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Author Topic:   Humans almost extinct 70,000 years ago?
Ben!
Member (Idle past 1699 days)
Posts: 1154
From: San Diego, CA
Joined: 10-14-2004


Message 1 of 4 (464303)
04-24-2008 5:54 PM


CNN.com article: http://www.cnn.com/2008/TECH/04/24/close.call.ap/index.html

Source (peer-reviewed journal) article:
http://www.ajhg.org/AJHG/fulltext/S0002-9297(08)00255-3

This discusses a lot of human origins / migration out of Africa, including information suggesting that humans almost went extinct about 70,000 years ago.

I was wondering if somebody could point me to some links / threads that might help deconstruct some of the technical methods behind this article? It's been a while since I was really "at" EvCForum, but I know people with the knowledge to help can certainly be found here!

Thanks!
Ben


Replies to this message:
 Message 2 by RAZD, posted 04-25-2008 8:20 PM Ben! has not yet responded
 Message 3 by Wounded King, posted 04-26-2008 9:18 AM Ben! has not yet responded
 Message 4 by AZPaul3, posted 04-26-2008 6:58 PM Ben! has not yet responded

    
RAZD
Member
Posts: 19756
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 5.5


Message 2 of 4 (464484)
04-25-2008 8:20 PM
Reply to: Message 1 by Ben!
04-24-2008 5:54 PM


Hey Ben.

It's been a while since I was really "at" EvCForum, but I know people with the knowledge to help can certainly be found here!

Unfortunately the ranks have dwindled (or been thinned depending on your view).

... help deconstruct some of the technical methods behind this article?

Personally, I have a lot of trouble using genetic information - as relics of the past preserved in the present - to talk about when certain changes/events/milestones occurred. To me they can talk about what happened, and the relative timing of different events, but not about absolute timescales.

Also see BBC Human Evolution, "the New Batch":

quote:
At one point, the numbers of modern humans living in the world may have dwindled to as few as 10,000 people.

The genetic data puts the likely date for this event at just before 100,000 years ago.


This is essentially the same concept of bottleneck evidence in genetics, but they are talking about very different timing. If this is the same event and one set says 70k and the other 130k ...

Enjoy.


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This message is a reply to:
 Message 1 by Ben!, posted 04-24-2008 5:54 PM Ben! has not yet responded

  
Wounded King
Member (Idle past 2172 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 3 of 4 (464518)
04-26-2008 9:18 AM
Reply to: Message 1 by Ben!
04-24-2008 5:54 PM


I think the actual source for the article must have been the National Geographic's own article, here, rather than the original AJHG paper.

From reading the paper and some of the references I can't see the support for a lot of the claims in the CNN article. Particularly I can't see anywhere in the paper where they discuss the estimated population size of 2000, wherever they reference that paper they don't do it in that context and I don't see how it can be described as noting that the study shows it. The National Geographic article on the other hand does briefly mention 'Previous studies have shown that while human populations had been quite small prior to the Late Stone Age, perhaps numbering fewer than 2,000 around 70,000 years ago...', although it doesn't give a reference.

So in fact the whole extinction thing seems to come from a totally different paper, so its a bit of a shame seeing that plastered up as the headline for this paper.

Were there any particular technical methods you were interested in? I have studied human genetics somewhat and I'd be happy to see if I can find some resources to clarify things but the paper does quite
a lot of different things so if there were specific things it might make things easier.

TTFN,

WK


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AZPaul3
Member
Posts: 3812
From: Phoenix
Joined: 11-06-2006
Member Rating: 3.0


Message 4 of 4 (464535)
04-26-2008 6:58 PM
Reply to: Message 1 by Ben!
04-24-2008 5:54 PM


Toba
Try Toba (Sumatra) which erupted about 74,000 years ago.

Super volcano about 10,000 times Mt. St. Helens.

I recall reading that human populations (from genetic studies) bottlenecked (some speculate) to less than 50 fertile females.

Will need to do some research to find the data later if I'm not too lazy.

BBC on Toba


This message is a reply to:
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