's NOT about
>>an "aquatic" (sensu cetacean) lifestyle..
>
>Well, it is fact that our line of humans developed from coastal-living
>groups. So there is no argument with this. (My apologies for my original
>post. I see red when the words 'aqua' and 'ape' appear together in front
>of me.) ;-)
Marc certrainly does himself no favours using the term, as most aspects of the
theory presented in his article are hardly revolutionary or controversial -
essentially, it consists of some well-considered observations about primate
migration patterns before the human/ape split and the hypothesis that humans
may have waded through rivers at some point in their existence - this isn't
informative enough to even qualify as a theory. What I question is the
conclusions about diving humans, swimming across oceans and largely aquatic
feeding habits that he draws - these are not justified by the lines of evidence
he presents, which do no more than indicate that humans lived in areas where
there was some water.
Philip Bowles
Marc Verhaegen
> >2) Pure land mammals don't drown: they don't swim.
>
> However, they are able to swim, at least at birth - this is true of all
mammals
> with, so far as I know, only two exceptions (the common and pygmy
hippopotami).
> Without training, human infants lose this ability just as many land
mammals do.
Yes, please try to follow the argument (you snipped a bit too much): it's
exactly because we like to swim that humans are more prone to drowning than
pure land mammals. Nobody uses the fact that in young primates falling out
of trees is an important cause of death in order to prove that primates are
not arboreal... OK?
> >> but one might note that
> >> ability to swim is a primitive trait among primates (and so more
> >> likely to have been *lost* in the apes than *gained* in humans
> >
> >:-D You think all the apes *lost" their swimming skills?? chimps lost
> >them, goruillas lost them, orangs lost them, etc.??
>
> If they were lost in a common ancestor with only neonatal abilities
remaining
> in the apes, why would this seem implausible?
Is there any indication for this most implausable idea that all apes retain
neonatal swimming abilites, but not the adult apes?? Please no nonsense,
Philip.
> > but developed diving skills (with a bit of
> >training we can stay a few minutes unerwater, which no pure
> >land mammal can do).
>
> Who has tried to train other land mammals to do this in order to
> test this hypothesis?
It's no hypothesis. Read the TREE paper & the refs therein.
Aquarboreal ancestors? [Opinion]
http://reviews.bmn.com/journals/atoz/latest?pii=S0169534702024904&node=TOC%4
0%40TREE%40017%4005%40017_05
Marc Verhaegen, Pierre-Francois Puech & Stephen Munro 2002
Trends in Ecology & Evolution 17:212-7
> How do you communicate to such a mammal that you want it to learn
> to hold its breath for so long at a time - simply dunking it underwater
until
> it splutters doesn't constitute 'training'.
Not only read the TREE paper, but also the referenced papers.
> >A seaside lifestyle nicely explains our typical features (eg, less
> >haired than chimps, more fat, larger brain, more erect, breath-hold
skills
> >etc.). It also explains how H.ergaster-erectus could disperse over the
world
> >in such a short time (fossils or Acheulian tools ca.1.8-1.7 Ma have been
> >found in Algeria, Georgia, Java, S-Africa, Kenya).
>
> Another explanation is that they used some form of boat or raft which, ...
1) No fantasies, please. Do you have 1 indication of boats or rafts ca.1.8
Ma?
2) Even if they used rafts, they had a seaside lifestyle, no?
Fact is: until ca.1.8 Ma hominids were confined to Africa. But at ca.1.8 Ma
we find H.ergaster-erectus or their tools at coasts from Algeria to Java.
Marc Verhaegen
If you're unconvinced, that's OK with me. At least you've read the paper.
But you still have not the slightest idea why humans got thicker SC fat (not
neotenous BTW, to the contrary), lost their fur, can stay underwater for a
few minutes, can swallow small fish underwater, need iodine, etc. etc.
Marc Verhaegen
> >2) Savanna?? :-D You still believe in the savanna fantasies? No
sensible
> >paleo-anthropologist still does, Saepie (=vocative of Saepius? :-)):
human
> >physiology is the opposite of that of savanna-dwelling mammals.
>
> Of course human physiology has more in common with forest animals than
savannah
> ones - the fact that human evolution progressed through many of its
crucial
> stages in a forested environment is now fairly well-established. However,
it
> cannot be denied that at some stage our ancestors left the forests, and
the
> environment they encountered upon doing so was savannah
No, it was not savanna. We find the early Homo at the lake & seaside, in &
later outside Africa, always near shellfish. Barnacles & shellfish & corals
(eg, Mojokerto) are not found in the savanna.
§ Malawi UR 501 early Homo: 'The Plio-Pleistocene Chiwondo Beds of
Northern Malawi have yielded molluscs and fragmented remains of fish,
turtles, crocodiles and large mammals [.] Microvertebrates and carnivores
are virtually unrepresented in the assemblage [.] The general ecological
setting of the Malawi Rift during the Late Pliocene was a mosaic environment
including open and closed, dry and wet habitats, and which harbored a small
and ecologically unstable paleolake Malawi' (Schrenk et al., 1995).
§ Chemeron KNM-BC1 early Homo: 'The Fish Beds [.] seem to be almost
entirely lacustrine and fluviatile; fish remains are abundant [.] Molluscs
also lived in the lake, and locally their remains accumulate to form shelly
limestones' (Martyn & Tobias, 1967).
§ Turkana Boy KNM-WT 15000 H. erectus: 'Mammalian fossils are rare
at this locality, the most abundant vertebrate fossils being parts of small
and large fish. The depositional environment was evidently an alluvial plain
of low relief [.] Typical lacustrine forms (for example, ostracods,
molluscs) could invade the area [.] The only other fauna found so far in the
fossiliferous bed are many opercula of the swamp snail Pila, a few bones of
the catfish Synodontis and two fragments of indeterminate large mammal bone
[.]' (Brown et al., 1985).
§ Mojokerto H. erectus: 'The basal part of the Putjangan Beds is
composed of volcanic breccias containing marine and freshwater molluscs. The
rest of the Putjangan Beds is composed of black clays of lacustrine origin'
(Ninkovich & Burckle, 1978).
> - had they been unable
> to adapt to some degree, we would not be here.
> One assumption aquatic ape theorists make which is unjustified is
> that we lost our thick body hair while still inhabiting a forest.
Nobody has ever claimed that AFAIK?
Where do you get this?? Why do you think that?
Marc Verhaegen
"Mike Noren" <michae...@yahoo.co.uk> schreef in bericht
news:ibegauotpac5ug27s...@4ax.com...
> Replying to "Marc Verhaegen" <marc.ve...@village.uunet.be> :
>
> >
> >"Corvųn & Celeste Sæpius" <theol...@hotmail.com> schreef in bericht
> >news:uaf9p9d...@corp.supernews.com...
> >> Who says the aquatic ape theory can't be debunked? Evidence for it:
> >> none that doesn't either imply neotony, adaptation for
> >> savannah-habitat, or combination of the two.
> >
> >1) Neoteny doesn't explain anything: it's only a description of possible
> >genetic mechanisms. It doesn't explain why we got larger brains, why we
> >became biped etc.
>
> Actually that is not entirely true, although selection is probably the
> driving force. Well, it is true of bipedalism, but not re: brain size,
> subcutaneous fat, or shorter/thinner hair.
>
> >2) Savanna?? :-D You still believe in the savanna fantasies?
>
> Your own references speak of a milieu reminiscent of a forest savanna,
> with gallery forest around the bodies of water.
Yes, you're right, I should have said "dry savanna", which is where the
savanna theorists believe human lost their fur etc.
> >No sensible
> >paleo-anthropologist still does, Saepie (=vocative of Saepius? :-)):
human
> >physiology is the opposite of that of savanna-dwelling mammals.
>
> It is?
>
> >See part of
> >my Scientific Correspondence letter to Nature many years ago
>
> Yes, lets.
>
> >Nature 325:305-306, 1987
> >"Origin of hominid bipedalism"
> >Sinclair et al. (1) believe that human bipedalism arose in scavenging
> >hominid ancestors that had to carry their children while following
migrating
> >savanna ungulates but this seems highly improbable.
>
> Well, that's your speculation against Sinclairs.
I can't say everything in 1 sentence. Be a bit patient: explanation follows.
>
> >There was no empty niche of migrating scavengers to be occupied by
hominid
> >ancestors.
>
> Speculation - you can not possibly know that.
Idem.
> > Not only vultures, but aso canid, felid and hyaenid carnivores
> >were much better preadapted for such a niche.
>
> Speculation - you can not possibly know that.
Are you denying that lions & dogs & vultures are better than humans in
scavenging?
> > They possessed sharp beaks or
> >long canine teeth and did not need to carry stones for cutting carcasses.
>
> One might equally well put it as that they COULDNT carry stones for
> driving off competitors.
Do you really see them carrying stones to carcasses & follow herds migrating
ungulates under the African?? (moreover: Leakey etc. were speaking of
australopiths...).
> >Moreover, the bipedal way of locomotion - whether fast of slow - is
> >inefficient and costly (2,3).
>
> I am skeptical about this claim, but it may be true.
>
> >Another argument against the migrating hypothesis in particular and the
> >savannah theory of human evolution in general is that it is highly
unlikely
> >that hominid ancestors ever lived in the savannas.
>
> Assertion.
Explanation follows. Not so impatient...
> > Man is the opposite of a
> >savanna inhabitant. Humans lack sun-reflecting fur (4) but have
> >thermo-insulative subcutaneous fat layers, which are never seen in
savanna
> >mammals.
>
> One might point out that the part of our upright body which is most
> subjected to the sun, the head, is indeed covered in a thick layer of
> fur.
:-D As I once wrote in a paper: "If we accept this reasoning, it must
have been the women who ranged over the plains at noon while the balding and
bearded males rested in the shade."
>And I think you will find that subcutaneous fat is found in e.g.
> baby chimps.
?? No, no, Mike. Chimp & even gorilla babies weigh about half human babies,
partly due to the absence of the thick SC fat in infant apes.
> (And in pigs, for that matter, are they 'aquarboreal'?)
Please a little bit of logic: it's notbecasue all dogs have fur, that all
furred animals are dogs...
> >We have a water- and sodium-wasting cooling system of abundant
> >sweat glands, totally unfit for a dry environment (5).
>
> And yet e.g. the bushmen of Kalahari do OK. We have to be able to find
> water, but that doesn't mean we have to live in or even near it.
Most humans live near the coasts & rivers. Not unlikely the less-populated
areas like where the KhoiSan live were colonised only lately thanks to
rel.advanced technological skills.
> >We need
> >much more water than other primates, and have to drink more often than
> >savanna inhabitants, yet we cannot drink large quantities at a time
(7-8).
>
> On the other hand we can bring water, and this is based on study of
> extant humans, which've been able to bring water along for probably
> the last twenty thousand generations.
20,000 generations = ca.0.5 Ma??
Why would they do that, carrying water into the dry savanna, if they lived
near rivers & seas? :-D
> BTW, I in an earlier post adviced you to write to Nature.
Did you?
P Bowles
>But you still have not the slightest idea why humans got thicker SC fat (not
>neotenous BTW, to the contrary)
You're right, I don't - fatty tissue isn't an area I know enough about to
comment on authoritatively. From what I can tell, however, your own theory does
nothing to explain its presence either - it draws a comparison with other
animals which have a subcutaneous fat layer, but nowhere have you attempted to
explain what that layer is *for* in a supposedly aquaboreal tropical hominid.
, lost their fur,
See my other post - hair loss makes sense once a dark-skinned hominid enters an
open tropical environment, whether coastal or savannah - the hair is
unnecessary for insulation, but exposing dark skin increases the efficiency of
vitamin production, as well as preventing a dark-skinned, dark-furred animal
from overheating.
can stay underwater for a
>few minutes, can swallow small fish underwater,
I don't know enough about the comparable abilities of other terrestrial species
to comment on this either.
need iodine, etc. etc.
We need iodine to protect us from harmful pathogens in water bodies to which we
are not normally exposed, but I'm not certain how this relates to the
'aquaboreal ape' either as an argument for or one against - we simply have no
immunity to unfamiliar diseases, any more than early Native Americans were
immune to European diseases.
Philip Bowles
P Bowles
>news:20020401065555...@mb-dd.aol.com...
>> >2) Pure land mammals don't drown: they don't swim.
>>
>> >> ability to swim is a primitive trait among primates (and so more
>> >> likely to have been *lost* in the apes than *gained* in humans
>> >
>> >:-D You think all the apes *lost" their swimming skills?? chimps lost
>> >them, goruillas lost them, orangs lost them, etc.??
>>
>> If they were lost in a common ancestor with only neonatal abilities
>remaining
>> in the apes, why would this seem implausible?
>
>Is there any indication for this most implausable idea that all apes retain
>neonatal swimming abilites, but not the adult apes?? Please no nonsense,
>Philip.
All mammals appear to retain neonatal swimming abilities, including such
creatures as terrestrial felines, which are lost as the animals mature (except
hippos, as mentioned). Implausible or not, it seems to be the case, and apes of
all kinds can indeed swim when young - either this ability was inherited from a
common ancestor, or independently evolved and lost in each ape lineage. Which
strikes you as being more plausible?
>> >A seaside lifestyle nicely explains our typical features (eg, less
>> >haired than chimps, more fat, larger brain, more erect, breath-hold
>skills
>> >etc.).
In itself it explains few if any of these - any open environment could provide
the impetus our ancestors needed to lose their hair, brain size appears to be
linked to increasing complexity of social organisation, our erect posture is a
simple progression from the clumsier bipedalism of other apes while our
breath-control skills relate to the formation of complex language (which cannot
have been spurred by an aquatic lifestyle, contrary to one contention in your
article - the wavelengths in which humans and other primates communicate do not
travel far underwater, and the wavelengths best-suited for such communication
are inaudible to us).
It also explains how H.ergaster-erectus could disperse over the
>world
>> >in such a short time (fossils or Acheulian tools ca.1.8-1.7 Ma have been
>> >found in Algeria, Georgia, Java, S-Africa, Kenya).
>>
>> Another explanation is that they used some form of boat or raft which, ...
>
>1) No fantasies, please. Do you have 1 indication of boats or rafts ca.1.8
>Ma?
I don't have any indication the Aborigines had boats or rafts 40,000 years ago,
but that doesn't mean I believe they swam to Australia. The evidence we have is
that humans found their way to Indonesia somehow, and unless land bridges which
once existed there have since been destroyed or submerged they can only have
done that using some mechanism to cross the water. H. erectus was a
sophisticated and varied tool-user, and there is no clear mechanical reason why
their technological skills shouldn't have extended to the creation of simple
boats - I find it less of a stretch to suppose a known tool-user with no
adaptions specifically designed for swimming (and none of the 'aquatic'
adaptions you have identified would have assisted in locomotion in a marine
environment) used tools to cross the sea than to suppose he swam. One could
hardly expect a raft or boat made of perishable materials to survive for 1.8
Ma. The other slight possibility is that H. erectus, like so many other
animals, dispersed itself accidentally through the same rafting that has
dispersed organisms across the globe since time immemorial.
>2) Even if they used rafts, they had a seaside lifestyle, no?
I haven't disputed that they could have had - it is perfectly possible that
some hominids would have subsisted from coastal shellfish found in rock pools
or along the beach, or even in the shallows on occasion, just as humans in
coastal habitats do today - you listed a variety of remains found in coastal
regions in another post. However, as others have pointed out these do nothing
to support the idea that these creatures were habitually aquatic, swimming from
place to place and diving for their meals on a regular basis. Yes, they may
have had boats or rafts, but that also doesn't imply evolutionary development
tied to the ocean any more than the existence of boats 20,000 years ago or
whatever implies that those humans were busy evolving into marine animals.
Philip Bowles
P Bowles
And these lakes were in what sort of environment...? Open grassland in at least
some cases - in other words, savannah. However, even if humans lost their fur
in a coastal habitat the same rationale would apply - in an environment exposed
to the tropical sun, hair loss in humans would make evolutionary sense. This
does not require any adaptions to a specifically marine environment or to a
habitually aquatic lifestyle.
& seaside, in &
>later outside Africa, always near shellfish.
In regions like Java and Flores, most of the inland habitat is rainforest, and
has been for 120 million years. This environment is not conducive to
fossilisation, while coastal sediments are a common source of fossil material
of all sorts, both terrestrial and marine. Plenty of dinosaurs have been found
in coastal environments, but that doesn't imply that they were habitually
marine. Your own article mentioned the difficulty with inferring details about
lifestyle from the locations where a fossil was preserved.
>> - had they been unable
>> to adapt to some degree, we would not be here.
>> One assumption aquatic ape theorists make which is unjustified is
>> that we lost our thick body hair while still inhabiting a forest.
>
>Nobody has ever claimed that AFAIK?
>Where do you get this?? Why do you think that?
In earlier posts as well as in your article I recall that you identified a
wading lifestyle in search of waterside vegetation as a possible cause of hair
loss, before discussions of the coastal divers began - I may be misrembering or
misinterpreting.
Philip Bowles
Corvùn & Celeste Sæpius
our ancestors only came out of the trees and into the savanna about 5
million years ago. Bipedality, for example, may have evolved first as
a means of brachiation (with the arms stretched above and the legs
dangling below or perched on a branch) and secondarily as a method of
crossing distances between forest areas. Human ancestors didn't adapt
*to* the Savanna, natural selection merely forced them *out* of the
forests and there was nowhere else to go. We've simply been
jury-rigged for the Savanna. Upright posture reduces heat absorption
from above and makes it easier to catch cool breases during the day --
it works, if only in part, as a means of thermoregulation. The layer
of fat? Like I said - most endotherms have at least a thin layer of
fat under the skin -- humans DO NOT carry this trait because of
aquatic ancestry (like I said before; in that part of the world, at
that time, there would be no reason for even an aquatic species to
have blubber...Australopithecines were not stream-lined, ocean-going
animals...at best they simply waded around in pools (which is all the
AAT suggests anyway)...)
You said:
> 1) Neoteny doesn't explain anything: it's only a description of
possible
> genetic mechanisms. It doesn't explain why we got larger brains, why
we
> became biped etc.
Juvenile chimp porportions (compared to adult chimp): small gut, big
brain. Adult human porportions (compared to adult chimp): small gut,
big brain. Chimpanzees eventually grow into their brain-size, while
humans retain the more juvenile porportions until adulthood (our gut
stays relatively small and our brains relatively large). Neotony DOES
explain why we got our larger brains. As far as bipedality goes? Well,
there are other genetic mechanisms at work there (other than neotony).
I may not know a hell of a lot about paleontology in general but
paleoanthropology is an obsession of mine. I know what I'm talking
about - and from what I can tell, you don't!
P.S. Sweat glands, although costly and often inefficient, are a LOT
better for dry habitats than non-glandular skin which is more prone to
over-heating. A human can survive in the hot sun a lot longer than a
husky or a german shepherd.
--
Corvun Sæpius
~ Coven of the Shadow Moon ~
"Hear Now the Words of the Witches,
The Secrets We Hid in the Night,
When Dark was Our Destiny's Pathway,
That Now We Bring Forth into Light!"
"Marc Verhaegen" <marc.ve...@village.uunet.be> wrote in message
news:3ca82791$0$252$ba62...@news.skynet.be...
>
> "Corvùn & Celeste Sæpius" <theol...@hotmail.com> schreef in
Rain
<pbo...@aol.com> writes
Yes I agree.
--
The Tungsten
http://www.earthpoetry.demon.co.uk
RC
Marc Verhaegen
> >If you're unconvinced, that's OK with me. At least you've read the paper.
> >But you still have not the slightest idea why humans got thicker SC fat
(not
> >neotenous BTW, to the contrary)
>
> You're right, I don't - fatty tissue isn't an area I know enough about to
> comment on authoritatively. From what I can tell, however, your own theory
does
> nothing to explain its presence either - it draws a comparison with other
> animals which have a subcutaneous fat layer, but nowhere have you
attempted to
> explain what that layer is *for* in a supposedly aquaboreal tropical
hominid.
I did not. And we have no direct evidence to know when we got thicker fat
layers. It fact, it probably isn't. You still haven't read the paper?
Schematically IMO:
1) early apes = aquarboreal (climbing-wading - unlikely to have been very
fat: climbing),
2) archaic Homo = waterside (wading-diving-walking, loss of climbing).
IOW, IMO we got our thicker SC fat after the aquarboreal phase.
>> , lost their fur,
>
> See my other post - hair loss makes sense once a dark-skinned hominid
enters an
> open tropical environment, whether coastal or savannah
We just don't know when we got dark skins. Pure speculation, Philip!
> - the hair is
> unnecessary for insulation, but exposing dark skin increases the
efficiency of
> vitamin production, as well as preventing a dark-skinned, dark-furred
animal
> from overheating.
>> can stay underwater for a
> >few minutes, can swallow small fish underwater,
>
> I don't know enough about the comparable abilities of other terrestrial
species
> to comment on this either.
>> need iodine, etc. etc.
>
> We need iodine to protect us from harmful pathogens in water bodies to
which we
> are not normally exposed, but I'm not certain how this relates to the
> 'aquarboreal ape' either as an argument for or one against - we simply
have no
> immunity to unfamiliar diseases, any more than early Native Americans were
> immune to European diseases. Philip Bowles
Iodine-dependency also was probably long after the aquarboreal phase, IMO,
in the "archaic"Homo phase. The astonishing percentages of cretinism,
goiter, myedema etc. in mountainous regions until the beginning of this
century (due to iodine deficiency in areas away from the sea) strongly
suggests our ancestors (note this says nothing about fossil relatives of
us!) must have lived near the coasts until "recently", IMO, possibly until
the sapiens LCA ca.200 ka or so
Marc Verhaegen
> >> >2) Pure land mammals don't drown: they don't swim.
> >>
> >> >> but one might note that
> >> >> ability to swim is a primitive trait among primates (and so more
> >> >> likely to have been *lost* in the apes than *gained* in humans
> >> >
> >> >:-D You think all the apes *lost" their swimming skills?? chimps
lost
> >> >them, goruillas lost them, orangs lost them, etc.??
> >>
> >> If they were lost in a common ancestor with only neonatal abilities
> >> remaining in the apes, why would this seem implausible?
> >
> >Is there any indication for this most implausable idea that all apes
retain
> >neonatal swimming abilites, but not the adult apes?? Please no nonsense,
> >Philip.
>
> All mammals appear to retain neonatal swimming abilities
?? Most mammals can swim at the sruface yes, but what has this to do with
neonatal swimming abilities??
> , including such
> creatures as terrestrial felines, which are lost as the animals mature
(except
> hippos, as mentioned). Implausible or not, it seems to be the case
:-D Do you have 1 indication for this statement?
> , and apes of
> all kinds can indeed swim when young - either this ability was inherited
from a
> common ancestor, or independently evolved and lost in each ape lineage.
Which
> strikes you as being more plausible?
No fairy tales please...
> >> >A seaside lifestyle nicely explains our typical features (eg, less
> >> >haired than chimps, more fat, larger brain, more erect, breath-hold
> >> >skills etc.).
>
> In itself it explains few if any of these - any open environment could
provide
> the impetus our ancestors needed to lose their hair,
No. Not one pirmate has lost its fur there.
> brain size appears to be
> linked to increasing complexity of social organisation
This is a hypothesis, not impossible, but not proven at all. Seals, eg, have
3 times larger brains than equally large terrestrial carnivores, but are not
lmore social.
> , our erect posture is a
> simple progression from the clumsier bipedalism of other apes
?? No just-so stories, please...
> while our
> breath-control skills relate to the formation of complex language
It's the other way round, of course: voluntary breathing (no doubt evolved
for diving, as in all diving mammals) was a preadaptation for speech.
> (which cannot
> have been spurred by an aquatic lifestyle, contrary to one contention in
your
> article - the wavelengths in which humans and other primates communicate
do not
> travel far underwater, and the wavelengths best-suited for such
communication
> are inaudible to us).
??
I hope you don't think I think our ancestors spoke underwater??
> >> >It also explains how H.ergaster-erectus could disperse over theworld
> >> >in such a short time (fossils or Acheulian tools ca.1.8-1.7 Ma have
been
> >> >found in Algeria, Georgia, Java, S-Africa, Kenya).
> >>
> >> Another explanation is that they used some form of boat or raft which,
...
> >
> >1) No fantasies, please. Do you have 1 indication of boats or rafts
ca.1.8
> >Ma?
>
> I don't have any indication the Aborigines had boats or rafts 40,000 years
ago,
> but that doesn't mean I believe they swam to Australia. The evidence we
have is
> that humans found their way to Indonesia somehow
Java was part of Sunda-land. No problem then (lower sea levels).
> , and unless land bridges which
> once existed there have since been destroyed or submerged they can only
have
> done that using some mechanism to cross the water. H.erectus was a
> sophisticated and varied tool-user, and there is no clear mechanical
reason why
> their technological skills shouldn't have extended to the creation of
simple
> boats - I find it less of a stretch to suppose a known tool-user with no
> adaptions specifically designed for swimming (and none of the 'aquatic'
> adaptions you have identified would have assisted in locomotion in a
marine
> environment) used tools to cross the sea than to suppose he swam. One
could
> hardly expect a raft or boat made of perishable materials to survive for
1.8
> Ma. The other slight possibility is that H.erectus, like so many other
> animals, dispersed itself accidentally through the same rafting that has
> dispersed organisms across the globe since time immemorial.
I agree it's no impossible, but until we find some direct indications, you
can't build theories on this.
> >2) Even if they used rafts, they had a seaside lifestyle, no?
>
> I haven't disputed that they could have had - it is perfectly possible
that
> some hominids
Not "some hominids". Our ancestors at one time: all humans have breath-hold
abilities & can easily learn to dive.
> would have subsisted from coastal shellfish found in rock pools
> or along the beach, or even in the shallows on occasion, just as humans in
> coastal habitats do today - you listed a variety of remains found in
coastal
> regions in another post. However, as others have pointed out these do
nothing
> to support the idea that these creatures were habitually aquatic, swimming
from
> place to place and diving for their meals on a regular basis.
Diving for food (probably shells) is strongly suggested by our superior
diving skills - unique among mammals. Other indications are, eg, the fatty
acid composition of marine-based foods; our tool-using & making skills (cf.
mangrove capuchins: to open mangrove oysters).
> Yes, they may
> have had boats or rafts, but that also doesn't imply evolutionary
development
> tied to the ocean any more than the existence of boats 20,000 years ago or
> whatever implies that those humans were busy evolving into marine animals.
> Philip Bowles
Nobody says they were marine mammals like whales.
I do say our ancestors once got a considerable part of their daily food from
the water & had adaptations to dive regularly.
Marc Verhaegen
> >No, it was not savanna. We find the early Homo at the lake
>
> And these lakes were in what sort of environment...? Open grassland in at
least
> some cases - in other words, savannah.
1) In some cases, yes, but not in most (note I'm talking about
H.erectus-ergaster - from Europe to Flores: no savanna).
2) And certainly not in dry savanna (as an "explanation" for our loss of fur
etc.), as the savanna-minded people used to believe. (I just read that some
well-known PAs still believe & publish this nonsense: Klein & Edgar 2002
"The Dawn of Human Culture" J.Wiley & sons: "... occurred between 7-5 Ma
when a group of Afr.apes, in response to shrinking forests & expanding open
savannas, began to walk upright." can you believe this?)
> However, even if humans lost their fur
> in a coastal habitat the same rationale would apply - in an environment
exposed
> to the tropical sun, hair loss in humans would make evolutionary sense.
No! No other primate has lost its fur. All primates are tropical. Baboons
are exposed to the tropical sun.
> This does not require any adaptions to a
> specifically marine environment or to a
> habitually aquatic lifestyle.
> > & seaside, in &
> >later outside Africa, always near shellfish.
>
> In regions like Java and Flores, most of the inland habitat is rainforest,
and
> has been for 120 million years. This environment is not conducive to
> fossilisation, while coastal sediments are a common source of fossil
material
> of all sorts, both terrestrial and marine. Plenty of dinosaurs have been
found
> in coastal environments, but that doesn't imply that they were habitually
> marine. Your own article mentioned the difficulty with inferring details
about
> lifestyle from the locations where a fossil was preserved.
Yes; but there's a difference between australopith fossils & Homo fossils:
the first are seldom found next to shellfish; the latter always AFAIK.
> >> - had they been unable
> >> to adapt to some degree, we would not be here.
> >> One assumption aquatic ape theorists make which is unjustified is
> >> that we lost our thick body hair while still inhabiting a forest.
> >
> >Nobody has ever claimed that AFAIK?
> >Where do you get this?? Why do you think that?
>
> In earlier posts as well as in your article I recall that you identified a
> wading lifestyle in search of waterside vegetation as a possible cause of
hair
> loss, before discussions of the coastal divers began - I may be
misrembering or
> misinterpreting. Philip Bowles
Yes, it's new to you. I forgive. :-)
Marc Verhaegen
"Corvųn & Celeste Sæpius" <theol...@hotmail.com> schreef in bericht
news:uahficf...@corp.supernews.com...
> The poor adaptations for a savanna-habitat are due to the fact that
> our ancestors only came out of the trees and into the savanna about 5
> million years ago.
No, no. Tobias: "From Sterkfontein, suggestions of greater woodland cover at
the time when Australopithecus was deposited in Member 4, had emerged from
studies on fossil pollen, but these were not compelling. Then Wits team
member Marian Bamford identified fossil vines or lianas of Dichapetalum in
the same Member 4: such vines hang from forest trees and would not be
expected in open savannah. The team at Makapansgat found floral and faunal
evidence that the layers containing Australopithecus reflected forest or
forest margin conditions. From Hadar, in Ethiopia, where "Lucy" was found,
and from Aramis in Ethiopia, where Tim White's team found Ardipithecus
ramidus, possibly the oldest hominid ever discovered, well-wooded and even
forested conditions were inferred from the fauna accompanying the hominid
fossils. All the fossil evidence adds up to the small-brained, bipedal
hominids of 4 to 2.5 million years ago having lived in a woodland or forest
niche, not savannah."
> Bipedality, for example, may have evolved first as
> a means of brachiation (with the arms stretched above and the legs
> dangling below or perched on a branch) and secondarily as a method of
> crossing distances between forest areas. Human ancestors didn't adapt
> *to* the Savanna, natural selection merely forced them *out* of the
> forests and there was nowhere else to go. We've simply been
> jury-rigged for the Savanna. Upright posture reduces heat absorption
> from above and makes it easier to catch cool breases during the day --
:-D Yes, that's why all savanna mammals run on 2 legs, you mean?
Saepius, sorry, I have no time for discussing this with you. Please inform a
bit first.
Marc
Marc Verhaegen
"Gerrit Hanenburg" <G.Han...@inter.nl.nomail.net.> schreef in bericht
news:ssmgau8gv1h37v17i...@4ax.com...
Other people claim the opposite. If bipedalism had been superior to
quadrupedalims, a lot more mammals than humans & kangaroos would run on 2
legs.
Jim McGinn
"P Bowles" <pbo...@aol.com> wrote in message
news:20020401055001...@mb-fh.aol.com...
> > 2) Savanna?? :-D You still believe in the savanna
> > fantasies? No sensible paleo-anthropologist still
> > does, Saepie (=vocative of Saepius? :-)): human
> > physiology is the opposite of that of
> > savanna-dwelling mammals.
>
> Of course human physiology has more in common with
> forest animals than savannah ones - the fact that human
> evolution progressed through many of its crucial stages
> in a forested environment is now fairly well-established.
> However, it cannot be denied that at some stage our
> ancestors left the forests, and the environment they
> encountered upon doing so was savannah - had they
> been unable to adapt to some degree, we would not be
> here.
I disagree with this last statement. There was really never
any reason for hominids to have been adapted to a true
savannah habitat. True widescale, fully open, savannah
habitats did not appear in Africa until about 2.3 mya at the
earliest. By this time our ancestors had already advanced
to where we had the expertise to live in more varied
habitats. All things considered, it is very unlikely that our
ancestors ventured out into the treeless savanna until after
we had developed the technology and cooperative
behavior without which our ancestors would have been
an easy meal for predators.
>
> One assumption aquatic ape theorists make which is unjustified is that we
lost
> our thick body hair while still inhabiting a forest. We cannot know this -
we
> have only skeletal remains from early hominids, no hair or skin. There is
no
> particular reason to suppose that hair loss occurred at the same time as,
for
> instance, increased brain size or bipedalism. You only need to look at the
> thickness and rate of growth of human hair in northern populations
compared
> with equatorial ones to know that losing or gaining hair is an adaption
which
> can occur over very short timescales. Unlike most savannah species, our
> ancestors would have had dark skin and exposing this skin to the powerful
> savannah sun makes evolutionary sense as a way to increase vitamin
production
> within the human body.
>
I think most theorist get too lost in trying to pick out which of three
habitats, savanna, forest, or water, our species first began to evolve.
Instead they should concentrate on a more explicit understanding of the
habitat that we know did exist at the time hominids emerged.
Accordingly, up until about 6mya the whole of Africa was closed canopy
rainforest. Then starting about 6mya a new elements started showing up,
seasonal dessication. (At the end of this post I have pasted another post,
entitled The Late Miocene Origins of Seasonal Dessication in Africa, wherein
I discuss the environmental and climatic factors that produced the seasonal
dessication that emerged on our planet. [It is an element that had not
existed on this planet up until this time.]) This resulted in a very
dramatic dry season with some very unique implications.
Before I touch upon these unique implications it's important that it be
understood how distinctively different was this habitat. Currently there
exists nothing like it on this planet. In terms of moisture it was like a
rainforest habitat for part of the year, and a desert the rest of the year.
The rainforest itself would have largely disappeared having been replaced by
patches of forest that persisted near sources of perrenial water--streams,
rivers, lakes, ponds, etc. Our ancestors, of course, would have inhabited
these well watered, still treed, localities in the greater environment.
One implication of this new habitat would have been the seasonal influx of
multiple species into these well watered, still treed, localities during the
dry season (kind of a larger version of the watering hole phenomena that
still continues on the african savanna). How would such have appeared from
the perspective of our earliest chimpanzee-like ancestors? During the rainy
part of the years they resided in a veritable garden of eden. Then, during
the dry season not only would their sources of food begin to become more
scarce but suddenly there comes an influx of other animals, refugees of
widespread dessication, including other bands of chimps.
What adaptations might we expect to arise in our chimpanzee-like ancestors
given the implications of this annual influx? I contend that one of the
adaptations would have involved a networked (communicative) type of
territorialism, a kind of communal territorialism that would have effected
the preservation of communal resources so that our earliest ancestors that
produced this networked communal territorialism. It might have been a
peculiarly effective kind of territorialism in that it might have enabled
our ancestors to effectively surround or circumscribe these well watered,
still treed, localities, and thereby effect the preservation of the
resources at these locations and thus facilitate their own survival through
the dry season.
Could our earliest ancestors have effected the communal territorialism that
would have preserved the resources in these well watered, still treed,
localities? And if they did how would the selective benefits of this
activity--the benefits being the ability to survive through periods of
seasonal dessication--be focussed primarily upon those that produced the
behavior rather than those that don't? In order to answer these questions
it's important to be aware of what a serious selective factor this
seasonally recurring dessication would have been. It was a true grim
reaper. Those that for whatever reason did not have access to resources
during the dry season died of starvation, thirst, as well as general
vulnerability to other factors, such as predators. These grim realities, I
contend, make it clear that those that lacked some concept of the value of
undepleted territory would be the first victims of seasonal dessication and
those that survived would have been those that came to set up property
claims and defend them. Accordingly, I theorize that--in a manner similar
to that of extant chimps--bands of our chimpanzee-like ancestors would have
divied up the acreage of these well watered, still treed, localities. These
property claims became the domain of the individual bands and also set the
stage for continual conflict and sometimes cooperation between them.
But how did community consciousness emerge? It might seem obvious that if
the sum effect of their territorialistic behaviors could reduce the
seasonally dessication inspired influx of other species by even 10% that
this would be a tremendous advantage in light of the fact that other well
watered, still treed, localities would now have 10% more influx to deal
with. Accordingly, community sites that were occupied by bands that
displayed such behavior might thrive and come to colonize (and
disenfranchise) community sites occupied by bands that don't display such
behavior. Over thousands of years we might, therby, envision all community
sites becoming occupied by such communally territorialistic animals. But
this still leaves open the question as to how an animal that was capable of
defending it's own bands territorial claims could also come to evolve the
ability to come to the assistance of other neighboring bands in the same
community when these claims were challenged by those external to the
community (including other bands of chimps)? Are there theoretical
obstacles (ie. Darwinism) to the supposition that the selective benefits of
such cooperative behavior would be focussed on those that perform this
activity rather than those that don't? It seems it would involve selection
at the level of the community. And doesn't Darwinism tell us that selection
at the level of the community is not possible? Or might there be aspects of
this habitat--specifically the geographic isolation of these well watered,
still treed, community sites--that allow us to overcome or dismiss such
theoretical obstacles? And what other adaptations would we expect to emerge
for an animal that begins to be selected for its communally oriented
territorialistic abilities. Might we expect the emergence of adaptations
that would facilitate informational precision so that the members of one's
commununity can better decide what actions are called for? And might we,
therefore, also expect the emergence of adaptations that facilitate
communicativeness over long distances. And might bipedalism be such an
adaptation by way of employing the body as a means of conveying emotional
and information rich messages? Might bipedalism also be advantageous in the
context of this scenario by way of enabling a collective rock throwing
behavior that would be effective in dissuading potential trespassers?
I think we can understand the emergence of humans from chimps. But first we
have to start with an explicit understanding of their habitat and the
implications thereof that could have facilitated this emergence.
Jim McGinn
jimm...@yahoo.com
Late Miocene Origins of Seasonal Dessication
One of the predictions of my hypothesis is that the
origins of human (hominid) evolution and the origins of
seasonal dessication in Africa will be coorelated in the
geologic record. In doing some research on the
internet I found evidence that confirms this prediction:
It seems that we have very little knowledge about the
specifics of the habitat back then. But there does
seem to be a preponderance of evidence (or, at least,
a preponderance of opinions about interpretations of
the evidence) that there was much more of a
widespread existence in Africa (during the late
miocene and early pliocene, 4 to 6 mya) of the kind of
mosaic, open woodland, more seasonally dessicate,
and more mosaic-like (dotted with patches of
remaining forest [and, presumably, sources of
perrenial water]) habitat that, up until about 6 mya, had
been closed canopy chimpanzee habitat. This is
precisely the kind of habitat that is indicated in my
hypothesis. (I should also mention that if one
studies the links below that there are also hints that a
shift to a cooler, drier, and more seasonal habitat may
have occurred in Africa even earlier than 6mya.)
Not only was this habitat of 4 to 6 mya both warmer and
wetter than the savanna habitat that we currently find in
Africa but during the interval between 4 mya and 3 mya
the climate shifted to become warmer and wetter still.
"The peak phases of warmth during the Pliocene were
mostly during the interval between 3 and 4 million years
ago (the mid-Pliocene), although almost all of the
Pliocene was warmer than today's world."
http://www.esd.ornl.gov/projects/qen/pliocene.html
Thus the habitat that
produced the transition of apes to hominids--seasonal,
patchy, forested, with numerous lakes, streams, rivers,
and other sources of perrenial water--has almost
completely disappeared in Africa. It seems to have
existed from about 6mya up to about 2.8 mya (possibly
returning to more or less of a rainforest in the interval
between 4.0 mya and 3.0 mya).
According to my hypothesis the most important element
was seasonal dessication--a distinct and dramatic
dry season. The proximate mechanism of seasonal
dessication is well known. It can most directly be
attributed to increased albedo (reflection of sunlight out
of the atmosphere) as a result of snow remaining
unmelted on the surface of landmasses at these northern
and southern extremities during the low sun months (winter
in the northern hemisphere; summer in the southern
hemisphere). This produces cooler ocean waters in
the northern and southern extremities. Ocean currents
are the transport mechanism that brings these
significantly cooler waters from the northern and
southern extremities to the western coast of Africa
which significantly reduces the amount of evaporation,
thus resulting in seasonal dessication to any regions to
the east of these cold water zones. (Note: since ocean
currents are not the fastest transport system we might
expect there to be a lag such that the actual season of
dessication would have been toward the latter part of
the low sun months [late winter, early autumn for the
northern hemisphere; late summer, early august in the
southern hemisphere]).
On a grander scale the determining factors
of seasonal dessication have to do with things such as:
the level of Co2 in the atmosphere; the flow of ocean
currents; the occurrence of significant winters (and
eventually glaciation) in the southern and northern
extremities; and the abridgement of North and South
America which seems to have occurred about 5 million
years ago. (This may have had the most significant effect
in that it shut off the flow of equatorial waters that
otherwise would flood the coast of northern Africa and
thereby prevent the occurrence of seasonal dessication.)
The following passages are not my words. They were
cut and pasted from the links that follow:
During the late Miocene, the diversity of large apes began to decline as
tropical and subtropical habitats of Europe and Asia began to contract and
become concentrated closer to the equator.
At the end of the cenozoic epoch we see yet another cooling event, related
to the expansion of the ice sheet that covered Antarctica. Ocean levels
dropped in response to the formation of ice on land, which resulted
repeatedly in the drying and catastrophic refilling of the Mediterranean
Sea.
http://www.mnh.si.edu/anthro/humanorigins/faq/gt/cenozoic/miocene.htm
7. World-wide drop in sea level in late Miocene (6
mya)-->Atlantic-Mediterranean channel pinched off, Mediterranean basin dries
up (refilled 3-2 mya); glaciation begins in Southern Hemisphere
http://oak.cats.ohiou.edu/~ballardh/pbio475/Diversification/Diversification.
htm
By the mid-late Miocene the climate started to dry as highlands formed
becoming increasingly seasonal with fragmented forest areas.
http://www.arts.auckland.ac.nz/ant/201/anth201-6.htm
Jacobs, B.F., and Deino, A., 1996, Test of climate-leaf physiognomy
regression models, their application to two Miocene floras from Kenya, and
40Ar/39Ar dating of the Late Miocene Kapturo site, Palaeogeography,
Palaeoclimatology, palaeoecology.123(1):259-271.
Jacbos, B.F., Estimation of rainfall variables from leaf characters in
tropical Africa, Palaeo3, in review.
Jacobs, B.F., Kingston, J., and Jacobs, L.L., Origin of grass-dominated
ecosystems. Conference Proceedings, The origin of modern terrestrial
ecosystems: fossils, phylogeny and biogeography, Special issue, Annals of
the Missouri Botanical Garden, in manuscript.
http://www.geology.smu.edu/~vineyard/bjacobs.html
These are the first quantitative estimates of climate for the Miocene of
East Africa. The seasonally dry climate inferred for Waril may indicate that
the Asian monsoon was established by about 9-10 Ma. Alternatively, the
seasonally dry climate may reflect local topographic changes caused by rift
valley development. However, the plant localities suggest that, although
progressive drying may have been a trend during the Tertiray, there was not
a unidirectional change from forested to open environments in the Kenya rift
between 12.6 and 6.8 Ma, the time interval just prior to the origin of
hominids.
http://www2.smu.edu/statistics/Jacobs%20Abstract.htm
If not ancient, then when (and why) did the diversity evolve?
Summer drought the key factor.
Circum-polar Antarctic current evolved in (late?) Miocene - spin-off the
Benguela cold current.
Upwelling triggered by Benguela creates stable summer conditions and a fire
climate in late dry season.
Demise of the forest communities results.
http://www.google.com/search?q=cache:90lPmKqSy-4C:www.egs.uct.ac.za/courses/
egs314/lect14-1.ppt+late+Miocene+africa+seasonal&hl=en&start=7&ie=ISO-8859-1
the Miocene hominoids (Miocene apes)
- Kenyapithecus, Oreopithecus, Dryopithecus, Sivapithecus, etc.
- general trend seems to have been towards more chewing -- eating harder or
more fibrous foods
- presumably in response to the drying, more seasonal climate
- which would have encouraged woodier, tougher plants compared to the
tropical rainforest
http://www.google.com/search?q=cache:P8gRqIOpDgUC:members.aol.com/anth201/20
101s13.doc+late+Miocene+africa+seasonal&hl=en&start=37&ie=ISO-8859-1
*************
Mike Noren
>> > Not only vultures, but aso canid, felid and hyaenid carnivores
>> >were much better preadapted for such a niche.
>>
>> Speculation - you can not possibly know that.
>
>Are you denying that lions & dogs & vultures are better than humans in
>scavenging?
A group of men working as a team, armed with sticks and throwing
stones, can certainly easily drive off jackals, dogs & vultures from a
carcass. Possibly even lions. Give them spears instead of sticks and
the lions dont stand a chance. I'd consider that a niche, although
that doesn't mean I consider Sinclairs scavenger scenario any more
supported than the aquatic ape scenario.
>> > They possessed sharp beaks or
>> >long canine teeth and did not need to carry stones for cutting carcasses.
>>
>> One might equally well put it as that they COULDNT carry stones for
>> driving off competitors.
>
>Do you really see them carrying stones to carcasses & follow herds migrating
>ungulates under the African?? (moreover: Leakey etc. were speaking of
>australopiths...).
Yes, I have no problem seeing them carrying sticks & stones to
carcasses and following herds of ungulates. That is, after all, the
most common lifestyle among neolithic humans. I can't say that
happened, but it's perfectly possible.
>> > Man is the opposite of a
>> >savanna inhabitant. Humans lack sun-reflecting fur (4) but have
>> >thermo-insulative subcutaneous fat layers, which are never seen in
>savanna mammals.
(except warthogs and other pigs)
>> One might point out that the part of our upright body which is most
>> subjected to the sun, the head, is indeed covered in a thick layer of
>> fur.
>
>:-D As I once wrote in a paper: "If we accept this reasoning, it must
>have been the women who ranged over the plains at noon while the balding and
>bearded males rested in the shade."
Again, considering extant primitive peoples, that scenario perhaps
isn't so far fetched. And of course there is little reason to suspect
they at all were active during the hottest hours of the day - very few
animals are. Or that these humans necessarily went bald at all.
>>And I think you will find that subcutaneous fat is found in e.g.
>> baby chimps.
>
>?? No, no, Mike. Chimp & even gorilla babies weigh about half human babies,
>partly due to the absence of the thick SC fat in infant apes.
I have a hard time believing this - they simply must have brown fat
depots to maintain temperature, not least considering their sparse fur
covering.
>> (And in pigs, for that matter, are they 'aquarboreal'?)
>
>Please a little bit of logic: it's notbecasue all dogs have fur, that all
>furred animals are dogs...
No, but here we have an animal whose lifestyle isn't so different from
humans - it's an omnivore like us, it is social like us, it is of the
approximate same size as us, it is not aquatic... And it's got reduced
fur and a thick subcutaneous fat layer.
If nothing else it shows that reduced fur and subcutaneous fat depots
are not necessarily adaptations to a life in water, no?
>Most humans live near the coasts & rivers. Not unlikely the less-populated
>areas like where the KhoiSan live were colonised only lately thanks to
>rel.advanced technological skills.
Apart from this being yet more speculation - what technology are you
referring to? Things such as knowing which roots to dig up and chew,
and having bowls?
>> >We need
>> >much more water than other primates, and have to drink more often than
>> >savanna inhabitants, yet we cannot drink large quantities at a time
>(7-8).
>>
>> On the other hand we can bring water, and this is based on study of
>> extant humans, which've been able to bring water along for probably
>> the last twenty thousand generations.
>
>20,000 generations = ca.0.5 Ma??
Shows the hazards of mental arithmetic. That should have read two
thousand generations.
>Why would they do that, carrying water into the dry savanna, if they lived
>near rivers & seas? :-D
Because it is so darn irritating to have to walk all that distance
everytime one gets thirsty...
>Marc Verhaegen
Mike Noren
>> explain what that layer is *for* in a supposedly aquaboreal tropical
>hominid.
>
>I did not. And we have no direct evidence to know when we got thicker fat
>layers. It fact, it probably isn't. You still haven't read the paper?
>Schematically IMO:
>1) early apes = aquarboreal (climbing-wading - unlikely to have been very
>fat: climbing),
>2) archaic Homo = waterside (wading-diving-walking, loss of climbing).
>IOW, IMO we got our thicker SC fat after the aquarboreal phase.
The thing is that the evidence is equally compatible with
'climbing-walking' or plain 'walking'.
You base your argument on an *assumption* that having fur is a
disadvantage in water, while having subcutaneous fat is an advantage.
I don't see how you can show either.
And again, pigs are not aquatic, and yet they have reduced fur and
subcutaneous fat.
>>> , lost their fur,
>>
>> See my other post - hair loss makes sense once a dark-skinned hominid
>enters an
>> open tropical environment, whether coastal or savannah
>
>We just don't know when we got dark skins. Pure speculation, Philip!
Well, considering that both chimps and gorillas are dark skinned, that
may not that much of a speculation.
>Iodine-dependency also was probably long after the aquarboreal phase, IMO,
>in the "archaic"Homo phase. The astonishing percentages of cretinism,
>goiter, myedema etc. in mountainous regions until the beginning of this
>century (due to iodine deficiency in areas away from the sea) strongly
>suggests our ancestors (note this says nothing about fossil relatives of
>us!) must have lived near the coasts until "recently", IMO, possibly until
>the sapiens LCA ca.200 ka or so
In most regions of the world you will get sufficient iodine through
the food and water, even far from the sea.
>Marc Verhaegen
Mike Noren
>> and that humans have less
>> hair than chimps (which incidentally we don't - we just have _shorter
>> and thinner_ hair).
>
>Notefven read the relevant literature?
>Shorter & thinner hairs is what Hardy said.
>Why IYO do humans have shorter & thinner hairs than chimps?
I don't know. It is not a thing one can really know. If I was to
speculate I'd say a combination of neoteny and sexual selection.
>> > Humans are strikingly different in appearance, in
>> >particular in terms of fat and body hair, than their nearest
>> >relatives, and they swim much better.
>>
>> Humans don't swim worth a sh*t unless taught how to, as attested by
>> the thousands of people who drown each year.
>
>Is this an argument?
>1) Dou deny humans descend from arboreal ancestors?? If not, why do humans
>have fear of heights? Why are humans so bad in climbing trees?
Because closer to us than those arboreal ancestors are ancestors
adapted to a lifestyle which involves endless treks across the
countryside, following herds of prey organisms. And humans aren't bad
at climbing - humans can be taught to climb better than, say, gorillas
and arguably better than chimps. I wonder if any chimp could scale
some of the cliffs solo climbers scale.
Not unlike humans can be taught to swim better than gorillas.
>2) Pure land mammals don't drown: they don't swim. In fact, swimming is one
>of the safest sports, safer than jogging...
If you've been taught how to swim, of course. If not you're just as
helpless in water as any ape.
>> but one might note that
>> ability to swim is a primitive trait among primates (and so more
>> likely to have been *lost* in the apes than *gained* in humans
>
>:-D You think all the apes *lost" their swimming skills?? chimps lost
>them, goruillas lost them, orangs lost them, etc.??
Well, you've just said that gorillas do breast strokes, so i guess
only chimps have lost their swimming skills. Sounds more and more like
a primitive trait, doesn't it.
>> ), and
>> also that the only monkey I know which does live an aquarboreal life
>> (proboscis monkey) have not developed much any traits similar to
>> humans. Except the magnificent nose.
>
>Please read our TREE paper.
>It's obvious that you have to discern several (gradual) phases:
>1) Proboscis monkeys are arboreal: all their food is in the trees, they only
>wade to reach other trees.
Ie much as you describe the so-called 'aquarboreal' lifestyle.
>2) Australopiths had "aquarboreal" features (adaptations to trees & water)
>for living in water-rich forests or wetlands (exactly where their bones have
>been found: gracile a'piths in swamp forests, robust a'piths in wetlands):
>they had some sort of bipedalism (wading in waist-deep forest swamps, as
>bonobos & gorillas occasioanlly do), had knuckle-walking features (wading in
>ankle-deep water, as gorillas do), and had a lot of climbing features (eg,
>curved finger & toe bones, to graps branches).
Neither of these are convincing adaptations for an aquatic lifestyle.
You keep claiming that no savanna mammal has subcutaneous fat
(however, consider wart hogs), but perhaps you'd like to point out one
semi-aquatic bipedal mammal? In short, what makes you think that
bipedal movement is an adaptation to wading?
>3) Homo: lost most climbing features (eg, we have straight finger & toe
>bones, unlike apes & a'piths), but developed diving skills (with a bit of
>training we can stay a few minutes unerwater, which no pure land mammal can
>do).
No pure land mammal can drive buses either. This only proves that no
other animal has cultural learning.
> A seaside lifestyle nicely explains our typical features (eg, less
>haired than chimps, more fat, larger brain, more erect, breath-hold skills
>etc.).
A life on the open plains explains the same characters - e.g. the fat
(need to store energy), erect (better overview & hands free), speech
(necessitates ability to hold breath), less hair (to improve cooling
via evaporation).
It's all just-so.
> It also explains how H.ergaster-erectus could disperse over the world
>in such a short time (fossils or Acheulian tools ca.1.8-1.7 Ma have been
>found in Algeria, Georgia, Java, S-Africa, Kenya).
Or they walked. You can get far in a couple of hundred thousand years.
Or rafted.
>> > The sort of moderate aquatic
>> > phase Marc Verhaegen is suggesting -- wading in marshes
>> > and seashores-- doesn't strike me as being totally crazy.
>>
>> No, it's just an unfalsifiable hypothesis based on idle speculations.
>
>No, it's based on comparative evidence.
Compatible with everything. Unfalsifiable speculations.
>Thick SC fat is more exclusively seen in species that spend a lot of time in
>water.
Ie pigs.
>Marc Verhaegen
deo...@usit.net
--
Deowll
New facts may cause me to change my opinion in and instant.
"Rain" <ti...@earthpoetry.demon.co.uk> wrote in message
news:EwdRPOJQ...@earthpoetry.demon.co.uk...
This poster reminds me of another poster called KC but I hope I'm wrong.
Marc does seem to be a nice person and I've been reading his posts off and
on for years. Marc is however a crack pot on his favorite topic and nothing
you say is going to mean anything. Facts don't matter to him. Debating with
him is like debating with a tape recorder. It is an obsession with him and
he will post about it as long as he can get anybody to post back.
If you find what he says pointless you will have to avoid responding to his
posts or kill file him.
If you enjoy it, go ahead. It's a free world. I will kill thread.
respectfully
deowll
Marc Verhaegen
> Replying to "Marc Verhaegen" <marc.ve...@village.uunet.be> :
>
> >> explain what that layer is *for* in a supposedly aquaboreal tropical
> >hominid.
> >
> >I did not. And we have no direct evidence to know when we got thicker fat
> >layers. It fact, it probably isn't. You still haven't read the paper?
> >Schematically IMO:
> >1) early apes = aquarboreal (climbing-wading - unlikely to have been very
> >fat: climbing),
> >2) archaic Homo = waterside (wading-diving-walking, loss of climbing).
> >IOW, IMO we got our thicker SC fat after the aquarboreal phase.
>
> The thing is that the evidence is equally compatible with
> 'climbing-walking' or plain 'walking'.
>
> You base your argument on an *assumption* that having fur is a
> disadvantage in water
I never said that: seals have fur. Furlessness in tropical mammals is not so
rare. It's often seen in species that spend a lot of time in water, but the
correlation is far from perfect.
>, while having subcutaneous fat is an advantage.
The correlation SC fat & water-dwelling is more compelling. But humans (not
aquatic any more) are much leaner than most water-dwelling species, of
course.
> I don't see how you can show either.
Not a question of showing. A question of comparing.
> And again, pigs are not aquatic, and yet they have reduced fur and
> subcutaneous fat.
Good argument IMO: the suid that is about as naked (& fat? I have no exact
data on this) as we are is the babirusa (a few patches of hair in some
places): medium-sized tropical, spending a great part of its day in water.
> >>> , lost their fur,
> >>
> >> See my other post - hair loss makes sense once a dark-skinned hominid
> >> enters an open tropical environment, whether coastal or savannah
> >
> >We just don't know when we got dark skins. Pure speculation, Philip!
>
> Well, considering that both chimps and gorillas are dark skinned, that
> may not that much of a speculation.
Some chimp populations are light-skinned.
> >Iodine-dependency also was probably long after the aquarboreal phase,
IMO,
> >in the "archaic"Homo phase. The astonishing percentages of cretinism,
> >goiter, myedema etc. in mountainous regions until the beginning of this
> >century (due to iodine deficiency in areas away from the sea) strongly
> >suggests our ancestors (note this says nothing about fossil relatives of
> >us!) must have lived near the coasts until "recently", IMO, possibly
until
> >the sapiens LCA ca.200 ka or so
(I meant of course: the beginning of last century)
> In most regions of the world you will get sufficient iodine through
> the food and water, even far from the sea.
Today, yes, but not 100 years ago, see the papers of Dobbs on cretinism
etc. (not that I believe him on his neandertal ideas).
P Bowles
>news:20020401120842...@mb-bh.aol.com...
>
>> >> >2) Pure land mammals don't drown: they don't swim.
>> >>
>> >> >> but one might note that
>> >> >> ability to swim is a primitive trait among primates (and so more
>> >> >> likely to have been *lost* in the apes than *gained* in humans
>> >> >
>> >> >:-D You think all the apes *lost" their swimming skills?? chimps
>lost
>> >> >them, goruillas lost them, orangs lost them, etc.??
>> >>
>> >> If they were lost in a common ancestor with only neonatal abilities
>> >> remaining in the apes, why would this seem implausible?
>> >
>> >Is there any indication for this most implausable idea that all apes
>retain
>> >neonatal swimming abilites, but not the adult apes?? Please no nonsense,
>> >Philip.
>>
>> All mammals appear to retain neonatal swimming abilities
>
>?? Most mammals can swim at the sruface yes, but what has this to do with
>neonatal swimming abilities??
From what I've read and heard in the past (I'm afraid I can't cite any
particular sources) most mammals lose these abilities as they grow, just as
humans will without training.
>> >> >A seaside lifestyle nicely explains our typical features (eg, less
>> >> >haired than chimps, more fat, larger brain, more erect, breath-hold
>> >> >skills etc.).
>>
>> In itself it explains few if any of these - any open environment could
>provide
>> the impetus our ancestors needed to lose their hair,
>
>No. Not one pirmate has lost its fur there.
Except for baboons, most open-habitat primates are light-skinned - the
likelihood, considering that both gorillas and chimps are dark-skinned and that
tropical modern humans share that feature, is that early hominids shared this
characteristic, rather than that they inexplicably lost it and then regained it
further down the line. Dark fur is better than their natural skin colour at
absorbing infrared radiation. The insulation provided by the human fat layer
also makes hair less essential for us than for a baboon.
In any case, you cannot argue from an absence, saying 'we couldn't have had
characteristic X because no other animal in the region does'. That's far too
simplistic a view of the factors at work relating to both lifestyle and ecology
- you might just as well say that a giraffe can't be adapted for a savannah
habitat because no other savannah-dweller has such a long neck relative to its
body, or that a rhino can't be because other savannah residents have antlers or
tusks rather than nose horns. The explanation I proposed for human hair loss in
an open environment seems plausible, but it may not have been the only factor
at work - maybe hairlessness provides resistance to some disease our ancestors
suffered from, maybe it enabled us to reduce the chances of infection from
ticks carried in fur, or maybe our hair was simply lost in a random mutation
and we never faced any pressures to regain hairyness.
>> brain size appears to be
>> linked to increasing complexity of social organisation
>
>This is a hypothesis, not impossible, but not proven at all. Seals, eg, have
>3 times larger brains than equally large terrestrial carnivores, but are not
>lmore social.
You only need to look at human behaviour to know that this is a social species
- comparisons with a relatively anti-social animal seem rather meaningless in
that context, particularly when one considers that there is a general
correlation between social complexity in other primates and brain size. There
is also evidence that increases in brain size were fuelled by a protein-rich
diet once we started eating big game (in the later species Homo habilis, and
specifically the example of Boxgrove Man, brain size has increased in exact
proportion to the reduction in gut size relative to earlier hominids). The
extra energy required to fuel the evolution of a large brain would not have
been available to creatures subsisting entirely on shellfish.
>> , our erect posture is a
>> simple progression from the clumsier bipedalism of other apes
>
>?? No just-so stories, please...
Why would this be a just-so story? Our erect gait is more efficient than the
bent-knee walking of gibbons or chimps, and once we found ourselves in an
environment with no trees to climb there would be a selective pressure to
develop a faster means of terrestrial locomotion. Increasing use of our
forelimbs to manipulate tools would also have encouraged a posture which left
our forelimbs free, especially if our ancestors regularly carried food back to
a nest or camp site - modern-day chimps have limb proportions and posture more
similar to ours than those of an orang-utan, not because they wade more often,
but because they are more terrestrial and they are tool-users, and this is true
even of animals in a forest environment.
>> while our
>> breath-control skills relate to the formation of complex language
>
>It's the other way round, of course: voluntary breathing (no doubt evolved
>for diving, as in all diving mammals) was a preadaptation for speech.
Are you saying that in all diving mammals voluntary breathing is a pre-adaption
for speech? :-) There isn't any necessity to invoke a diving past - the simple
need to communicate (with all that hair gone, we can't go about grooming each
other to exchange information after all...) combined with the increasing
complexity of the social world around them is enough to explain why humans
would have developed the breath control required to formulate language.
Assuming that characteristic X must have evolved as a result of particular
condition Y and cannot have any other cause is as simplistic as assuming that
since we have some differences from other animals, we can't have evolved in the
same environment.
>> (which cannot
>> have been spurred by an aquatic lifestyle, contrary to one contention in
>your
>> article - the wavelengths in which humans and other primates communicate
>do not
>> travel far underwater, and the wavelengths best-suited for such
>communication
>> are inaudible to us).
>
>??
>I hope you don't think I think our ancestors spoke underwater??
No, but as I recall from your article you did speculate that they may have used
some form of vocal communication due to the inefficiency of other senses in an
aquatic environment. This seems implausible given our range of vocalisations.
I don't plan to; I regard the most likely explanation as a now-unknown land
bridge, lost due to either rising sea levels of volcanism that left the remnant
that is now Flores separated from Sunda-land. However, among the alternatives I
regard the possibility of boat-building as greater than that of swimming.
>> would have subsisted from coastal shellfish found in rock pools
>> or along the beach, or even in the shallows on occasion, just as humans in
>> coastal habitats do today - you listed a variety of remains found in
>coastal
>> regions in another post. However, as others have pointed out these do
>nothing
>> to support the idea that these creatures were habitually aquatic, swimming
>from
>> place to place and diving for their meals on a regular basis.
>
>Diving for food (probably shells) is strongly suggested by our superior
>diving skills - unique among mammals. Other indications are, eg, the fatty
>acid composition of marine-based foods; our tool-using & making skills (cf.
>mangrove capuchins: to open mangrove oysters).
Mangrove capuchins have a rather more primitive level of tool use than the
hominids who are likely to have colonised the coast; if our ancestors were even
as sophisticated as chimpanzees they would have developed the use of a variety
of tools related to the acquisition of food, including the hammer and anvil
technique. On the other hand, the coastal habitat offers few incentives for
developing tool use beyond this level that wouldn't be found elsewhere (with
the possible exception of boat construction possibly primitive harpoons, both
of which might be learned in areas around inland lakes, and neither of which
would emerge until the community switched to a piscine diet).
Philip Bowles
P Bowles
>>
>> And these lakes were in what sort of environment...? Open grassland in at
>least
>> some cases - in other words, savannah.
>
>1) In some cases, yes, but not in most (note I'm talking about
>H.erectus-ergaster - from Europe to Flores: no savanna).
H. erectus was not the first hominid to abandon the forests, so far as I am
aware. It also had a fully-developed bipedal posture and may well have had the
hairlessness and subcutaneous fat for all we can tell from the specimens. It
had a wide variety of tools made using a number of different materials, and
could conceivably have possessed sufficient vocal control to produce
vocalisations akin to primitive language. Most of the adaptations you are
attributing to H. erectus' seaside lifestyle had already taken place in its
ancestors. The only truly significant difference between H. erectus and its
descendants is the increased brain size of later humans.
>2) And certainly not in dry savanna (as an "explanation" for our loss of fur
>etc.), as the savanna-minded people used to believe. (I just read that some
>well-known PAs still believe & publish this nonsense: Klein & Edgar 2002
>"The Dawn of Human Culture" J.Wiley & sons: "... occurred between 7-5 Ma
>when a group of Afr.apes, in response to shrinking forests & expanding open
>savannas, began to walk upright." can you believe this?)
No, simply because the most recent evidence shows that the forests weren't in
decline at that time and that our ancestors remained in forests for rather
longer than once believed. However, I don't see anything inherently implausible
about the theory itself and I can see that someone who is unaware of the more
recent findings could subscribe to it - the theory happens to be wrong on the
basis of the evidence, but it isn't crazy.
>> However, even if humans lost their fur
>> in a coastal habitat the same rationale would apply - in an environment
>exposed
>> to the tropical sun, hair loss in humans would make evolutionary sense.
>
>No! No other primate has lost its fur. All primates are tropical. Baboons
>are exposed to the tropical sun.
See my other post.
Plenty of dinosaurs have been
>found
>> in coastal environments, but that doesn't imply that they were habitually
>> marine. Your own article mentioned the difficulty with inferring details
>about
>> lifestyle from the locations where a fossil was preserved.
>
>Yes; but there's a difference between australopith fossils & Homo fossils:
>the first are seldom found next to shellfish; the latter always AFAIK.
Then that is indeed good evidence for a lifestyle subsisting on shellfish and
consequently living at the coast - but this still doesn't imply that they were
early pearl-divers. There are baboons living on the Gabon coast who routinely
eat crabs, but they don't go swimming in the sea itself to look for them (and,
inexplicably, they still have all their fur! :-) )
Philip Bowles
Marc Verhaegen
> Replying to "Marc Verhaegen" <marc.ve...@village.uunet.be> :
>
> >> and that humans have less
> >> hair than chimps (which incidentally we don't - we just have _shorter
> >> and thinner_ hair).
> >
> >Shorter & thinner hairs is what Hardy said.
> >Why IYO do humans have shorter & thinner hairs than chimps?
>
> I don't know. It is not a thing one can really know. If I was to
> speculate I'd say a combination of neoteny and sexual selection.
1) Neoteny? no: neoteny is at best a genetic mechanism, it doesn't explain a
thing: what have humans in common with axolotls?
2) Sex.selection: all mammals & primates have sex.selection. Only 1 primate
is furless.
> >> > Humans are strikingly different in appearance, in
> >> >particular in terms of fat and body hair, than their nearest
> >> >relatives, and they swim much better.
> >>
> >> Humans don't swim worth a sh*t unless taught how to, as attested by
> >> the thousands of people who drown each year.
> >
> >Is this an argument?
> >1) Dou deny humans descend from arboreal ancestors?? If not, why do
humans
> >have fear of heights? Why are humans so bad in climbing trees?
>
> Because closer to us than those arboreal ancestors are ancestors
> adapted to a lifestyle which involves endless treks across the
> countryside, following herds of prey organisms.
There's not 1 shred of evidence that the sapiens LCA or earlier ancestors
followed herds...
> And humans aren't bad
> at climbing - humans can be taught to climb better than, say, gorillas
> and arguably better than chimps. I wonder if any chimp could scale
> some of the cliffs solo climbers scale.
1) First you said that humans were as hairy as chimps, now you're saying
that humans climb as well as chimps?? please, a bit serious: we're trying to
explain why we differ from chimps...
2) Cliffs? some AAT people think our ancestors lived at cliffy coasts...
:-)
> Not unlike humans can be taught to swim better than gorillas.
In Polynesia, human infants swim before they can walk.
> >2) Pure land mammals don't drown: they don't swim. In fact, swimming is
one
> >of the safest sports, safer than jogging...
>
> If you've been taught how to swim, of course. If not you're just as
> helpless in water as any ape.
Polynesian islanders can swim before they can walk. Humans are superb
acrobats in the water. Gorillas in zoos learn to swim (not unexpected:
lowland gorillas spend a lot of time in forest swamps), but always at the
surface, never diving.
> >> but one might note that
> >> ability to swim is a primitive trait among primates (and so more
> >> likely to have been *lost* in the apes than *gained* in humans
> >
> >:-D You think all the apes *lost" their swimming skills?? chimps lost
> >them, goruillas lost them, orangs lost them, etc.??
>
> Well, you've just said that gorillas do breast strokes, so i guess
> only chimps have lost their swimming skills. Sounds more and more like
> a primitive trait, doesn't it.
And all the other primate species??
But what has to be explained is that humans are far better divers than any
other primate.
> >> ), and
> >> also that the only monkey I know which does live an aquarboreal life
> >> (proboscis monkey) have not developed much any traits similar to
> >> humans. Except the magnificent nose.
> >
> >Please read our TREE paper.
> >It's obvious that you have to discern several (gradual) phases:
> >1) Proboscis monkeys are arboreal: all their food is in the trees, they
only
> >wade to reach other trees.
>
> Ie much as you describe the so-called 'aquarboreal' lifestyle.
No: aquarboreal is already a step further, eg, collecting food in the water,
eg, mangrove oysters.
> >2) Australopiths had "aquarboreal" features (adaptations to trees &
water)
> >for living in water-rich forests or wetlands (exactly where their bones
have
> >been found: gracile a'piths in swamp forests, robust a'piths in
wetlands):
> >they had some sort of bipedalism (wading in waist-deep forest swamps, as
> >bonobos & gorillas occasioanlly do), had knuckle-walking features (wading
in
> >ankle-deep water, as gorillas do), and had a lot of climbing features
(eg,
> >curved finger & toe bones, to graps branches).
>
> Neither of these are convincing adaptations for an aquatic lifestyle.
Certainly. Nobody is talking about a"quatic" (which reminds of whales etc.).
> You keep claiming that no savanna mammal has subcutaneous fat
> (however, consider wart hogs
Very lean AFAIK. You must be thinking of domestic pigs, which they're not.
> ), but perhaps you'd like to point out one
> semi-aquatic bipedal mammal? In short, what makes you think that
> bipedal movement is an adaptation to wading?
After our TREE paper: "Most primates are quadrupedal tree-dwellers with very
flexible spines & limbs, which enable them to reach, climb or leap through
trees and to stand or walk bipedally when necessary. Human-like 'erect
bipedalism', although less common than 'hopping bipedalism' [kangaroos,
jerboas, tarsiers, indris...], is regularly seen in lowland gorillas that
seek sedges in forest swamps, in proboscis monkeys that wade between
mangrove trees, and possibly in the 'swamp ape' Oreopithecus bambolii (Table
1), whose diet is believed to have included wetland plants and whose anatomy
"provides evidence that bipedal activities made up a significant part of the
positional behavior". We find non-wading explanations for human bipedalism
(e.g. standing-up to reach fruit in trees, aggressive posturing, looking
over savannah grass, and carrying tools, food or babies) unconvincing,
because the advantages appear to be only of a temporary nature, and because
no other primates or savannah mammals have developed bipedalism for similar
reasons. Quite possibly, the features that typically distinguish apes
from monkeys (i.e. large size, tail-loss and arm-hanging) were adaptations
for what we call an 'aquarboreal' locomotion in an environment that included
both trees and water. A vertical posture and an ability to climb with the
arms raised above the head could have helped a wading primate to enter or
leave the water by grasping overhanging branches or waterside vegetation,
and to grasp fruits above the water. Body enlargement and tail reduction
would hinder agile arborealism, whereas a larger body is more easily
supported in water and helps reduce heat loss (explaining why aquatic
mammals are larger than related terrestrial forms). Tails would be of little
use for a wading and/or swimming primate and cause both drag and heat loss.
Early hominids could have waded bipedally in swamp forests using the trees
for refuge, sleep and fruit-gathering, whilst finding part of their food in
shallow water."
Or look at it the other way round. The Miocene was warmer & wetter than
today. There were probably more forest swamps of the kind that we seen today
in Congo (where the western lowland gorillas live). Primates (arboreal) were
of course preadapted to occupy such niches (trees + water). Which changes
might be expected if monkey-like creatures would start living several hours
per day in these swamps (+- as western gorillas do occasionally, in search
for aquatic herbs & sedges, or perhaps only like proboscis monkeys that have
to wade to reach other mangrove trees)? They would tend to become larger (as
all mammals that spend a lot of time in water), get adaptations to grasp the
vegetation (or fruits) around & above the swamps, reduce their tails (of
less use in large animals, and only a hindrance in water (drag & heat
loss)), walk more upright in deeper water, etc. These changes are exactly
the changes we seen in hominoids vs. monkeys.
> >3) Homo: lost most climbing features (eg, we have straight finger & toe
> >bones, unlike apes & a'piths), but developed diving skills (with a bit of
> >training we can stay a few minutes unerwater, which no pure land
> >mammal can do).
>
> No pure land mammal can drive buses either. This only proves that no
> other animal has cultural learning.
Please no nonsense. Do you think the Polynesian infants that swim before
they can walk needed "cultural learning" to do so?
> > A seaside lifestyle nicely explains our typical features (eg, less
> >haired than chimps, more fat, larger brain, more erect, breath-hold
skills
> >etc.).
>
> A life on the open plains explains the same characters - e.g. the fat
> (need to store energy), erect (better overview & hands free), speech
> (necessitates ability to hold breath), less hair (to improve cooling
> via evaporation). It's all just-so.
Not al all: this is purely wioshful thinking:
- fat: no savanna animal is fat!
- erect: only savanna kangaroos are bipedal (but not erect)
- speech: savanna mammals have less sound variation than arboreal or
(semi)aquatic animals
- breath-hold: do I need to comment?
- less hair: no savanna primate is furless!
> > It also explains how H.ergaster-erectus could disperse over the world
> >in such a short time (fossils or Acheulian tools ca.1.8-1.7 Ma have been
> >found in Algeria, Georgia, Java, S-Africa, Kenya).
>
> Or they walked. You can get far in a couple of hundred thousand years.
> Or rafted.
Yes, of course they walked (or rafted): along the coasts & got their food
from the sea. That's what I'm saying.
> >> > The sort of moderate aquatic
> >> > phase Marc Verhaegen is suggesting -- wading in marshes
> >> > and seashores-- doesn't strike me as being totally crazy.
> >>
> >> No, it's just an unfalsifiable hypothesis based on idle speculations.
> >
> >No, it's based on comparative evidence.
>
> Compatible with everything. Unfalsifiable speculations.
Not at all: see the comparative evidence. To the contrary: the (dry) savanna
stories are falsifiable speculations.
(snipped about the pigs: see other post)
Marc Verhaegen
> Replying to "Marc Verhaegen" <marc.ve...@village.uunet.be> :
>
> >> > Not only vultures, but aso canid, felid and hyaenid carnivores
> >> >were much better preadapted for such a niche.
> >>
> >> Speculation - you can not possibly know that.
> >
> >Are you denying that lions & dogs & vultures are better than humans in
> >scavenging?
>
> A group of men working as a team, armed with sticks and throwing
> stones,
Chimps can do that (they throw very accurately). But they're not furless,
not fat, not erect...
> can certainly easily drive off jackals, dogs & vultures from a
> carcass. Possibly even lions. Give them spears instead of sticks and
> the lions dont stand a chance. I'd consider that a niche, although
> that doesn't mean I consider Sinclairs scavenger scenario any more
> supported than the aquatic ape scenario.
It's much easier to survive along a lagoon (fruits, shells, fish) than in a
dry savanna, don't you think?
> >> > They possessed sharp beaks or
> >> >long canine teeth and did not need to carry stones for cutting
carcasses.
> >>
> >> One might equally well put it as that they COULDNT carry stones for
> >> driving off competitors.
> >
> >Do you really see them carrying stones to carcasses & follow herds
migrating
> >ungulates under the African?? (moreover: Leakey etc. were speaking of
> >australopiths...).
>
> Yes, I have no problem seeing them carrying sticks & stones to
> carcasses and following herds of ungulates. That is, after all, the
> most common lifestyle among neolithic humans.
Where do you get this idea? references please? this is just a common view
made popular in books for the general public, but without evidence.
> I can't say that
> happened, but it's perfectly possible.
I don't think so: see my scient.correspondence letter to Nature.
> >> > Man is the opposite of a
> >> >savanna inhabitant. Humans lack sun-reflecting fur (4) but have
> >> >thermo-insulative subcutaneous fat layers, which are never seen in
> >savanna mammals.
>
> (except warthogs and other pigs)
Warthogs are very lean AFAIK. Have more fur than humans, less than forest
hogs (probably because wartnogs spend a lot of time in holes: friction).
> >> One might point out that the part of our upright body which is most
> >> subjected to the sun, the head, is indeed covered in a thick layer of
> >> fur.
> >
> >:-D As I once wrote in a paper: "If we accept this reasoning, it must
> >have been the women who ranged over the plains at noon while the
> >balding and bearded males rested in the shade."
>
> Again, considering extant primitive peoples, that scenario perhaps
> isn't so far fetched. And of course there is little reason to suspect
> they at all were active during the hottest hours of the day
Please a bit serious. First you claim that they walked erect to minimise
solar radiation. Now you say they were not active when the sun was
highest...
> - very few
> animals are. Or that these humans necessarily went bald at all.
I said: men are balder than women.
> >>And I think you will find that subcutaneous fat is found in e.g.
> >> baby chimps.
> >
> >?? No, no, Mike. Chimp & even gorilla babies weigh about half human
babies,
> >partly due to the absence of the thick SC fat in infant apes.
>
> I have a hard time believing this - they simply must have brown fat
> depots to maintain temperature, not least considering their sparse fur
> covering.
I think you have do a bit of reading. We're talking here of white adipose
tissue (not in chimps). Human (& I believe) chimps infants have brown fat
tissues, but the amount of these is at least ten times less than the WAT.
Please have a look at a newborn human & chimp.
> >> (And in pigs, for that matter, are they 'aquarboreal'?)
> >
> >Please a little bit of logic: it's not becasue all dogs have fur, that
all
> >furred animals are dogs...
>
> No, but here we have an animal whose lifestyle isn't so different from
> humans - it's an omnivore like us, it is social like us, it is of the
> approximate same size as us, it is not aquatic... And it's got reduced
> fur and a thick subcutaneous fat layer.
As I already said a few times: forest suids are very hairy, warthogs are
lean & +-furless (living in holes), babirusas are comparable to humans in
fat & fur, but these spend a lot of time in water...
> If nothing else it shows that reduced fur and subcutaneous fat depots
> are not necessarily adaptations to a life in water, no?
See above.
> >Most humans live near the coasts & rivers. Not unlikely the
less-populated
> >areas like where the KhoiSan live were colonised only lately thanks to
> >rel.advanced technological skills.
>
> Apart from this being yet more speculation - what technology are you
> referring to? Things such as knowing which roots to dig up and chew,
> and having bowls?
Bowls, poisons, water containing things...
> >> >We need
> >> >much more water than other primates, and have to drink more often than
> >> >savanna inhabitants, yet we cannot drink large quantities at a time.
> >>
> >> On the other hand we can bring water, and this is based on study of
> >> extant humans, which've been able to bring water along for probably
> >> the last twenty thousand generations.
> >
> >20,000 generations = ca.0.5 Ma??
>
> Shows the hazards of mental arithmetic. That should have read two
> thousand generations.
Yes, 50 ka: of course: sapiens = us.
> >Why would they do that, carrying water into the dry savanna, if they
lived
> >near rivers & seas? :-D
>
> Because it is so darn irritating to have to walk all that distance
> everytime one gets thirsty...
Yes, that's why they were never more than a few meters away from the water.
Unlike typical savanna mammals.
Marc Verhaegen
P Bowles
>thing:
Very true.
what have humans in common with axolotls?
>2) Sex.selection: all mammals & primates have sex.selection. Only 1 primate
>is furless.
All mammals have sexual selection, yet only one engages in ritual neck-twining
/hitting the rival with its neck. Sexual selection takes many forms.
>- erect: only savanna kangaroos are bipedal (but not erect)
Irrelevant - bipedalism at least started in a forest habitat if it didn't
evolve entirely in that environment. Once the species was a) at least
functionally bipedal and b) had become dependent on tool-using techniques that
required the freedom of its forelimbs it would have been much easier and more
efficient for the selective process to select for true bipedalism - by
contrast, something with the body form of a rhino has no incentive to develop
into a bipedal animal - the limb proportions are entirely wrong and its
lifestyle doesn't require the change.
>- speech: savanna mammals have less sound variation than arboreal or
>(semi)aquatic animals
Yet primates have more variation than most savannah animals - comparisons with
lions or gazelles are of no relevance as these are completely different types
of animal. Humans didn't suddenly evolve from scratch in one environment - they
have an entire lineage stretching back more than 65 million years which has
given rise to characters distinct from those of 'savannah mammals' like lions,
rhinos, gazelles, elephants etc.
>- breath-hold: do I need to comment?
You already have, frequently.
>- less hair: no savanna primate is furless!
Few primates inhabit savannah at all, and no other primate is hairless
regardless of its environment. It seems strange that you insist on drawing
comparisons with 'savannah mammals' for all your other points, but here you
restrict yourself to 'savannah primates' (because of course hairlessness is not
altogether uncommon among savannah mammal species). Such a comparison might be
the black and white rhinos - hairless savannah animals probably derived from
hairy tropical forest dwellers similar to the extant Javan rhino (as the rhinos
are an Asian group - unlike the elephants, which probably remained hairless in
Africa and secondarily developed hairiness to cope with ice age conditions in
the northern hemisphere)..
Philip Bowles
Gerrit Hanenburg
>> It isn't. See Rodman & McHenry (1980): "The actual costs of travel for
>> walking humans are slightly less than those predicted for a
>> quadrupedal mammal of the same size" (p.104), while it is much more
>> efficient compared to chimpanzee quadrupedalism, and that is where the
>> comparison is most relevant because we share a more recent common
>> ancestor with chimps than with artiodactyls.
>Other people claim the opposite. If bipedalism had been superior to
>quadrupedalims, a lot more mammals than humans & kangaroos would run on 2
>legs.
Nonsense. Bipedalism is not necessarily always more efficient than
quadrupedalism. It depends on where you're coming from. There is such
a thing as historical constraint.
If you already are a hindlimb dominated orthograde hominoid then the
shift to bipedalism is much easier than when you're a dedicated
quadruped without a history of life in the trees.
Gerrit
Corvùn & Celeste Sæpius
> > in a coastal habitat the same rationale would apply - in an
environment
> exposed
> > to the tropical sun, hair loss in humans would make evolutionary
sense.
>
> No! No other primate has lost its fur. All primates are tropical.
Baboons
> are exposed to the tropical sun.
All primates are tropical? Haven't you ever heard of a snow-monkey? Or
Gigantopithecus (who lived in a temperate-subtropical environment at
best)? Besides, have you ever even SEEN a chimpanzee? Some of them
have such thin, sparse hair that even some humans look hairier! (See:
Italy).
Maybe increased cephalization required extra-resources and since the
thick, dense hair wasn't really *needed* anymore, it was lost in favor
of larger brains and such, no matter what type of habitat this occured
in - as long as it weren't a cold one.
> Yes; but there's a difference between australopith fossils & Homo
fossils:
> the first are seldom found next to shellfish; the latter always
AFAIK.
That's because Australopithecines were the first ones to walk out into
the Savannah. Homonines were the first to spread out of africa...H.
erectus survived in very cold, wet climates; very hot, humid climates,
any climate that fire and tools came in handy. And H. ergaster? It's
hard to find info on that kritter since there is controversy over
whether it's even a legitimate species!
--
Corvun & Celeste Sæpius
~ Coven of the Shadow Moon ~
"Hear Now the Words of the Witches,
The Secrets We Hid in the Night,
When Dark was Our Destiny's Pathway,
That Now We Bring Forth into Light!"
"Marc Verhaegen" <marc.ve...@village.uunet.be> wrote in message
news:3ca8d6b1$0$246$ba62...@news.skynet.be...
Corvùn & Celeste Sæpius
inform a
> bit first.
Did you even bother to *read* my post? You really have no clue what
you're talking about. Ardipithecus and early Australopithecines were
undoubtedly mostly arboreal, but this is when they began crossing
expanses between the forests...and, like gibbons, they walked on two
legs when on the ground. The animals became jury-rigged for a savannah
lifestyle, and were already bipedal before moving out there (just like
quadrupedal savannah-dwellers were already quadrupedal before they
moved out into the savannah).
> :-D Yes, that's why all savanna mammals run on 2 legs, you mean?
No. Most are quadrupedal...some are facultative bipeds who hop accross
savannahs and deserts (ever heard of a Kangaroo?)...some are obligate
bipeds (the bush-people of africa). Of course, if you look at
tetrapods in *any* land-environment, *most* will be quadrupedal. But
there will be exceptions. Humans and their ancestors were the
savannah's bipeds.
--
Corvun Sæpius
~ Coven of the Shadow Moon ~
"Hear Now the Words of the Witches,
The Secrets We Hid in the Night,
When Dark was Our Destiny's Pathway,
That Now We Bring Forth into Light!"
"Marc Verhaegen" <marc.ve...@village.uunet.be> wrote in message
news:3ca8d7e8$0$253$ba62...@news.skynet.be...
>
> "Corvùn & Celeste Sæpius" <theol...@hotmail.com> schreef in
P Bowles
>Gigantopithecus (who lived in a temperate-subtropical environment at
>best)?
Or indeed the Barbary 'ape' - though probably introduced to the European island
of Gibraltar, its natural habitat in Morocco is high-altitude conifer forest,
areas where winter snows are common.
>Maybe increased cephalization required extra-resources and since the
>thick, dense hair wasn't really *needed* anymore, it was lost in favor
>of larger brains and such, no matter what type of habitat this occured
>in - as long as it weren't a cold one.
There is also the possibility I raised - exposing melanistic skin to the sun
increases the efficiency of vitamin production. One reason humans may have
needed to lose hair in this way while animals like baboons didn't could be that
our ancestors' diet was low in these vitamins (most commonly found naturally in
fruit and in fish) and we needed to produce them ourselves to supplement our
diet. Just one possibility of several that have been raised (including a need
to avoid overheating - bear in mind that the larger the animal, the greater
this risk becomes with a hair-covered body hence the bare skins of elephants in
open tropical habitats (for example), and humans are substantially larger than
baboons - resistance to parasites which live in fur, sexual selection, or
simple random mutation), but one which indicates the complexity of
environmental factors and selective pressures which might at first seem
unrelated to something like hair loss. That and the fact that the proposed
aquatic lifestyle does not actually explain human characteristics
satisfactorily are my grounds for rejecting that part of Marc's hypothesis -
some elements of his theory, such as primate migration patterns and even the
proposed waterside lifestyle of our forest-dwelling ancestors deserve serious
consideration, and it's a shame they are unlikely to get it because of the
aquatic ape stigma attached to the later claims of a diving ancestor and the
questionable parallels drawn with unrelated mammal species.
Philip Bowles
Corvùn & Celeste Sæpius
thing to consider is that dark, dark skin is more resistant to
burning.
There were probably many, many factors in the reduction of
hair-density among human ancestors.
--
Corvun & Celeste Sæpius
~ Coven of the Shadow Moon ~
"Hear Now the Words of the Witches,
The Secrets We Hid in the Night,
When Dark was Our Destiny's Pathway,
That Now We Bring Forth into Light!"
"P Bowles" <pbo...@aol.com> wrote in message
news:20020402111041...@mb-ct.aol.com...
P Bowles
>thing to consider is that dark, dark skin is more resistant to
>burning.
It also occurs to me that the fur loss in marine mammals (which is largely
restricted to the bigger seals, manatees and cetaceans) seems more likely to
relate to their size and the fact that water (particularly salt water) is a
good heat conductor than to streamlining adaptions for an aquatic or diving
lifestyle - manatees and most whales are far from aerodynamic, and the majority
don't need to be powerful or fast swimmers - sea grass doesn't run terribly
quickly and neither does plankton. Even some of the animals which do lead a
predatory lifestyle and need to be powerful swimmers, such as leopard seals, do
have a short coat of fur - as I was reminded by Marc himself earlier in the
thread, no less. It's all very well pointing out that an animal in environment
X has this-or-that characteristic, but you can't use that as a basis of an
argument without explaining why that animal has that characteristic - Marc
assumes that 'some aquatic animals don't have hair, so hairlessness must be an
aquatic adaption', failing to recognise that even an aquatic animal has
selective pressures acting on it which don't durectly relate to its ability to
swim or whatever.
Philip Bowles
Marc Verhaegen
(sorry no time: in a hurry)
> >> >> Isn't it what it's always been - free speculations about human
traits
> >> >> discussed out of context?
> >> >
> >> >:-) Apparently you haven't read the paper..
> >
> >No answer?
>
> Actually, I thought that
> http://allserv.rug.ac.be/~mvaneech/Verhaegen.html WAS the article. I
> now see you provide a reference, and I'll have a look at it.
>
> >Please have a look at the files. (You can also find our TREE paper
there.)
>
> OK.
>
> >> The second is an article in the vein of the 'documentaries' sometimes
> >> seen on TV, where 'may' 'could' 'might' 'possibly' and 'perhaps' are
> >> piled upon eachother until eventually they are treated as facts
> >> leading to a conclusion.
> >
> >It's one of the papers presented at the "Water and human evolution"
> >symposium 2 years ago. All very speculatieve, of course (what had you
> >expected?)
>
> That was in fact exactly what I expected. However, I seem to recall
> you referred me to that article in response to my statement that the
> AAT is nothing but idle speculation about human traits discussed out
> of context.
Speculation, but not idle.
> >> Several of the statements are, to my eyes, surprising: what kind of
> >> dentition suggests a diet of fruit (soft), water plants (soft), and
> >> grass (extremely hard)?
> >
> >Read our TREE paper & the refs eg, of Puech & of Ungar.
> >Trends in Ecology & Evolution 17, No. 5, May 2002
> >Aquarboreal ancestors?
>
> Will do. It will be quite interesting to see the details of this novel
> type of dentition.
>
> >> And the statement about great ape fossils from 12 - 8Myrs ago; I
> >> wasn't aware that any ape fossils had been found from that period?
> >
> >Not my fault, Mike...
>
> True. Do you have a reference?
Lots. Some can be found in the TREE paper.
Betw.12-8 Ma: Dryopith, Sivapith.
> >> The rest is the standard fare speculation. Take this sentence, for
> >> instance:
> >> "The fossil data indicates that the early australopithecines of 4-3
> >> million years ago lived in waterside forests or woodlands; and their
> >> larger, robust relatives of 2-1 million years ago in generally more
> >> open milieus near marshes and reedbeds, where they could
> >> have waded bipedally." What is this based on?
> >
> >4-3 Ma apiths: waterside forests & woodlands:
>
> More or less.
All of them AFAIK.
> >§ Ardipithecus ramidus: 'Sedimentological, botanical and faunal
> >evidence suggests a wooded habitat for the Aramis hominids [.] Aquatic
> >elements (turtle, fish, crocodile) are rare.
>
> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
Yes, I have the impression that Ardipith was more forested (cf. also thinner
enamel).
> >§ Kanapoi KNM-KP 29281 Australopithecus anamensis: Fish, aquatic
> >reptiles, kudus and monkeys are prevalent. 'A wide gallery forest would
have
> >almost certainly been present on the large river that brought in the
> >sediments' (Leakey et al., 1995).
>
> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
Why not? The aquarboreal lifestyle of the early hominids is based on their
anatomy, see the TREE paper.
>
> >§ Chad KT 12 A. cf. afarensis: 'The non-hominid fauna contains
> >aquatic taxa (such as Siluridae, Trionyx, cf. Tomistoma), taxa adapted to
> >wooded habitats (such as Loxodonta, Kobus, Kolpochoerus) and to more open
> >areas (such as Ceratotherium, Hipparion) [.] compatible with a lakeside
> >environment' (Brunet et al., 1995).
>
> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
Idem.
> >§ Hadar, Afar Locality: 'Generally, the sediments represent
> >lacustrine, lake margin, and associated fluvial deposits related to an
> >extensive lake that periodically filled the entire basin' (Johanson et
al.,
> >1982)
>
> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
Idem.
> >§ Hadar AL.333 A. afarensis: 'The bones were found in swale-like
> >features [.] it is very likely that they died and partially rotted at or
> >very near this site [.] this group of hominids was buried in streamside
> >gallery woodland' (Radosevich et al., 1992).
>
> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
Idem.
> >§ Hadar AL.288 gracile A. afarensis: Lucy lay in a small, slow
> >moving stream. 'Fossil preservation at this locality is excellent,
remains
> >of delicate items such as crocodile and turtle eggs and crab claws being
> >found' (Johanson & Taieb, 1976).
>
> Ie at least this one probably died in the water, although this doesn't
> really lend support to an 'aquarboreal' lifestyle for Lucy either.
Same answer. Point is: water & trees were abundantly present in (all?)
cases.
> (And incidentally it seems vertebrate paleontologists have a different
> view of what is 'delicate' than invertebrate paleontologists)
:-)
> >§ Makapan A. africanus: '[.] very different conditions from those
> >prevailing today. Higher rainfall, fertile, alkaline soils and moderate
> >relief supported significant patches of sub-tropical forest and thick
bush,
> >rather than savannah. Taphonomic considerations [.] suggest that
> >sub-tropical forest was the hominins' preferred habitat rather than
> >grassland or bushveld, and the adaptations of these animals was therefore
> >fitted to a forest habitat' (Rayner et al., 1993; see also Reed, 1993;
and
> >Wood, 1993).
>
> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
Idem.
> >§ Taung australopithecine: 'the clayey matrix from which the
Taung
> >cranium was extracted, and the frequent occurrence of calcite veins and
void
> >fillings within it (Butzer, 1974, 1980) do suggest a more humid
environment
> >during its accumulation' (Partridge, 1985).
>
> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
Idem.
> Again, fossils tend to be found in sediments deposited in water
> because sediments accumulate in water but erodes in air.
Again: our attempt to reconstruct the apith environments is based on their
anatomy (incl. microwear etc. see the TREE paper).
> If one million Lucys all died on mountain slopes only the ones which
> happened to be flushed into a lake (or slipped on the embankment and
> drowned) would fossilize.
>
> Simply put, finding a fossil in a lacustrine sediment is not in any
> way proof it actually lived there.
>
> >2-1 Ma robust apiths: more open wetlands:
>
> And here you just did one of those glidings to conclusion. Your
> references speak of forest, not of open wetlands.
No, no. You must make the difference:
- graciles: always a lot of trees,
- robusts: less trees.
(Note: al this has nothing to do with human ancestors: at that time we
already had Homo in Europe, Java etc.)
> >§ Kromdraai: A. robustus was found near grassveld and streamside
or
> >marsh vegetation, in the vicinity of quail, pipits, starlings, swallows,
and
> >parrots, lovebirds and similar psittacine birds (T. N. Pocock in Brain,
> >1981).
>
> Ie this fossil suggest an 'aquarboreal' lifestyle for the ancestors of
> lovebirds and swallows.
:-)
> >§ Turkana KNM-ER 17000 and 16005: A. aethiopicus was discovered
near
> >the boundary between overbank deposits of large perennial river and
alluvial
> >fan deposits, amid water- and reedbucks (Walker et al., 1986).
>
> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
Why not? Same answer.
> >§ Lake Turkana: 'The lake margins were generally swampy, with
> >extensive areas of mudflats [.] Australopithecus boisei was more abundant
in
> >fluvial environments, whereas Homo habilis was rare in such environments
[.]
> >Australopithecus fossils are more common than Homo both in channel and
> >floodplain deposits. The gracile hominids [.] seem to be more restricted
> >ecologically to the lake margin than are the robust forms' (Conroy,
1990).
>
> This is speculation on Conroys part. It's not like the amount of
> fossils allows one to actually make a statistical evaluation (and even
> if they did, living on the banks of a lake does not necessarily imply
> an 'aquarboreal' lifestyle).
See Puech's papers. To befound in the TREE paper.
> >§ Ileret A. boisei: 'the fossil sample reflects climatic and
> >ecological environmental conditions differing significantly from those of
> >the present day. At Ileret, 1.5 Myr ago, climatic conditions must have
been
> >cooler and more humid than today, and more favourable to extensive
forests
> >[.] The prominence of montane forest is particularly striking [.]
dominated
> >by Gramineae and Chenopodiaceae appropriate to the margins of a slightly
> >saline or alkaline lake' (Bonnefille, 1976).
>
> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
>
> >§ Chesowanja A. boisei: 'The fossiliferous sediments were
deposited
> >in a lagoon [.] Abundant root casts [.] suggest that the embayment was
> >flanked by reeds and the presence of calcareous algae indicates that the
> >lagoon was warm and shallow. Bellamya and catfish are animals tolerant of
> >relatively stagnant water, and such situation would also be suitable for
> >turtles and crocodiles' (Carney et al., 1971).
>
> Well, atleast that implies it, like lucy, died in situ, or were
> flushed there during torrential rains. Still not really support for an
> 'aquarboreal' lifestyle, although it is support for the view that they
> atleast occasionally, possibly voluntarily, entered water.
>
> >§ Kaye E. Reed 1997 "Early hominid evolution and ecological
change
> >through the African Plio-Pleistocene" JHE 32:289-322: "... Reconstructed
> >habitats show that Australopithecus species existed in fairly wooded,
> >well-watered regions. Paranthropus species lived in similar environs and
> >also in more open regions, but always in habitats that include wetlands."
>
> So do Zebras, Lions and extant humans. Ie this fossil doesn't suggest
> an 'aquarboreal' lifestyle, only that they needed regular access to
> water (and fossilized in lacustrine sediments). Which, regarding early
> humans, I'd say is fairly uncontroversial.
Zebras don't have the apith locomotion, see the TREE paper.
>
> >If the robust apiths lived in wetlands, they must have waded bipedally
> >there, just as western lowland gorillas frequently do.
>
> And that is another gliding into conclusion based on 'could'
> 'possibly' 'might' speculation.
> I will give you one piece of advice, though: rewrite the article and
> send it to Nature. You're almost guaranteed to be accepted, and you
> will get instant widespread acceptance of your theory.
Instant?? no chance: see you reaction.
Mike Noren
>> >> And the statement about great ape fossils from 12 - 8Myrs ago; I
>> >> wasn't aware that any ape fossils had been found from that period?
>> >
>> >Not my fault, Mike...
>>
>> True. Do you have a reference?
>
>Lots. Some can be found in the TREE paper.
>Betw.12-8 Ma: Dryopith, Sivapith.
Yes... Those are Orangutan-like creatures, and I realize now that I
was confused by your usage of the word hominid as including Gorilla
and Pan. My fault - I interpreted hominid to mean Homo and relations
post the Homo/Pan/Gorilla split.
>> >> The rest is the standard fare speculation. Take this sentence, for
>> >> instance:
>> >> "The fossil data indicates that the early australopithecines of 4-3
>> >> million years ago lived in waterside forests or woodlands; and their
>> >> larger, robust relatives of 2-1 million years ago in generally more
>> >> open milieus near marshes and reedbeds, where they could
>> >> have waded bipedally." What is this based on?
>> >
>> >4-3 Ma apiths: waterside forests & woodlands:
>>
>> More or less.
>
>All of them AFAIK.
Well, they all fossilized in water. Nearly all fossils do. In these
particular cases, the surroundings of the bodies of water in which
they fossilized appear to have been forest and woodland, or forest
savanna. This doesn't necessarily mean they lived or even died where
they were found.
However, I don't dispute that there were forests; it is the
speculation about "where they could have waded bipedally" I'm having
problems with, as the evidence suggests nothing of the sort.
>> >§ Kanapoi KNM-KP 29281 Australopithecus anamensis: Fish, aquatic
>> >reptiles, kudus and monkeys are prevalent. 'A wide gallery forest would
>have
>> >almost certainly been present on the large river that brought in the
>> >sediments' (Leakey et al., 1995).
>>
>> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
>
>Why not? The aquarboreal lifestyle of the early hominids is based on their
>anatomy, see the TREE paper.
It doesn't IMO suggest an aquarboreal lifestyle other than in the
trivial sense that this was an omnivore which lived in a place where
there were rivers with gallery forests by the rivers (and, by
inference, open plains surrounding the gallery forest).
As such, it has no bearing on anything to do with the aquatic ape
theory of human evolution.
Nothing about this fossil suggests wading, swimming,
water-plant-eating, or says anything about reduction of fur or
development of subcutaneous fat. That part is all speculation, and it
is that part I have a problem with.
The fact that it fossilized in a lacustrine environment means nothing:
there may have been untold numbers of A. anamensis which had no chance
to fossilize simply because they didn't drown or get flushed post
mortem into a body of water. Fossilization is essentially an aquatic
process.
I skip your other instances where my response is as above.
>> >§ Hadar AL.288 gracile A. afarensis: Lucy lay in a small, slow
>> >moving stream. 'Fossil preservation at this locality is excellent,
>remains
>> >of delicate items such as crocodile and turtle eggs and crab claws being
>> >found' (Johanson & Taieb, 1976).
>>
>> Ie at least this one probably died in the water, although this doesn't
>> really lend support to an 'aquarboreal' lifestyle for Lucy either.
>
>Same answer. Point is: water & trees were abundantly present in (all?)
>cases.
And my points are:
1) They would not have fossilized except in water
2) Where you have sufficient water for fossilization you also tend to
have at least some trees
3) Even when water and trees were common all round, the leap to
wading/swimming as the cause for reduction of hair and development of
all other proposed 'aquatic ape' characters is totally unsupported by
the evidence.
>> Again, fossils tend to be found in sediments deposited in water
>> because sediments accumulate in water but erodes in air.
>
>Again: our attempt to reconstruct the apith environments is based on their
>anatomy (incl. microwear etc. see the TREE paper).
I don't doubt for a second that they were omnivores.
>> >2-1 Ma robust apiths: more open wetlands:
>>
>> And here you just did one of those glidings to conclusion. Your
>> references speak of forest, not of open wetlands.
>
>No, no. You must make the difference:
>- graciles: always a lot of trees,
>- robusts: less trees.
>(Note: al this has nothing to do with human ancestors: at that time we
>already had Homo in Europe, Java etc.)
So "less trees" == wetland?
>> >§ Kaye E. Reed 1997 "Early hominid evolution and ecological
>change
>> >through the African Plio-Pleistocene" JHE 32:289-322: "... Reconstructed
>> >habitats show that Australopithecus species existed in fairly wooded,
>> >well-watered regions. Paranthropus species lived in similar environs and
>> >also in more open regions, but always in habitats that include wetlands."
>>
>> So do Zebras, Lions and extant humans. Ie this fossil doesn't suggest
>> an 'aquarboreal' lifestyle, only that they needed regular access to
>> water (and fossilized in lacustrine sediments). Which, regarding early
>> humans, I'd say is fairly uncontroversial.
>
>Zebras don't have the apith locomotion, see the TREE paper.
If bipedal locomotion is necessary for an aquarboreal lifestyle, then
your argument that bipedal locomotion arised because of an aquarboreal
lifestyle is circular.
>> >If the robust apiths lived in wetlands, they must have waded bipedally
>> >there, just as western lowland gorillas frequently do.
>>
>> And that is another gliding into conclusion based on 'could'
>> 'possibly' 'might' speculation.
>> I will give you one piece of advice, though: rewrite the article and
>> send it to Nature. You're almost guaranteed to be accepted, and you
>> will get instant widespread acceptance of your theory.
>
>Instant?? no chance: see you reaction.
Well, that's partly because my default action to anything published in
nature is to distrust it. The policy of nature is to publish anything
which a) has to do with dinosaurs or human origins, or b) is
guaranteed to cause debate. My recommendation was based on the fact
that your theory fit both these criteria.
Regarding acceptance, your article was a letter. I think many don't
realize that the letters are real, if short, publications, but think
they are like letters to the editor in newspapers. I've published a
letter in nature myself, and although the implications of what we
reported can be likened to an evolutionary daisy-cutter, I don't think
it's been referenced more than a dozen times total.
I still think you should write it up larger, add some nice color
pictures for Nature to put on the cover, and submit again.
>Marc Verhaegen
deowll
> Trends in Ecology & Evolution Vol. 17, No. 5, May 2002
> http://journals.bmn.com/journals/list/latest?jcode=tree
>
>
>
> Opinion
> ================================================================
> Aquarboreal ancestors?
>
http://reviews.bmn.com/journals/atoz/latest?pii=S0169534702024904&node=TOC%4
> 0%40TREE%40017%4005%40017_05
>
> New evidence confirms the idea that human ancestors were not
> savannah-dwellers at all, but instead became bipedal in swampy forests,
and
> evolved during the Ice Ages into coastal omnivores along the Indian Ocean.
>
> ================================================================
>
>
>
>
>
> Marc Verhaegen, Pierre-Francois Puech and Stephen Munro
>
>
>
> Aquarboreal ancestors? [Opinion]
> Trends in Ecology & Evolution, 2002, 17:5:212-217
>
>
> Abstract
>
> According to biomolecular data, the great apes split into Asian pongids
> (orang-utan) and African hominids (gorillas, chimpanzees and humans) 18-12
> million years ago (Mya) and hominids split into gorillas and
> humans-chimpanzees 10-6 Mya. Fossils with pongid features appear in
Eurasia
> after c. 15 Mya, and fossils with hominid fossils appear in Africa after
c.
> 10 Mya. Instead of the traditional savannah-dwelling hypothesis, we argue
> that a combination of fossil (including the newly discovered Orrorin,
> Ardipithecus and Kenyanthropus hominids) and comparative data now provides
> evidence showing that: (1) the earliest hominids waded and climbed in
swampy
> or coastal forests in Africa-Arabia and fed partly on hard-shelled fruits
> and molluscs; (2) their australopith descendants in Africa had a
comparable
> locomotion but generally preferred a diet including wetland plants; and
(3)
> the Homo descendants migrated to or remained near the Indian Ocean coasts,
> lost most climbing abilities, and exploited waterside resources.
>
>
>
>
>
>
>
>
I don't question that their Homo descendents exploited wet land resources
but they obviously weren't that limited. I see little reason to think the
founders of the group were either.
Marc Verhaegen
> >> >> And the statement about great ape fossils from 12 - 8Myrs ago; I
> >> >> wasn't aware that any ape fossils had been found from that period?
> >> >
> >> >Not my fault, Mike...
> >>
> >> True. Do you have a reference?
> >
> >Lots. Some can be found in the TREE paper.
> >Betw.12-8 Ma: Dryopith, Sivapith.
>
> Yes... Those are Orangutan-like creatures, and I realize now that I
> was confused by your usage of the word hominid as including Gorilla
> and Pan. My fault - I interpreted hominid to mean Homo and relations
> post the Homo/Pan/Gorilla split.
OK.
> >> >> The rest is the standard fare speculation. Take this sentence, for
> >> >> instance:
> >> >> "The fossil data indicates that the early australopithecines of 4-3
> >> >> million years ago lived in waterside forests or woodlands; and their
> >> >> larger, robust relatives of 2-1 million years ago in generally more
> >> >> open milieus near marshes and reedbeds, where they could
> >> >> have waded bipedally." What is this based on?
> >> >
> >> >4-3 Ma apiths: waterside forests & woodlands:
> >>
> >> More or less.
> >
> >All of them AFAIK.
>
> Well, they all fossilized in water. Nearly all fossils do. In these
> particular cases, the surroundings of the bodies of water in which
> they fossilized appear to have been forest and woodland, or forest
> savanna. This doesn't necessarily mean they lived or even died where
> they were found.
We ddin't say that.
1) climbing: Early apiths show climbing adaptations, eg, curved hand & foot
phalanges. IOW, they lived in & near trees.
2) wading: see our TREE paper: (1) comparisons of postcranial skeleton, (2)
tooth enamel microwear, (3) strontium:calcium ratios, (4) isotopic evidence.
> However, I don't dispute that there were forests; it is the
> speculation about "where they could have waded bipedally" I'm having
> problems with, as the evidence suggests nothing of the sort.
What evidence would you expect here?
> >> >§ Kanapoi KNM-KP 29281 Australopithecus anamensis: Fish,
aquatic
> >> >reptiles, kudus and monkeys are prevalent. 'A wide gallery forest
would
> >> >have almost certainly been present on the large river that brought in
the
> >> >sediments' (Leakey et al., 1995).
> >>
> >> Ie this fossil doesn't suggest an 'aquarboreal' lifestyle.
> >
> >Why not? The aquarboreal lifestyle of the early hominids is based on
their
> >anatomy, see the TREE paper.
>
> It doesn't IMO suggest an aquarboreal lifestyle other than in the
> trivial sense that this was an omnivore which lived in a place where
> there were rivers with gallery forests by the rivers (and, by
> inference, open plains surrounding the gallery forest).
No, see Puech's papers in the refs.
> As such, it has no bearing on anything to do with the aquatic ape
> theory of human evolution.
So? Not my problem. What's your point?
> Nothing about this fossil suggests wading, swimming,
> water-plant-eating
See Puech's papers.
> , or says anything about reduction of fur or
> development of subcutaneous fat.
You don't expect fossils to have fat or fur?
> That part is all speculation, and it
> is that part I have a problem with.
What did the paper say about fat or fur??
> The fact that it fossilized in a lacustrine environment means nothing:
> there may have been untold numbers of A. anamensis which had no chance
> to fossilize simply because they didn't drown or get flushed post
> mortem into a body of water. Fossilization is essentially an aquatic
> process.
What had you expected?
Again: it's the comparative evidence that you need here.
> >> >§ Hadar AL.288 gracile A. afarensis: Lucy lay in a small, slow
> >> >moving stream. 'Fossil preservation at this locality is excellent,
> >> >remains
> >> >of delicate items such as crocodile and turtle eggs and crab claws
being
> >> >found' (Johanson & Taieb, 1976).
> >>
> >> Ie at least this one probably died in the water, although this doesn't
> >> really lend support to an 'aquarboreal' lifestyle for Lucy either.
> >
> >Same answer. Point is: water & trees were abundantly present in (all?)
> >cases.
>
> And my points are:
> 1) They would not have fossilized except in water
Of course.
> 2) Where you have sufficient water for fossilization you also tend to
> have at least some trees
?? Do you have refs for this statement?
> 3) Even when water and trees were common all round, the leap to
> wading/swimming as the cause for reduction of hair and development of
> all other proposed 'aquatic ape' characters is totally unsupported by
> the evidence.
What are you talking about 'aquatic ape'characters? What are 'aq.ape'
characters IYO?
> >> >2-1 Ma robust apiths: more open wetlands:
> >>
> >> And here you just did one of those glidings to conclusion. Your
> >> references speak of forest, not of open wetlands.
> >
> >No, no. You must make the difference:
> >- graciles: always a lot of trees,
> >- robusts: less trees.
> >(Note: al this has nothing to do with human ancestors: at that time we
> >already had Homo in Europe, Java etc.)
>
> So "less trees" == wetland?
Did I say that??
Kaye E. Reed 1997 "Early hominid evolution and ecological change through the
African Plio-Pleistocene" JHE 32:289-322: "... Reconstructed habitats show
that Australopithecus species existed in fairly wooded, well-watered
regions. Paranthropus species lived in similar environs and also in more
open regions, but always in habitats that include wetlands."
> If bipedal locomotion is necessary for an aquarboreal lifestyle
We didn't say that! Just look at the first table.
> , then
> your argument that bipedal locomotion arised because of
> an aquarboreal lifestyle
We didn't say that. Please read the text.
> is circular.
In that case, yes...
Marc Verhaegen
http://www.onelist.com/community/AAT
http://allserv.rug.ac.be/~mvaneech/Verhaegen.html
Marc Verhaegen
> >> >No, it was not savanna. We find the early Homo at the lake
> >>
> >> And these lakes were in what sort of environment...? Open grassland in
at
> >> least some cases - in other words, savannah.
> >
> >1) In some cases, yes, but not in most (note I'm talking about
> >H.erectus-ergaster - from Europe to Flores: no savanna).
>
> H. erectus was not the first hominid to abandon the forests, so far as I
am
> aware. It also had a fully-developed bipedal posture
Some people doubt this, eg, F.Marchal 2000 "A new morphometric analysis of
the hominid pelvic bone" JHE 38:347-365: "...possible to detect 2 levels of
difference. The first separates Australopith. from Homo and could be seen as
reflecting locomotor differences betw. both genera. The 2d splits both
H.erectus & Neandertal from modern human pelvic bones."
> and may well have had the
> hairlessness and subcutaneous fat
?? Fossils have no hair or fur!
> for all we can tell from the specimens. It
> had a wide variety of tools made using a number of different materials,
and
> could conceivably have possessed sufficient vocal control to produce
> vocalisations akin to primitive language. Most of the adaptations you are
> attributing to H. erectus' seaside lifestyle had already taken place in
its
> ancestors.
No. Why do you think that?
> The only truly significant difference between H. erectus and its
> descendants is the increased brain size of later humans.
>
> >2) And certainly not in dry savanna (as an "explanation" for our loss of
fur
> >etc.), as the savanna-minded people used to believe. (I just read that
some
> >well-known PAs still believe & publish this nonsense: Klein & Edgar 2002
> >"The Dawn of Human Culture" J.Wiley & sons: "... occurred between 7-5 Ma
> >when a group of Afr.apes, in response to shrinking forests & expanding
open
> >savannas, began to walk upright." can you believe this?)
>
> No, simply because the most recent evidence shows that the forests weren't
in
> decline at that time and that our ancestors remained in forests for rather
> longer than once believed. However, I don't see anything inherently
implausible
> about the theory itself and I can see that someone who is unaware of the
more
> recent findings could subscribe to it - the theory happens to be wrong on
the
> basis of the evidence, but it isn't crazy.
Crazy, no, stupid, yes. This whole savanna idea is based on Dart's
misunderstanding that the climate where Taung lived ("fringe of the
Kalahari") was the same as today. But a simple consideration of human
physiology shows that humans are more dependent on water than chimps are.
IOW, we didn't move from forests to savannas!
> >> However, even if humans lost their fur
> >> in a coastal habitat the same rationale would apply - in an environment
> >> exposed
> >> to the tropical sun, hair loss in humans would make evolutionary sense.
> >
> >No! No other primate has lost its fur. All primates are tropical. Baboons
> >are exposed to the tropical sun.
>
> See my other post.
OK.
Marc Verhaegen
"Corvųn & Celeste Sæpius" <theol...@hotmail.com> schreef in bericht
news:uajl1sc...@corp.supernews.com...
> > > However, even if humans lost their fur
> > > in a coastal habitat the same rationale would
> > > apply - in an environment exposed
> > > to the tropical sun, hair loss in humans would
> > > make evolutionary sense.
> >
> > No! No other primate has lost its fur. All primates are tropical.
> > Baboons are exposed to the tropical sun.
>
> All primates are tropical? Haven't you ever heard of a snow-monkey?
Of course, but that's irrelevant to the reasoning. You understood what I
wanted to say, didn't you? Rephrase: No other primate has lost its fur. Not
even in tropical regions. Baboons are exposed to the tropical sun & have
fur.
> Or Gigantopithecus (who lived in a temperate-
> subtropical environment at best)?
:-D What do you know about Gigantopith's fur?
> Besides, have you ever even SEEN a chimpanzee? Some of them
> have such thin, sparse hair that even some humans look hairier! (See:
> Italy).
You are not going to convince me that there's no difference in fur between
chimps & humans?
> Maybe increased cephalization required extra-resources and since the
> thick, dense hair wasn't really *needed* anymore
Why IYO?
> , it was lost in favor
> of larger brains
please re-read what you wrote: fur lost in favor of brains????
> and such, no matter what type of habitat this occured
> in - as long as it weren't a cold one.
?? Do you have 1 indication for this story?
> > Yes; but there's a difference between australopith
> > fossils & Homo fossils:
> > the first are seldom found next to shellfish;
> > the latter alwaysAFAIK.
>
> That's because Australopithecines were the first ones to
> walk out into the Savannah.
?? Why do you think that? You don't have the slightest evidence for this
idea.
Marc Verhaegen
> There is also the possibility I raised - exposing melanistic skin to the
sun
> increases the efficiency of vitamin production. One reason humans may have
> needed to lose hair in this way while animals like baboons didn't could be
that
> our ancestors' diet was low in these vitamins (most commonly found
naturally in
> fruit and in fish) and we needed to produce them ourselves to supplement
our
> diet.
Vit.D is not found in fruits.
> Just one possibility of several that have been raised (including a need
> to avoid overheating - bear in mind that the larger the animal, the
greater
> this risk becomes with a hair-covered body hence the bare skins of
elephants in
> open tropical habitats (for example)
Giraffes?
The large fat ones ("pachyuderms") seem to be naked (hippo, rhino,
elephant), the more slenderly-built, even if very large, not.
> , and humans are substantially larger than
> baboons - resistance to parasites which live in fur, sexual selection, or
> simple random mutation), but one which indicates the complexity of
> environmental factors and selective pressures which might at first seem
> unrelated to something like hair loss. That
"That"? I haven't seen 1 argument, Philip. :-)
> and the fact that the proposed
> aquatic lifestyle does not actually explain human characteristics
> satisfactorily
Why not IYO? What in our TREE hypothesis is incompatible with our present
human characteristics?
> are my grounds for rejecting that part of Marc's hypothesis -
> some elements of his theory, such as primate migration patterns and even
the
> proposed waterside lifestyle of our forest-dwelling ancestors deserve
serious
> consideration, and it's a shame they are unlikely to get it because of the
> aquatic ape stigma attached to the later claims of a diving ancestor and
the
> questionable parallels drawn with unrelated mammal species. Philip Bowles
Questionable? Darwin's theory is based on parallelism. Birds & bats are not
related, both evolved wings.
Marc Verhaegen
>Marc assumes that 'some aquatic animals don't have hair, so
>hairlessness must be an aquatic adaption', Philip Bowles
Please Philip, don't misrepresent me. I never said that!
Marc Verhaegen
"Corvųn & Celeste Sæpius" <theol...@hotmail.com> schreef in bericht
news:uajljvt...@corp.supernews.com...
> > Saepius, sorry, I have no time for discussing this with you.
> > Please inform a bit first.
>
> Did you even bother to *read* my post? You really have no clue what
> you're talking about. Ardipithecus and early Australopithecines were
> undoubtedly mostly arboreal, but this is when they began crossing
> expanses between the forests...
?? do you have 1 indication for this assertion?
I assume the rest of what you wrote is of equal quality?
If you start from such prejudices...
Marc Verhaegen
"Gerrit Hanenburg" <G.Han...@inter.nl.nomail.net.> schreef in bericht
news:hocjau8fm80lp18v0...@4ax.com...
> "Marc Verhaegen" <marc.ve...@village.uunet.be> wrote:
>
> >> It isn't. See Rodman & McHenry (1980): "The actual costs of travel for
> >> walking humans are slightly less than those predicted for a
> >> quadrupedal mammal of the same size" (p.104), while it is much more
> >> efficient compared to chimpanzee quadrupedalism, and that is where the
> >> comparison is most relevant because we share a more recent common
> >> ancestor with chimps than with artiodactyls.
>
> >Other people claim the opposite. If bipedalism had been superior to
> >would run on 2 legs.
>
> Nonsense. Bipedalism is not necessarily always more efficient than
> quadrupedalism. It depends on where you're coming from. There is such
> a thing as historical constraint.
> If you already are a hindlimb dominated orthograde hominoid then the
> shift to bipedalism is much easier than when you're a dedicated
> quadruped without a history of life in the trees. Gerrit
Yes, that's why baboons are bipedal, you mean?? :-D
Marc Verhaegen
......
> There is also evidence that increases in brain size
> were fuelled by a protein-rich diet...
Pleae don't believe this nonsense, Philip. One of those many just-so stories
in the field of human evolution.
1) Primates & esp. humans are slow growers. Human milk (brain growth is
fastest in babies) has a very low protein content.
2) Brains don't need special proteins, they need special lipids, see, eg,
http://biology.uindy.edu/langdon/symposium.htm
"Docosahexaenoic acid and cerebral evolution"
CL Broadhurst, MA Crawford, SC Cunnane, H Holmsen, K Ghebremeskel, J
Parkington, WF Schmidt & M Bloom
Docosahexaenoic acid DHA 22:6n-3 accounts for high percentage of the fatty
acids in the retina & brain. DHA is concentrated in human fetal plasma by
the placenta to support fetal brain growth. Fetal/neonatal DHA deficiency
has been shown to impair cognit.& visual development. In theory, DHA can be
synthesized from a precursor FA found in vegetation (a-linolenic acid
18:3n-3), but in practice conversion is slow or nonexistent. DHA is
specifically & selectively incorporated into photo-reception & neural cell
membranes at a rate 20-40 x greater than the rate of synthesis from 18:3n-3.
Apparently, involvement of DHA in photoreceptor & synaptic membranes has
been conserved throughout advanced evolution, similar to the conservation of
key membrane proteins. Conservation dates to the origin of the visual system
& brain in the marine environment c.600 Ma.
This biochem.evidence is relevant to the origins of H.sapiens. DHA is found
in abundance only in animal food resources of marine, littoral & lacustrine
environments. Savanna resources are rel.poor in DHA with the minor
exceptions of organ meats & bone marrow. Since DHA is essential for brain
expansion & the development of complex synaptic interconnections, consistent
access to coastal food resources could have provided significant competitive
evol.advantages. Foods such as shellfish & marine bird eggs require no
sophistication to collect & utilize, yet readily provide the raw materials
for neural construction. Early H.sapiens remains dating to c.100 ka from
coastal S.African sites support this hypothesis.
Marc Verhaegen
> >1) Neoteny? no: neoteny is at best a genetic mechanism,
> >it doesn't explain a thing:
>
> Very true.
:-) I'm glad we agree on something.
> >what have humans in common with axolotls?
> >2) Sex.selection: all mammals & primates have sex.selection.
> >Only 1 primate is furless.
>
> All mammals have sexual selection, yet only one engages in ritual
neck-twining
> /hitting the rival with its neck. Sexual selection takes many forms.
1) I can understand that hitting your rival has something to do with
sex.selection, but what has losing your fur to do with it IYO?
2) Babies have less fur than adults. Sex.selection??
3) If nakedness were for sex.selection, why are both women & men furless?
> >- erect: only savanna kangaroos are bipedal (but not erect)
>
> Irrelevant - bipedalism at least started in a forest habitat if it didn't
> evolve entirely in that environment.
Baboons are even less bipedal than forest-dwelling primates.
> Once the species was a) at least functionally
> bipedal and b) had become dependent on tool-using
> techniques that required the freedom of its forelimbs ...
Tool-using mammals are not bipedal (sea otter, chimps, capuchins).
The reverse is also wrong: kangaroos, hopping mouses etc; don't use tools.
> >- speech: savanna mammals have less sound variation than arboreal or
> >(semi)aquatic animals
>
> Yet primates have more variation than most savannah animals
Yes, that's what I'm saying.
.....
> Few primates inhabit savannah at all, and no other primate is hairless
> regardless of its environment. It seems strange that you insist on drawing
> comparisons with 'savannah mammals' for all your other points, but here
you
> restrict yourself to 'savannah primates' (because of course hairlessness
is not
> altogether uncommon among savannah mammal species). Such a comparison
might be
> the black and white rhinos - hairless savannah animals probably derived
from
> hairy tropical forest dwellers similar to the extant Javan rhino (as the
rhinos
> are an Asian group - unlike the elephants, which probably remained
hairless in
> Africa and secondarily developed hairiness to cope with ice age conditions
in
> the northern hemisphere). Philip Bowles
Possible. Furless "pachyderms":
- hippo & pygmy hippo,
- 4 of 5 rhino species are furless, 2 of these 4 live in swamps,
- of 3 (or 4) elephant species only 1 could be called savanna-dwelling.
P Bowles
>news:20020402040622...@mb-ms.aol.com...
>> >> >No, it was not savanna. We find the early Homo at the lake
>> >>
>> >> And these lakes were in what sort of environment...? Open grassland in
>at
>> >> least some cases - in other words, savannah.
>> >
>> >1) In some cases, yes, but not in most (note I'm talking about
>> >H.erectus-ergaster - from Europe to Flores: no savanna).
>>
>> H. erectus was not the first hominid to abandon the forests, so far as I
>am
>> aware. It also had a fully-developed bipedal posture
>
>Some people doubt this, eg, F.Marchal 2000 "A new morphometric analysis of
>the hominid pelvic bone" JHE 38:347-365: "...possible to detect 2 levels of
>difference. The first separates Australopith. from Homo and could be seen as
>reflecting locomotor differences betw. both genera. The 2d splits both
>H.erectus & Neandertal from modern human pelvic bones."
How then do they explain the Laetoli footprints, made by a hominid *walking*
(not leaping or swaggering like apes) bipedally? Or the fact that that hominid
had a human-like heel and ankle designed to support bipedal walking (as
evidenced by the fossil Little Foot)?
Besides, the hominid and australopithicene lines have been distinguished from
the start by limb proportions better-adapted for a truly bipedal lifestyle than
those of a chimpanzee, and fossils from Australopithecus and Kenyanthropithecus
to Homo erectus itself display a gradual progression from an ape-like to a
human-like posture long before the emergence of H. erectus itself, whether or
not it or they were fully bipedal - clearly whatever pressure led to bipedalism
in humans was at work even while our ancestors were still forest-dwellers
barely distinct from chimpanzees (indeed, when walking bipedally the bonobo has
a more human-like posture than the common chimpanzee).
>> and may well have had the
>> hairlessness and subcutaneous fat
>
>?? Fossils have no hair or fur!
They don't have muscles or organs either, but the living animal did. The point
is that the hypothesis that these features evolved before the emergence of H.
erectus is as valid as your contention that they first appeared in that
species; all you have said in support of your position is that some aquatic
animals share this trait. Comparative evidence is not an argument in itself;
you need a theory to explain why certain animals have features in common with
humans with reference to their own lifestyle. Humans emerging out of the forest
aren't going to suddenly transform into something resembling a hippo or a seal
any more than they would transform into an elephant or a baboon if they found
themselves in the savannah. In fact, hairlessness in most aquatic mammals has
nothing at all to do with the fact that they live or forage underwater (the
exceptions being streamlined fully marine animals like dolphins, and you've
said yourself you don't regard these as an appropriate comparison), and a lot
more to do with their size and exposure to heat; exactly the same as in
elephants and rhinos.
>> for all we can tell from the specimens. It
>> had a wide variety of tools made using a number of different materials,
>and
>> could conceivably have possessed sufficient vocal control to produce
>> vocalisations akin to primitive language. Most of the adaptations you are
>> attributing to H. erectus' seaside lifestyle had already taken place in
>its
>> ancestors.
>
>No. Why do you think that?
See above - whatever the contentions regarding specific anatomical features,
the evidence is good that hominids were already bipedal before H. erectus
evolved. Hairlessness and fat are more of a stretch; they may have evolved
before H. erectus, in that species, or later in H. habilis or H. sapiens; they
may have evolved more or less together in one species or at different times in
two separate ones.
>> No, simply because the most recent evidence shows that the forests weren't
>in
>> decline at that time and that our ancestors remained in forests for rather
>> longer than once believed. However, I don't see anything inherently
>implausible
>> about the theory itself and I can see that someone who is unaware of the
>more
>> recent findings could subscribe to it - the theory happens to be wrong on
>the
>> basis of the evidence, but it isn't crazy.
>
>Crazy, no, stupid, yes. This whole savanna idea is based on Dart's
>misunderstanding that the climate where Taung lived ("fringe of the
>Kalahari") was the same as today. But a simple consideration of human
>physiology shows that humans are more dependent on water than chimps are.
That's your (so far unproven) contention. Yes, the climatic evidence put the
nail in the savannah hypothesis coffin, but until then it was widely accepted
and respected by paleontologists, anthropologists and evolutionary biologists
alike. I reiterate: there is nothing implausible about the theory. The
mechanisms and pressures proposed for the evolution of the human form make
evolutionary sense, hence the wide acceptance over several decades.
Philip Bowles
P Bowles
>sun
>> increases the efficiency of vitamin production. One reason humans may have
>> needed to lose hair in this way while animals like baboons didn't could be
>that
>> our ancestors' diet was low in these vitamins (most commonly found
>naturally in
>> fruit and in fish) and we needed to produce them ourselves to supplement
>our
>> diet.
>
>Vit.D is not found in fruits.
IIRC we can produce another vitamin in small quantities which is found in
fruits (C or E?). However, hair loss to facilitate production of vitamin D
makes sense as well as wherever they lived, our ancestors probably didn't have
a piscine diet.
>> Just one possibility of several that have been raised (including a need
>> to avoid overheating - bear in mind that the larger the animal, the
>greater
>> this risk becomes with a hair-covered body hence the bare skins of
>elephants in
>> open tropical habitats (for example)
>
>Giraffes?
>The large fat ones ("pachyuderms") seem to be naked (hippo, rhino,
>elephant), the more slenderly-built, even if very large, not.
But that's just it - the giraffe *is* slenderly-built - with long, thin legs
and neck and a reasonably small body, it is not particularly massive and has a
low surface area relative to an animal like the hippopotamus or rhino - the
larger your surface area, the more heat you are exposed to, and the greater the
insulating effect of a hairy body. Bear in mind that every diving mammal which
has lost its hair is more massive than a human being.
>> and the fact that the proposed
>> aquatic lifestyle does not actually explain human characteristics
>> satisfactorily
>
>Why not IYO? What in our TREE hypothesis is incompatible with our present
>human characteristics?
The problem isn't that they are incompatible, it is that your hypothesis does
nothing to explain those characteristics or why they are especially well-suited
for the lifestyle you propose, beyond pointing out that some marine animals
share some similarities with humans (and without explaining why those animals
exhibit these particular characteristics).
>> are my grounds for rejecting that part of Marc's hypothesis -
>> some elements of his theory, such as primate migration patterns and even
>the
>> proposed waterside lifestyle of our forest-dwelling ancestors deserve
>serious
>> consideration, and it's a shame they are unlikely to get it because of the
>> aquatic ape stigma attached to the later claims of a diving ancestor and
>the
>> questionable parallels drawn with unrelated mammal species. Philip Bowles
>
>Questionable? Darwin's theory is based on parallelism. Birds & bats are not
>related, both evolved wings.
Your parallels are more along the lines of 'bats and birds both fly. Bats are
featherless. Therefore feathers cannot have evolved for the purpose of flight.'
You have tried to use parallels to show what is *not* possible, but evolution
is not that rigid. Yes, convergence is an important evolutionary concept, but
it is not the sole factor in evolution. You can't say 'hippos and humans both
lack hair. Therefore early humans must have had the same lifestyle as a hippo',
which is the essence of your contention (replace 'hippo' with 'seal' or
'walrus' if you feel that's more appropriate). Convergence must be supported by
theory and, for preference, actual physical evidence of such a lifestyle.
Philip Bowles
pz
pbo...@aol.com (P Bowles) wrote:
[snip]
> But that's just it - the giraffe *is* slenderly-built - with long,
> thin legs and neck and a reasonably small body, it is not
> particularly massive and has a low surface area relative to an animal
> like the hippopotamus or rhino - the larger your surface area, the
> more heat you are exposed to, and the greater the insulating effect
> of a hairy body.
You've got that backwards. An animal with a slender build will have a
greater surface area than an animal of equal mass with a more compact
build.
[snip]
--
pz
P Bowles
>> >2) Sex.selection: all mammals & primates have sex.selection.
>> >Only 1 primate is furless.
>>
>> All mammals have sexual selection, yet only one engages in ritual
>neck-twining
>> /hitting the rival with its neck. Sexual selection takes many forms.
>
>1) I can understand that hitting your rival has something to do with
>sex.selection, but what has losing your fur to do with it IYO?
I was merely making the point that one cannot argue that a characteristic
cannot have evolved due to sexual selection simply on the basis that no other
animal exhibits the same form of sexual selection - I wasn't defending this
hypothesis for human hairlessness per se, simply pointing out the flaw in the
argument you raised against it. The points you raise below are telling, however
- there doesn't seem to be an adequate explanation based on sexual selection.
>> >- erect: only savanna kangaroos are bipedal (but not erect)
>>
>> Irrelevant - bipedalism at least started in a forest habitat if it didn't
>> evolve entirely in that environment.
>
>Baboons are even less bipedal than forest-dwelling primates.
IIRC, they evolved from grazing animals similar to modern geladas, which have
roughly similar fore- and hind-limb proportions - a posture which placed them
low to the ground would have been the most efficient way for them to feed.
>> Once the species was a) at least functionally
>> bipedal and b) had become dependent on tool-using
>> techniques that required the freedom of its forelimbs ...
>
>Tool-using mammals are not bipedal (sea otter, chimps, capuchins).
All three use their forelimbs to manipulate tools, and the primates adopt a
sitting or bipedal crouching posture which gives them full use of those limbs
when doing so. One thing they are poor at is carrying and using tools on the
move, and animals with the ability to do so would have an advantage when
foraging - being able to crack nuts where they were found or to carry a
termite-fishing stick rather than discarding each tool and spending time
finding and preparing a new one every time it was needed.
>The reverse is also wrong: kangaroos, hopping mouses etc; don't use tools.
They are also poor analogies for people - their bipedal motion developed for
efficiency of gait when hopping, which is not the natural human form of
locomotion. Clearly their development of a bipedal posture is unrelated to that
which led to bipedalism in hominids. Also, 'bipedal' marsupials invariably use
a long, often thick, tail as a balancing aid - apes and hominids don't.
>> >- speech: savanna mammals have less sound variation than arboreal or
>> >(semi)aquatic animals
>>
>> Yet primates have more variation than most savannah animals
>
>Yes, that's what I'm saying.
But this is true of primates that live in savannahs as well.
>Possible. Furless "pachyderms":
>- hippo & pygmy hippo,
The latter largely terrestrial. If anecdotal reports can be relied upon and are
not best confined to the realms of cryptozoology, the same was true of the
Madagascar dwarf hippo, which also seems to have been hairless. The common
hippo, the aquatic form, appears to be derived from already hairless
terrestrial ancestors similar to these more primitive species.
>- 4 of 5 rhino species are furless, 2 of these 4 live in swamps,
And 2 in savannah - could go either way...
>- of 3 (or 4) elephant species only 1 could be called savanna-dwelling.
4 species?
As for the forest elephant, like most Congo Basin inhabitants it is descended
from savannah animals which inhabited the area a mere few thousand years ago -
maybe even less than ten thousand. The forest elephant is derived from the
hairless savannah form rather than vice versa.
Philip Bowles
P Bowles
>greater surface area than an animal of equal mass with a more compact
>build.
>
What I'm saying is that the hippo is a more massive animal than the giraffe
(which is the case) and so has a larger surface area - I'm not talking about
animals with a mass equal to that of a giraffe.
Philip Bowles
Gerrit Hanenburg
>> Nonsense. Bipedalism is not necessarily always more efficient than
>> quadrupedalism. It depends on where you're coming from. There is such
>> a thing as historical constraint.
>> If you already are a hindlimb dominated orthograde hominoid then the
>> shift to bipedalism is much easier than when you're a dedicated
>> quadruped without a history of life in the trees. Gerrit
>Yes, that's why baboons are bipedal, you mean?? :-D
That's what I mean with historical constraint. Baboons are
cercopithecoids. They have the typical cercopithecoid narrow bodyshape
(chest deeper than wide) with long lumbar region and laterally placed
scapula that facilitates movement of both fore and hind limb in a
parasaggital plane. They were and still are habitual pronogrades,
unlike the hominoids.
Gerrit
Gerrit Hanenburg
>> So "less trees" == wetland?
>Did I say that??
>Kaye E. Reed 1997 "Early hominid evolution and ecological change through the
>African Plio-Pleistocene" JHE 32:289-322: "... Reconstructed habitats show
>that Australopithecus species existed in fairly wooded, well-watered
>regions. Paranthropus species lived in similar environs and also in more
>open regions, but always in habitats that include wetlands."
But that same paper also says:
"Homo is the first hominid to exist in areas of fairly open, arid
grassland."
and
"Homo species appear the first to be adapted to open, arid
environments."
So, if you accept Reed's ecological structure analysis with regard to
Australopithecus then why reject it with regard to Homo?
Gerrit
Gerrit Hanenburg
>>Crazy, no, stupid, yes. This whole savanna idea is based on Dart's
>>misunderstanding that the climate where Taung lived ("fringe of the
>>Kalahari") was the same as today. But a simple consideration of human
>>physiology shows that humans are more dependent on water than chimps are.
>That's your (so far unproven) contention. Yes, the climatic evidence put the
>nail in the savannah hypothesis coffin,
I tend to disagree (see also Denton 1999, Behrensmeyer et al. 2002).
In particular the mid-Pliocene (ca. 2.95-2.5 mya, OIS G17 - 100) is
characterized by a shift in Oxygen isotope values indicating cooling
and more arid conditions in Africa. This coincides with a shift in the
fauna (and pollen assemblages) indicating more open and arid
environments. This is also the time of origin of Homo.
Denton, G.H. (1999). Cenozoic Climate Change. In Bromage & Schrenk.
African Biogeography, Climate Change, and Human Evolution. Oxford
Univ. Press. p. 94-114.
Behrenmeyer. K. et al. (2002). Faunal change, environmental
variability and late Pliocene hominin evolution. Jour. of Human
Evolution 42: 475-497
Gerrit
John Wilkins
How do mammals that do not live in DHA-rich environments grow brains? Do
they synthesise it somehow? If so, secondary loss of that pathway would
be evidence in favour of humans living at a critical point in their
evolution in coastal ecologies.
--
John Wilkins
Occasionally making sense for over 46 years
Marc Verhaegen
http://journals.bmn.com/journals/list/latest?jcode=tree
Marc Verhaegen, Pierre-Francois Puech and Stephen Munro
Aquarboreal ancestors? [Opinion]
http://reviews.bmn.com/journals/atoz/latest?pii=S0169534702024904&node=TOC%4
0%40TREE%40017%4005%40017_05
New evidence confirms the idea that human ancestors were not
savannah-dwellers at all, but instead became bipedal in swampy forests, and
evolved during the Ice Ages into coastal omnivores along the Indian Ocean.
==================================================
(orang-utan) and African hominids (gorillas, chimpanzees and humans) 18-12
million years ago (Mya) and hominids split into gorillas and
humans-chimpanzees 10-6 Mya. Fossils with pongid features appear in Eurasia
c.10 Mya. Instead of the traditional savannah-dwelling hypothesis, we argue
that a combination of fossil (including the newly discovered Orrorin,
Ardipithecus and Kenyanthropus hominids) and comparative data now provides
evidence showing that: (1) the earliest hominids waded and climbed in swampy
or coastal forests in Africa-Arabia and fed partly on hard-shelled fruits
and molluscs; (2) their australopith descendants in Africa had a comparable
locomotion but generally preferred a diet including wetland plants; and (3)
the Homo descendants migrated to or remained near the Indian Ocean coasts,
lost most climbing abilities, and exploited waterside resources.
> I don't question that their Homo descendents exploited wet land resources
> but they obviously weren't that limited.
Obviously, you say? I have yet to see the first good evidence they (whether
apiths or early Homo) regularly dwelt in dry savanna. The idea that our
ancestors became naked & got sweat glands & thick SC fat to run over the
open savanna (as was the usual interpreation) is clearly nonsense.
> I see little reason to think the founders of the group were either.
But have you read the paper?
Marc Verhaegen
Because apparently he's wrong here. AFAIK all early Homo fossils have been
found near molluscs. Did Reed specifically analysed H.erectus' ecology? or
did he only rely on the usual traditional interpretations? In any case,
H.erectus-ergaster lived from Algeria to Java. I wouldn't call all that
savanna... Open, less trees, yes, very likely: after all, Homo (vs. apiths &
apes) lost most climbing skills. I see no reason to doubt they dispersed
along the coasts (exactly as the comparative data suggest).
pz
wil...@wehi.edu.au (John Wilkins) wrote:
I wonder about all those people I know who dislike fish and shellfish.
They also tend to avoid organ meats and bone marrow, which, you've got
to admit, aren't exactly high on the list of preferred american foods.
Do they have teeny-tiny shriveled-up brains?
This seems to be a theory based on a 'fact' (that brain development
requires an essential factor found in adequate supply only in limited
environments) that just isn't true.
--
pz
P Bowles
>requires an essential factor found in adequate supply only in limited
>environments) that just isn't true.
The theory doesn't require any such thing - it holds that the additional energy
provided by a switch to a protein-rich diet spurred the *evolution* of larger
brains as the energetic costs of maintaining them were no longer
disadvantagous. The theory says nothing about the development and functioning
of individual brains in any given species. It is also corroborated by fossil
evidence that humans began to first consume bone marrow and later to hunt at
periods which coincided with the most dramatic rates of brain growth (hunting,
for instance, coincides with the evolution of Homo habilis, with roughly twice
the brain size of its immediate predecessor Homo erectus). This change in brain
size also coincides with a comparable reduction in gut size, as hominids
shifted from a vegetable-rich diet which required a large gut to digest
supplemented by occasional meat, to a predominantly carnivorous diet with
considerably less vegetable matter.
Philip Bowles
Gerrit Hanenburg
>> So, if you accept Reed's ecological structure analysis with regard to
>> Australopithecus then why reject it with regard to Homo?
>Because apparently he's wrong here.
She.
>AFAIK all early Homo fossils have been found near molluscs.
That's not true. And as usual you mistake the waterlaid depositional
context for the habitat of the organism. Ever heard of taphonomy?
>Did Reed specifically analysed H.erectus' ecology? or
>did he only rely on the usual traditional interpretations?
She analyzed all major African sites that have generated hominin
fossils, including Homo erectus.
The analysis is based on the total mammalian fauna's of these sites.
These faunal assemblages were than compared with modern communities
and death assemblages using ecomorphological variables such as
percentage arboreal, terrestrial, aquatic, frugivorous, fresh grass
grazer, etc. in order to determine resemblance.
Homo erectus fauna's are most similar to those occupying modern open
environments.
>In any case, H.erectus-ergaster lived from Algeria to Java. I wouldn't call all that
>savanna... Open, less trees, yes, very likely: after all, Homo (vs. apiths &
>apes) lost most climbing skills. I see no reason to doubt they dispersed
>along the coasts (exactly as the comparative data suggest).
Well, studies of the ecological morphology of early Homo (e.g. upright
narrow bodies with long distal limb elements) indicate that they were
well adapted to dealing with heat stress (Ruff 1991, Walker 1993).
Based on its crural and brachial indices the mean annual temperature
of the environment of the Turkana boy (KNM-WT 15000) is estimated to
have been 29.2 C and 30.8 C respectively.
And Feibel et al. (1991) report that the Lake Turkana region had much
the same climate 1.5 Mya as it has today (i.e. arid).
These hominids were there and apparently were able to make a living in
such environments. This is based on decent paleoecological and
ecomorphological analysis, unlike the paleofantasy of the aquatic
scenario.
Feibel, C.S., Harris, J.M., and Brown, F.H. (1991).
Palaeoenvironmental context for the Late Neogene of the Turkana Basin.
In Harris, J.M. Koobi Fora Research Project Vol. 3: The fossil
ungulates: geology, fossil artiodactyls, and palaeoenvironments. p.
321-346.
Ruff, C.B. (1991). Climate and body shape in hominid evolution.
Journal of Human Evolution 21: 81-105.
Walker, A. (1993). Perspectives on the Nariokotome Discovery. In
Walker, A. and Leakey, R. The Nariokotome Homo erectus Skeleton.
Springer Verlag. p. 411-430.
Gerrit
pz
pbo...@aol.com (P Bowles) wrote:
> >This seems to be a theory based on a 'fact' (that brain development
> >requires an essential factor found in adequate supply only in
> >limited environments) that just isn't true.
>
> The theory doesn't require any such thing - it holds that the
> additional energy provided by a switch to a protein-rich diet
I was commenting on a claim by Verhaegen that protein-richness was not
important -- it all depended on one specific lipid. Did you read what
he wrote?
> spurred
> the *evolution* of larger brains as the energetic costs of
> maintaining them were no longer disadvantagous.
So carnivores and fish-eaters in general ought to be 'spurred' on more
to make bigger brains?
> The theory says
> nothing about the development and functioning of individual brains in
> any given species. It is also corroborated by fossil evidence that
> humans began to first consume bone marrow and later to hunt at
> periods which coincided with the most dramatic rates of brain growth
> (hunting, for instance, coincides with the evolution of Homo habilis,
> with roughly twice the brain size of its immediate predecessor Homo
> erectus). This change in brain size also coincides with a comparable
> reduction in gut size, as hominids shifted from a vegetable-rich diet
> which required a large gut to digest supplemented by occasional meat,
> to a predominantly carnivorous diet with considerably less vegetable
> matter.
How much fish and bone marrow do you eat?
I don't argue with the idea that diet can have substantial evolutionary
effects on morphology, and personally, I favor the idea that large
brains are a side-effect of developmental allometry and a dietary shift,
with selection favoring overall larger size. What I find remarkable and
unlikely is the specific claim that "DHA is ESSENTIAL for brain
expansion" and that it is "found in abundance ONLY in animal food
resources of marine, littoral & lacustrine environments". As is typical
for him, Verhaegen is grossly overstating the significance of a minor
observation. Is DHA a good thing in your diet? Sure. Is a supply of DHA
from fish/bone marrow/animal guts the only way to support a big brain?
No -- the existence of millions of big brained people who avoid those
things in their diets says that that claim is false.
--
pz
P Bowles
writes:
>> >This seems to be a theory based on a 'fact' (that brain development
>> >requires an essential factor found in adequate supply only in
>> >limited environments) that just isn't true.
>>
>> The theory doesn't require any such thing - it holds that the
>> additional energy provided by a switch to a protein-rich diet
>
>I was commenting on a claim by Verhaegen that protein-richness was not
>important -- it all depended on one specific lipid. Did you read what
>he wrote?
Yes, but I misunderstood which theory your comment referred to.
>> spurred
>> the *evolution* of larger brains as the energetic costs of
>> maintaining them were no longer disadvantagous.
>
>So carnivores and fish-eaters in general ought to be 'spurred' on more
>to make bigger brains?
One would expect that in the absence of other factors (for instance, many
animals are probably carnivorous because they need the energy protein can
provide to support aspects of their lifestyle unrelated to brain size) - has
anyone carried out studies into the relative brain sizes of carnivores and
their herbivorous or truly omnivorous (as in having no particular preference
for either meat or vegetable matter) ancestors/close relatives?
>> The theory says
>> nothing about the development and functioning of individual brains in
>> any given species. It is also corroborated by fossil evidence that
>> humans began to first consume bone marrow and later to hunt at
>> periods which coincided with the most dramatic rates of brain growth
>> (hunting, for instance, coincides with the evolution of Homo habilis,
>> with roughly twice the brain size of its immediate predecessor Homo
>> erectus). This change in brain size also coincides with a comparable
>> reduction in gut size, as hominids shifted from a vegetable-rich diet
>> which required a large gut to digest supplemented by occasional meat,
>> to a predominantly carnivorous diet with considerably less vegetable
>> matter.
>
>How much fish and bone marrow do you eat?
None, but I do consume red meat and eggs regularly, both of which are
particularly rich in protein. Obviously humans still have a fairly substantial
amount of vegetable matter in their diet, but our dentition has more in common
with omnivores with a prediliction for meat such as wolves than with true
omnivores such as rats, and so far as I know no human culture in existence
lives a purely vegetarian lifestyle, and some of the healthiest have large
quantities of meat in their diet - those in areas like Japan and Tibet, where
fish or other white meat is the staple.
>I don't argue with the idea that diet can have substantial evolutionary
>effects on morphology, and personally, I favor the idea that large
>brains are a side-effect of developmental allometry and a dietary shift,
>with selection favoring overall larger size. What I find remarkable and
>unlikely is the specific claim that "DHA is ESSENTIAL for brain
>expansion" and that it is "found in abundance ONLY in animal food
>resources of marine, littoral & lacustrine environments".
I'd be inclined to agree that this is overstating the case - while it is common
sense that a larger brain needs more energy than a smaller one, I'm wary of the
sort of categorical statement that Marc favours or implies along the lines of
'one effect MUST have one cause'. My contention is that the available evidence
appears to indicate a strong link between changing diet and increasing brain
size, but I certainly wouldn't rule out the theoretical possibility that brain
growth could be attributable to other causes - I just don't feel the evidence
is there to support that hypothesis with relation to hominid evolution.
Philip Bowles
Marc Verhaegen
> >> >> >No, it was not savanna. We find the early Homo at the lake
> >> >>
> >> >> And these lakes were in what sort of environment...? Open grassland
in
> >> >> at least some cases - in other words, savannah.
> >> >
> >> >1) In some cases, yes, but not in most (note I'm talking about
> >> >H.erectus-ergaster - from Europe to Flores: no savanna).
> >>
> >> H. erectus was not the first hominid to abandon the forests, so far as
I
> >> am aware. It also had a fully-developed bipedal posture
> >
> >Some people doubt this, eg, F.Marchal 2000 "A new morphometric analysis
of
> >the hominid pelvic bone" JHE 38:347-365: "...possible to detect 2 levels
of
> >difference. The first separates Australopith. from Homo and could be seen
as
> >reflecting locomotor differences betw. both genera. The 2d splits both
> >H.erectus & Neandertal from modern human pelvic bones."
>
> How then do they explain the Laetoli footprints, made by a hominid
*walking*
> (not leaping or swaggering like apes) bipedally? Or the fact that that
hominid
> had a human-like heel and ankle designed to support bipedal walking (as
> evidenced by the fossil Little Foot)?
I don't see your problem, Philip. R.J.Clarke 2000 "What the StW 573
Australopithecus skeleton reveals about early hominid bipedalism" AAPA
abstracts:126: "... Preliminary assessment indicates that the foot had both
bipedal & climbing capabilities, whilst the arm & hand indicate adaptation
to arboreal locomotion. This skeleton's foot morphology is consistent with
the bipedal Laetoli footprint trails, which are not those of fully human
feet, but which have very clear ape-like morphology."
> Besides, the hominid and australopithicene lines have been distinguished
from
> the start by limb proportions better-adapted for a truly bipedal lifestyle
than
> those of a chimpanzee, and fossils from Australopithecus and
Kenyanthropithecus
> to Homo erectus itself display a gradual progression from an ape-like to a
> human-like posture long before the emergence of H. erectus itself, whether
or
> not it or they were fully bipedal - clearly whatever pressure led to
bipedalism
> in humans was at work even while our ancestors were still forest-dwellers
> barely distinct from chimpanzees (indeed, when walking bipedally the
bonobo has
> a more human-like posture than the common chimpanzee).
You're making up your own facts, Philip, you see things that weren't there:
by which "start"? "better"(?)adapted to what? what is "true" bipedalism?
"gradual"? "progression"?? etc. Please read carefully the above abstract of
Clarke.
> >> and may well have had the
> >> hairlessness and subcutaneous fat
> >
> >?? Fossils have no hair or fur!
>
> They don't have muscles or organs either, but the living animal did. The
point
> is that the hypothesis that these features evolved before the emergence of
H.
> erectus is as valid as your contention that they first appeared in that
> species; all you have said in support of your position is that some
aquatic
> animals share this trait.
OK.
> Comparative evidence is not an argument in itself;
It is: what is true for other animals is also true for us: we're no
exception. OTOH, fossil evidence is not an argument in itself IMO: fossils
say only something about the fossils, but the connection with us is
uncertain, eg, it was believed for many years that Lucy was our ancestor: my
impression (see my Hum.Evol.papers
http://allserv.rug.ac.be/~mvaneech/Fil/Verhaegen_Human_Evolution.html ) that
she was not has now been confirmed by the fact that Kenyanthropus 3.5 Ma is
more humanlike than Lucy.
> you need a theory to explain why certain animals have features in common
with
> humans with reference to their own lifestyle. Humans emerging out of the
forest
> aren't going to suddenly transform into something resembling a hippo or a
seal
> any more than they would transform into an elephant or a baboon if they
found
> themselves in the savannah. In fact, hairlessness in most aquatic mammals
has
> nothing at all to do with the fact that they live or forage underwater
(the
> exceptions being streamlined fully marine animals like dolphins, and
you've
> said yourself you don't regard these as an appropriate comparison), and a
lot
> more to do with their size and exposure to heat; exactly the same as in
> elephants and rhinos.
:-D
1) Exactly the same? elephant man? We're smaller than rhinos & elephants,
don't you think?
2) Some people think that all "pachyderms" (hippos, elephants & rhinos) had
semiaquatic ancestors, see, eg, http://unisci.com/stories/20004/1115002.htm
http://www.abc.net.au/science/news/print/print_24742.htm
http://www.academicpress.com/inscight/05101999/graphb.htm Besides 3 of 5
rhino species are semiaquatic, only 1 of 5 rhinos, & 1 of 3 elephants is
exposed to solar radiation.
....
> >> No, simply because the most recent evidence shows that
> >> the forests weren't in decline at that time and that our
> >> ancestors remained in forests for rather longer than once
> >> believed. However, I don't see anything inherently
> >> implausible about the theory itself and I can see that
> >> someone who is unaware of the more recent findings
> >> could subscribe to it - the theory happens to be wrong on
> >> the basis of the evidence, but it isn't crazy.
> >
> >Crazy, no, stupid, yes. This whole savanna idea is based on Dart's
> >misunderstanding that the climate where Taung lived ("fringe of the
> >Kalahari") was the same as today. But a simple consideration of human
> >physiology shows that humans are more dependent on water than chimps are.
>
> That's your (so far unproven) contention. Yes, the climatic evidence put
the
> nail in the savannah hypothesis coffin, but until then it was widely
accepted
> and respected by paleontologists, anthropologists and evolutionary
biologists
> alike. I reiterate: there is nothing implausible about the theory.
Everything is, esp. human physiology is.
> The mechanisms and pressures
> proposed for the evolution of the human form make
> evolutionary sense, hence the wide acceptance over
> several decades. Philip Bowles
No, Philip, they were just-so stories, completely irrealistic, no better
than the hypothetical land bridges between S.America & Africa in geology
before the theory of plate tectonics.
Marc Verhaegen
OK, nobody doubt the climate was cooling & drying. Gerrit, don't you see the
flaws in this reasoning: not only human ancestors, but all African mammals
at that time lived in these cooling & more arid conditions... It's not
because the climates cools & dries that mammals have to evolve into the
human direction. (To the contrary, of course: just see our physiology:
totally unfit for a dry environment: we're extremely dependent on water,
totally unlike savanna mammals.)
Marc
P Bowles
<marc.ve...@village.uunet.be> writes:
The problem isn't mine - the below quote points out that the animal was capable
of bipedal locomotion long before Homo erectus emerged, which is rather
inconsistent with your claim regarding Marchal's paper.
R.J.Clarke 2000 "What the StW 573
>Australopithecus skeleton reveals about early hominid bipedalism" AAPA
>abstracts:126: "... Preliminary assessment indicates that the foot had both
>bipedal & climbing capabilities, whilst the arm & hand indicate adaptation
>to arboreal locomotion. This skeleton's foot morphology is consistent with
>the bipedal Laetoli footprint trails, which are not those of fully human
>feet, but which have very clear ape-like morphology."
They do indeed - the digits are posed in a very ape-like fashion and would have
been suitable for grasping branches. Like other Sterkfontein fossils, Little
Foot lived in a forest so this is no surprise. However, the heel and the ankle
joint are recognisably hominid in form.
>> Besides, the hominid and australopithicene lines have been distinguished
>from
>> the start by limb proportions better-adapted for a truly bipedal lifestyle
>than
>> those of a chimpanzee, and fossils from Australopithecus and
>Kenyanthropithecus
>> to Homo erectus itself display a gradual progression from an ape-like to a
>> human-like posture long before the emergence of H. erectus itself, whether
>or
>> not it or they were fully bipedal - clearly whatever pressure led to
>bipedalism
>> in humans was at work even while our ancestors were still forest-dwellers
>> barely distinct from chimpanzees (indeed, when walking bipedally the
>bonobo has
>> a more human-like posture than the common chimpanzee).
>
>You're making up your own facts, Philip, you see things that weren't there:
>by which "start"?
"Start" as in "the first classifications which separated australopithicenes
from apes" - the recognisable difference between one and the other is that the
australopithicene is a biped.
"better"(?)adapted to what?
For locomotion on two legs - the feature we're discussing.
what is "true" bipedalism?
The ability to move on two legs at all times without the assistance of a
balancing aid such as a tail - the characteristic in humans described as
bipedalism. What else would it be?
>"gradual"? "progression"??
Fairly obvious - the shift from quadrupedal to bipedal motion was not
instantaneous, as evidenced by both the motions of living apes and the change
in hindlimb proportions in fossil australopithecines over time. Therefore it
makes sense to describe it as 'gradual'. As the trend in these specimens is
from a quadrupedal to a bipedal form, this sequence forms a progression.
etc. Please read carefully the above abstract of
>Clarke.
I have - it indicates that we have an animal which is bipedal when on the
ground buyt which retains the ability to climb. This isn't inconsistent with
anything I've said, but does call into question the idea that bipedalism arose
from selective pressures operating on Homo erectus.
>> Comparative evidence is not an argument in itself;
>
>It is: what is true for other animals is also true for us
You have yet to define what is true for other animals, and again you need a
reason *why* it is true for us. Plenty of things are true of other animals - it
is true that the proboscis monkey has developed a nose which allows its calls
to resonate further as a means of sexual selection. This is not true for us,
even though we are also subject to sexual selection. It is true that big cats
have claws to enable them to bring down prey. This is not true for us, even
though our recent ancestors have been hunters. Evolution is far more complex
than you suppose in the hypotheses you have presented. For instance, some seals
with a diving lifestyle are hairless, but others are hairy. What reason is
there for supposing that we lost our hair like a walrus rather than keeping it
like a fur seal?
: we're no
>exception. OTOH, fossil evidence is not an argument in itself IMO
You're right - fossil *evidence* is just that, evidence to be used in support
of an argument, not as an argument in itself. Comparative evidence is the same
in that respect, but you have treated comparisons with other animals as though
they were arguments in their own right.
: fossils
>say only something about the fossils, but the connection with us is
>uncertain, eg, it was believed for many years that Lucy was our ancestor: my
>impression (see my Hum.Evol.papers
>http://allserv.rug.ac.be/~mvaneech/Fil/Verhaegen_Human_Evolution.html ) that
>she was not has now been confirmed by the fact that Kenyanthropus 3.5 Ma is
>more humanlike than Lucy.
That's one advantage fossil evidence has as a basis for theorising - new
discoveries can invalidate an incorrect theory and help support a new one. Your
position is not based on anything so solid - you are making speculative
interpretations of existing fossils with very little theoretical justification
and no actual evidence which satisfactorily explains why your interpretation is
more plausible than currently-accepted hypotheses - you have no fossils with
specific evidence of an aquatic or aquaboreal lifestyle which cannot equally
well be explained by existing theories, and your comparisons with living
animals don't bear close examination.
>> you need a theory to explain why certain animals have features in common
>with
>> humans with reference to their own lifestyle. Humans emerging out of the
>forest
>> aren't going to suddenly transform into something resembling a hippo or a
>seal
>> any more than they would transform into an elephant or a baboon if they
>found
>> themselves in the savannah. In fact, hairlessness in most aquatic mammals
>has
>> nothing at all to do with the fact that they live or forage underwater
>(the
>> exceptions being streamlined fully marine animals like dolphins, and
>you've
>> said yourself you don't regard these as an appropriate comparison), and a
>lot
>> more to do with their size and exposure to heat; exactly the same as in
>> elephants and rhinos.
>
>:-D
>
>1) Exactly the same? elephant man? We're smaller than rhinos & elephants,
>don't you think?
My comment above is that "hairlessness in most aquatic mammals
has nothing at all to do with the fact that they live or forage underwater ...
and a lot more to do with their size and exposure to heat; exactly the same as
in elephants and rhinos" - I'm not suggesting human hairlessness has the same
cause as hairlessness in elephants or rhinos, I'm suggesting that hairlessness
in whales and walruses has the same cause as hairlessness in elephants and
rhinos, and *not* with the human condition.
>2) Some people think that all "pachyderms" (hippos, elephants & rhinos) had
>semiaquatic ancestors, see, eg, http://unisci.com/stories/20004/1115002.htm
>http://www.abc.net.au/science/news/print/print_24742.htm
>http://www.academicpress.com/inscight/05101999/graphb.htm
And did wildebeest, warthogs and other hairless wonders? What about lions in
Tsavo, whose mane loss is thought by some researchers to be due to the
particularly high temperatures? The evidence for aquatic elephant ancestors has
nothing to do with their lack of hair and rather more to do with their trunks
and neonatal development: whether aquatic or not, an elephant with substantial
amounts of body hair would overheat in an open tropical climate, which is why
the only extant elephant with even a sparse covering of hair lives in forests,
often at some altitude. The same is true of rhinos and hippos; a semi-aquatic
origin does not need to be postulated to explain these features. Hippos in
particular also have vast fat reserves to enable them to cope in dry season
conditions, and if they were furred the additional insulation would kill them.
Besides 3 of 5
>rhino species are semiaquatic, only 1 of 5 rhinos, & 1 of 3 elephants is
>exposed to solar radiation.
They still get pretty warm in a tropical environment, even with forest cover -
which is probably why the only really hairy rhino is also the smallest. Humans,
being rather smaller, wouldn't have had the same sorts of problems large
animals would face keeping cool in a forest, but might well have had trouble
adjusting to a more open habitat - assuming for the moment that the pressure on
humans to lose hair was the same as for rhinos, elephants or walruses, which I
doubt.
>> >> No, simply because the most recent evidence shows that
>> >> the forests weren't in decline at that time and that our
>> >> ancestors remained in forests for rather longer than once
>> >> believed. However, I don't see anything inherently
>> >> implausible about the theory itself and I can see that
>> >> someone who is unaware of the more recent findings
>> >> could subscribe to it - the theory happens to be wrong on
>> >> the basis of the evidence, but it isn't crazy.
>> >
>> >Crazy, no, stupid, yes. This whole savanna idea is based on Dart's
>> >misunderstanding that the climate where Taung lived ("fringe of the
>> >Kalahari") was the same as today. But a simple consideration of human
>> >physiology shows that humans are more dependent on water than chimps are.
>>
>> That's your (so far unproven) contention. Yes, the climatic evidence put
>the
>> nail in the savannah hypothesis coffin, but until then it was widely
>accepted
>> and respected by paleontologists, anthropologists and evolutionary
>biologists
>> alike. I reiterate: there is nothing implausible about the theory.
>
>Everything is, esp. human physiology is.
Again, nothing to support this claim. You haven't shown, for instance, that the
points Gerrit has made in support of a savannah-derived physiology make no
adaptive sense.
>> The mechanisms and pressures
>> proposed for the evolution of the human form make
>> evolutionary sense, hence the wide acceptance over
>> several decades. Philip Bowles
>
>No, Philip, they were just-so stories, completely irrealistic,
You'll need to do more than make a blanket statement to win any converts, and
showing how an adaption might conceivably have arisen from an aquatic lifestyle
is not an argument against a savannah or forest hypothesis unless you can show
why this explanation makes more sense than savannah or forest adaptions, which
so far you haven't done.
Philip Bowles
Marc Verhaegen
> "Marc Verhaegen" <marc.ve...@village.uunet.be> wrote:
>
> >> So, if you accept Reed's ecological structure analysis with regard to
> >> Australopithecus then why reject it with regard to Homo?
>
> >Because apparently he's wrong here.
>
> She.
>
> >AFAIK all early Homo fossils have been found near molluscs.
>
> That's not true.
Examples please?
> And as usual you mistake the waterlaid depositional
> context for the habitat of the organism. Ever heard of taphonomy?
>
> >Did Reed specifically analysed H.erectus' ecology? or
> >did he only rely on the usual traditional interpretations?
>
> She analyzed all major African sites that have generated hominin
> fossils, including Homo erectus.
> The analysis is based on the total mammalian fauna's of these sites.
> These faunal assemblages were than compared with modern communities
> and death assemblages using ecomorphological variables such as
> percentage arboreal, terrestrial, aquatic, frugivorous, fresh grass
> grazer, etc. in order to determine resemblance.
> Homo erectus fauna's are most similar to those occupying modern open
> environments.
That's clear. Nobody doubts that. No climbing in Homo.
> >In any case, H.erectus-ergaster lived from Algeria to Java. I wouldn't
call all that
> >savanna... Open, less trees, yes, very likely: after all, Homo (vs.
apiths &
> >apes) lost most climbing skills. I see no reason to doubt they dispersed
> >along the coasts (exactly as the comparative data suggest).
>
> Well, studies of the ecological morphology of early Homo (e.g. upright
> narrow bodies with long distal limb elements) indicate that they were
> well adapted to dealing with heat stress (Ruff 1991, Walker 1993).
Wishful thinking. Turkana boy was clearly different from sapiens, eg, very
low vertebrae, different ilia, less basicranial flexion, flattened skull
etc. IOW, Ruff is comparing 2 different things. His analysis is as realistic
as Wheeler's puppet of an apith standing still & vertical under the hot
African sun...
> Based on its crural and brachial indices the mean annual temperature
> of the environment of the Turkana boy (KNM-WT 15000) is estimated to
> have been 29.2 C and 30.8 C respectively.
> And Feibel et al. (1991) report that the Lake Turkana region had much
> the same climate 1.5 Mya as it has today (i.e. arid).
> These hominids were there and apparently were able to make a living in
> such environments. This is based on decent paleoecological and
> ecomorphological analysis, unlike the paleofantasy of the aquatic
> scenario.
Whether you like it or not, Turkana boy was aquatic when he died:
'Mammalian fossils are rare at this locality, the most abundant vertebrate
fossils being parts of small and large fish. The depositional environment
was evidently an alluvial plain of low relief [.] Typical lacustrine forms
(for example, ostracods, molluscs) could invade the area [.] The only other
fauna found so far in the fossiliferous bed are many opercula of the swamp
snail Pila, a few bones of the catfish Synodontis and two fragments of
indeterminate large mammal bone [.]' (Brown et al., 1985).
The usual savanna fantasy is that the boy had fever, went into the water to
cool & died from the infection.... :-D