Summarised Notes
Introduction
The timing of Hardy's theory coincided with the EAHOS (East African Hominid
Origins School) theory losing favour.
The drought - the savannah theory - "if one searches the literature, no
evidence was ever offered in support of such a drought" p 127.
That another
response
was the adoption of creation science -
"Creation
scientists took one course of action .. whilst the aquatic ape school apparently
plunged for the opposite of 'aridity' as a moulder of humanness, and so was
born the concept of the watery past in human evolution." p 128
Discussion of the AAT
AAT as with drought theory is that the hominid goes
through
a trying
time and emerges different on the other side.
Hardy, Morgan Verhaegen - look for analogies. 'Commonality of selection
pressure' - until quite an impressive list of features have emerged.
Differences seldom feature in their studies - - similarity evidently
outweighing differences in their studies. Homology has seldom, if ever
entered.
AAT evidence - from neontological record - not fossil record.
AAT evidence "lacks
time dimension" - strength of paleoanthropology.
However "before we dismiss the AAT out of hand" we ought to examine fossil.
Verhaegen & LaLumiere think so. Verhaegen thinks taphonomic evidence.
LaLumier - there will be evidence if we look in the right place.
Check the evidence - long term aquatic - LaLumier and Verhaegen of old - or
recent - like Verhaegen does now. (aquatic Neanderthal?)-
The early scenario
"Of all the pre-hominid fossils recovered in
the Old
World, now totalling more than 3,000 specimens from hundreds of localities
|
ranging
in age from the lower Miocene (18 mya) to the Holocene ... only a minute
proportion of specimens has, to my knowledge, been found in fully lacustrine
sediments or marine (including littoral) strata." p130
Only
kenyapithecus and
oreopithecus
and they are arboreal.
"Richest concentrations .. occur in sediments which accumulated subaerially,
well away from lakes." Pickford 1986.
The late scenario
ditto.fossils are not found in fully lacustrine or marine strata. - instead
in subaerial strata such as commonly acumulate in flood plains, volcanic
slopes, palaesols and cave systems.
Critcised 'lake beds'
"We estimate that only 5% of the volume of sediment in the Gregory Rift
Valley accumulated under fully lacustrine conditions. For the Nyanza Rift,
the figure is even less (0.01%). In contrast 70% of the vol of sediment in
the Albert basin of the western rift is lacustrine, yet only a single ape
tooth has been found in these fossiliferous strata" p 131
"If geological
evidence is to be a source of support of the AAT, then all positive evidence
as to
paleo-environemnt
that is currently available has to be discarded or discounted and recourse
taken to what the geological record
'might'
yeild.
Conclusion
"Any other conclusion,
including
the suggestion that we have not looked in the right place,
must come
under the heading
'special pleading'. Under this category I place LaLumiere
and Verhaegen.
He was rebuffed
by editor for claiming that apes and hominids "avoid lakes and seas" - but
he siad that because 'six out of 172 sp of primates enter water' it does not
bolster the AAT. |
Counter-Arguments
1. Fossil evidence is important but it is not the only evidence that should
be considered. Where is the fossil evidence of chimps and gorillas in the
last 5 million
years?
There is none. Does this mean that we conclude that they did not live in
Africa during that
time?
Soft tissue evidence - analogous evidence is just as important and cannot
simply
be ignored.
2. Pickford is careful to show that few hominid sites were 'fully
lacustrine'. This is hardly a contradiction. AAH does not claim that the
aquatic ape was as
aquatic as a
fish. A
Littoral (coastal) habitat is all
that was
claimed.
Pickford here
demonstrates a
typical pre-conceived view of AAH:
that it argues for an aquatic ape ancestor
being fully aquatic.
3. To claim the
fossil evidence does not support the AAH is, IMHO,
one of his
cases
of
"special
pleading" Almost all fossils have been
found in deposital substrates -
i.e.
waterside. Few
chimps/gorillas have been found there.
The argument of taphonomic bias can be countered by the fact that many stone
tools have also been found in these regions.
4. His
criticism of the AAH
about timescale
is fair. Hardy only
suggested that the 'phase' happened sometime
after Proconsul and
Morgan
never
speculated
very precisely about a
date until relatively recently (about 6 mya).
His point about Neanderthals was a little facile. Verhaegen is merely
emphasising that the aquatic phase probably was longer than we thought and
even included H erectus and Neanderthals.
5. His arguments about Hardy's timing
for going public
and comparison
with the rise of creationism is another case of 'special pleading'. Hardy
kept the theory in the dark for 30 years. He released it only because he was
about to retire.
6. His
implication that no-one ever claimed the savannah theory was the model is
yet
another case of
'special pleading' - Even today it is still de rigueur. Did anyone
see the documentary 'Ape
Man'
or the BBC's
'Walking
with Beasts.'
Their depiction of Australopithecus afarensis.
It's
the savannah theory alive and
kicking. |