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Flores Man: a newly discovered small human species
This thread is a continuation of the earlier discussion about homo florsiensis, the small humanoid species that was recently discovered on the Indonesian island of Flores.
quote:When a new fossil is found it is often claimed that it will rewrite the anthropological textbooks. But in the case of an astonishing new discovery from Indonesia, this claim is fully justified.
That phylogenetic tree threw me for a moment, until I realized that it was trying to show geographic distribution as well. So it looks like the name Homo erectus is now applied only to the Asian populations. Is this generally accepted, and is H. ergaster the African population previously assigned to H. erectus?
I guess a DNA sample would be a bit too much to hope for...
[ 02 November 2004: Message edited by: Mike Keenan ]
quote:By 1.9 million years ago, another lineage of the genus Homo emerged in Africa. This species was Homo ergaster. Traditionally, scientists have referred to this species as Homo erectus and linked this species name with a proliferation of populations across Africa, Europe, and Asia. Yet, since the first discoveries of Homo erectus, it had been noted that there were differences between the early populations of "Homo erectus" in Africa, and the later populations of Europe, Africa and Asia. Many researchers now separate the two into distinct species Homo ergaster for early African "Homo erectus", and Homo erectus for later populations mainly in Asia. Since modern humans share the same differences as H. ergaster with the Asian H. erectus, scientist consider H. ergaster as the probable ancestor of later Homo populations. H. ergaster had a rounded cranium and a prominent browridge. Its teeth were much reduced in size, especially when compared to Australopithecus. Several features that distinguish H. ergaster from H. erectus are thinner bones of the skull and the lack of an obvious sulcus, or depression, just behind the browridge.
It's the sort of incredibly minor difference that leads to 'lump/split' debates among biologists of all stripes. I'd bet anything that ergaster could breed successfully with erectus, and there likely wouldn't be much to distinguish them visually (perhaps even less than a Neanderthal from a modern sapiens), but there you have it.
Edit: Note that this 'map', like all maps, is an approximation, as it doesn't (and can't actually easily show) Neanderthals and late Javan erectus (not just -Flores Man') coexisting with sapiens.
quote:Originally posted by Mike Keenan: That phylogenetic tree threw me for a moment, until I realized that it was trying to show geographic distribution as well.
Yeah, for a second it looked like it was showing we're all descended from moose antlers. [img]wink.gif" border="0[/img]
I think I've read that DNA extraction from fossils is difficult to impossible.
Generally that's true, but under exceptional circumstances it's possible. Apparently they managed to get their hands on mitochondrial DNA from H. neanderthalensis, anyway.
[ 02 November 2004: Message edited by: Mike Keenan ]
So, is it agreed by anthropologists that Neanderthals and Homo Sapien Sapien evolved from different species of homo? That we're more than "once removed"? When did they find the DNA?! That's very cool.
I heard an Ideas program last year and the scientists had found a "gold mine" of copperlite, fossilized poop, which they think might be from Neanderthals, and they were searching for DNA in that, and all of the other great info that can be gleaned from poop.
Did y'all hear about the ape-type creature they found that's from 13 million years ago in Spain? They think it COULD be a common ancestor.
I don't know if there's any really solid consensus, but certainly the idea has been around for quite a while. Apparently one of the Leakeys thought that H. neanderthalsis evolved from H. erectus (which included H. ergaster when I took Human Evolution) while H. sapiens evolved directly from H. habilis. That part seems not to have caught on though; habilis isn't even shown on this new phylogeny.
Thing is, phylogeny has its limits. Even though DNA has been found, it's extremely rare, so we don't have much opportunity to compare various ancient and modern DNA sequences. I think the treatment of H. neanderthalsis as a separate species, rather than a race of H. sapiens, only really caught on fairly recently, and I think the discovery of mitochondrial DNA from neanderthalsis was a big factor. Unfortunately we seldom have the opportunity to make such direct comparisons, so there's a lot of guesswork in constructing a family tree like this.
[ 26 November 2004: Message edited by: Mike Keenan ]
Meanwhile, an older ancestor strides out of the family closet Link here:
quote: A team of U.S. and Ethiopian scientists has discovered the fossilized remains of what they believe is humankind's first walking ancestor, a hominid that lived in the wooded grasslands of the Horn of Africa nearly 4 million years ago.
The bones were discovered in February at a new site called Mille, in the northeastern Afar region of Ethiopia, said Bruce Latimer, director of the Cleveland Museum of Natural History in the U.S. state of Ohio. They are estimated to be 3.8-4 million years old...
...Paleontologists previously discovered in Ethiopia the remains of Ardipithecus ramidus, a transitional creature with significant ape characteristics dating back as many as 4.5 million years. There is some dispute over whether it walked upright on two legs, Latimer and Aillo said.
Scientists know little about A. ramidus. A few skeletal fragments suggest it was even smaller than Australopithecus afarensis, the 3.2 million-year-old species widely known by the nearly complete "Lucy" fossil, which measures about 1.2 meters (4 feet) tall.
Scientists are yet to classify the new find, which they believe falls between A. ramidus and A. afarensis...
Huh. My first reaction was "Hey, but Lucy wasn't bipedal," how could this guy be when it's almost 1 million years older? But according to Wikipedia:
quote:The existence of Australopithecus seems to have put firmly to rest the theory that human-like intelligence evolved first and bipedalism followed. Australopithecus had a brain case not significantly larger than a modern chimpanzee. Yet Australopithecus was certainly bipedal, suggesting it was bipedalism which made human-like intelligence possible and not the other way around.
It was indeed a new species closely related to humans after all, says a new study (link):
quote:The tiny skeletal remains of human "Hobbits" found on an Indonesian island belong to a completely new branch of our family tree, a study has found.
The finds caused a sensation when they were announced to the world in 2004.
But some researchers argued the bones belonged to a modern human with a combination of small stature and a brain disorder called microcephaly.
That claim is rejected by the latest study, which compares the tiny people with modern microcephalics.
In the new study, Dean Falk, of Florida State University, and her colleagues say the remains are those of a completely separate human species: Homo floresiensis.
They have published their findings in Proceedings of the National Academy of Sciences.
quote:"People refused to believe that someone with that small of a brain could make the tools," said Professor Falk.
She said the Hobbit brain was nothing like that of a microcephalic and was advanced in a way that is different from living humans.
A previous study of LB1's endocast revealed that large parts of the frontal lobe and other anatomical features were consistent with higher cognitive processes.
"LB1 has a highly evolved brain," said Professor Falk. "It didn't get bigger, it got rewired and reorganised, and that's very interesting."
Background: Nature.com special on Flores man.
The rest.Dr. Peter Brown, who led the team that excavated the site on Flores, interviewed by Bob McDonald on CBC's Quirks & Quarks (mp3 format).
And finally, a proposed "family tree", again courtesy of Nature magazine:
[ 02 November 2004: Message edited by: Albireo ]
I guess a DNA sample would be a bit too much to hope for...
[ 02 November 2004: Message edited by: Mike Keenan ]
Another phylogenetic tree
From the H.ergaster link:
It's the sort of incredibly minor difference that leads to 'lump/split' debates among biologists of all stripes. I'd bet anything that ergaster could breed successfully with erectus, and there likely wouldn't be much to distinguish them visually (perhaps even less than a Neanderthal from a modern sapiens), but there you have it.
Edit: Note that this 'map', like all maps, is an approximation, as it doesn't (and can't actually easily show) Neanderthals and late Javan erectus (not just -Flores Man') coexisting with sapiens.
[ 02 November 2004: Message edited by: aRoused ]
Yeah, for a second it looked like it was showing we're all descended from moose antlers. [img]wink.gif" border="0[/img]
I think I've read that DNA extraction from fossils is difficult to impossible.
[ 02 November 2004: Message edited by: Mike Keenan ]
I heard an Ideas program last year and the scientists had found a "gold mine" of copperlite, fossilized poop, which they think might be from Neanderthals, and they were searching for DNA in that, and all of the other great info that can be gleaned from poop.
Did y'all hear about the ape-type creature they found that's from 13 million years ago in Spain? They think it COULD be a common ancestor.
Thing is, phylogeny has its limits. Even though DNA has been found, it's extremely rare, so we don't have much opportunity to compare various ancient and modern DNA sequences. I think the treatment of H. neanderthalsis as a separate species, rather than a race of H. sapiens, only really caught on fairly recently, and I think the discovery of mitochondrial DNA from neanderthalsis was a big factor. Unfortunately we seldom have the opportunity to make such direct comparisons, so there's a lot of guesswork in constructing a family tree like this.
[ 26 November 2004: Message edited by: Mike Keenan ]
Younger one has much nicer teeth
[Less than stellar preceding babble thread is here.]
[ 29 January 2007: Message edited by: Albireo ]