Posted on 08/06/2010 6:41:18 PM PDT by SunkenCiv
At some point between 195,000 and 123,000 years ago, the population size of Homo sapiens plummeted, thanks to cold, dry climate conditions that left much of our ancestors' African homeland uninhabitable. Everyone alive today is descended from a group of people from a single region who survived this catastrophe...
...studies of the DNA of modern-day people indicate that, once upon a time, our ancestors did in fact undergo a dramatic population decline. Although scientists lack a precise timeline for the origin and near extinction of our species, we can surmise from the fossil record that our forebears arose throughout Africa shortly before 195,000 years ago. Back then the climate was mild and food was plentiful; life was good. But around 195,000 years ago, conditions began to deteriorate. The planet entered a long glacial stage known as Marine Isotope Stage 6 (MIS6) that lasted until roughly 123,000 years ago.
A detailed record of Africa's environmental conditions during glacial stage 6 does not exist, but based on more recent, better-known glacial stages, climatologists surmise that it was almost certainly cool and arid and that its deserts were probably significantly expanded relative to their modern extents. Much of the landmass would have been uninhabitable. While the planet was in the grip of this icy regime, the number of people plummeted perilously -- from more than 10,000 breeding individuals to just hundreds. Estimates of exactly when this bottleneck occurred and how small the population became vary among genetic studies, but all of them indicate that everyone alive today is descended from a small population that lived in one region of Africa sometime during this global cooling phase.
(Excerpt) Read more at scientificamerican.com ...
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To all -- please ping me to other topics which are appropriate for the GGG list. |
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Climate ping. :’)
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Total BS, mankind was down to eight people. Noah and his family
Surmise -- kind of a weak reed there, guys.
Thanks JPB, that’s gorgeous!
There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact -- Mark Twain
That’s rich, coming as it does from the atheist and socialist Mark Twain. :’P Thanks FGS.
The Scars of Evolution:"The most remarkable aspect of Todaro's discovery emerged when he examined Homo Sapiens for the 'baboon marker'. It was not there... Todaro drew one firm conclusion. 'The ancestors of man did not develop in a geographical area where they would have been in contact with the baboon. I would argue that the data we are presenting imply a non-African origin of man millions of years ago.'"
What Our Bodies Tell Us
About Human Origins
by Elaine Morgan
Tinypic has been having issues of late, d’jnotice? That’s bad, because I use it for all the logos for my smaller lists. At one point, I had to resort to a graphic to TABLE conversion for a smaller one I use a lot (the Obama face one), but I don’t like to do that, because it winds up at 100s of K.
Dude!
You rock!
There really is no evidence that an ice age happened. On the other hand, many cultures have ancient stories of floods.
Haven’t noticed any problems with tinypic. In the past some images I’ve uploaded have been scrubbed.
Haven’t noticed any problems with tinypic. In the past some images I’ve uploaded have been scrubbed.
One would think he might have had more sympathy for the scientific community® eh? Be that as it may, from some accounts he experienced an awakening in his later years and softened his criticism of The Almighty. And for that matter, maybe his progressive political tendencies as well. Dunno about that.
In any case, it's easy enough to be cynical towards God because of our lack of understanding of His MO. Been there, done that myself in an earlier life. Maybe ol' Sam knew enough of God to realize He would not smite the old reprobate for his blasphemy. After all, the planet would have very few inhabitants were He to raise His hand to every non-believer. Word would soon get around and leave the remaining occupants with no choice but to believe. NOT God's plan IMHO and generally not His style. But whadda I know???
Bush’s Fault?
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