Humans nearly wiped out 70,000 years ago

Rokcet Scientist · Post by **Rokcet Scientist** » Fri Apr 25, 2008 4:30 am

CNN has a story discussing evidence found by researchers which indicates that humans came close to extinction roughly 70,000 years ago. A similar study by Stanford scientists suggests that droughts reduced the population to as few as 2,000 humans, who were scattered in small, isolated groups.

Quoting:
"'This study illustrates the extraordinary power of genetics to reveal insights into some of the key events in our species' history,' said Spencer Wells, National Geographic Society explorer in residence. 'Tiny bands of early humans, forced apart by harsh environmental conditions, coming back from the brink to reunite and populate the world. Truly an epic drama, written in our DNA.'"

http://edition.cnn.com/2008/TECH/04/24/ ... index.html

Phew!
We nearly bought it there!

CShark · Post by **CShark** » Fri Apr 25, 2008 8:15 am

Sounds like something I read in Genesis...

Beagle · Post by **Beagle** » Fri Apr 25, 2008 8:37 am

We were yacking about a report on this yesterday RS. This one is better reported, as it says humans were in small isolated groups during this time. An earlier report said that two separate species of man were in Africa.

Glad you found this one.

Post by **Minimalist** » Fri Apr 25, 2008 9:27 am

Still faces the problem of why there is not a similar "bottleneck" among other species which need food and water to survive.

Beagle · Post by **Beagle** » Fri Apr 25, 2008 11:43 am

And that's the kicker. They seem very certain that a "bottleneck" occurred. So we may get a number of theories. But the other animals are exposed to the same conditions, and no bottleneck exists with them. They will have to come up with a theory that takes that into account.

Post by **Minimalist** » Fri Apr 25, 2008 12:13 pm

Yes...or, as Clubs do most often, simply say "that's not our field" and punt.

Rokcet Scientist · Post by **Rokcet Scientist** » Sat Apr 26, 2008 4:18 am

Beagle wrote:And that's the kicker. They seem very certain that a "bottleneck" occurred. So we may get a number of theories. But the other animals are exposed to the same conditions, and no bottleneck exists with them. They will have to come up with a theory that takes that into account.

Maybe an extra complicating factor, like a contagious disease (malaria, TB, HIV/AIDS, etc. etc.) whittled down their numbers and the drought nearly finished them off?

Beagle · Post by **Beagle** » Sat Apr 26, 2008 5:12 am

Rokcet Scientist wrote:
Beagle wrote:And that's the kicker. They seem very certain that a "bottleneck" occurred. So we may get a number of theories. But the other animals are exposed to the same conditions, and no bottleneck exists with them. They will have to come up with a theory that takes that into account.
Maybe an extra complicating factor, like a contagious disease (malaria, TB, HIV/AIDS, etc. etc.) whittled down their numbers and the drought nearly finished them off?

Right now RS, you're guess is as good as any scientist out there. I don't know. Geneticists say a bottleneck happened about 70,000 ya. There is no reason not to believe them but their has been no good explanation. Toba has been thrown out. This theory has the same problems. Who knows?

Post by **Minimalist** » Sat Apr 26, 2008 8:51 am

Maybe the geneticists are simply trying to make their particular science do too much?

Beagle · Post by **Beagle** » Sat Apr 26, 2008 9:20 am

Minimalist wrote:Maybe the geneticists are simply trying to make their particular science do too much?

Genetics is a young science, and I think they started off with all the answers, but now they're realizing that there is a lot more to the science.

The entire Neanderthal debacle has been based on mDNA, which now has little value alongside nuclear DNA findings.

Post by **Minimalist** » Sat Apr 26, 2008 11:38 am

They wouldn't be the first group to aim too high.

Rokcet Scientist · Post by **Rokcet Scientist** » Sun Apr 27, 2008 10:43 am

As long as that supposed 70,000 years BP bottleneck is not corroborated by independent evidence – which would be the scientific approach, it is of course just a theory.

Beagle · Post by **Beagle** » Tue May 06, 2008 11:51 am

http://johnhawks.net/weblog/reviews/gen ... -2008.html

As you can see, these data allow a direct test of the hypothesis of a 70,000-year-old bottleneck in Africa, and they refute the hypothesis. The new data allow a powerful model of ancient African population size to be built, one that comes together with archaeological data to give us a really interesting picture of the early evolution of "modern" humans. The model can be tested with new, massive sets of information from single nucleotide polymorphisms, as well as a more detailed chronology of late MSA sites.

John Hawks blogs on this "bottleneck" hypothesis. He obviously disagrees with it. This is a long and maybe arduous blog, and I have quoted his conclusion.

Digit · Post by **Digit** » Tue May 06, 2008 12:29 pm

That guy's getting to be a real pain in the neck for the club isn't he?

Beagle · Post by **Beagle** » Tue May 06, 2008 12:47 pm

Hi Dig. Hawks is actually kinda in the Club, but he was brought up as a grad student by Wolpoff. In his heart he is a multi-regionalists, but feels that there is definate African introgression of some genes.

I like him because he blogs on most of these papers that have a new hypothesis. He's pretty tough on them.