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Aquatic Ape: You Asked For It.
NICHOLLS PHILIP A (pn8886@thor.albany.edu)
Sun, 1 May 94 04:22:59 GMT
>> NICHOLLS PHILIP A <pn8886@thor.albany.edu> wrote:
> cm315c09@nova.umd.edu (5121 Student 09) writes:
>> Because such bodies of water tend to promote fossilization, isn't
>> it odd that no aquatic apes have turned up in the fossil record?
> Yes, I do. I also think it is odd that no fossils have turned up
> for an entire 4 million year stretch. The very same stretch that
> would clear up this mess.
There are plenty of fossils from the middle and late Miocene. There
are even plenty of fossil apes. The problem is that none of the make
good candidates for a common ancestor.
>>> 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.
> Which is exactly why I must strongly question everything you post.
Paleoclimatological data is hard evidence. Comparative anatomy is
hard evidence. Fossils are hard evidence. Feel free to question
anything I say. It's only fair since I haven't let you get away with
anything. If you don't consider this to be hard evidence then a more
convincing reply would have been an explanation as to WHY you don't
consider it to be hard evidence.
>Please explain (since it is *so* simple) how the following are
>savannah adaptations?
>Hairlessness
>> Once bipedal, hair loss promotes evaporative cooling.
> I thought Pete Wheeler explained that water is a much better cooler.
Water is indeed much better at cooling than evaporation. However, you
maintain that protohominids didn't swim, they just sat in the water,
cooled off and occasionally caught some fish. If this is the case,
they why did they lose body hair? The only aquatic mammals to lose
body hair are those that are completely aquatic.
> Increased adipose fat tissue in the breast and thighs of women
> developing at puberty. Sexual selection [hint: puberty]
>> Fat chick float better. [hint: buoyancy]
So why puberty? Do aquatic apes only need to float when they become
reproductive? Why the breasts and thighs? Why only females? Don't
males need to be buoyant also.
Of course, all of this begs the question of whether or not body fat
increases bouyancy. I don't know of any evidence to support that
claim. Do you have any?
> Dilute urine
>> Compared to what?
> Beats me. I just made that up :-)
Gee, I could have sworn Morgan used that one.
> 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.
> Who said they were? I just want to know how they are a savannah
> adaptation.
Morgan originally proposed salty tears as evidence for an aquatic
past by suggesting they were a means of excreting excess salt. That
is the basis of my response, which points out they they clearly
cannot be an excretion.
Why do they have to be a savannah adaptation?
>>the Diving reflex
>
>Identical to "fight-or-flight" reflexes.
The bronchiols in the lungs actually contract when the face comes
in contact with water. Decreased lung function is *not* fight or flight.
>Ventro-ventral mating
>> Also occurs very often in pygmie chimpanzees. Also not a human
>> universal.
> It also occurs in dolphins, whales, and manatees. What's your point?
> I want to know how it is a savannah adaptation. Come on guy, this
> is *so* simple. Remember?
I don't recall anyone claiming it was a savannah adaptation to begin
with. I do recall Morgan claiming it was evidence of a past aquatic
stage. My point, oh dense one, is that if Morgan's reasoning is
valid then pygmie chimpanzees evolved from aquatic ancestors AND
those human cultures that do not engage in ventral-ventral copulation
must have different ape-like ancestors than those that do.
>Floating infants
>> Infants tend to drown easily.
> Only because they are not raised in an aquatic environment. Infants
> in such an environment can swim *before* they can walk.
> Babies can and do float. This is an indisputable fact. I've seen
> it with my own eyes. How is this a savannah adaptation. *so* simple.
I dispute this fact. Provide scientific evidence to support it.
Please not that I am not disputing the possiblity that infants can
learn to float. I am disputing that they will do so without the
assistance of an adult.
>Sheltered nostrils
>> Flat faces
> Oh, of course, flat faces ... savannah, an immediate connection there.
I am providing explanations for each item you list. They are not all
necessarily savannah adaptations. What I am trying to show is that
they are definitely not aquatic adaptations. It is a fact that the
human face has become flattened during the course of evolution and
that the shape of the human nose reflects changes that have occurred
in mid-facial morphology during hominid evolution.
>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.
> Very good. To bad the same can be said for cooling off in the
> nearest pond. Head is exposed, must remain covered. Body is
> cool, no need for hair.
The difference between the two is that the one I offer is supported
by experimental data collected by Pete Wheeler and is consistant with
evolutionary theory, namely that the loss of hair promotes better
evaporative cooling.
Your statement is conjecture on your part and invokes a neo-Lamarkian
explanation to explain hair loss. Evolution doesn't follow Lamarkian
"use it or lose it" logic.
>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.
> I agree. Unfortunatly, this seems to be the basis for the
> entire savannah theory (oh sorry, I forgot you mentioned before
> that there is not "savannah theory").
There is no savannah theory. There are numerous hypotheses about the
origins of bipedalism and most of them involve the savannah. One of
them, however (suspensory feeding) does not.
Each of the above is based on observed primate behaviors. In
otherwords, evolution tends to work with what is on hand in terms of
behavior as well as morphology. Bipedalism is part of the behavioral
repetiore of most anthropoid primates. Aquatic behavior is not.
>>find hand-grasping ability
>
>Retention of primitive primate condition. Fine motor skills are
>associated with manipulation.
> Well, good. I'm sure that could only be used on the savannah.
> Wow, it's all so simple.
Once again, no one is claiming that this is a savannah adaptation.
As a matter of fact, this is specifically an arboreal adaptation. It
is not an aquatic adaptation.
>>communication through calls rather than badges or pheromones
>
>In general, this is the rule for anthropoid primates
I've never heard this. Can you back it up with a reference please?
Primate Behavior, by Allison Jolly.
The Antecedents of Man W. LeGros Clark
Primates show a reduction in the size of the olfactory lobe of the
brain relative to other mammals.
>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.
> I feel like I'm on Jeopardy. What question goes with this answer?
The point is that since the earliest hominids did not have large
brains, and since the aquatic ape lived before these established
hominids the aquatic ape could not have had a large brain. It's so
easy, really it is.
> feet not grasping
>> Toe placement stablizes stance for bipedal locomotion.
> Of course we all know human ancestors would never stand in water.
> This is something they would just never, never do. Bad, ape,
> stay away from that water, or else.
Suppose they did. Since water supports most of the body weight, why
do they need to move the big toe inward. This only makes sense for a
terrestrial biped.
>>>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.
> Well that's because it was all so simple and here I was trying
> to make it complicated by trying to think of something that
> makes sense. Silly me.
The only way for any of the above to make sense is to ignore some
very basic facts of biology. You don't understand evolution, you
don't understand what paleontologists have to say about the human
fossil record and you don't understand Morgan's or Hardy's positions
regarding the aquatic ape.
We are not talking about "man" here (or woman, for that matter). We
are talking about something that had just diverged from the common
ancestor we share with the modern great apes but which was not yet a
full hominid -- i.e., it had not achieved bipedal gait. The only
thing we KNOW is that hominids made the transition to bipedalism.
You want protohominids to get a drink of water? Fine, no problem.
All primates do this. You want them to jump INTO the water to cool
off, well, now you have problems. Only two primates do this on a
regular basis and both of them are monkeys. Still, I'll give you
this one.
What does that explain?
Does it explain the one transition we know occurred at this specific
time? No, it does not. In water most of the bodies weight is
supported by water. There is no advantage to the various
re-arangements of muscle and bone associated with bipedalism -- all
of which are changes that are associated with distribution of weight.
--
Philip Nicholls "To ask a question,
Department of Anthropology you must first know
SUNY Albany most of the answer."
pn8886@thor.albany.edu
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