Re: Paleosols of the Turkana Basin

On Tue, 2 Dec 2003 20:06:15 +0800, "Algis Kuliukas"
<[EMAIL PROTECTED]> wrote:

>Thank you for a very thorough and well written piece, Phillp. (What's the
>actual reference to the paper you cited though?)
>
>I liked your emphasis on the energy-based arguments of habitat and you make
>a good case that rainforest would have been a more plausible ancestral home
>of Homo than open grasslands.
>
>However, what strikes me is this: Does it have to be one or the other? One
>of the clearest long-term effects of aridification on rainforest is their
>shrinkage clser to sources of water. Therefore aren't you somewhat
>discounting the riparian forest habitat in your quest? 

I think riparian habitats were extremely important close to
the end of human isolation in africa. One of the critical
technologies I see is the transition of the hand ax, light
ax to the ax and the frequent use of dugouts. This is the
only stone technology that one really needs in a rainforest.
Everything else can be made with bone and wood.
This particular technology makes the rainforest particularly
useful by humans. My prediction here is that the 10 kind
isolation occurred within the west central rainforest of
africa, the only way that this group remains a interbreeding
population at those numbers spread within a rainforest is if
they are capable of traveling around the rainforest much
faster than chimps or gorillas, both species have isolated
are reisolated into species and subspecies. Therefore I
consider the congo and niger rivers to be critical 
passageways within this context. 
  This technology I believe is critical for the rate of
expansion and initial success out of africa, and every H/G
equitorial forest tribe in the world is capable of making
dugouts suggesting this is a common technology that has
never been lost by human kind. If we place these intial
steps in the 170 to 140 kya range and the expansive steps in
the 150 to 110 kya range then one can postulate that the 
small scale inventions, possible single 2 person boats
suitable for smooth water travel (remember the 2 persons
would possible pygmies weight 60 to 120 lbs at adult) 

>Your 7-point summary
>at the end of the piece, the one that began "1. Most Ape species live in
>rainforest" is, I think, spot on - but it seems clear to me that forest
>inhabiting ape species are more likely to stay with forests as they shrink
>closer to rivers and lakes than to move out into more open habitats. In
>parts of the world which are not arid, it makes sense that humans would
>naturally find tropical rainforests suitable places to live but I don't see
>anything to suggest that is where the process of hominization took place.
>Any model that suggests this, begs the question why did the same process not
>work with gibbons, orang-utans, gorillas, chimpanzees or bonobos?

Why do chimps and gorillas interdisperse in the african
forests. I am not going to lead the argument by first
confining it. Without predators chimpanzees move onto
foraging in the grasslands, therefore chimpanzees are not
limited to rainforest either, but are kept there fore
selective reasons. 
  What you are logically trying to do is beg a question, a
point of propoganda. However, the rainforest, as I already
pointed out is at the spearhead for direct energy
competition which puts it at the forefront of what drives
evolution. The drive on evolution drives also variation, and
therefore there is a huge potential for a forest to drive
variation of any genera that occupies it. It also seems to
drive radiation, IOW animals the flow out into other
habitats. Africanus may be a variant of a forest dwelling
human intermediate. Habilis may be a variant. Therefore
protohumans are not so SPECIALIZED within the rainforest
that they have difficulty radiating variants. 
  We could compare this to say protowhales, that were
rainforest dwellers that specialized in aquatic activities,
no whales have returned to the rainforest, once they under
went transition to fully aquatic, the ability to
despecialize was lost. 

 There is another consideration another faulty logic, we
examine dryopithicus, gorilla, chimpanzee and we assume that
each of these species was more similar to the LCA of humans;
however one might also consider that protohuman lines MAY
not have branched off the core, but these peripheral buds
splintered off over time specialized and formed new species
at the periphery of the sites most choice to humans, these
are not neccesarily in the depths of the rainforest, but in
places where the rainforest opens up creating a more
luxurious habitat. Again the critical issue is that split
times of chimpanzees, gorillas and humans are often so close
to each other one has to make the consideration of the
following. gorilla lines gave rise to C/H, why then are C/H
lines more variable than gorilla lines which subbranch about
the same time as C/H. Alternatively C/H lines maintained
variation while G line were constrained in terms of
variation, is this a bud? If so it explains the close
temporal placement of G/(C/H) to C/H. However what about
apiths, if H was a bud off of C/H why then do we see all
this apith variation and very little variation in chimp
morphology. Once again one could argue that perhaps there
was not a split, but that once again protochimp lines budded
off a more diverse protohomo core population. 
  If one uses this hypothesis and considers how big the
rainforest once were and how much more diverse they would
have been, then it is not difficult to see some ? species
throwing off gorilla in one segement of the forest were
specialization was selective, then throwing of chimpanzees
for the same reason; however variation at the core couple
with the diversifying/evolving demands of the high entropy
building rainforest is keeping the core evolving at pace,
throwing of apith variants such as afarensis, africanus,
habilines and even possibly erectoids along the way. 
As the forest; however, shrinks it is possible that the
species became more limited, with homo outcompeting most
other hominid lines and then finally eliminating all other
homo variants while continue to evolve at the rapid pace
at the center of the system. Each subsequent line thrown out
of the ecosystem would then displace earlier derivatives. 
  This possibly explains why chimp and gorilla survive, we
see frequently that humans have been very good at displacing
species worldwide but the similar animals in africa persist.
These species evolved and adapted along side the core of
human evolution, and as a result they adapt to new human
strategies as they appear, rather then being confronted with
10 new strategies all at once. Chimpanzees appear to have
survived by being under constant selection by humans versus
abrupt selection. Hominids that leave the forest would then
detach themselves from the constant selection and undergo
selection under grassland predation only to have every
million years a new variant of human come crashing out of
the forest a variant for which they are unprepared to
compete. 
  The genetics is not alltogether moot on the point. For
example if one looks at the genetics of eurasians, one sees
that there are many waves of humans that appear to have
spread in africa, but at different times. The first wave
spreads east, south and apparently into indochina and
beyond. Secondary waves appear to have moved bilaterally
east, west and still other waves appear to have spread
north. There is some debate now that the first pastoral
herders appear in northwest africa, and the first
agriculture also. If pastoral herding is a guage there is
ample genetic evidence to suggest the expansion of pastoral
herding from west africa into europe was responsible for no
less than 10% of current european genetic make-up and
previous waves, probably tool technology driven account for
very high percentages of peoples living on the atlantic
coastal proximity of europe from iberia to ireland. The
probable ancestors appear to come from the more forested
regions (of that time) from west africa and extending all
the way to central africa. So why are forest dwelling
peoples feeding technological innovation into europe? 
  The answer probably can be found in Ecuador. If humans
move through beringia or proximal regions, genetics confirm
route, why is it that cultural development is equitorial?

1. Constant sunlight
2. Constant climate
3. Constant rainfall

Let us reconsider Ecuador for a moment, let us assume that
ancient ecuadorians came from Japanese region and brought
fractional technologies to the new world. They may have
brought seeds to the new world, but my recent survey of
seeds domestication has revealed that ancient peoples
favored early conversion from whatever seeds in hand to
whatever seeds were best growing in their region. There are
no particularly evidence squash species, for example in
Japan, however the first species to be domesticated in
ecuador is the squash. Squash have several features.
1. like rich soils
2. like sunlight
3. fruits are particularly insect and rodentavore resistent.

IOW, you average moron can through a few squash seeds into a
dung heap and within a few months have nice delicious
squash. Settlement of new world from beringia ~15 kya,
appearance of first plant domesticants 10 kya in ecuador.
First appearance of pottery 8 kya in ecuador, first
metallugy 3 to 4 kya in eucuador. 

Thus one has to consider that regions proximal to equitorial
rainforest may provide a critical driving force for
technological innovation that we have not previously
considered. In the past rainforest have been treated as the
no-man's-land of human evolution. However, I think this
logic may be critically flawed. While rainforest cannot
maintain huge human or hominid populations, they can
maintain populations for long periods of time under constant
selection for based on the rapid evolution of other species
in the forest. There are many paths to specialization that
will result in non- human 'buds' however within the
preferred area the selection may have been for a generalist
capable of increasing exploitation no matter which curve
ball evolution throws. 
  Within the rainforest context there are multiple reasons
for generalizing adaptations.
1. Presence of riparian transportation corridors. 
2. Presence of broken grasslands, meadows and marshes, for
more open range hunting.
3. Presense at boundaries of ocean habitats and salt marshes
as transitions to maritime activities. 
4. Presense at margins of lakes and other bodies of water. 
And a long list of other features.