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Author Topic:   Neandethal Bones dated 2.5 mya
bluescat48
Member (Idle past 4210 days)
Posts: 2347
From: United States
Joined: 10-06-2007


Message 16 of 20 (456732)
02-19-2008 7:36 PM
Reply to: Message 9 by RAZD
02-19-2008 4:01 PM


RAZD
Like the National Enquirer? (cue Men In Black theme). The oldest official record I could find of neander fossils was ~200,000 years ago.
This site keeps fairly up to date with new discoveries and most current thinking on relationships, and has hot links on each branch for further information
Same here all I could find in all my refs was ~200,000 years

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RAZD
Member (Idle past 1425 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 17 of 20 (456740)
02-19-2008 8:43 PM
Reply to: Message 16 by bluescat48
02-19-2008 7:36 PM


MRCA'a and genetic clocks ...
The only reference I found to anything older was a genetic article using molecular clock to put the date of divergence of H. neander DNA from H. sapiens DNA at over 300K years, but I don't trust the dates of those clocks at that kind of projection.
Just a moment...
PNAS Vol. 96, Issue 10, 5581-5585, May 11, 1999
quote:
The date of divergence between the mtDNAs of the Neandertal and contemporary humans is estimated to 465,000 years before the present, with confidence limits of 317,000 and 741,000 years.
Dates of Divergences. For the estimation of the ages of MRCAs of different groups of mtDNAs, the observed nucleotide differences were corrected for multiple substitutions by using the Tamura-Nei algorithm (17). The resulting genetic distances and the estimated age of the modern human-chimpanzee split of 4-5 million years (22, 23) were used to calculate the substitution rate of 0.94 10-7 substitutions per site per year per lineage with 5.92 10-8 and 1.38 10-7 as the lower and upper confidence limits. These estimates are in reasonable agreement with previous rate estimations for the mtDNA control region (32, 33). Using these rates, the age of the MRCA of the Neandertal and modern human mtDNAs was estimated to be 465,000 years, with confidence limits of 317,000 and 741,000 years. This age is significantly older than that of the MRCA of modern human mtDNAs, which, by the same procedure, was determined to be 163,000 years, with 111,000 and 260,000 years as confidence limits. Finally, the age of the MRCA of the mtDNAs of the seven chimpanzees and the two bonobos was calculated as 2,844,000 years (confidence limits: 1,940,000 and 4,534,000 years).
Of course that could also mean that there were one or two species and other members of the Homo clade between the common ancestor pool and either H. neander or H. sapiens, not that each species necessarily extends back that far -- for instance they imply that Homo sapiens starts at 163K years ago -- while actual fossil information pushes that to 200K:
Ethiopia is top choice for cradle of Homo sapiens : Nature News
quote:
Radioactive dating finds that fossil skulls are 195,000 years old.
Two Ethiopian fossils have been crowned as the oldest known members of our species. An estimated 195,000 years old, the pair were witness to the earliest days of H. sapiens .
To read this story in full you will need to login or make a payment (see right).
Taking this genetic information as an indication of relative dating (which is as far as I trust it, but where I think it is valid) this means that the divergence of Neander ancestors from H. sapiens ancestor occurred after hominids diverged from chimpanzees, but before H. sapiens ancestors diverged from Homo heidelbergensis
ie - that we are at least cousins once removed from H. neander relations rather than first cousins.
It would also mean that this diagram
http://www.handprint.com/LS/ANC/evol.html
(Last revised 08.17.2007 ” © 2007 Bruce MacEvoy)
Is more accurate than the one I posted earlier
Anthropology | Smithsonian National Museum of Natural History
(Last revised unknown)
... in this area. It also goes back to almost 400K for H. neander, but then it says the reason is:
quote:
” Time spans for modern humans, Neanderthals and archaic H. sapiens (H. heidelbergensis) have been extended back beyond accepted fossil limits to accommodate recent genetic evidence that the divergence between the Neanderthal and human lines occurred around 500,000 years ago.
Sorry, but I trust hard fossil dates much more than extrapolated genetic ones. The tree by the Smithsonian Institute appears to be based on fossils, not genetic "dates" ... which gets us back to ~200K for H. neander fossils .... sigh.
Enjoy.
Edited by RAZD, : consistent nomenclature

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This message is a reply to:
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Dr Adequate
Member (Idle past 304 days)
Posts: 16113
Joined: 07-20-2006


Message 18 of 20 (456911)
02-20-2008 4:58 PM
Reply to: Message 1 by Riptowtan
02-19-2008 1:27 PM


I think I've figured it out. The civics teacher hasn't learned his lines properly.
I think what he's trying to repeat is the creationist bibble about the skull KNM-ER 1470. This is not a Neanderthal, it is Homo rudolphensis (or Homo habilis, or Australopithicus rudolphensis --- intemediate forms are kinda hard to classify).
When it was found, it was dated at 2.9 mya. At the time, this was a puzzle, because that made it older than any known australopithecine. This is, of course, why creationists started babbling about it, because, as we know, every unsolved puzzle in biology is a proof that EVIL-UTION IS A LIE!!!
Since then, older australopithecines have been found (older than 3 mya, see the graph below) and the original date of KNM-ER 1470 has also been corrected:
The specimen was originally thought to be around 2.9 myr old, due to an inaccurate dating of 2.6 myr for the KBS volcanic tuff located above it. This inaccuracy was caused by contamination of older material, and the tuff is now know to be much younger. The specimen is now thought to date to approximately 1.8 myr ... Though this date is now generally accepted for the specimen, the geologists who orignally dated the KBS tuff continue to argue for a later date for the specimen. While the admit the dating of the volcanic tuff was inaccurate, F. Fitch and colleagues claim that the depth of the specimen beneath the tuff shows a much earlier age, dating to around 2.4 myr.

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websnarf
Junior Member (Idle past 5185 days)
Posts: 9
From: San Jose, CA, USA
Joined: 11-30-2009


Message 19 of 20 (537679)
11-30-2009 8:53 AM
Reply to: Message 1 by Riptowtan
02-19-2008 1:27 PM


A 2.5 million year old Neanderthal? I think not ...
Neanderthals first appeared about 200k years. Their most immediate ancestors were *probably* Homo heidelbergensis whose earliest appearance was 800k years ago. A genetic estimate shows that Homo sapiens and Homo neanderthalensis diverged from their common ancestor (possibly Homo antecessor, whatever that turns out to be) about 500-600k years ago. So before that, there's no way that there could be a Homo neanderthalensis.
At 2.5 million years ago, you have a mix Australopithecines, the earliest Homo habilis and maybe some Paranthropuses but they were all hanging around Africa. As far as we know the first of our ancestors did not appear in Europe in any way shape or form before 1.8 million years ago (that was Homo georgicus, which some think of as just an early Homo erectus or Homo ergaster.)
In short, your teacher is dead wrong.

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websnarf
Junior Member (Idle past 5185 days)
Posts: 9
From: San Jose, CA, USA
Joined: 11-30-2009


Message 20 of 20 (537680)
11-30-2009 8:56 AM
Reply to: Message 18 by Dr Adequate
02-20-2008 4:58 PM


The graph you show is useful for figuring out brain size evolution, but unfortunately it is limited to fossils that included a skull.
Basically it means we actually have more fossils than that graph shows.

This message is a reply to:
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