"Red Dragon"  wrote 

> > It's completely supported by the paleoclimatic evidence.  Think about
> > it.  What are the odds that this climate would just happen to emerge
> > at the right place and time (about 8mya) as our ancestors emerged.
> > Check out this link:
> > http://tinyurl.com/22de3
> 
> I do not know how accurate we can be in determining the paleoclimatic 
> condition at that moment of time.  What geotechnical evidence do we 
> have?  

Follow this link:
http://tinyurl.com/2cabf

> The monsoon theory does make a lot of sense but  has to have a 
> very dry season that will motivate some rather more intelligent 
> primates, to come down from the trees and make a living  on its 2 legs. 
> The monsoon theory is also more logical because the Australopithecus 
> were much more ape-like than Homo.  Despite being bipedal, their body 
> features were more towards tree dwellers and their brain sizes were 
> small.

In my scenario they reside in treed habitat.  And 
intelligence was not a big requirement because for 
the most part their lifestyle was not that much 
different than that of the chmpanzee lifestyle.  
They still ate the same foods or same general type 
of food and they still had continuing problems with 
being preyed upon by large cats.  This all continued.  
But in the context of this continuing chimpanzee 
lifestyle they now also needed to add strategies to 
deal with the dry season.  And as I explained these 
strategies involve communally territorialistic based, 
rock-throwing, stick-wielding behavior against their 
biggest enemy, food competitors.  But even these 
behaviors were not the engine of head growth--or, at 
least, not yet--in that their opponents were 
relatively small brained migratory mammals.  It was 
not until they began competing with themselves, 
community vs. community, that intellectual capacity 
became selectively advantageous.

> > The shift to bipedalism was, primarily, a rock-throwing,
> > stick-wielding adaptation.
> 
> More to this.  Bipedalism improved environmental vision, and also gave 
> greater mobility in running.  There is also spear throwing ability which 
> was very deadly. 

> > > Climatic changes  propelled  Australopithecus into 
> > > bipedalism,  but in no
> > > way  was it related to the  evolution from it to Homo.
> >
> > You lost me here.  Rock-throwing, stick-wielding provides the perfect
> > evolutionary uprampt to more sophisticated tool/weapons usage.
> 
> I am thinking of the question of why  Australopithecus needed to evolve 
> to Homo. 

Because of the selective aspects of community vs. 
community.  

> And had it anything to do with bipedalism?  Being bipedal and 
> clutching weapons had already solved their survival problem, but they 
> did not stop at that.  They continued to do better,  unlike the ape and 
> the chimp.  I have seen the chimp and ape clutching sticks and beating 
> their opponent.  But I have never seen them throw stones or throw a 
> sharp stick at their opponent.  Their evolutionary pattern stagnated.  
> Why?

Because their environment lacked the element of 
seasonal dessication.  Consequently the community 
vs. community aspects never became a factor.

> > No, they'd be dead meat on a treeless savanna.  A'pith weapons were
> > only effective in large groups and only to defend territory (against
> > inmigrating food competitors).
> 
> Exactly.  I was talking about them living and hunting as a group.  With 
> stones,  sticks and spears in they hands ,  survival is no more an 
> issue.

Well, survival is always an issue.  But this image 
of homo being primarily a meat eater/hunter is hard 
for me to swallow.

> 
> > > It was then a stable entity,  just like the lion, the
> > > cheetah. and the crocodile etc.   No problem  was faced with 
> > > obtaining food
> > > and producing offsprings.
>  
> > You lost me here. 
> 
> My point is that the evolutionary law had stopped applying to these =
> animals and they had remained like they are now for umpteen million =
> years. An evolutionary dead end.   Why?

Because they were parts of stable, long-standing 
ecosytems.  This new monsoon habitat was different.

> Because they had achieved a =
> very stable form  in surviving.  This is unlike the Australopithecus =
> which after achieving this state, continued to developed bigger brains =
> and achieve greater things.
> 
> So it brings to me some perplexing questions.  Primates are found 
> everywhere in the world.  And the monsoon climate and dessication 
> phenomena  happened everywhere on earth.

Not exactly true.  East Africa, India, and South China 
are the only parts of the world that currently have a 
monsoon habitat.  On whole our planet is a lot drier 
than it was 8mya.  This causes the dry seasons to be 
longer now than it was 8 million years ago.  Currently 
the dry season in east Africa is too dry to support 
the scenario that I suggest.  But, I'm thinking, it 
would have been just right 8mya.  (Also the dry season 
would have been too short in India and South China 
8mya, but now it's just right--which, by the way, is 
consistent with the fact that these two areas currently 
have the larges human populations.)


> So why was it that  
> bipedalism of the Astralopithecus was found only in East Africa?   Why 
> did it not happened in the Gobi, the Attacama and all other places 
> that also experience the same thing?

I'm not so sure we can assume they did experience the 
same thing.

Jim
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