Re: Human bottlenecks and bird taxonomy (was: Re: "Dinosaurs Died Within Hours...)

[Eric Martichuski <herewiss13@hotmail.com>]

> > Within the past 450 million years, we know of only one eruption that was 
> > larger.
>
> Which was that?

I honestly don't know.  That's just what one particular article said. (I 
know, I know: _bad_ scholar, no cookie!)

> We see human "races" in the fossil record!?! This is total news to me...
> sure, 50 years ago everyone thought so, but that was dropped.

Well, I did put "race" in quotations.  How about "regional phenotypic 
differences in cranial osteology?"  I know the "multiple origins" theory of 
human evolution relies on supposed observations of just such differences 
(I'm not convinced the theory is valid, but it's hardly 50 years old and 
totally outdated).  The volcanic bottleneck idea says that such differences 
were selected and amplified through the umpteen different tiny "founder 
effect" populations Toba's eruption created in a single "instant".

> Interesting.  Do any other species show evidence for such a bottleneck at
> that time?

According to a book called "Tears of the Cheetah", which has a bunch of neat 
anecdotes about the combination of genetics with wildlife 
biology/conservation, both cougars and cheetahs show similar indications of 
bottlenecks (which I _believe_ are dated to the same basic time period.  
It's been a few months since I read the book, though).  The cheetah 
bottleneck _may_ be more recent, or it may just have been exacerbated 
recently.  At the moment, any random cheetah can accept skin grafts from any 
other cheetah with no risk of rejection.  And the cougar bottleneck is in 
North American cougars which apparently all spring from Central American 
stock after the original nothern populations were wiped out (by ice age 
activity, IIRC).  Possibly Toba related, but I just can't recall the dates, 
sorry.

Thanks for the clarifications about vultures, btw.  I hadn't _thought_ they 
were somehow taxonomically "special", but it's not as familar a subject for 
me as others.

Eric
______________________________________________________________________
"There is no other wisdom,
And no other hope for us
But that we grow wise. -- Diane Duane
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