Scientists Find Skull of Human Ancestor

Associated Press ^ | Sat 25 March | DAGNACHEW TEKLU

[Alter Kaker]

Scientists in northeastern Ethiopia said Saturday that they have discovered the skull of a small human ancestor that could be a missing link between the extinct Homo erectus and modern man.

The hominid cranium — found in two pieces and believed to be between 500,000 and 250,000 years old — "comes from a very significant period and is very close to the appearance of the anatomically modern human," said Sileshi Semaw, director of the Gona Paleoanthropological Research Project in Ethiopia.

Archaeologists found the early human cranium five weeks ago at Gawis in Ethiopia's northeastern Afar region, Sileshi said.

Several stone tools and fossilized animals including two types of pigs, zebras, elephants, antelopes, cats, and rodents were also found at the site.

Sileshi, an Ethiopian paleoanthropologist based at Indiana University, said most fossil hominids are found in pieces but the near-complete skull — a rare find — provided a wealth of information.

"The Gawis cranium provides us with the opportunity to look at the face of one of our ancestors," the archaeology project said in a statement.

Homo erectus, which many believe was an ancestor of modern Homo sapiens, is thought to have died out 100,000 to 200,000 years ago.

The cranium dates to a time about which little is known — the transition from African Homo erectus to modern humans. The fossil record from Africa for this period is sparse and most of the specimens poorly dated, project archaeologists said.

The face and cranium of the fossil are recognizably different from those of modern humans, but bear unmistakable anatomical evidence that it belongs to the modern human's ancestry, Sileshi said.

"A good fossil provides anatomical evidence that allows us to refine our understanding of evolution. A great fossil forces us to re-examine our views of human origins. I believe the Gawis cranium is a great fossil," said Scott Simpson, a project paleontologist from Case Western Reserve University School of Medicine at Cleveland, Ohio.

Scientists conducting surveys in the Gawis River drainage basin found the skull in a small gully, the project statement said.

"This is really exciting because it joins a limited number of fossils which appear to be evolutionary between Homo erectus and our own species Homo sapiens," said Eric Delson, a paleoanthropologist at Lehman College of the City University of New York, who was not involved in the discovery but has followed the project.

Homo erectus left Africa about 2 million years ago and spread across Asia from Georgia in the Caucasus to China and Indonesia. It first appeared in Africa between 1 million and 2 million years ago.

Between 1 million and perhaps 200,000 years ago, one or more species existed in Africa that gave rise to the earliest members of our own species Homo sapiens — between 150,000 and 200,000 years ago.

Delson said the fossil found in Ethiopia "might represent a population broadly ancestral to modern humans or it might prove to be one of several side branches which died out without living descendants."

In this photo released by the Stone Age Institute, Gona Project member Ashmed Humet, holds the newly discovered skull of a small human ancestor on Feb. 16, 2006 in Gona, Ethiopia. Scientists in northeastern Ethiopia said Saturday March 25, 2006 that they have discovered the skull of a small human ancestor that could be a missing link between the extinct Homo erectus and modern man. The hominid cranium, found in two pieces and believed to be between 500,000 and 250,000 years old, 'comes from a very significant period and is very close to the appearance of the anatomically modern human,' said Sileshi Semaw, director of the Gona Paleoanthropological Research Project in Ethiopia. (AP Photo/Stone Age Institute, Sileshi Semaw, HO) MANDATORY CREDIT

[PatrickHenry]

Thanks, but we had a thread on this topic a few days ago: Skull discovery could fill origins gap.

[HankReardon]

Yet another article told with the premise that evolution is a proven fact. What organ did animals have before the eye went through it's hundreds of mutations to attain present form?

A real question, but I doubt if I get any real answers.

[Alter Kaker]

Yet another article told with the premise that evolution is a proven fact. What organ did animals have before the eye went through it's hundreds of mutations to attain present form?

Non sequitur.

Evolution of the Eye:

When evolution skeptics want to attack Darwin's theory, they often point to the human eye. How could something so complex, they argue, have developed through random mutations and natural selection, even over millions of years?

If evolution occurs through gradations, the critics say, how could it have created the separate parts of the eye -- the lens, the retina, the pupil, and so forth -- since none of these structures by themselves would make vision possible? In other words, what good is five percent of an eye?

Darwin acknowledged from the start that the eye would be a difficult case for his new theory to explain. Difficult, but not impossible. Scientists have come up with scenarios through which the first eye-like structure, a light-sensitive pigmented spot on the skin, could have gone through changes and complexities to form the human eye, with its many parts and astounding abilities.

Through natural selection, different types of eyes have emerged in evolutionary history -- and the human eye isn't even the best one, from some standpoints. Because blood vessels run across the surface of the retina instead of beneath it, it's easy for the vessels to proliferate or leak and impair vision. So, the evolution theorists say, the anti-evolution argument that life was created by an "intelligent designer" doesn't hold water: If God or some other omnipotent force was responsible for the human eye, it was something of a botched design.

Biologists use the range of less complex light sensitive structures that exist in living species today to hypothesize the various evolutionary stages eyes may have gone through.

Here's how some scientists think some eyes may have evolved: The simple light-sensitive spot on the skin of some ancestral creature gave it some tiny survival advantage, perhaps allowing it to evade a predator. Random changes then created a depression in the light-sensitive patch, a deepening pit that made "vision" a little sharper. At the same time, the pit's opening gradually narrowed, so light entered through a small aperture, like a pinhole camera.

Every change had to confer a survival advantage, no matter how slight. Eventually, the light-sensitive spot evolved into a retina, the layer of cells and pigment at the back of the human eye. Over time a lens formed at the front of the eye. It could have arisen as a double-layered transparent tissue containing increasing amounts of liquid that gave it the convex curvature of the human eye.

In fact, eyes corresponding to every stage in this sequence have been found in existing living species. The existence of this range of less complex light-sensitive structures supports scientists' hypotheses about how complex eyes like ours could evolve. The first animals with anything resembling an eye lived about 550 million years ago. And, according to one scientist's calculations, only 364,000 years would have been needed for a camera-like eye to evolve from a light-sensitive patch.

Source: A PBS basic primer.

[HankReardon]

Ah yes! The light sensitive patch of skin! And the light sensitive patch was what before it was a light sensitive patch of skin? No need for eye sockets before you have eyes, especially before you have light sensitive patches.

Then we move any to the very intricate human cell that could not function if any of it's too numerous components were absent, waiting for the mutating opportunity.

have an open mind, afterall, we are not liberals.

Evolutionists should give it up, no need to for Truth.

[Alter Kaker]

The light sensitive patch of skin!

Yes, which a number of organisms currently possess.

And the light sensitive patch was what before it was a light sensitive patch of skin?

A non-light sensitive patch of skin. The thing is, a single mutation can trigger light sensitivity.

No need for eye sockets before you have eyes

Correct. Light-sensing apparati evolved before eye sockets.

Then we move any to the very intricate human cell that could not function if any of it's too numerous components were absent, waiting for the mutating opportunity.

You're still not understanding the basic mechanism of evolution. Eye evolution is pretty straightforward, once you understand that nobody's suggesting that the eye evolved instantaneously. I presented a perfectly plausible incremental framework and you're still pretending that us silly evil-utionists think that -- zap -- the eye evolved overnight. Keep your strawmen to yourself.

[HankReardon]

I'm not "pretending" anything. And I would never tell you what to say or what not say. It would be unreasonable for me to imagine something as intricate and complicated as the human eye could just happenstancely come into being through mutations. I'd have to see the evolutionary drawing on that one. Like the cartoon that shows the monkey to the becoming a man.

I try keep an open mind about things that are yet to be proven.

The question that comes to my mind is how would the light taken in by the "light sensitive patches of skin" penetrate through a skull with no openings, eye sockets.

A thought! possibly non-vertbrae animals, such as earthworms would be sensive to light, my flashlight when I'm looking for bait! But an earthworm and I most definately do not share any ancestors, cousins nor in-laws.

you know, it's all just such a far stretch of little reason and a whole lot of faith to believe in evolution.

[Alter Kaker]

If you need cartoons to understand, here's a cartoon.

The question that comes to my mind is how would the light taken in by the "light sensitive patches of skin" penetrate through a skull with no openings, eye sockets.

Because it evolved long before skulls. There are primitive light sensing mechanisms in single celled protozoa. Vertebrate evolution is comparatively recent.

A thought! possibly non-vertbrae animals, such as earthworms would be sensive to light, my flashlight when I'm looking for bait!

I don't know what that sentence means. But yes, invertebrates do have a variety of different eye types. For a chart of invertebrate eye evolution, see below.

But an earthworm and I most definately do not share any ancestors, cousins nor in-laws.

Most definitely? If you say so, but science indicates otherwise.

you know, it's all just such a far stretch of little reason and a whole lot of faith to believe in evolution.

So if I get this right, your entire argument is "I can't wrap my mind around evolution -- it's just too complicated for me to understand -- therefore it is implausible." An argument from incredulity is not an argument.

[HankReardon]

Hey! It's cartoon Saturday!

[HankReardon]

My main thing was to comment on yet another article based on the premise of an unproven, far out theory.

people must be very religious to totally believe in evolution because it takes so much faith.

[Alter Kaker]

Do you have anything worth contributing to this discussion?

[Geronimo]

Cartoon Saturday...lol

[HankReardon]

If you mean do have cartoons also, no, I liked yours though, they were very nice, thank you.

[Alter Kaker]

If you mean do have cartoons also, no, I liked yours though, they were very nice, thank you.

You just don't seem to have much to say.

Originally, you were trying to argue that evolution can't provide any explanation for the origin of the eye. So I provided a perfectly plausible mechanism.

Do we know how eyes evolved? No, we don't. But I provided a plausible pedigree, one that uses evolutionary mechanisms to lead to modern eyes.

Now you seem to be arguing that my pedigree is conjecture. Of course it is! But you're not saying we don't know how eyes evolved, you're saying there's no way evolution can lead to the evolution of eyes which is clearly, and patently false.

So stop with your pithy comments and start being honest. With me, with yourself and with the rest of the posters on this forum.

[HankReardon]

You're a bossy sort, that's alright, you can be any way you choose to be.

I assure you, I read your eye evolution theory. I found it very interesting, thank you.

I must still continue to find it hard to believe very complicated and intricate biological attributes could accidently come into being.

The burden of proof of a theory is on the person(s) providing the theory.

I find the defenders of the evolutionary theory to be often defensive and condescending. That's alright with me.

Again, what prompted my remarks was yet another artcle erroneously written as if evolution was proven, undisputed fact.

Thanks again for the info.

[SunkenCiv]

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