Re: Fossil Evidence for AAT
Phillip Bigelow (n8010095@henson.cc.wwu.edu)
Fri, 23 Dec 1994 06:36:42 GMT
Troy Kelley <tkelley@hel4.brl.mil> writes:
>sircpu@aol.com (Sir CPU) writes:
>----
>Since everyone is so concerned with fossil evidence for AAT and that is
>all the opponents will discuss, the let's talk about the fossil evidence.
>Again, most of this was taken from Marc Verhaegen's article "Aquatic
>Features in Fossil Hominids?" from the "Aquatic Ape: Fact or Fiction"
>conference proceedings.
>1. Fossils of H. erectus indicate a very thick cranial vault which is
>accompanied by very dense bones in the rest of the skeleton. This is
>consistent with an aquatic environment adaptation.
No it is not. According to Wall (the Journal of Paleontology research
that I cited in the earlier post), only _limb bones_ should be used. The
cranial region is not comparative in this case. Homo erectus' limb bones
are, indeed, rather thick, however, no density value has been provided, as
far as I know, so, until such accurate density values are published, I would
regard this as uncertain data. Further, A. afarensis bones are thin and
long ("gracile" in the paleontological term). Even visual inspection of the
bones indicates that the species had average (or even possibly less dense)
bones than us. To muddy the waters even further, Homo sapiens neanderthalis had
even more massive bones that H. erectus, yet neanderthals were clearly
terrestrial, and in addition, lived _later_ than H. erectus.
<pb>
>2. Neanderthals and H. erectus show extensive and bilateral ear
>exostoses. This anomaly is only seen in people who do a lot of diving,
>especially in cold water.
WHERE IS YOUR DATA ON THIS!?! H. erectus has been unequivically shown to
be a savannah scavenger (from tools and scavenging marks on animal bones
attributed to H. erectus). So, if it is a savannah scavenger, are you
claiming that H. erectus did a lot of diving?
<pb>
>3. Air sinus passageways developed in Australopithecines and are present
>in early Homo. Sinus cavities are usually associated with aquatic
>creatures.
Extensive sinus cavities are found on cats, canids (dogs, wolves, foxes,
etc.), bats, and most other mammals that have a good sense of smell. Sinus
cavities and sinus bones (i.e., "turbinals") are all found in animals that
need to use the sense of smell to find food. Most terrestrial animals have
better developed sinuses than aquatic animals.
<pb>
>4. Lucy had a barrel shaped thorax which was different from most
>quadrupeds which have latero-laterally flattened thoraxes. Most marine
>mammals have barrel shaped thoraxes, although some monkeys do show the
>tendency.
All of the higher apes also have a barrel-shaped thorax. Modern humans
have a flatter thorax. Lucy had a thorax shape that was roughly between
that on the higher apes and that on humans. No suprise there, as Lucy is a
transitional form between an ape-like biped and a human. No need for the
AAT in this case.
<pb>
>5. Most fossil hominids have phalanges with very broad shafts, even
>broader than man. Broad phalanges are seen in all aquatic mammals.
Again, this is probably a transitional condition between the higher
apes and humans. Chimpanzees and gorillas have larger phalanges than do
humans, and they are terrestrial/arboreal. By the way, sea otters do _not_
have broad phalanges. I suspect that there are many more. I may look into
this more.
<pb>
>6. Early hominids had much shorter legs than later homo. In comparison to
>orangs, their legs are more reduced at the knees and still more at the
>ankles, rather than at the hip. This is consistent with an aquatic
>adaptation.
That is probably because the orang was used in the comparison. Why not
compare the leg lengths of Lucy with our closest living relative, the
chimpanzee? That would give a better comparison of adaptive structural
change.
<pb>
>7. H. erectus and Neanderthal show femur shafts with anterior convexity.
>Broad femurs would help in swimming. Both femur and tibiae of Neanderthal
>and erectus is thicker than in modern man. This is consistent with
>aquatic adaptations.
Hold on there! Are you claiming that Neanderthal was aquatic?!?
Besides, Lucy's species had rather slender, gracile femurs. Are you
claiming that aquaticness was "regained" in the later H. erectus and
Neanderthals?!?
<pb>
>8. Feet of early hominids were very broad with Neanderthal having broader
>feet than many people today. A. afarenis had a shorter heel and longer
>forefoot than modern man and it bears a striking resemblance to a
>sea-lion foot.
It bears a stronger resemblance to a chimpanzee foot. The higher apes
all have a greater foot-length/leg-length ratio than do modern humans.
Lucy's foot was proportionally large, but it was _between_ the ratios for
the higher apes and modern humans. This shows that Lucy was simply
transitional between an ape-like hominid and a fully modern human. No need
for the AAT here. Apes needed large feet for arboreal climbing.
<pb>
>If the AAT proponents want to just talk about fossils then this is
>evidence IN THE FOSSIL RECORD. It is "hard" evidence, and I think it
>shows very clearly human beings had an aquatic stage in their past.
>Troy Kelley
The evidence you provided us indicates a transition between an ape-like
morphology and a fully human morphology. The AAT is more like a peripheral
speculation, at least with the evidence you provided.
<pb>
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