Re: Oh No! No More AAT Please!

Wed, 27 Apr 94 02:49:17 GMT

> (5121 Student 09) writes:

>Leon LaLumiere writes in _The Evolution of Genu Homo: Where it
> According to Hsu,Cita and Ryan(1973), starting at the beginning
> of the Messinian (latest Miocene stage) the Mediterranean Sea was
> repeatedly isolated and then rejoined to the Atlantic Ocean, causing
> the sea to dry and then refill. They suggest this cycle of drying
> and refilling was repeated at least seven times, and perhaps as
> many as fourteen...
> No fossils of proto-hominids have yet been found for the two million
> years before the afarensis skeletons at Hadar, the 'follil gap'
> during which the split between apes and man took place...
> A very high percentage of hominid fossil remains have been found
> in sites which were close to lakes and rivers.

Yet, all of the ape fossils from the middle to late miocene are
arboreal quadrupeds while all hominids, including A afarensis, are
terrestrial bipeds. Molecular clocks put the hominid-pongid divergence
at about 5 million years ago. Australopithecine fossils are known
going back to at least 4 million years.

Hominid fossils are retrieved largely from areas associated with
bodies of water because the water source plays a role in fossilization
process. For permineralization of the bone to occur, water must
perculate through the soil and pick up mineral salts.

Because such bodies of water tend to promote fossilization, isn't it
odd that no aquatic apes have turned up in the fossil record?

>> and overwhelmingly massive comparative data for a
>>wide variety of other mammals, all showing the transition to savannah-
>>adapted forms as the climate altered with the uplift to the west and
>>the capture of the Indian Ocean climate between that and the growing
>>Himalayan massif.
>>All of that is hard evidence, against not a single "aquatic" specimen.
>That hardly qualifies as *hard* evidence.

It does in my book.

>>This is so simple that only one committed to "clever" speculation as if
>>scientific investigation were somehow always matched to the romantic
>>idea of a rejected genius finally triumphing could think much of AAH.
>>Clever speculations *often* fail in the cold light of facts that the
>>speculator did not account for. Get used to it. That's science.
>>If you are only contrasting adaptive "just so" stories, you might have
>>a point -- except that savannah adapations have the real advantage of
>>matching the data, and hence the POSSIBILITY of confirmation in detail
>>as detail accumulates.
>Please explain (since it is *so* simple) how the following are
>savannah adaptations?

[here we go]


Once bipedal, hair loss promotes evaporative cooling.

>Increased adipose fat tissue in the breast and thighs of women developing
> at puberty.

Sexual selection [hint: puberty]

>Dilute urine

Compared to what?

>Salty tears

All body excretions contain salt. The concentration of salt in sweat and
tears is HYPOTONIC relative to blood plasma. That means that they are not
a means of excreting excess salt.

>the Diving reflex

Identical to "fight-or-flight" reflexes.

>Ventro-ventral mating

Also occurs very often in pygmie chimpanzees. Also not a human

>Floating infants

Infants tend to drown easily.

>Sheltered nostrils

Flat faces

>head hair with rest of body hairless

Bipedalism reduces the amount of body surface exposed to the sun.
The one area of the body for which this is not true is the top
of the head.

>Upright stance

[1] Reduction of heat stress.
[2] Increases range of visual field
[3] Hands are free to gather and carry foods.
[4] Primates that are suspensory feeder tend to be
bipeds when they have to be terrestrial.
[5] Bipedalism is more efficient energetically than
primate-style quadrupedal locomotion when covering long distances.

>find hand-grasping ability

Retention of primitive primate condition. Fine motor skills are
associated with manipulation.

>communication through calls rather than badges or pheromones

In general, this is the rule for anthropoid primates

>enlarged complex brain

The fossil record clearly shows that the brain did not enlarge,
relative to body size, or become significantly more complex until
Homo habilis. Australopithecus afarensis has a very small brain.

>feet not grasping

Toe placement stablizes stance for bipedal locomotion.

>>And the picture leaves little or
>>no room for an aquatic ape, but a whole geological province for savannah
>>apes, which we are -- regardless of whether our every feature can be
>>(or should be) "explained" by that.
>Yea let's ignore those pesky details that don't agree with our
>preconceived notions.

Which is exactly what you are doing.

>I don't disagree with your interpretation of the available evidence.
>I do, however, strongly disagree with your assertion that it is the
>only sensible and reasonable interpretation of that evidence.

You have yet to show that your interpretation is either sensible or

Philip Nicholls "To ask a question,
Department of Anthropology you must first know
SUNY Albany most of the answer."