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Author Topic:   Two New Hominid Finds (re: Time overlap of H. habilis and H. erectus)
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 1 of 10 (415363)
08-09-2007 5:43 PM


We have a couple of takes on this:
A Kenyan researcher has discovered two fossils that are likely to stir fresh debate on evolution of man.
quote:
A Kenyan researcher has discovered two fossils that are likely to stir fresh debate on evolution of man.
Mr Frederick Manthi, a researcher with the National Museums of Kenya, discovered the fossils dating more than a million years at Illeret location of Marsabit district, East of Lake Turkana.
Yesterday, the National Museums of Kenya in a letter inviting the media for a press conference to announce the new discoveries said, the fossils that Mr Manthi discovered include an exquisitely preserved skull of Homo Erectus and an upper jaw bone of Homo Habilis.
The former according to the museums dates 1.55 million years while the latter is 1.44 million years old.
Note this makes the most recent Homo habilis more recent than the oldest Homo erectus ... and their fossil records now overlap.
News | The Scotsman
quote:
IT IS the iconic image of human evolution: the gradual transformation over millions of years of an ape-like creature into a tall, modern-day human.
But the startling discovery of two fossils in Africa has cast serious doubt on this traditional picture, as they prove an early form of human called Homo habilis did not evolve into Homo erectus, as previously believed.
This of course is not at all what the current picture of human evolution shows. Where do journalists get off publishing such poppycock ... especially when later in the article it says:
quote:
Professor Fred Spoor, an anatomist from University College, London and lead author of the paper, said human evolution was much more complex than once thought. The classic single line from ape to human is something we already knew is not the case," he said.
"But we know a bit more about the process of human evolution [as a result of this research]. It is very much like the evolutionary path of any other animal, with lots of side branches and not a single straight line that you see in cartoons."
So they interview the lead author who clearly states the current thinking and they STILL get it wrong!
Just as an aside the current human evolutionary tree can be seen on
http://www.handprint.com/LS/ANC/evol.html
quote:
Hominds seem remarkable for the sheer diversity of the fossil record. No other mammal has spread over as large a geographic and ecological range, and evolved so many new forms of behavior, within just a few million years.
As a further complication, fossils document the coexistence of different hominid species over the last 2 million years ” sometimes in adjacent or overlapping geographic regions. Exactly how these different species coexisted or interacted is unclear.
White numbers inside the vertical bars indicate the approximate count of distinct individuals in each species from whom fossil remains survive.
This finds adds two individuals to the count, and they add another overlap, coexistence, between species. But the evolution of Homo sapiens has been considered descending from Homo ergaster and NOT from Homo habilis for some time (the above graphic is two years old).
{abe} Note that many of the branches in this graphic are from the middle of other species -- because speciation can branch from existing species. So even IF there were a linear descent of sapiens from habilis it wouldn't have to be from the last habilis. {/abe}
Enjoy.
Edited by RAZD, : abe
Edited by Adminnemooseus, : Added "(re: Time overlap of H. habilis and H. erectus)" part to topic title.

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Replies to this message:
 Message 3 by Archer Opteryx, posted 08-09-2007 9:02 PM RAZD has replied
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AdminNem
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Message 2 of 10 (415367)
08-09-2007 6:33 PM


Thread moved here from the Proposed New Topics forum.

  
Archer Opteryx
Member (Idle past 3597 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 3 of 10 (415386)
08-09-2007 9:02 PM
Reply to: Message 1 by RAZD
08-09-2007 5:43 PM


Thanks for posting this, RAZD. Fascinating.
You inspired me to bone up a bit on hominid fossils. Here's a good first stop for us non-specialists:
Smithsonian Institute: Hall of Human Ancestors
The text is well written and the 3D graphics enable examination of specimens in the round. (You need QuickTime.) The site is still in progress, though. Some species still lack profile pages.
Here are their discussions of the early human species now in the news.

Homo habilus
Homo erectus

The posted material gives some idea what a jolt it is that these creatures were contemporaries.
How do you see this discovery shuffling the usual suspects? Did Homo rudolfensis just became the prime suspect in the Homo ergaster paternity suit, or is habilus in it as much as ever?

Homo rudolfensis
Homo ergaster

____
Edited by Archer Opterix, : html.
Edited by Archer Opterix, : tinkering.

Archer
All species are transitional.

This message is a reply to:
 Message 1 by RAZD, posted 08-09-2007 5:43 PM RAZD has replied

Replies to this message:
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Minnemooseus
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Posts: 3941
From: Duluth, Minnesota, U.S. (West end of Lake Superior)
Joined: 11-11-2001
Member Rating: 10.0


Message 4 of 10 (415395)
08-09-2007 10:15 PM
Reply to: Message 1 by RAZD
08-09-2007 5:43 PM


What Terry at Terry's Talk Origins thinks
See here.
Terry says:
The funniest quote there is "This is not questioning the idea at all of evolution; it is refining some of the specific points," Anton said. "This is a great example of what science does and religion doesn't do. It's a continous self-testing process."
So the Old Earth Evolutionists are wrong again, and that is spun into a GOOD thing?
LOL!
Moose

This message is a reply to:
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RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 5 of 10 (415396)
08-09-2007 10:41 PM
Reply to: Message 3 by Archer Opteryx
08-09-2007 9:02 PM


Smithsonian Institute: Hall of Human Ancestors
The text is well written and the 3D graphics enable you to examine specimens in the round. The site is still in progress, though, so some species still lack profile pages.
Yes I have their pages bookmarked too. They keep adding material and revising to keep as up to date as possible, so it is good in that regard too.
How do you see this discovery shuffling the usual suspects? Did Homo rudolfensis just became the prime suspect in the Homo ergaster paternity suit, or is habilus in it as much as ever?
The handprint site (my link above) has it as rudolfensis, while the Smithsonian tree has it as habilis or rudolfensis:
http://www.mnh.si.edu/anthro/humanorigins/ha/a_tree.html
quote:
A phylogenetic tree is a graphical means to depict the evolutionary relationships of a group of organisms. The phylogenetic tree below shows one reconstruction of the relationships among early human species, as we best know them today. It is a clickable image map. To go to a species page, click on the bar below the species name, or you can choose from the text links below. The question marks in red signify debated phylogenetic (ancestor/descendent) relationships of early humans. Click on these to view a page detailing the debate.

See the website for the hypertext linked version of the graphic.
Their page on the debated phylogenetic relationships for Homo ergaster talks of this specific debate (which precedes these finds):
http://www.mnh.si.edu/anthro/humanorigins/ha/habdebate.html
quote:
Originally, both were assigned to the species Homo habilis, with ER 1470 thought of as male and the smaller ER 1813 a female in a strongly dimorphic species. However, the anatomies of the two skulls differ considerably.
One debate in paleoanthropology today is whether or not ER 1470, and several other fossils previously identified as H. habilis, should be grouped into a new species, Homo rudolfensis. This classification would acknowledge that ER 1470 and the other members of Homo rudolfensis differ more from Homo habilis, sensu stricto ("in the strict sense," meaning: as originally defined), than could possibly be accounted for by variation within a population or between sexes. This would place two species of the genus Homo in Africa during the same time period in addition to two members of the genus Paranthropus, and, possibly, late surviving members of the species Australopithecus africanus. Far more complicated than the original neat, linear model.
Certainly it is logical that there were many subpopulations of hominids moving into new ecological areas, and this could cause some speciation events. When you read Mayr on peripheral isolates leading to speciation you get the feeling that there could have been a lot of experimentation going on back then with a number of different ecologies being explored (though Mayr lumped most hominids into one or two species).
Such peripheral isolates could evolve into new species while the main population still carried on, so yes it could go either way. This of course brings up the question of rates of change in new ecological situations compared to old ones (faster? same?). One of the keys here is the difference in diet noted in the article, as that is a clue on the difference in ecologies between the two species -- if we can get the same info on rudolfensis and ergaster that would be a further clue (but there are much fewer specimens yet). Think ecological and behavioral isolation rather than just geographic isolation.
My feeling is that the ancestral tree will get more branches as we get more fossil finds. Species will continue after branching (if we evolved from x why are x still around ...) and this may make a final answer messy.
Enjoy.

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we are limited in our ability to understand
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This message is a reply to:
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Replies to this message:
 Message 6 by Dr Jack, posted 08-10-2007 6:26 AM RAZD has replied

  
Dr Jack
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Posts: 3514
From: Immigrant in the land of Deutsch
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Member Rating: 8.7


Message 6 of 10 (415447)
08-10-2007 6:26 AM
Reply to: Message 5 by RAZD
08-09-2007 10:41 PM


Homo rudolfensis is known from only one skull I believe, and a badly damaged one at that. And a recent reconstruction suggests that the skull shows considerable differences to earlier reconstructions.
Link to Abstract
Popular Science version

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 Message 5 by RAZD, posted 08-09-2007 10:41 PM RAZD has replied

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Archer Opteryx
Member (Idle past 3597 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 7 of 10 (415457)
08-10-2007 7:46 AM
Reply to: Message 6 by Dr Jack
08-10-2007 6:26 AM


rudofensis
Thanks, Mr Jack.
Here's a link to a student site summarizing the fossil evidence for rudolfensis:
http://www.msu.edu/~heslipst/contents/ANP440/rudolfensis.htm
Looks like just the type skull and various bits. You have to wonder if this one won't eventually be considered a variant of habilus.
____
Edited by Archer Opterix, : typo repair.
Edited by Archer Opterix, : brev.

Archer
All species are transitional.

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 Message 6 by Dr Jack, posted 08-10-2007 6:26 AM Dr Jack has not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 8 of 10 (415481)
08-10-2007 11:17 AM
Reply to: Message 6 by Dr Jack
08-10-2007 6:26 AM


Thanks Mr Jack.
Your abstract discusses fossil Stw 53 from Sterkfontein, S.Africa (Raymond Dart country), while the other concerns KNM-ER 1470 (Koobi Fora, Kenya) ... which is considered the type specimen for Homo rudolfensis.
quote:
Bromage also found that the reconstruction of Leakey's famous skull, called KNM-ER 1470, didn't agree with the pattern of facial development his analysis predicted.
"I discovered that the plan of the face, which is common to all mammals, was way off in the reconstruction of this skull," Bromage told Cosmos Online. "Also it was odd that the reconstructed brain size of this skull was always [anomalous] with respect to all other early humans of that time period."
On repositioning the face of H.rudolfensis according to his model, Bromage found that it was protruding - more like an ape. His team also found that the brain was much smaller than previously estimated and more in line with early human contemporaries.
While it is always possible to update reconstructions based on new information, it is also true that this method here is new and relatively untested. The computer model will only predict certain changes, and we see from evo-devo that there can be environmental effects of development that can account for different kinds of changes.
But yes, H.rudolfensis has a very small set of fossils to represent it at this time.
Thanks.

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we are limited in our ability to understand
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RebelAAmericanOZen[Deist
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This message is a reply to:
 Message 6 by Dr Jack, posted 08-10-2007 6:26 AM Dr Jack has replied

Replies to this message:
 Message 9 by Dr Jack, posted 08-10-2007 11:37 AM RAZD has replied

  
Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 9 of 10 (415483)
08-10-2007 11:37 AM
Reply to: Message 8 by RAZD
08-10-2007 11:17 AM


Sorry, wrong link
The actual abstract I was looking for
My bad.

This message is a reply to:
 Message 8 by RAZD, posted 08-10-2007 11:17 AM RAZD has replied

Replies to this message:
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RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 10 of 10 (415502)
08-10-2007 1:40 PM
Reply to: Message 9 by Dr Jack
08-10-2007 11:37 AM


Thanks
quote:
Results: The face is found to be relatively prognathic and, according to previously published analyses, the cranial capacity is significantly lower and within the range of other Late Pliocene Homo. KNM-ER 1470 was once an outlier in most mensurational investigations, now it can be properly re-measured and interpreted with other earliest humans.
I notice they do not make any judgment of which species it should represent, leaving that to the taxonomists to see if they put it back in habilis or put it in ergaster -- or keep it as rudolfensis due to the other differences. And we still have the issue of diet.
It looks like this came out in March this year -- any response from the Leakey camp?
Enjoy.

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we are limited in our ability to understand
by our ability to understand
RebelAAmericanOZen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

This message is a reply to:
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